68 results on '"Measey, J."'
Search Results
2. Detection of the Hormone Receptors Controlling the Female Genital Tract throughout the Sexual Cycle of an Oviparous Caecilian Amphibian, Boulengerula taitana
- Author
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Brun, C., primary, Measey, J., additional, Exbrayat, J. M., additional, and Raquet, M., additional
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- 2023
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3. Diverse aging rates in ectothermic tetrapods provide insights for the evolution of aging and longevity
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Reinke, B.A., Cayuela, H., Janzen, F.J., Lemaître, J.-F., Gaillard, J.-M., Lawing, A.M., Iverson, J.B., Christiansen, D.G., Martínez-Solano, I., Sánchez-Montes, G., Gutiérrez-Rodríguez, J., Rose, F.L., Nelson, N., Keall, S., Crivelli, A.J., Nazirides, T., Grimm-Seyfarth, Annegret, Henle, Klaus, Mori, E., Guiller, G., Homan, R., Olivier, A., Muths, E., Hossack, B.R., Bonnet, X., Pilliod, D.S., Lettink, M., Whitaker, T., Schmidt, B.R., Gardner, M.G., Cheylan, M., Poitevin, F., Golubović, A., Tomović, L., Arsovski, D., Griffiths, R.A., Arntzen, J.W., Baron, J.-P., Le Galliard, J.-F., Tully, T., Luiselli, L., Capula, M., Rugiero, L., McCaffery, R., Eby, L.A., Briggs-Gonzalez, V., Mazzotti, F., Pearson, D., Lambert, B.A., Green, D.M., Jreidini, N., Angelini, C., Pyke, G., Thirion, J.-M., Joly, P., Léna, J.-P., Tucker, A.D., Limpus, C., Priol, P., Besnard, A., Bernard, P., Stanford, K., King, R., Garwood, J., Bosch, J., Souza, F.L., Bertoluci, J., Famelli, S., Grossenbacher, K., Lenzi, O., Matthews, K., Boitaud, S., Olson, D.H., Jessop, T.S., Gillespie, G.R., Clobert, J., Richard, M., Valenzuela-Sánchez, A., Elmberg, J., Brown, G.P., Shine, R., Bendik, N.F., O’Donnell, L., Davis, C.L., Lannoo, M.J., Stiles, R.M., Cox, R.M., Reedy, A.M., Warner, D.A., Bonnaire, E., Grayson, K., Ramos-Targarona, R., Baskale, E., Muñoz, D., Measey, J., de Villiers, F.A., Selman, W., Ronget, V., Bronikowski, A.M., Miller, D.A.W., Reinke, B.A., Cayuela, H., Janzen, F.J., Lemaître, J.-F., Gaillard, J.-M., Lawing, A.M., Iverson, J.B., Christiansen, D.G., Martínez-Solano, I., Sánchez-Montes, G., Gutiérrez-Rodríguez, J., Rose, F.L., Nelson, N., Keall, S., Crivelli, A.J., Nazirides, T., Grimm-Seyfarth, Annegret, Henle, Klaus, Mori, E., Guiller, G., Homan, R., Olivier, A., Muths, E., Hossack, B.R., Bonnet, X., Pilliod, D.S., Lettink, M., Whitaker, T., Schmidt, B.R., Gardner, M.G., Cheylan, M., Poitevin, F., Golubović, A., Tomović, L., Arsovski, D., Griffiths, R.A., Arntzen, J.W., Baron, J.-P., Le Galliard, J.-F., Tully, T., Luiselli, L., Capula, M., Rugiero, L., McCaffery, R., Eby, L.A., Briggs-Gonzalez, V., Mazzotti, F., Pearson, D., Lambert, B.A., Green, D.M., Jreidini, N., Angelini, C., Pyke, G., Thirion, J.-M., Joly, P., Léna, J.-P., Tucker, A.D., Limpus, C., Priol, P., Besnard, A., Bernard, P., Stanford, K., King, R., Garwood, J., Bosch, J., Souza, F.L., Bertoluci, J., Famelli, S., Grossenbacher, K., Lenzi, O., Matthews, K., Boitaud, S., Olson, D.H., Jessop, T.S., Gillespie, G.R., Clobert, J., Richard, M., Valenzuela-Sánchez, A., Elmberg, J., Brown, G.P., Shine, R., Bendik, N.F., O’Donnell, L., Davis, C.L., Lannoo, M.J., Stiles, R.M., Cox, R.M., Reedy, A.M., Warner, D.A., Bonnaire, E., Grayson, K., Ramos-Targarona, R., Baskale, E., Muñoz, D., Measey, J., de Villiers, F.A., Selman, W., Ronget, V., Bronikowski, A.M., and Miller, D.A.W.
- Abstract
Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging.
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- 2022
4. Diverse aging rates in ectothermic tetrapods provide insights for the evolution of aging and longevity
- Author
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Reinke B.A., Cayuela H., Janzen F.J., Lemaitre J.F., Gaillard J.M., Lawing A.M., Iverson J.B., Christiansen D.G., Martinez-Solano I., Sanchez-Montes G., Gutierrez-Rodriguez J., Rose F.L., Nelson N., Keall S., Crivelli A.J., Nazirides T., Grimm-Seyfarth A., Henle K., Mori E., Guiller G, Homan R., Olivier A., Muths E., Hossack B.R., Bonnet X., Pilliod D.S., Lettnik M., Whitaker T., Schmidt B.R., Gardner M.G., Cheylan M., Poitevin F., Golubovic A., Tomovic L., Arsovski D., Griffiths R.A., Arntzen J.W., Baron J.B., Le Galliard J.F., Tully T., Luiselli L., Capula M., Rugiero L., McCaffery R., Eby L.A., Briggs-Gonzalez V., Mazzotti F., Pearson D., Lambert B.A., Green D.M., Jreidini N., Angelini C., Pyke G., Thirion J.M., Joly P., Lena J.P., Tucker A.D., Limpus C., Priol P., Besnard A., Bernard P., Stanford K., King R., Garwood J., Bosch J., Souza F.L., Bertoluci J., Famelli S., Grossenbacher K., Lenzi O., Matthews K., Boitaud S., Olson D.H., Jessop T.S., Gillespie G.R., Clobert J., Richard M., Valenzuela-Sanchez A., Fellers G.M., Kleeman P.M., Halstead B.J., Campbell Grant E.H., Byrne P.G., Fretey T., Le Garff B., Levionnois P., Maerz J.C., Pichenot J., Olgun K., Uzum N., Avci A., Miaud C., Elmberg J., Brown G.P., Shine R., Bendik N.F., O'Donnell L., Davis C.L., Lannoo M.J., Stiles R.M., Cox R.M., Reedy A.M., Warner D.A., Bonnaire E., Grayson K., Ramos-Targarona R., Baskale E., Munoz D., Measey J., Andre de Villiers F., Selman W., Ronget V., Bronikowski A.M., and Miller D.A.W.
- Subjects
__ - Abstract
Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging.
- Published
- 2022
5. Additional file 1 of The relationship between bite force, morphology, and diet in southern African agamids
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Tan, W. C., Measey, J., Vanhooydonck, B., and Herrel, A.
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urogenital system ,fungi ,cardiovascular diseases ,urologic and male genital diseases ,female genital diseases and pregnancy complications - Abstract
Additional file 1: Table S1. Morphology, bite force, and the index of relative importance (IRI) of each dietary item found in all six species. N = sample size. IRI values were multiplied by 100 to facilitate the reading of the table. Standard deviation is shown in brackets.
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- 2021
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6. Additional file 2 of The relationship between bite force, morphology, and diet in southern African agamids
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Tan, W. C., Measey, J., Vanhooydonck, B., and Herrel, A.
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fungi - Abstract
Additional file 2: Table S2. Results of phylANOVAs performed on size, head variables and bite force testing for differences between habitat groups due to phylogenetic relationship. The averages of each species were taken for the calculation of each variable. Table S3. Results of phylANOVAs performed on prey IRI testing for diet differences between habitat groups due to phylogenetic relationship.
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- 2021
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7. Additional file 3 of The relationship between bite force, morphology, and diet in southern African agamids
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Tan, W. C., Measey, J., Vanhooydonck, B., and Herrel, A.
- Abstract
Additional file 3: Table S4. ANCOVAs performed on head morphological variables testing for differences in adults (N for ground dwelling = 14, rock dwelling = 16, arboreal = 28) and juveniles (N for ground dwelling = 7, rock dwelling = 27, arboreal = 11) among habitat groups. Table S5. Results of the ANOVAs testing for differences in prey IRI in adults (N for ground dwelling = 2, rock dwelling = 19, arboreal = 15) and juveniles (N for ground dwelling = 6, rock dwelling = 19, arboreal = 6) between habitat groups.
