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Aim: Forest regeneration data provide an early signal of the persistence and migration of tree species, so we investigated whether species shifts due to climate change exhibit a common signal of response or whether changes vary by species. Location: California Floristic Province, United States; mediterranean biome. Methods: We related Forest Inventory and Analysis (FIA) data from 2000-07 for 13 tree species to high-resolution climate and geographical data. Using methods from invasion ecology, we derived indices of species-specific regeneration overlap and central tendency change (range-wide global indicators) based on kernel density estimation of presence and absence of regeneration. We then built regeneration surfaces to identify areas of occurrence of high regeneration (regeneration hotspots, local indicators) in both geographical and climate space for 13 common tree species. Results: Differences between presence and absence of regeneration in forests varied in magnitude across species, with little evidence that tree regeneration is shifting to higher latitudes and elevations, the expected geographical fingerprint of climate change. We also identified potential topographic mediators of regeneration dynamics. Multiple regeneration hotspots were found for many species, suggesting the influence of non-climatic factors on regeneration. Differences between the presence and absence of regeneration in geographic and climate spaces were not always congruent, suggesting that shifting climate space and range area are not entirely coupled. Main conclusions: The distributions of regeneration in Californian forests show diverse signals, not always tracking the higher latitudinal-elevation fingerprint of climate change. Local regeneration hotspots are common in our analysis, suggesting spatially varying persistence of forest linked to natural and anthropogenic disturbances. Our results emphasize that projections of tree range shifts in the context of climate change should consider the variation of regeneration drivers within species ranges, beyond the overall climate signal.

Aim: Forest regeneration data provide an early signal of the persistence and migration of tree species, so we investigated whether species shifts due to climate change exhibit a common signal of response or whether changes vary by species. Location: California Floristic Province, United States; mediterranean biome. Methods: We related Forest Inventory and Analysis (FIA) data from 2000-07 for 13 tree species to high-resolution climate and geographical data. Using methods from invasion ecology, we derived indices of species-specific regeneration overlap and central tendency change (range-wide global indicators) based on kernel density estimation of presence and absence of regeneration. We then built regeneration surfaces to identify areas of occurrence of high regeneration (regeneration hotspots, local indicators) in both geographical and climate space for 13 common tree species. Results: Differences between presence and absence of regeneration in forests varied in magnitude across species, with little evidence that tree regeneration is shifting to higher latitudes and elevations, the expected geographical fingerprint of climate change. We also identified potential topographic mediators of regeneration dynamics. Multiple regeneration hotspots were found for many species, suggesting the influence of non-climatic factors on regeneration. Differences between the presence and absence of regeneration in geographic and climate spaces were not always congruent, suggesting that shifting climate space and range area are not entirely coupled. Main conclusions: The distributions of regeneration in Californian forests show diverse signals, not always tracking the higher latitudinal-elevation fingerprint of climate change. Local regeneration hotspots are common in our analysis, suggesting spatially varying persistence of forest linked to natural and anthropogenic disturbances. Our results emphasize that projections of tree range shifts in the context of climate change should consider the variation of regeneration drivers within species ranges, beyond the overall climate signal.

The characteristics of flower‒visitor networks, comprised of multiple species interacting with each other, predict ecological and evolutionary processes. Intraspecific and interspecific variations in interaction patterns should affect network structures. Because female and male visitors usually differ in flower‐visiting patterns due to mating strategy, visitor sex should affect nestedness, in which specialist species interact with a subset of species that interact with generalist species. I hypothesized that a network of male visitors and flowering plants would be more nested than a female network because males are less picky about which flowers they visit. To examine the effect of visitor sex on nestedness, I used museum specimens of insects and built 11 flower–visitor species networks, each composed of female and male subnetworks, and compared the strength of nestedness and related network metrics between the subnetworks. I found that male subnetworks were significantly more nested than female ones, and species networks were less nested than male or female subnetworks. The result may be attributable to the by‐chance selection of flowers by males. Because a nested structure is predicted to promote community stability in mutualistic flower–visitor networks, the greater nestedness of male subnetworks may suggest a positive effect of male visitors on pollination community stability. [ABSTRACT FROM AUTHOR]