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- 2021
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8. Mechanistic reconciliation of community and invasion ecology
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Latombe, G, Richardson, DM, McGeoch, MA, Altwegg, R, Catford, JA, Chase, JM, Courchamp, F, Esler, KJ, Jeschke, JM, Landi, P, Measey, J, Midgley, GF, Minoarivelo, HO, Rodger, JG, Hui, C, Latombe, G, Richardson, DM, McGeoch, MA, Altwegg, R, Catford, JA, Chase, JM, Courchamp, F, Esler, KJ, Jeschke, JM, Landi, P, Measey, J, Midgley, GF, Minoarivelo, HO, Rodger, JG, and Hui, C
- Abstract
Community and invasion ecology have mostly grown independently. There is substantial overlap in the processes captured by different models in the two fields, and various frameworks have been developed to reduce this redundancy and synthesize information content. Despite broad recognition that community and invasion ecology are interconnected, a process-based framework synthesizing models across these two fields is lacking. Here we review 65 representative community and invasion models and propose a common framework articulated around six processes (dispersal, drift, abiotic interactions, within-guild interactions, cross-guild interactions, and genetic changes). The framework is designed to synthesize the content of the two fields, provide a general perspective on their development, and enable their comparison. The application of this framework and of a novel method based on network theory reveals some lack of coherence between the two fields, despite some historical similarities. Community ecology models are characterized by combinations of multiple processes, likely reflecting the search for an overarching theory to explain community assembly and structure, drawing predominantly on interaction processes, but also accounting largely for the other processes. In contrast, most models in invasion ecology invoke fewer processes and focus more on interactions between introduced species and their novel biotic and abiotic environment. The historical dominance of interaction processes and their independent developments in the two fields is also reflected in the lower level of coherence for models involving interactions, compared to models involving dispersal, drift, and genetic changes. It appears that community ecology, with a longer history than invasion ecology, has transitioned from the search for single explanations for patterns observed in nature to investigate how processes may interact mechanistically, thereby generating and testing hypotheses. Our framework paves t
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- 2021
9. Supp. Info for Mohanty et al. (2020; Biological Invasions)
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Mohanty NP, Crottini A, Garcia RA, and Measey J
- Abstract
Supplementary Information for the paper "Non-native populations and global invasion potential of the Indian bullfrog Hoplobatrachus tigerinus: a synthesisfor risk-analysis" (Mohanty et al., 2020; Biological Invasions;10.1007/s10530-020-02356-9)
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- 2020
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10. In a Pinch: Mechanisms Behind Potential Biotic Resistance Toward Two Invasive Crayfish by Native African Freshwater Crabs
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South, J, Madzivanzira, TC, Tshali, N, Measey, J, and Weyl, OLF
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It is essential to incorporate mechanisms of biotic resistance into predictions of ecological impact conferred by invasive species. Trophically and functionally analogous native species have high potential to confer biotic resistance or to be susceptible to competitive exclusion by the invading species. In species with dominance hierarchies and high aggression the role of weapons, such as chelae, is emphasised and selected for. Differences in traits such as crushing capacity can indicate prey handling capabilities, while correlations between closing force and morphology can be used to understand the role of signaling in agonistic contests. Closing force strength can be used to infer the outcomes of both direct (predation) and indirect (competition) trophic interactions. Southern Africa has been invaded by two freshwater crayfish species (Cherax quadricarinatus and Procambarus clarkii). Biotic resistance of freshwater crabs toward crayfish invasions varies between geographic location and co-evolutionary history, thus comparing invasion histories without incorporating geographic context can produce unequivocal conclusions. We compared the closing force and chelae morphology of both crayfish species with a native trophically analogous freshwater crab, Potamonautes perlatus. Closing force increased significantly with mass for all species. There was significant interaction between sex and species on closing force. Potamonautes perlatus females showed significantly stronger maximum chela closing force than male P. perlatus, both sexes of P. clarkii and female C. quadricarinatus. Contrastingly, male C. quadricarinatus had significantly higher closing forces than both sexes of P. clarkii and female C. quadricarinatus, however, there was no difference between female P. perlatus. Native P. perlatus has the capacity to hold a competitive mechanical advantage over both invaders, but this varies with sex. Chelae length was not a significant predictor for closing strength in any of the species, which may be related to dishonest signaling in decapod species. This makes it imperative to assess whether factors such as closing force actually translate to resource holding potential in a contest scenario. We thus provide evidence that African freshwater crabs may exhibit biotic resistance toward invasion and the first measurements for C. quadricarinatus closing force strength.
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- 2020
11. Invasive alien aquatic plants in South African freshwater ecosystems
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Hill, M.P., Coetzee, J.A., Martin, G.D., Smith, R., Strange, E.F., Wilgen, B.W. van, Richardson, D.M., Wilson, J.R., Zengeya, T.A., and Measey J.
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Colonisation ,Geography ,Ecology ,Aquatic ecosystem ,Aquatic plant ,Biodiversity ,Ecosystem ,Freshwater ecosystem ,Invasive species ,Macrophyte - Abstract
South Africa has a long history of managing the establishment and spread of invasive floating macrophytes. The past thirty years of research and the implementation of nation-wide biological and integrated control programmes has led to widespread control of these species in many degraded freshwater ecosystems. Such initiatives are aimed at restoring access to potable freshwater and maintaining native biodiversity. However, in recent years, there has been a decline in populations of floating invasive plants, and an increase in the establishment and spread of submerged and emergent invasive plant species, which poses significant threats to aquatic ecosystems. This chapter highlights the vulnerability of South Africa’s eutrophic systems to successful colonisation by this suite of new macrophytes following the successful biological control of floating invasive macrophytes, and explores a new regime shift in invasive populations partly driven by biological control. We suggest that a more holistic approach to the control of invasive plants would be required to ensure long-term ecosystem recovery and sustainability.
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- 2020
12. Morphology, locomotor performance and habitat use in southern African agamids
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Tan, W C, primary, Vanhooydonck, B, primary, Measey, J, primary, and Herrel, A, primary
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- 2020
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13. Molecular phylogenetics reveals a complex history underlying cryptic diversity in the Bush Squeaker Frog (Arthroleptis wahlbergii) in southern Africa
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Tolley, KA, primary, Conradie, W, additional, Harvey, J, additional, Measey, J, additional, and Blackburn, DC, additional
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- 2018
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14. Freshwater paths across the ocean: molecular phylogeny of the frog Ptychadena newtoni gives insights into amphibian colonization of oceanic islands
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Measey, J., Vences, M., Drewes, R.C., Chiari, Y., Melo, M., Bourlès, Bernard, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)
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Amphibia ,Gulf of Guinea ,island biogeography ,Cameroon line ,Gymnophiona ,Anura ,colonization ,dispersal ,phylogeny ,[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography - Abstract
International audience; Aim Amphibians are a model group for studies of the biogeographical origins of salt-intolerant taxa on oceanic islands. We used the Gulf of Guinea islands to explore the biogeographical origins of island endemism of one species of frog, and used this to gain insights into potential colonization mechanisms. Location Sao Tome and Principe, two of the four major islands in the Gulf of Guinea, West Africa, are truly oceanic and have an exceptionally high biodiversity. Methods Mitochondrial DNA is used to test the endemic status of a frog from Sao Tome and compare it with congeneric taxa from tropical Africa. Existing data on surface currents, surface salinity, atmospheric circulation and bird migration in the Gulf of Guinea are summarized to address hypotheses concerning colonization mechanisms. Results The endemic status of Ptychadena newtoni (Bocage) is supported here by mitochondrial DNA sequences, and analysis of this and other molecular data indicates that an East African species close to Ptychadena mascareniensis (Dumeril and Bibron) is its nearest relative. We refute the possibility that this population was anthropogenically introduced, in favour of a natural dispersal mechanism. Main conclusions With six endemic frogs and one caecilian, the Gulf of Guinea islands harbour a diverse amphibian fauna. Five of these species appear to have their closest relatives in East Africa. Insufficient evidence exists for transportation by storms, birds or rafts alone. However, we propose a synergy of rafting, favourable surface currents and a reduction in salinity of surface waters. Catastrophic events, or wet periods in climatic history, could allow freshwater paths to open far enough to enable continental flora and fauna to reach these and other isolated oceanic islands.
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- 2007
15. Parasite introduction to the endangered western leopard toad : spill over or spill back?
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Kruger, Natasha, Du Preez, L., Measey, J., and 23891874 - Measey, Gavin John (Supervisor)
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Spill back ,PCR ,Scanning electron-microscopy ,Amphibian ,Spill over ,Macro-parasite ,Light-microscopy - Abstract
MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2017 South Africa has a diverse anuran fauna consisting of 161 described species. Amphibians are suffering large-scale regressions due to various threats: (1) pollution, (2) habitat engineering and (3) invasive species. The endangered Western Leopard toad (Sclerophrys pantherina) endemic to the Western Cape is currently experiencing major external pressures from these above-mentioned threats. The latter being a local invader, namely the Guttural toad (Sclerophrys gutturalis), which (through human-assisted translocation) was introduced from KwaZulu-Natal into the native range of the Western Leopard Toad. The direct effects such as predation and competition have received extensive attention, seeing that invasive species can have devastating effects on native fauna. However, a more neglected field of research is the indirect threats invasive species pose to the native fauna such as interactions with infectious agents, which include spill back and spill over of parasites. The present study aimed to understand this interaction by focusing on the relationship between parasites, native species, and invasive species. The research examined mechanisms such as spill back and spill over for a better understanding of the indirect drives and consequences invasive species may hold. Morphological markers (light microscopy and scanning electron microscopy) as well as molecular markers (COI and 28S) were applied to survey parasites found in collected toads from five populations: (1) native Guttural Toad in KwaZulu-Natal; (2) invasive Guttural Toad isolated in Western Cape; (3) invasive Guttural Toad and native Western Leopard Toad in Western Cape; (4) native Western Leopard Toad isolated in Western Cape; and (5) native Guttural Toad from Potchefstroom. Parasites that were observed was a nasal mite Lawrencarus eweri (Lawrence, 1952); a lung nematode Rhabdias cf. africana Kuzmin, 2001; intestinal nematode Cosmocerca sp. Diesing, 1861; intestinal trematode Mesocoelium cf. monodi Dolfus, 1929; two blood parasites Hepatozoon ixoxo Netherlands, Cook, & Smit 2014, as well as Trypanosoma sp. Gruby, 1843. It was found that the introduced species may have vacated their parasites throughout the invasion, possibly due to the ‘enemy release hypothesis’ (Marr et al. 2008). This can enhance the invaders competitive ability as defence costs against parasites can be decreased and reproductive rates can increase (Hatcher & Dunn, 2011). The native Western Leopard Toad population co-existing with invasive Guttural Toad was found to contain less parasites than the isolated native Western Leopard Toad population. In this case, it is possible that the invader decreased the parasite loads of the native population by acting as a ‘sink’ for native parasites (Kelly et al., 2009). If so, native parasites are taken up by the invader but fail to complete their life cycle due to disorientation and lack of co-evolutionary history (Hempel et al., 2003). Encysted nematodes (presumably third-stage larvae), collected from native Western Leopard Toads and invasive Guttural Toads from the Western Cape, appear to have a host-size and niche specificity rather than a specificity to the host itself. Few life cycles have been described for nematodes in South African fauna to which a toad acts as an intermediate host for the third-stage larvae. Thus, without further identification and molecular studies it is uncertain whether these cysts in native Western Leopard Toads and invasive Guttural Toads are a result of spill back or spill over. However, each case of parasite-host relationship is unique since the relationship can be dynamic. This makes it difficult to predict the consequences. Furthermore, as is the case with restoration ecology, irreversible changes may have to be accepted in certain ecosystems that are subject to invading parasites and their introduced hosts (Dunn & Hatcher, 2014). Masters
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- 2017
16. Using the IUCN Environmental Impact Classification for Alien Taxa to inform decision-making.
- Author
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Kumschick S, Bertolino S, Blackburn TM, Brundu G, Costello KE, de Groot M, Evans T, Gallardo B, Genovesi P, Govender T, Jeschke JM, Lapin K, Measey J, Novoa A, Nunes AL, Probert AF, Pyšek P, Preda C, Rabitsch W, Roy HE, Smith KG, Tricarico E, Vilà M, Vimercati G, and Bacher S
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- Humans, Conservation of Natural Resources, Biodiversity, Ecosystem, Introduced Species
- Abstract
The Environmental Impact Classification for Alien Taxa (EICAT) is an important tool for biological invasion policy and management and has been adopted as an International Union for Conservation of Nature (IUCN) standard to measure the severity of environmental impacts caused by organisms living outside their native ranges. EICAT has already been incorporated into some national and local decision-making procedures, making it a particularly relevant resource for addressing the impact of non-native species. Recently, some of the underlying conceptual principles of EICAT, particularly those related to the use of the precautionary approach, have been challenged. Although still relatively new, guidelines for the application and interpretation of EICAT will be periodically revisited by the IUCN community, based on scientific evidence, to improve the process. Some of the criticisms recently raised are based on subjectively selected assumptions that cannot be generalized and may harm global efforts to manage biological invasions. EICAT adopts a precautionary principle by considering a species' impact history elsewhere because some taxa have traits that can make them inherently more harmful. Furthermore, non-native species are often important drivers of biodiversity loss even in the presence of other pressures. Ignoring the precautionary principle when tackling the impacts of non-native species has led to devastating consequences for human well-being, biodiversity, and ecosystems, as well as poor management outcomes, and thus to significant economic costs. EICAT is a relevant tool because it supports prioritization and management of non-native species and meeting and monitoring progress toward the Kunming-Montreal Global Biodiversity Framework (GBF) Target 6., (© 2023 The Authors. Conservation Biology published by Wiley Periodicals LLC on behalf of Society for Conservation Biology.)
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- 2024
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17. The bii4africa dataset of faunal and floral population intactness estimates across Africa's major land uses.
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Clements HS, Do Linh San E, Hempson G, Linden B, Maritz B, Monadjem A, Reynolds C, Siebert F, Stevens N, Biggs R, De Vos A, Blanchard R, Child M, Esler KJ, Hamann M, Loft T, Reyers B, Selomane O, Skowno AL, Tshoke T, Abdoulaye D, Aebischer T, Aguirre-Gutiérrez J, Alexander GJ, Ali AH, Allan DG, Amoako EE, Angedakin S, Aruna E, Avenant NL, Badjedjea G, Bakayoko A, Bamba-Kaya A, Bates MF, Bates PJJ, Belmain SR, Bennitt E, Bradley J, Brewster CA, Brown MB, Brown M, Bryja J, Butynski TM, Carvalho F, Channing A, Chapman CA, Cohen C, Cords M, Cramer JD, Cronk N, Cunneyworth PMK, Dalerum F, Danquah E, Davies-Mostert HT, de Blocq AD, De Jong YA, Demos TC, Denys C, Djagoun CAMS, Doherty-Bone TM, Drouilly M, du Toit JT, Ehlers Smith DA, Ehlers Smith YC, Eiseb SJ, Fashing PJ, Ferguson AW, Fernández-García JM, Finckh M, Fischer C, Gandiwa E, Gaubert P, Gaugris JY, Gibbs DJ, Gilchrist JS, Gil-Sánchez JM, Githitho AN, Goodman PS, Granjon L, Grobler JP, Gumbi BC, Gvozdik V, Harvey J, Hauptfleisch M, Hayder F, Hema EM, Herbst M, Houngbédji M, Huntley BJ, Hutterer R, Ivande ST, Jackson K, Jongsma GFM, Juste J, Kadjo B, Kaleme PK, Kamugisha E, Kaplin BA, Kato HN, Kiffner C, Kimuyu DM, Kityo RM, Kouamé NG, Kouete T M, le Roux A, Lee ATK, Lötter MC, Lykke AM, MacFadyen DN, Macharia GP, Madikiza ZJK, Mahlaba TAM, Mallon D, Mamba ML, Mande C, Marchant RA, Maritz RA, Markotter W, McIntyre T, Measey J, Mekonnen A, Meller P, Melville HI, Mganga KZ, Mills MGL, Minnie L, Missoup AD, Mohammad A, Moinde NN, Moise BFE, Monterroso P, Moore JF, Musila S, Nago SGA, Namoto MW, Niang F, Nicolas V, Nkenku JB, Nkrumah EE, Nono GL, Norbert MM, Nowak K, Obitte BC, Okoni-Williams AD, Onongo J, O'Riain MJ, Osinubi ST, Parker DM, Parrini F, Peel MJS, Penner J, Pietersen DW, Plumptre AJ, Ponsonby DW, Porembski S, Power RJ, Radloff FGT, Rambau RV, Ramesh T, Richards LR, Rödel MO, Rollinson DP, Rovero F, Saleh MA, Schmiedel U, Schoeman MC, Scholte P, Serfass TL, Shapiro JT, Shema S, Siebert SJ, Slingsby JA, Sliwa A, Smit-Robinson HA, Sogbohossou EA, Somers MJ, Spawls S, Streicher JP, Swanepoel L, Tanshi I, Taylor PJ, Taylor WA, Te Beest M, Telfer PT, Thompson DI, Tobi E, Tolley KA, Turner AA, Twine W, Van Cakenberghe V, Van de Perre F, van der Merwe H, van Niekerk CJG, van Wyk PCV, Venter JA, Verburgt L, Veron G, Vetter S, Vorontsova MS, Wagner TC, Webala PW, Weber N, Weier SM, White PA, Whitecross MA, Wigley BJ, Willems FJ, Winterbach CW, and Woodhouse GM
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- Animals, Biodiversity, Mammals, Vertebrates, Plants, Africa, Conservation of Natural Resources, Ecosystem
- Abstract
Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on species' population abundances. Drawing on recent advances in expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process to estimate 'intactness scores': the remaining proportion of an 'intact' reference population of a species group in a particular land use, on a scale from 0 (no remaining individuals) to 1 (same abundance as the reference) and, in rare cases, to 2 (populations that thrive in human-modified landscapes). The resulting bii4africa dataset contains intactness scores representing terrestrial vertebrates (tetrapods: ±5,400 amphibians, reptiles, birds, mammals) and vascular plants (±45,000 forbs, graminoids, trees, shrubs) in sub-Saharan Africa across the region's major land uses (urban, cropland, rangeland, plantation, protected, etc.) and intensities (e.g., large-scale vs smallholder cropland). This dataset was co-produced as part of the Biodiversity Intactness Index for Africa Project. Additional uses include assessing ecosystem condition; rectifying geographic/taxonomic biases in global biodiversity indicators and maps; and informing the Red List of Ecosystems., (© 2024. The Author(s).)
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- 2024
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18. Author Correction: Ongoing declines for the world's amphibians in the face of emerging threats.
- Author
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Luedtke JA, Chanson J, Neam K, Hobin L, Maciel AO, Catenazzi A, Borzée A, Hamidy A, Aowphol A, Jean A, Sosa-Bartuano Á, Fong G A, de Silva A, Fouquet A, Angulo A, Kidov AA, Muñoz Saravia A, Diesmos AC, Tominaga A, Shrestha B, Gratwicke B, Tjaturadi B, Martínez Rivera CC, Vásquez Almazán CR, Señaris C, Chandramouli SR, Strüssmann C, Cortez Fernández CF, Azat C, Hoskin CJ, Hilton-Taylor C, Whyte DL, Gower DJ, Olson DH, Cisneros-Heredia DF, Santana DJ, Nagombi E, Najafi-Majd E, Quah ESH, Bolaños F, Xie F, Brusquetti F, Álvarez FS, Andreone F, Glaw F, Castañeda FE, Kraus F, Parra-Olea G, Chaves G, Medina-Rangel GF, González-Durán G, Ortega-Andrade HM, Machado IF, Das I, Dias IR, Urbina-Cardona JN, Crnobrnja-Isailović J, Yang JH, Jianping J, Wangyal JT, Rowley JJL, Measey J, Vasudevan K, Chan KO, Gururaja KV, Ovaska K, Warr LC, Canseco-Márquez L, Toledo LF, Díaz LM, Khan MMH, Meegaskumbura M, Acevedo ME, Napoli MF, Ponce MA, Vaira M, Lampo M, Yánez-Muñoz MH, Scherz MD, Rödel MO, Matsui M, Fildor M, Kusrini MD, Ahmed MF, Rais M, Kouamé NG, García N, Gonwouo NL, Burrowes PA, Imbun PY, Wagner P, Kok PJR, Joglar RL, Auguste RJ, Brandão RA, Ibáñez R, von May R, Hedges SB, Biju SD, Ganesh SR, Wren S, Das S, Flechas SV, Ashpole SL, Robleto-Hernández SJ, Loader SP, Incháustegui SJ, Garg S, Phimmachak S, Richards SJ, Slimani T, Osborne-Naikatini T, Abreu-Jardim TPF, Condez TH, De Carvalho TR, Cutajar TP, Pierson TW, Nguyen TQ, Kaya U, Yuan Z, Long B, Langhammer P, and Stuart SN
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- 2024
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19. Does aquatic performance predict terrestrial performance: a case study with an aquatic frog, Xenopus laevis.
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Araspin L, Measey J, and Herrel A
- Subjects
- Animals, Xenopus laevis, Hindlimb anatomy & histology, Water, Locomotion, Swimming
- Abstract
The physical properties of the environment impose strong selection on organisms and their form-function relationships. In water and on land, selective pressures differ, with water being more viscous and denser than air, and gravity being the most important external force on land for relatively large animals such as vertebrates. These different properties of the environment could drive variation in the design and mechanics of the locomotor system of organisms. Animals that use multiple environments can consequently exhibit locomotion conflicts between the demands imposed by the media, leading to potential trade-offs. Here, we tested for the presence of such locomotor trade-offs depending on the environment (water or land) in a largely aquatic frog, Xenopus laevis. We focused on terrestrial and aquatic exertion capacity (time and distance swum or jumped until exhaustion) and aquatic and terrestrial burst capacity (maximal instantaneous swimming velocity and maximal force jump) given the ecological relevance of these traits. We tested these performance traits for trade-offs, depending on environments (water versus air) and locomotor modes (i.e. exertion and burst performance). Finally, we assessed the contribution of morphological traits to each performance trait. Our data show no trade-offs between the performance traits and between the environments, suggesting that X. laevis is equally good at swimming and jumping thanks to the same underlying morphological specialisations. We did observe, however, that morphological predictors differed depending on the environment, with variation in head shape and forelimb length being good predictors for aquatic locomotion and variation in hindlimb and forelimb segments predicting variation in jumping performance on land., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2023. Published by The Company of Biologists Ltd.)
- Published
- 2023
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20. Ongoing declines for the world's amphibians in the face of emerging threats.