This study aimed to identify the importance of ecological factors to distribution patterns of the invasive Clam (Corbicula fluminea) relative to native mussels (family: Unionidae) across seven rivers within the Mobile and Tennessee basins, Southeast United States. We quantitatively surveyed dense, diverse native mussel aggregations across 20 river reaches and estimated mussel density, biomass, and species richness along with density of invasive C. fluminea (hereafter Corbicula). We measured substrate particle size, velocity, and depth in quadrats where animals were collected. Additionally, we characterized reach scale environmental parameters including seston quantity and quality (% Carbon, % Nitrogen, % Phosphorous), water chemistry (ammonium [NH4+], soluble reactive phosphorous [SRP]), and watershed area and land cover. Using model selection, logistic regression, and multivariate analysis, we characterized habitat features and their association to invasive Corbicula within mussel beds. We found that Corbicula were more likely to occur and more abundant in quadrats with greater mussel biomass, larger substrate size, faster water velocity, and shallower water depth. At the reach scale, Corbicula densities increased where particle sizes were larger. Mussel richness, density, and biomass increased with watershed area. Water column NH4+ increased at reaches with more urban land cover. No land cover variables influenced Corbicula populations or mussel communities. The strong overlapping distribution of Corbicula and mussels support the hypothesis that Corbicula are not necessarily limited by habitat factors and may be passengers of change in rivers where mussels have declined due to habitat degradation. Whether Corbicula is facilitated by mussels or negatively interacts with mussels in these systems remains to be seen. Focused experiments that manipulate patch scale variables would improve our understanding of the role of species interactions (e.g., competition, predation, facilitation) or physical habitat factors in influencing spatial overlap between Corbicula and native mussels. [ABSTRACT FROM AUTHOR]

Aquatic habitats are severely threatened by human activities. For anadromous species, managing freshwater habitats to maximize production of more, larger juveniles could improve resilience to threats in marine habitats and enhance population viability. In some juvenile salmonid habitats, complexity created by large substrates provides resources and reduces competitive interactions, thereby promoting juvenile production. In lowland rivers, which lack large substrates, aquatic plants might provide similar complexity and enhance fish productivity. To test the influence of aquatic plants on juvenile Atlantic salmon and sympatric brown trout in a lowland river, we directly manipulated the cover of the dominant macrophyte, Ranunculus, in nine sites during summer and autumn for two years. We quantified the abundance, site retention and growth of salmon and trout under high, medium or low Ranunculus cover. To investigate the effects of Ranunculus cover on feeding opportunities and interspecific competition, we quantified available prey biomass and body size, fish diet composition and compared dietary niche overlap. Experimentally increased Ranunculus cover supported higher salmon abundance in summer and autumn, and higher site retention and growth of salmon in summer. Trout abundance and growth were not influenced by Ranunculus cover, but trout site retention doubled in high, relative to low, cover sites. Despite the weak effects of Ranunculus cover on prey availability, salmon and trout inhabiting high cover sites consumed larger prey and a higher biomass of prey. Furthermore, dietary niche overlap was lower in high, relative to low, cover sites, suggesting that abundant Ranunculus reduced interspecific competition. This field experiment shows that high Ranunculus cover can support more and better growing juvenile salmon, and facilitate foraging and co‐existence of sympatric salmonid species. Maintaining or enhancing natural macrophyte cover can be achieved through sympathetic in‐river and riparian vegetation management and mitigating pressures on them, such as sediment inputs and low flows, or through planting. Further research should test whether macrophyte cover benefits propagate to subsequent life stages, particularly juvenile overwintering associated with high mortality. This knowledge, in combination with our findings, would further clarify whether beneficial juvenile habitat can improve the viability of at‐risk salmonid populations. Overall, our findings suggest that the aims of river restoration might be achieved through promotion of in‐stream aquatic vegetation. [ABSTRACT FROM AUTHOR]

Modern North American carnivorous mammal assemblages consist of species from a single clade: the Carnivora. Carnivorans once coexisted with members of other meat-eating clades, including the creodonts (Hyaenodontida and Oxyaenida). Creodonts, however, went extinct in North America during the late Eocene and early Oligocene, potentially due to niche overlap and resource competition with contemporary carnivorans. In this study, we employ a community ecology approach to understand whether the dietary niches of coexisting creodonts and carnivorans overlapped during the late Eocene (Chadronian North American Land Mammal Age), a time when creodonts were dwindling and carnivorans were diversifying. We quantify niche overlap based on inferences of diet from carnassial tooth shape estimated using Orientation Patch Count, Dirichlet's Normal Surface Energy, and linear dental measurements as well as from body mass for all species in the Calf Creek Local Fauna of Cypress Hills, Saskatchewan (Treaty 4 land). Although creodonts and carnivorans shared characteristics of their carnassial tooth shape, suggesting similar chewing mechanics and feeding habits, we find that marked differences in body size likely facilitated niche partitioning, at least between the largest creodonts and carnivorans. Calculations of prey focus masses and prey mass spectra indicate that only the smallest creodont may have experienced significant competition for prey with the coeval carnivorans. We suggest that the ultimate extinction of creodonts from North America during the late Eocene and Oligocene was unlikely to have been driven by factors related to niche overlap with carnivorans. [ABSTRACT FROM AUTHOR]