- Author
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Luedtke JA, Chanson J, Neam K, Hobin L, Maciel AO, Catenazzi A, Borzée A, Hamidy A, Aowphol A, Jean A, Sosa-Bartuano Á, Fong G A, de Silva A, Fouquet A, Angulo A, Kidov AA, Muñoz Saravia A, Diesmos AC, Tominaga A, Shrestha B, Gratwicke B, Tjaturadi B, Martínez Rivera CC, Vásquez Almazán CR, Señaris C, Chandramouli SR, Strüssmann C, Cortez Fernández CF, Azat C, Hoskin CJ, Hilton-Taylor C, Whyte DL, Gower DJ, Olson DH, Cisneros-Heredia DF, Santana DJ, Nagombi E, Najafi-Majd E, Quah ESH, Bolaños F, Xie F, Brusquetti F, Álvarez FS, Andreone F, Glaw F, Castañeda FE, Kraus F, Parra-Olea G, Chaves G, Medina-Rangel GF, González-Durán G, Ortega-Andrade HM, Machado IF, Das I, Dias IR, Urbina-Cardona JN, Crnobrnja-Isailović J, Yang JH, Jianping J, Wangyal JT, Rowley JJL, Measey J, Vasudevan K, Chan KO, Gururaja KV, Ovaska K, Warr LC, Canseco-Márquez L, Toledo LF, Díaz LM, Khan MMH, Meegaskumbura M, Acevedo ME, Napoli MF, Ponce MA, Vaira M, Lampo M, Yánez-Muñoz MH, Scherz MD, Rödel MO, Matsui M, Fildor M, Kusrini MD, Ahmed MF, Rais M, Kouamé NG, García N, Gonwouo NL, Burrowes PA, Imbun PY, Wagner P, Kok PJR, Joglar RL, Auguste RJ, Brandão RA, Ibáñez R, von May R, Hedges SB, Biju SD, Ganesh SR, Wren S, Das S, Flechas SV, Ashpole SL, Robleto-Hernández SJ, Loader SP, Incháustegui SJ, Garg S, Phimmachak S, Richards SJ, Slimani T, Osborne-Naikatini T, Abreu-Jardim TPF, Condez TH, De Carvalho TR, Cutajar TP, Pierson TW, Nguyen TQ, Kaya U, Yuan Z, Long B, Langhammer P, and Stuart SN
- Subjects
- Animals, Biodiversity, Conservation of Natural Resources economics, Conservation of Natural Resources trends, Extinction, Biological, Risk, Urodela classification, Amphibians classification, Climate Change statistics & numerical data, Ecosystem, Endangered Species statistics & numerical data, Endangered Species trends
- Abstract
Systematic assessments of species extinction risk at regular intervals are necessary for informing conservation action
1,2 . Ongoing developments in taxonomy, threatening processes and research further underscore the need for reassessment3,4 . Here we report the findings of the second Global Amphibian Assessment, evaluating 8,011 species for the International Union for Conservation of Nature Red List of Threatened Species. We find that amphibians are the most threatened vertebrate class (40.7% of species are globally threatened). The updated Red List Index shows that the status of amphibians is deteriorating globally, particularly for salamanders and in the Neotropics. Disease and habitat loss drove 91% of status deteriorations between 1980 and 2004. Ongoing and projected climate change effects are now of increasing concern, driving 39% of status deteriorations since 2004, followed by habitat loss (37%). Although signs of species recoveries incentivize immediate conservation action, scaled-up investment is urgently needed to reverse the current trends., (© 2023. The Author(s).)- Published
- 2023
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21. Shifts in the Thermal Dependence of Locomotor Performance across an Altitudinal Gradient in Native Populations of Xenopus laevis .
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Araspin L, Wagener C, Padilla P, Herrel A, and Measey J
- Subjects
- Animals, Xenopus laevis, Temperature, Altitude, Locomotion
- Abstract
AbstractEctothermic species are dependent on temperature, which drives many aspects of their physiology, including locomotion. The distribution of the native populations of Xenopus laevis is characterized by an exceptional range in latitude and altitude. Along altitudinal gradients, thermal environments change, and populations experience different temperatures. In this study, we compared critical thermal limits and thermal performance curves of populations from the native range across an altitudinal gradient to test whether optimal temperatures for exertion differ depending on altitude. Data on exertion capacity were collected at six different temperatures (8°C, 12°C, 16°C, 19°C, 23°C, and 27°C) for four populations spanning an altitudinal gradient (60, 1,016, 1,948, and 3,197 m asl). Results show that the thermal performance optimum differs among populations. Populations from cold environments at high altitudes exhibit a lower optimal performance temperature than populations from warmer environments at lower altitudes. The ability of this species to change its optimal temperature for locomotor exertion across extremely different climatic environments within the native range may help explain its exceptional invasive potential. These results suggest that ectothermic species capable of adapting to broad altitudinal ranges may be particularly good at invading novel climatic areas, given their ability to cope with a wide range of variation in environmental temperatures.
- Published
- 2023
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22. The conservation value of freshwater habitats for frog communities of lowland fynbos.
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Terblanche N and Measey J
- Subjects
- Animals, Fresh Water, Ecosystem, Water, Anura, Bufonidae
- Abstract
Amphibians are more threatened than any other vertebrate class, yet evidence for many threats is missing. The Cape lowland fynbos (endemic scrub biome) is threatened by habitat loss, and natural temporary freshwater habitats are removed in favour of permanent impoundments. In this study, we determine amphibian assemblages across different freshwater habitat types with special attention to the presence of invasive fish. We find that anuran communities differ primarily by habitat type, with permanent water habitats having more widespread taxa, while temporary water bodies have more range restricted taxa. Invasive fish are found to have a significant impact on frogs with toads most tolerant of their presence. Temporary freshwater habitats are a conservation priority in the area, and their amphibian assemblages represent endemic taxa that are intolerant of invasive fish. Conservation of a biodiverse amphibian assemblage in lowland fynbos areas will rely on the creation of temporary freshwater habitats, rather than a northern hemisphere pond based solution., Competing Interests: John Measey is an Academic Editor for PeerJ., (© 2023 Terblanche and Measey.)
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- 2023
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23. Population genomics and subgenome evolution of the allotetraploid frog Xenopus laevis in southern Africa.
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Premachandra T, Cauret CMS, Conradie W, Measey J, and Evans BJ
- Subjects
- Animals, Xenopus laevis genetics, Genomics, Africa, Southern, Evolution, Molecular, Phylogeny, Metagenomics, Genome
- Abstract
Allotetraploid genomes have two distinct genomic components called subgenomes that are derived from separate diploid ancestral species. Many genomic characteristics such as gene function, expression, recombination, and transposable element mobility may differ significantly between subgenomes. To explore the possibility that subgenome population structure and gene flow may differ as well, we examined genetic variation in an allotetraploid frog-the African clawed frog (Xenopus laevis)-over the dynamic and varied habitat of its native range in southern Africa. Using reduced representation genome sequences from 91 samples from 12 localities, we found no strong evidence that population structure and gene flow differed substantially by subgenome. We then compared patterns of population structure in the nuclear genome to the mitochondrial genome using Sanger sequences from 455 samples from 183 localities. Our results provide further resolution to the geographic distribution of mitochondrial and nuclear diversity in this species and illustrate that population structure in both genomes corresponds roughly with variation in seasonal rainfall and with the topography of southern Africa., Competing Interests: Conflicts of interest The authors declare no conflict of interest., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Genetics Society of America.)
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- 2023
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24. The anatomy of the head muscles in caecilians (Amphibia: Gymnophiona): Variation in relation to phylogeny and ecology?
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Lowie A, De Kegel B, Wilkinson M, Measey J, O'Reilly JC, Kley NJ, Gaucher P, Adriaens D, and Herrel A
- Subjects
- Animals, Phylogeny, X-Ray Microtomography, Muscle, Skeletal, Amphibians anatomy & histology, Skull anatomy & histology
- Abstract
In limbless fossorial vertebrates such as caecilians (Gymnophiona), head-first burrowing imposes severe constraints on the morphology and overall size of the head. As such, caecilians developed a unique jaw-closing system involving the large and well-developed m. interhyoideus posterior, which is positioned in such a way that it does not significantly increase head diameter. Caecilians also possess unique muscles among amphibians. Understanding the diversity in the architecture and size of the cranial muscles may provide insights into how a typical amphibian system was adapted for a head-first burrowing lifestyle. In this study, we use dissection and non-destructive contrast-enhanced micro-computed tomography (μCT) scanning to describe and compare the cranial musculature of 13 species of caecilians. Our results show that the general organization of the head musculature is rather constant across extant caecilians. However, the early-diverging Rhinatrema bivittatum mainly relies on the 'ancestral' amphibian jaw-closing mechanism dominated by the m. adductores mandibulae, whereas other caecilians switched to the use of the derived dual jaw-closing mechanism involving the additional recruitment of the m. interhyoideus posterior. Additionally, the aquatic Typhlonectes show a greater investment in hyoid musculature than terrestrial caecilians, which is likely related to greater demands for ventilating their large lungs, and perhaps also an increased use of suction feeding. In addition to three-dimensional interactive models, our study provides the required quantitative data to permit the generation of accurate biomechanical models allowing the testing of further functional hypotheses., (© 2022 Anatomical Society.)
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- 2023
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25. Invasive Amphibian Gut Microbiota and Functions Shift Differentially in an Expanding Population but Remain Conserved Across Established Populations.
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Wagener C, du Plessis M, and Measey J
- Subjects
- Animals, Phylogeny, South Africa, Bufonidae, RNA, Ribosomal, 16S genetics, Gastrointestinal Microbiome genetics, Microbiota genetics
- Abstract
Studies of laboratory animals demonstrate extensive variation of host gut microbiomes and their functional capabilities across populations, but how does anthropogenic change impact the microbiomes of non-model species? The anthropogenic movement of species to novel environments can drastically alter animals' microbiomes; however, factors that shape invasive species gut microbiota during introduction remain relatively unexplored. Through 16S amplicon sequencing on guttural toad (Sclerophrys gutturalis) faecal samples, we determine that residence time does not impact microbiome variation between source and introduced populations. The youngest population (~ 20 years in Cape Town) has the most distinct microbiome and associated functional capabilities, whereas longer residence times (~ 100 years in Réunion and Mauritius) produce less divergent microbial compositional, phylogenetic, and predicted functional diversity and differential abundance from source populations (Durban). Additionally, we show extensive variation of microbial and functional diversity, as well as differential abundance patterns in an expanding introduced population (Cape Town) between core and periphery sites. Contrasting previous studies, we suggest that introduction pathways might be an important factor impacting host microbial divergence. These findings also imply that the microbiome can diverge in accordance with host population dynamics., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)
- Published
- 2022
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26. Phenotypic variation in Xenopus laevis tadpoles from contrasting climatic regimes is the result of adaptation and plasticity.
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Kruger N, Secondi J, du Preez L, Herrel A, and Measey J
- Subjects
- Animals, Larva, Plastics, Xenopus laevis, Adaptation, Physiological, Biological Variation, Population
- Abstract
Phenotypic variations between populations often correlate with climatic variables. Determining the presence of phenotypic plasticity and local adaptation of a species to different environments over a large spatial scale can provide insight on the persistence of a species across its range. Amphibians, and in particular their larvae, are good models for studies of phenotypic variation as they are especially sensitive to their immediate environment. Few studies have attempted to determine the mechanisms that drive phenotypic variation between populations of a single amphibian species over a large spatial scale especially across contrasting climatic regimes. The African clawed frog, Xenopus laevis, occurs in two regions with contrasting rainfall regimes in southern Africa. We hypothesised that the phenotypic variation of life-history traits of X. laevis tadpoles emerges from a combination of plastic and genetic responses. We predicted that plasticity would allow the development of tadpoles from both regions in each environment. We also predicted that local adaptation of larval traits would drive the differentiation of reaction norms between populations and lower survival in tadpoles reared away from their home environment. We measured growth, time to metamorphosis, and survival in a reciprocal transplant experiment using outdoor mesocosms. Supporting our prediction, we found that the measured variation of all traits was explained by both adaptation and plasticity. However, the reaction norms differed between populations suggesting adaptive and asymmetric plasticity. All tadpoles experienced lower survival when translocated, but only translocated tadpoles from the winter rainfall region matched survival of local tadpoles. This has implications for the dynamics of translocated X. laevis into novel environments, especially from the winter rainfall region. Our discovery of their asymmetric capacity to overcome novel environmental conditions by phenotypic plasticity alone provides insight into their invasion success., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
- Published
- 2022
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27. Island Hopping through Urban Filters: Anthropogenic Habitats and Colonized Landscapes Alter Morphological and Performance Traits of an Invasive Amphibian.
- Author
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Baxter-Gilbert J, Riley JL, Wagener C, Baider C, Florens FBV, Kowalski P, Campbell M, and Measey J
- Abstract
A prominent feature of the modern era is the increasing spread of invasive species, particularly within island and urban ecosystems, and these occurrences provide valuable natural experiments by which evolutionary and invasion hypotheses can be tested. In this study, we used the invasion route of guttural toads ( Sclerophrys gutturalis ) from natural-native and urban-native populations (Durban, South Africa) to their urban-invasive and natural-invasive populations (Mauritius and Réunion) to determine whether phenotypic changes that arose once the toads became urbanized in their native range have increased their invasive potential before they were transported (i.e., prior adaptation) or whether the observed changes are unique to the invasive populations. This urban/natural by native/invasive gradient allowed us to examine differences in guttural toad morphology (i.e., body size, hindlimb, and hindfoot length) and performance capacity (i.e., escape speed, endurance, and climbing ability) along their invasion route. Our findings indicate that invasive island populations have reduced body sizes, shorter limbs in relation to snout-vent length, decreased escape speeds, and decreased endurance capacities that are distinct from the native mainland populations (i.e., invasion-derived change). Thus, these characteristics did not likely arise directly from a pre-transport anthropogenic "filter" (i.e., urban-derived change). Climbing ability, however, did appear to originate within the urban-native range and was maintained within the invasive populations, thereby suggesting it may have been a prior adaptation that provided this species with an advantage during its establishment in urban areas and spread into natural forests. We discuss how this shift in climbing performance may be ecologically related to the success of urban and invasive guttural toad populations, as well as how it may have impacted other island-derived morphological and performance phenotypes.
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- 2022
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28. Regional differences in vertebral shape along the axial skeleton in caecilians (Amphibia: Gymnophiona).
- Author
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Lowie A, De Kegel B, Wilkinson M, Measey J, O'Reilly JC, Kley NJ, Gaucher P, Brecko J, Kleinteich T, Herrel A, and Adriaens D
- Subjects
- Animals, Amphibians anatomy & histology, Spine anatomy & histology, Spine diagnostic imaging
- Abstract
Caecilians are elongate, limbless and annulated amphibians that, as far as is known, all have an at least partly fossorial lifestyle. It has been suggested that elongate limbless vertebrates show little morphological differentiation throughout the postcranial skeleton. However, relatively few studies have explored the axial skeleton in limbless tetrapods. In this study, we used μCT data and three-dimensional geometric morphometrics to explore regional differences in vertebral shape across a broad range of caecilian species. Our results highlight substantial differences in vertebral shape along the axial skeleton, with anterior vertebrae being short and bulky, whereas posterior vertebrae are more elongated. This study shows that despite being limbless, elongate tetrapods such as caecilians still show regional heterogeneity in the shape of individual vertebrae along the vertebral column. Further studies are needed, however, to understand the possible causes and functional consequences of the observed variation in vertebral shape in caecilians., (© 2022 Anatomical Society.)
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- 2022
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29. Diverse aging rates in ectothermic tetrapods provide insights for the evolution of aging and longevity.
- Author
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Reinke BA, Cayuela H, Janzen FJ, Lemaître JF, Gaillard JM, Lawing AM, Iverson JB, Christiansen DG, Martínez-Solano I, Sánchez-Montes G, Gutiérrez-Rodríguez J, Rose FL, Nelson N, Keall S, Crivelli AJ, Nazirides T, Grimm-Seyfarth A, Henle K, Mori E, Guiller G, Homan R, Olivier A, Muths E, Hossack BR, Bonnet X, Pilliod DS, Lettink M, Whitaker T, Schmidt BR, Gardner MG, Cheylan M, Poitevin F, Golubović A, Tomović L, Arsovski D, Griffiths RA, Arntzen JW, Baron JP, Le Galliard JF, Tully T, Luiselli L, Capula M, Rugiero L, McCaffery R, Eby LA, Briggs-Gonzalez V, Mazzotti F, Pearson D, Lambert BA, Green DM, Jreidini N, Angelini C, Pyke G, Thirion JM, Joly P, Léna JP, Tucker AD, Limpus C, Priol P, Besnard A, Bernard P, Stanford K, King R, Garwood J, Bosch J, Souza FL, Bertoluci J, Famelli S, Grossenbacher K, Lenzi O, Matthews K, Boitaud S, Olson DH, Jessop TS, Gillespie GR, Clobert J, Richard M, Valenzuela-Sánchez A, Fellers GM, Kleeman PM, Halstead BJ, Grant EHC, Byrne PG, Frétey T, Le Garff B, Levionnois P, Maerz JC, Pichenot J, Olgun K, Üzüm N, Avcı A, Miaud C, Elmberg J, Brown GP, Shine R, Bendik NF, O'Donnell L, Davis CL, Lannoo MJ, Stiles RM, Cox RM, Reedy AM, Warner DA, Bonnaire E, Grayson K, Ramos-Targarona R, Baskale E, Muñoz D, Measey J, de Villiers FA, Selman W, Ronget V, Bronikowski AM, and Miller DAW
- Subjects
- Animals, Longevity, Phylogeny, Aging, Amphibians classification, Amphibians physiology, Biological Evolution, Reptiles classification, Reptiles physiology
- Abstract
Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging.
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- 2022
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30. Is vertebral shape variability in caecilians (Amphibia: Gymnophiona) constrained by forces experienced during burrowing?
- Author
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Lowie A, De Kegel B, Wilkinson M, Measey J, O'Reilly JC, Kley NJ, Gaucher P, Brecko J, Kleinteich T, Adriaens D, and Herrel A
- Subjects
- Animals, Head, Spine, Amphibians physiology, Skull
- Abstract
Caecilians are predominantly burrowing, elongate, limbless amphibians that have been relatively poorly studied. Although it has been suggested that the sturdy and compact skulls of caecilians are an adaptation to their head-first burrowing habits, no clear relationship between skull shape and burrowing performance appears to exist. However, the external forces encountered during burrowing are transmitted by the skull to the vertebral column, and, as such, may impact vertebral shape. Additionally, the muscles that generate the burrowing forces attach onto the vertebral column and consequently may impact vertebral shape that way as well. Here, we explored the relationships between vertebral shape and maximal in vivo push forces in 13 species of caecilian amphibians. Our results show that the shape of the two most anterior vertebrae, as well as the shape of the vertebrae at 90% of the total body length, is not correlated with peak push forces. Conversely, the shape of the third vertebrae, and the vertebrae at 20% and 60% of the total body length, does show a relationship to push forces measured in vivo. Whether these relationships are indirect (external forces constraining shape variation) or direct (muscle forces constraining shape variation) remains unclear and will require quantitative studies of the axial musculature. Importantly, our data suggest that mid-body vertebrae may potentially be used as proxies to infer burrowing capacity in fossil representatives., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2022. Published by The Company of Biologists Ltd.)
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- 2022
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31. Finding rare species and estimating the probability that all occupied sites have been found.
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Becker FS, Slingsby JA, Measey J, Tolley KA, and Altwegg R
- Subjects
- Animals, Probability, Endangered Species
- Abstract
Detecting occupied sites of rare species, and estimating the probability that all occupied sites are known within a given area, are desired outcomes for many ecological or conservation projects. Examples include managing all occupied sites of a threatened species or eradicating an emerging invader. Occupied sites may remain undetected because (1) sites where the species potentially occurs had not been searched, and (2) the species could have been overlooked in the searched sites. For rare species, available data are typically scant, making it difficult to predict sites where the species probably occurs or to estimate detection probability in the searched sites. Using the critically endangered Rose's mountain toadlet (Capensibufo rosei), known from only two localities, we outline an iterative process aimed at estimating the probability that any unknown occupied sites remain and maximizing the chance of finding them. This includes fitting a species distribution model to guide sampling effort, testing model accuracy and sampling efficacy using the occurrence of more common proxy species, and estimating detection probability using sites of known presence. The final estimate of the probability that all occupied sites were found incorporates the uncertainties of uneven distribution, relative area searched, and detection probability. Our results show that very few occupied sites of C. rosei are likely to remain undetected. We also show that the probability of an undetected occupied site remaining will always be high for large unsearched areas of potential occurrence, but can be low for smaller areas intended for targeted management interventions. Our approach is especially useful for assessing uncertainty in species occurrences, planning the required search effort needed to reduce probability of unknown occurrence to desired levels, and identifying priority areas for further searches or management interventions., (© 2021 The Ecological Society of America.)
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- 2022
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32. No evidence for innate differences in tadpole behavior between natural, urbanized, and invasive populations.
- Author
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Mühlenhaupt M, Baxter-Gilbert J, Makhubo BG, Riley JL, and Measey J
- Abstract
Abstract: Animals are increasingly challenged to respond to novel or rapidly changing habitats due to urbanization and/or displacement outside their native range by humans. Behavioral differences, such as increased boldness (i.e., propensity for risk-taking), are often observed in animals persisting in novel environments; however, in many cases, it is unclear how these differences arise (e.g., through developmental plasticity or evolution) or when they arise (i.e., at what age or developmental stage). In the Guttural Toad ( Sclerophrys gutturalis ), adult urban toads from both native and invasive ranges are bolder than conspecifics in natural habitats. Here, we reared Guttural Toad tadpoles in a common garden experiment, and tested for innate differences in boldness across their development and between individuals whose parents and lineage came from rural-native, urban-native, and urban-invasive localities (i.e., origin populations). Tadpoles did not differ in their boldness or in how their boldness changed over ontogeny based on their origin populations. In general, tadpoles typically became less bold as they aged, irrespective of origin population. Our findings indicate that differences in boldness in free-living adult Guttural Toads are not innate in the tadpole stage and we discuss three possible mechanisms driving phenotypic divergence in adult boldness for the focus of future research: habitat-dependent developmental effects on tadpole behavior, decoupled evolution between the tadpole and adult stage, and/or behavioral flexibility, learning, or acclimatization during the adult stage., Significance Statement: To determine if animals can persist in urban areas or become invasive outside their native ranges, it is important to understand how they adapt to life in the city. Our study investigates if differences in boldness that have been found in adult Guttural Toads ( Sclerophrys gutturalis ) represent heritable differences that can also be found in early life stages by rearing tadpoles from eggs in a common garden experiment. We did not find any differences in boldness among tadpoles from rural-native, urban-native, and urban-invasive origin populations. Our findings suggest that differences in boldness are not innate and/or that boldness is a behavioral trait that is decoupled between the tadpole and the adult stage., Competing Interests: Conflict of interestThe authors declare no competing interests., (© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2022.)
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- 2022
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33. The relationship between head shape, head musculature and bite force in caecilians (Amphibia: Gymnophiona).
- Author
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Lowie A, De Kegel B, Wilkinson M, Measey J, O'Reilly JC, Kley NJ, Gaucher P, Brecko J, Kleinteich T, Adriaens D, and Herrel A
- Subjects
- Animals, Biomechanical Phenomena, Head, Jaw physiology, Muscle, Skeletal, Skull, Amphibians physiology, Bite Force
- Abstract
Caecilians are enigmatic limbless amphibians that, with a few exceptions, all have an at least partly burrowing lifestyle. Although it has been suggested that caecilian evolution resulted in sturdy and compact skulls as an adaptation to their head-first burrowing habits, no relationship between skull shape and burrowing performance has been demonstrated to date. However, the unique dual jaw-closing mechanism and the osteological variability of their temporal region suggest a potential relationship between skull shape and feeding mechanics. Here, we explored the relationships between skull shape, head musculature and in vivo bite forces. Although there is a correlation between bite force and external head shape, no relationship between bite force and skull shape could be detected. Whereas our data suggest that muscles are the principal drivers of variation in bite force, the shape of the skull is constrained by factors other than demands for bite force generation. However, a strong covariation between the cranium and mandible exists. Moreover, both cranium and mandible shape covary with jaw muscle architecture. Caecilians show a gradient between species with a long retroarticular process associated with a large and pennate-fibered m. interhyoideus posterior and species with a short process but long and parallel-fibered jaw adductors. Our results demonstrate the complexity of the relationship between form and function of this jaw system. Further studies that focus on factors such as gape distance or jaw velocity will be needed in order to fully understand the evolution of feeding mechanics in caecilians., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2022. Published by The Company of Biologists Ltd.)
- Published
- 2022
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34. Public Awareness and Perceptions of Invasive Alien Species in Small Towns.
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Jubase N, Shackleton RT, and Measey J
- Abstract
Invasive alien species (IAS) are a growing threat globally and cause a variety of ecological, economic, and social impacts. People can introduce IAS and facilitate their spread, and can also implement, support, or oppose their management. Understanding local knowledge, awareness, and perceptions are therefore crucial if management and policy are to be effective. We administered questionnaires to members of the public in eight small towns along the Berg River Catchment in the biodiverse fynbos biome of South Africa. We aimed to assess: (1) awareness of IAS by the general public, (2) local perceptions of the impacts associated with IAS, (3) whether awareness of IAS is correlated with demographic covariates and IAS density, and (4) people's willingness to detect, report, and support IAS management. Overall, 262 respondents participated in the survey. Most respondents (65%) did not know what IAS are, and 10% were unsure. Many respondents also perceived IAS as beneficial. Using a logistic regression, we found that IAS density, educational level, and gender influenced people's knowledge and perceptions about IAS in the region. There were a small number (4%) of respondents currently detecting and reporting IAS, but many respondents were interested to learn more. We concluded that people living in small towns in the Western Cape of South Africa remain largely unaware of IAS and their impacts. It is crucial to increase awareness-raising initiatives, and build support and engagement in management of IAS in small towns.
- Published
- 2021
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35. Burrowing in blindsnakes: A preliminary analysis of burrowing forces and consequences for the evolution of morphology.
- Author
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Herrel A, Lowie A, Miralles A, Gaucher P, Kley NJ, Measey J, and Tolley KA
- Subjects
- Animals, Biological Evolution, Snakes classification, Snakes physiology
- Abstract
Burrowing is a common behavior in vertebrates. An underground life-style offers many advantages but also poses important challenges including the high energetic cost of burrowing. Scolecophidians are a group of morphologically derived subterranean snakes that show great diversity in form and function. Although it has been suggested that leptotyphlopids and anomalepidids mostly use existing underground passageways, typhlopids are thought to create their own burrows. However, the mechanisms used to create burrows and the associated forces that animals may be able to generate remain unknown. Here, we provide the first data on push forces in scolecophidians and compare them with those in some burrowing alethinophidian snakes. Our results show that typhlopids are capable of generating higher forces for a given size than other snakes. The observed differences are not due to variation in body diameter or length, suggesting fundamental differences in the mechanics of burrowing or the way in which axial muscles are used. Qualitative observations of skull and vertebral shape suggest that the higher forces exerted by typhlopids may have impacted the evolution of their anatomy. Our results provide the basis for future studies exploring the diversity of form and function in this fascinating group of animals. Quantitative comparisons of the cranial and vertebral shape in addition to collecting functional and ecological data on a wider array of species would be particularly important to test the patterns described here., (© 2021 American Association for Anatomy.)
- Published
- 2021
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36. Under pressure: the relationship between cranial shape and burrowing force in caecilians (Gymnophiona).
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Lowie A, De Kegel B, Wilkinson M, Measey J, O'Reilly JC, Kley NJ, Gaucher P, Brecko J, Kleinteich T, Van Hoorebeke L, Herrel A, and Adriaens D
- Subjects
- Animals, Biological Evolution, Body Weights and Measures, Phylogeny, X-Ray Microtomography, Amphibians, Skull
- Abstract
Caecilians are elongate, limbless and annulated amphibians that, with the exception of one aquatic family, all have an at least partly fossorial lifestyle. It has been suggested that caecilian evolution resulted in sturdy and compact skulls with fused bones and tight sutures, as an adaptation to their head-first burrowing habits. However, although their cranial osteology is well described, relationships between form and function remain poorly understood. In the present study, we explored the relationship between cranial shape and in vivo burrowing forces. Using micro-computed tomography (µCT) data, we performed 3D geometric morphometrics to explore whether cranial and mandibular shapes reflected patterns that might be associated with maximal push forces. The results highlight important differences in maximal push forces, with the aquatic Typhlonectes producing a lower force for a given size compared with other species. Despite substantial differences in head morphology across species, no relationship between overall skull shape and push force could be detected. Although a strong phylogenetic signal may partly obscure the results, our conclusions confirm previous studies using biomechanical models and suggest that differences in the degree of fossoriality do not appear to be driving the evolution of head shape., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2021. Published by The Company of Biologists Ltd.)
- Published
- 2021
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37. Sex chromosome degeneration, turnover, and sex-biased expression of sex-linked transcripts in African clawed frogs ( Xenopus ).
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Song XY, Furman BLS, Premachandra T, Knytl M, Cauret CMS, Wasonga DV, Measey J, Dworkin I, and Evans BJ
- Subjects
- Animals, Female, Male, Sex Characteristics, Sex Chromosomes genetics, Sex Determination Processes, Transcription, Genetic, Xenopus genetics
- Abstract
The tempo of sex chromosome evolution-how quickly, in what order, why and how their particular characteristics emerge during evolution-remains poorly understood. To understand this further, we studied three closely related species of African clawed frog (genus Xenopus ), that each has independently evolved sex chromosomes. We identified population polymorphism in the extent of sex chromosome differentiation in wild-caught Xenopus borealis that corresponds to a large, previously identified region of recombination suppression. This large sex-linked region of X. borealis has an extreme concentration of genes that encode transcripts with sex-biased expression, and we recovered similar findings in the smaller sex-linked regions of Xenopus laevis and Xenopus tropicalis . In two of these species, strong skews in expression (mostly female-biased in X. borealis , mostly male-biased in X. tropicalis ) are consistent with expectations associated with recombination suppression, and in X. borealis , we hypothesize that a degenerate ancestral Y-chromosome transitioned into its contemporary Z-chromosome. These findings indicate that Xenopus species are tolerant of differences between the sexes in dosage of the products of multiple genes, and offer insights into how evolutionary transformations of ancestral sex chromosomes carry forward to affect the function of new sex chromosomes. This article is part of the theme issue 'Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part I)'.
- Published
- 2021
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38. Progeny of Xenopus laevis from altitudinal extremes display adaptive physiological performance.
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Wagener C, Kruger N, and Measey J
- Subjects
- Animals, Larva, Temperature, Xenopus laevis genetics, Altitude, Swimming
- Abstract
Environmental temperature variation generates adaptive phenotypic differentiation in widespread populations. We used a common garden experiment to determine whether offspring with varying parental origins display adaptive phenotypic variation related to different thermal conditions experienced in parental environments. We compared burst swimming performance and critical thermal limits of African clawed frog (Xenopus laevis) tadpoles bred from adults captured at high (∼2000 m above sea level) and low (∼ 5 m above sea level) altitudes. Maternal origin significantly affected swimming performance. Optimal swimming performance temperature (Topt) had a >9°C difference between tadpoles with low altitude maternal origins (pure- and cross-bred, 35.0°C) and high-altitude maternal origins (pure-bred, 25.5°C; cross-bred, 25.9°C). Parental origin significantly affected critical thermal (CT) limits. Pure-bred tadpoles with low-altitude parental origins had higher CTmax (37.8±0.8°C) than pure-bred tadpoles with high-altitude parental origins and all cross-bred tadpoles (37.0±0.8 and 37.1±0.8°C). Pure-bred tadpoles with low-altitude parental origins and all cross-bred tadpoles had higher CTmin (4.2±0.7 and 4.2±0.7°C) than pure-bred tadpoles with high-altitude parental origins (2.5±0.6°C). Our study shows that the varying thermal physiological traits of Xenopus laevis tadpoles are the result of adaptive responses to their parental thermal environments. This study is one of few demonstrating potential intraspecific evolution of critical thermal limits in a vertebrate species. Multi-generation common garden experiments and genetic analyses would be required to further tease apart the relative contribution of plastic and genetic effects to the adaptive phenotypic variation observed in these tadpoles., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2021. Published by The Company of Biologists Ltd.)
- Published
- 2021
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39. Challenges of a novel range: Water balance, stress, and immunity in an invasive toad.
- Author
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Barsotti AMG, Madelaire CB, Wagener C, Titon B Jr, Measey J, and Gomes FR
- Subjects
- Animals, Blood Bactericidal Activity, Bufonidae immunology, Lymphocyte Count, Neutrophils cytology, South Africa, Bufonidae physiology, Dehydration physiopathology, Introduced Species, Stress, Physiological, Water-Electrolyte Balance
- Abstract
Species introduced by human activities can alter the normal functioning of ecosystems promoting negative impacts on native biodiversity, as they can rapidly expand their population size, demonstrating phenotypic plasticity and possible adaptive capacity to novel environments. Twenty years ago, the guttural toad, Sclerophrys gutturalis, was introduced to a peri-urban area of Cape Town, with cooler and drier climatic characteristics than its native source population, Durban, South Africa. Our goal was to understand the phenotypic changes, in terms of physiology and immunity, of populations in native and novel environments. We evaluated body index (BI), field hydration level, plasma corticosterone levels (CORT), proportion of neutrophils: lymphocytes (N: L), plasma bacterial killing ability (BKA), and hematocrit (HTC) in the field, and after standardized stressors (dehydration and movement restriction) in males from the native and invasive populations. Toads from the invasive population presented lower BI and tended to show a lower field hydration state, which is consistent with living in the drier environmental conditions of Cape Town. Additionally, invasive toads also showed higher BKA and N:L ratio under field conditions. After exposure to stressors, invasive animals presented higher BKA than the natives. Individuals from both populations showed increased CORT after dehydration, an intense stressor for these animals. The highest BKA and N:L ratio in the field and after submission to stressors in the laboratory shows that the invasive population has a phenotype that might increase their fitness, leading to adaptive responses in the novel environment and, thus, favoring successful dispersion and population increase., (Copyright © 2020 Elsevier Inc. All rights reserved.)
- Published
- 2021
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40. Mechanistic reconciliation of community and invasion ecology.
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Latombe G, Richardson DM, McGeoch MA, Altwegg R, Catford JA, Chase JM, Courchamp F, Esler KJ, Jeschke JM, Landi P, Measey J, Midgley GF, Minoarivelo HO, Rodger JG, and Hui C
- Abstract
Community and invasion ecology have mostly grown independently. There is substantial overlap in the processes captured by different models in the two fields, and various frameworks have been developed to reduce this redundancy and synthesize information content. Despite broad recognition that community and invasion ecology are interconnected, a process-based framework synthesizing models across these two fields is lacking. Here we review 65 representative community and invasion models and propose a common framework articulated around six processes (dispersal, drift, abiotic interactions, within-guild interactions, cross-guild interactions, and genetic changes). The framework is designed to synthesize the content of the two fields, provide a general perspective on their development, and enable their comparison. The application of this framework and of a novel method based on network theory reveals some lack of coherence between the two fields, despite some historical similarities. Community ecology models are characterized by combinations of multiple processes, likely reflecting the search for an overarching theory to explain community assembly and structure, drawing predominantly on interaction processes, but also accounting largely for the other processes. In contrast, most models in invasion ecology invoke fewer processes and focus more on interactions between introduced species and their novel biotic and abiotic environment. The historical dominance of interaction processes and their independent developments in the two fields is also reflected in the lower level of coherence for models involving interactions, compared to models involving dispersal, drift, and genetic changes. It appears that community ecology, with a longer history than invasion ecology, has transitioned from the search for single explanations for patterns observed in nature to investigate how processes may interact mechanistically, thereby generating and testing hypotheses. Our framework paves the way for a similar transition in invasion ecology, to better capture the dynamics of multiple alien species introduced in complex communities. Reciprocally, applying insights from invasion to community ecology will help us understand and predict the future of ecological communities in the Anthropocene, in which human activities are weakening species' natural boundaries. Ultimately, the successful integration of the two fields could advance a predictive ecology that is urgently required in a rapidly changing world., (© 2021 The Authors.)
- Published
- 2021
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41. Ecophysiological models for global invaders: Is Europe a big playground for the African clawed frog?
- Author
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Ginal P, Mokhatla M, Kruger N, Secondi J, Herrel A, Measey J, and Rödder D
- Subjects
- Animals, Europe, Animal Distribution, Ecosystem, Introduced Species, Models, Biological, Xenopus laevis physiology
- Abstract
One principle threat prompting the worldwide decline of amphibians is the introduction of nonindigenous amphibians. The African Clawed Frog, Xenopus laevis, is now one of the widest distributed amphibians occurring on four continents with ongoing range expansion including large parts of Europe. Species distribution models (SDMs) are essential tools to predict the invasive risk of these species. Previous efforts have focused on correlative approaches but these can be vulnerable to extrapolation errors when projecting species' distributions in nonnative ranges. Recent developments emphasise more robust process-based models, which use physiological data like critical thermal limits and performance, or hybrid models using both approaches. Previous correlative SDMs predict different patterns in the potential future distribution of X. laevis in Europe, but it is likely that these models do not assess its full invasive potential. Based on physiological performance trials, we calculate size and temperature-dependent response surfaces, which are scaled to geographic performance layers matching the critical thermal limits. We then use these ecophysiological performance layers in a standard correlative SDM framework to predict the potential distribution in southern Africa and Europe. Physiological performance traits (standard metabolic rate and endurance time of adult frogs) are the main drivers for the predicted distribution, while the locomotor performance (maximum velocity and distance moved in 200 ms) of adults and tadpoles have low contributions., (© 2020 Wiley Periodicals LLC.)
- Published
- 2021
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42. Shrinking before our isles: the rapid expression of insular dwarfism in two invasive populations of guttural toad ( Sclerophrys gutturalis ).
- Author
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Baxter-Gilbert J, Riley JL, Wagener C, Mohanty NP, and Measey J
- Subjects
- Animals, Biological Evolution, Bufonidae, Female, Male, South Africa, Dwarfism, Ecosystem
- Abstract
Island ecosystems have traditionally been hailed as natural laboratories for examining phenotypic change, including dramatic shifts in body size. Similarly, biological invasions can drive rapid localized adaptations within modern timeframes. Here, we compare the morphology of two invasive guttural toad ( Sclerophrys gutturalis ) populations in Mauritius and Réunion with their source population from South Africa. We found that female toads on both islands were significantly smaller than mainland counterparts (33.9% and 25.9% reduction, respectively), as were males in Mauritius (22.4%). We also discovered a significant reduction in the relative hindlimb length of both sexes, on both islands, compared with mainland toads (ranging from 3.4 to 9.0%). If our findings are a result of natural selection, then this would suggest that the dramatic reshaping of an amphibian's morphology-leading to insular dwarfism-can result in less than 100 years; however, further research is required to elucidate the mechanism driving this change (e.g. heritable adaptation, phenotypic plasticity, or an interaction between them).
- Published
- 2020
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43. Rapid Shifts in the Temperature Dependence of Locomotor Performance in an Invasive Frog, Xenopus laevis, Implications for Conservation.
- Author
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Araspin L, Martinez AS, Wagener C, Courant J, Louppe V, Padilla P, Measey J, and Herrel A
- Subjects
- Animals, Female, France, Introduced Species, Male, South Africa, Acclimatization, Conservation of Natural Resources, Locomotion physiology, Temperature, Xenopus laevis physiology
- Abstract
Temperature is a critical abiotic factor impacting all aspects of the biology of organisms, especially in ectotherms. As such, it is an important determinant of the potential invasive ability of organisms and may limit population expansion unless organisms can physiologically respond to changes in temperature either through plasticity or by adapting to their novel environment. Here, we studied the African clawed frog, Xenopus laevis, which has become invasive on a global scale. We compared adults from an invasive population of western France with individuals from two populations in the native range in South Africa. We measured the thermal dependence of locomotor performance in adults given its relevance to dispersal, predator escape, and prey capture. Our results show significant differences in the limits of the 80% performance breadth interval for endurance with the French population showing a left shift in its limits congruent with the colder climate experienced in France. The French invasive population was introduced only about 40 years ago suggesting a rapid shift in the thermal physiology. Given that all individuals were acclimated under laboratory conditions at 23°C for 2 months this suggests that the invasive frogs have adapted to their new environment. These data may allow the refinement of physiologically informed species distribution models permitting better estimates of future ranges at risk of invasion., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.)
- Published
- 2020
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44. The role of ambient temperature and body mass on body temperature, standard metabolic rate and evaporative water loss in southern African anurans of different habitat specialisation.
- Author
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Mokhatla M, Measey J, and Smit B
- Abstract
Temperature and water availability are two of the most important variables affecting all aspects of an anuran's key physiological processes such as body temperature ( T
b ), evaporative water loss (EWL) and standard metabolic rate (SMR). Since anurans display pronounced sexual dimorphism, evidence suggests that these processes are further influenced by other factors such as vapour pressure deficit (VPD), sex and body mass ( Mb ). However, a limited number of studies have tested the generality of these results across a wide range of ecologically relevant ambient temperatures ( Ta ), while taking habitat use into account. Thus, the aim of this study was to investigate the role of Ta on Tb , whole-animal EWL and whole-animal SMR in three wild caught African anuran species with different ecological specialisations: the principally aquatic African clawed frog ( Xenopus laevis ), stream-breeding common river frog ( Amietia delalandii ), and the largely terrestrial raucous toad ( Sclerophrys capensis ). Experiments were conducted at a range of test temperatures (5-35 °C, at 5 °C increments). We found that VPD better predicted rates of EWL than Ta in two of the three species considered. Moreover, we found that Tb , whole-animal EWL and whole-animal SMR increased with increasing Ta , while Tb increased with increasing Mb in A. delalandii and S. capensis but not in X. laevis . Whole-animal SMR increased with increasing Mb in S. capensis only. We did not find any significant effect of VPD, Mb or sex on whole-animal EWL within species. Lastly, Mb did not influence Tb , whole-animal SMR and EWL in the principally aquatic X. laevis . These results suggest that Mb may not have the same effect on key physiological variables, and that the influence of Mb may also depend on the species ecological specialisation. Thus, the generality of Mb as an important factor should be taken in the context of both physiology and species habitat specialisation., Competing Interests: John Measey is an Academic Editor for PeerJ. The authors declare there are no competing interests., (© 2019 Mokhatla et al.)- Published
- 2019
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45. The world needs BRICS countries to build capacity in invasion science.
- Author
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Measey J, Visser V, Dgebuadze Y, Inderjit, Li B, Dechoum M, Ziller SR, and Richardson DM
- Subjects
- Developing Countries, Introduced Species
- Abstract
Developed countries are producing policies to reduce the flow of invasive species and control or eradicate existing invasions, but most developing countries are under-resourced to tackle either aspect without help. Emerging economies, such as Brazil, Russia, India, China, and South Africa (BRICS), are responsible for donating many of the world's invasive species that have the potential to reach nearly all terrestrial biomes. Implementing a proactive 'facilitated network' model is urgently required to build capacity and stimulate effective appropriate invasion science. We contend that creating a BRICS network of invasion scientists will have the immediate impact required to meet future policy demands., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2019
- Full Text
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46. Emerging infectious diseases and biological invasions: a call for a One Health collaboration in science and management.
- Author
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Ogden NH, Wilson JRU, Richardson DM, Hui C, Davies SJ, Kumschick S, Le Roux JJ, Measey J, Saul WC, and Pulliam JRC
- Abstract
The study and management of emerging infectious diseases (EIDs) and of biological invasions both address the ecology of human-associated biological phenomena in a rapidly changing world. However, the two fields work mostly in parallel rather than in concert. This review explores how the general phenomenon of an organism rapidly increasing in range or abundance is caused, highlights the similarities and differences between research on EIDs and invasions, and discusses shared management insights and approaches. EIDs can arise by: (i) crossing geographical barriers due to human-mediated dispersal, (ii) crossing compatibility barriers due to evolution, and (iii) lifting of environmental barriers due to environmental change. All these processes can be implicated in biological invasions, but only the first defines them. Research on EIDs is embedded within the One Health concept-the notion that human, animal and ecosystem health are interrelated and that holistic approaches encompassing all three components are needed to respond to threats to human well-being. We argue that for sustainable development, biological invasions should be explicitly considered within One Health. Management goals for the fields are the same, and direct collaborations between invasion scientists, disease ecologists and epidemiologists on modelling, risk assessment, monitoring and management would be mutually beneficial., Competing Interests: The authors declare no competing interests.
- Published
- 2019
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47. A global meta-analysis of the ecological impacts of alien species on native amphibians.
- Author
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Nunes AL, Fill JM, Davies SJ, Louw M, Rebelo AD, Thorp CJ, Vimercati G, and Measey J
- Subjects
- Amphibians growth & development, Animals, Genetic Fitness, Invertebrates, Plants, Population Dynamics, Vertebrates, Amphibians physiology, Animal Distribution, Introduced Species
- Abstract
The exponential increase in species introductions during the Anthropocene has brought about a major loss of biodiversity. Amphibians have suffered large declines, with more than 16% considered to be threatened by invasive species. We conducted a global meta-analysis of the impacts of alien species on native amphibians to determine which aspects of amphibian ecology are most affected by plant, invertebrate, fish, amphibian, reptile, or mammal introductions. Measures of fitness were most strongly affected; amphibian performance was consistently lower in the presence of alien species. While exposure to alien species caused a significant decrease in amphibian behavioural activity when compared with a no species control, this response was stronger towards a control of native impacting species. This indicates a high degree of prey naiveté towards alien species and highlights the importance of using different types of controls in empirical studies. Alien invertebrates had the greatest overall impact on amphibians. This study sets a new agenda for research on biological invasions, highlighting the lack of studies investigating the impacts of alien species on amphibian terrestrial life-history stages. It also emphasizes the strong ecological impacts that alien species have on amphibian fitness and suggests that future introductions or global spread of alien invertebrates could strongly exacerbate current amphibian declines.
- Published
- 2019
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48. A taxonomically and geographically constrained information base limits non-native reptile and amphibian risk assessment: a systematic review.
- Author
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van Wilgen NJ, Gillespie MS, Richardson DM, and Measey J
- Abstract
For many taxa, new records of non-native introductions globally occur at a near exponential rate. We undertook a systematic review of peer-reviewed publications on non-native herpetofauna, to assess the information base available for assessing risks of future invasions, resulting in 836 relevant papers. The taxonomic and geographic scope of the literature was also compared to a published database of all known invasions globally. We found 1,116 species of herpetofauna, 95% of which were present in fewer than 12 studies. Nearly all literature on the invasion ecology of herpetofauna has appeared since 2000, with a strong focus on frogs (58%), particularly cane toads ( Rhinella marina ) and their impacts in Australia. While fewer papers have been published on turtles and snakes, proportionately more species from both these groups have been studied than for frogs. Within each herpetofaunal group, there are a handful of well-studied species: R. marina , Lithobates catesbeianus, Xenopus laevis , Trachemys scripta , Boiga irregularis and Anolis sagrei . Most research (416 papers; 50%) has addressed impacts, with far fewer studies on aspects like trade (2%). Besides Australia (213 studies), most countries have little location-specific peer-reviewed literature on non-native herpetofauna (on average 1.1 papers per established species). Other exceptions were Guam, the UK, China, California and France, but even their publication coverage across established species was not even. New methods for assessing and prioritizing invasive species such as the Environmental Impact Classification for Alien Taxa provide useful frameworks for risk assessment, but require robust species-level studies. Global initiatives, similar to the Global Amphibian Assessment, using the species and taxonomic groups identified here, are needed to derive the level of information across broad geographic ranges required to apply these frameworks. Expansive studies on model species can be used to indicate productive research foci for understudied taxa., Competing Interests: John Measey is an Academic Editor for PeerJ.
- Published
- 2018
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49. Size-dependent functional response of Xenopus laevis feeding on mosquito larvae.
- Author
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Thorp CJ, Alexander ME, Vonesh JR, and Measey J
- Abstract
Predators can play an important role in regulating prey abundance and diversity, determining food web structure and function, and contributing to important ecosystem services, including the regulation of agricultural pests and disease vectors. Thus, the ability to predict predator impact on prey is an important goal in ecology. Often, predators of the same species are assumed to be functionally equivalent, despite considerable individual variation in predator traits known to be important for shaping predator-prey interactions, like body size. This assumption may greatly oversimplify our understanding of within-species functional diversity and undermine our ability to predict predator effects on prey. Here, we examine the degree to which predator-prey interactions are functionally homogenous across a natural range of predator body sizes. Specifically, we quantify the size-dependence of the functional response of African clawed frogs ( Xenopus laevis ) preying on mosquito larvae ( Culex pipiens ). Three size classes of predators, small (15-30 mm snout-vent length), medium (50-60 mm) and large (105-120 mm), were presented with five densities of prey to determine functional response type and to estimate search efficiency and handling time parameters generated from the models. The results of mesocosm experiments showed that type of functional response of X. laevis changed with size: small predators exhibited a Type II response, while medium and large predators exhibited Type III responses. Functional response data showed an inversely proportional relationship between predator attack rate and predator size. Small and medium predators had highest and lowest handling time, respectively. The change in functional response with the size of predator suggests that predators with overlapping cohorts may have a dynamic impact on prey populations. Therefore, predicting the functional response of a single size-matched predator in an experiment may misrepresent the predator's potential impact on a prey population., Competing Interests: John Measey is an Academic Editor for PeerJ.
- Published
- 2018
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50. What's for dinner? Diet and potential trophic impact of an invasive anuran Hoplobatrachus tigerinus on the Andaman archipelago.
- Author
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Mohanty NP and Measey J
- Abstract
Amphibian invasions have considerable detrimental impacts on recipient ecosystems. However, reliable risk analysis of invasive amphibians still requires research on more non-native amphibian species. An invasive population of the Indian bullfrog, Hoplobatrachus tigerinus , is currently spreading on the Andaman archipelago and may have significant trophic impacts on native anurans through competition and predation. We carried out diet analyses of the invasive H. tigerinus and native anurans, across four habitat types and two seasons; we hypothesized that (i) small vertebrates constitute a majority of the H. tigerinus diet, particularly by volume and (ii) the diet of H. tigerinus significantly overlaps with the diet of native anurans, thereby, leading to potential competition. We assessed the diet of the invasive H. tigerinus ( n = 358), and individuals of the genera Limnonectes ( n = 375) and Fejervarya ( n = 65) and found a significant dietary overlap of H . tigerinus with only Limnonectes . Small vertebrates, including several endemic species, constituted the majority of H. tigerinus , diet by volume, suggesting potential impact by predation. Prey consumption and electivity of the three anurans indicated a positive relationship between predator-prey body sizes. Individuals of H. tigerinus and Fejervarya chose evasive prey, suggesting that these two taxa are mostly ambush predators; individuals of Limnonectes chose a mixture of sedentary and evasive prey indicating that the species employs a combination of 'active search' and 'sit and wait' foraging strategies. All three species of anurans mostly consumed terrestrial prey. This intensive study on a genus of newly invasive amphibian contributes to knowledge of the impact of amphibian invasions , and elucidates the feeding ecology of H . tigerinus , and species of the genera Limnonectes and Fejervarya . We also stress the necessity to evaluate prey availability and volume in future studies for meaningful insights into diet of amphibians., Competing Interests: John Measey is an Academic Editor for PeerJ.
- Published
- 2018
- Full Text
- View/download PDF
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