Three species of Rattus , Norway rat (R. norvergicus), black rat (R. rattus) and Asian house rat (R. tanezumi) are currently known to occur in South Africa. The latter two species are cryptic and form part of the Rattus rattus species complex. Historically, R. norvegicus has been reported to occur along the coast and in urban centres, R. rattus is widespread in most urban areas, except in the drier areas, while R. tanezumi was only recorded to occur in the country (and Africa) ca. 15 years ago, and its distribution remains unknown. The aim of this study was to predict the potential distribution of R. tanezumi in South Africa and assess how it overlaps with that of R. norvegicus and R. rattus using species distribution modelling. Rattus tanezumi was predicted to mainly occur in most inland urban areas and along the coast. The distribution of R. rattus was as expected, in contrast, the predicted range of R. norvegicus was not restricted to the coast but also included inland urban areas. All three species showed broad potential distributional ranges that overlapped extensively indicating that their establishment and spread may be influenced by similar factors such as proximity to urban areas and a wet and moderate climate. These results allow insights into assessing their risk of establishment and for formulating appropriate intervention strategies for their management and control. [ABSTRACT FROM AUTHOR]

Temporary water bodies are temporally variable ecosystems supported primarily by rainwater. The biota supported by such water bodies present a range of capacities to remain in this environment for all or part of their life cycles. During floods, temporary pools can connect with permanent streams, promoting changes in trophic networks in the aquatic food webs. The aim of this research was to analyse the feeding ecology of a fish community in a temporary pool near of Tlacotalpan, in the Mexican southeast, in order to understand the dynamics of the feeding habits. First, we identified feeding habits that can be interpreted as guilds of the fishes in the temporary pool: the annual killifish Millerichthys robustus (the only autochthonous species) is planktophagous; Cynodonichthys tenuis and Astyanax aeneus are insectivores; Dormitator maculatus and larvae of amphibians (Lithobates sp.) are mainly detritivorous; and Poecilia mexicana is planktophagous and insectivorous. We then estimated the effect of coexistence on niche breadth and overlap. The niches of M. robustus and P. mexicana evidenced overlap, but the breadth was adjusted inversely, suggesting feeding specialisation in M. robustus in response to competition. We documented the existence of two cohorts of M. robustus; the niche breadth of the first and second cohorts suggesting different strategies probably related to competition under variable conditions. The niche of C. tenuis and A. aeneus, and D. maculatus and tadpoles overlapped, following a pattern of feeding generalisation in response to competition. [ABSTRACT FROM AUTHOR]

Species with similar ecological requirements that overlap in range tend to segregate their niches to minimize competition for resources. However, the niche segregation possibilities for centrally foraging predators that breed on isolated Subantarctic islands may be reduced by spatial constraints and limitations in the availability of alternative prey. In this study we examined spatial and trophic aspects of the foraging niches of two sympatrically breeding penguin species, macaroni (Eudyptes chrysolophus; MAC) and chinstrap (Pygoscelis antarcticus; CHIN) penguins, at Bouvetøya over two breeding seasons. To measure at-sea movements and diving behaviour, 90 MACs and 49 CHINs were equipped with GPS loggers and dive recorders during two austral summer breeding seasons (2014/15 and 2017/18). In addition, blood samples from tracked birds were analysed for stable isotopes to obtain dietary information. CHINs displayed marked interannual variation in foraging behaviour, diving deeper, utilizing a larger foraging area and displaying enriched values of δ15N in 2014/15 compared to the 2017/18 breeding season. In contrast, MACs dove to similar depths and showed similar δ15N values, while consistently utilizing larger foraging areas compared to CHINs. We suggest that low krill abundances in the waters around Bouvetøya during the 2014/15 season resulted in CHINs shifting toward a diet that increased their niche overlap with MACs. Our findings may partly explain the decreasing number of breeding CHINs at the world's most remote island, Bouvetøya, while also highlighting the importance of characterizing niche overlap of species using multi-season data sets. [ABSTRACT FROM AUTHOR]

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Abstract The distribution of mangroves is influenced by the environment. We aimed to understand the ecological adaptability of various mangrove species within the range of the exotic species, Sonneratia apetala Buch.‐Ham., in Dongzhai Harbor, Hainan Island, China. We used three niche breadth indexes (Simpson, Levins, and Shannon–Weiner) and two niche overlap indexes (Pianka and Levins) to quantitatively determine the niche characteristics of nine mangrove species. The results showed that the order of the niche breadth values of mangrove species was as follows: Aegiceras corniculatum (Linn.) Blanco > Kandelia obovata Sheue et al. > Bruguiera gymnorrhiza (L.) Poir. > Avicennia marina (Forsk.) Vierh. Hailanci > S. apetala > S. caseolaris (L.) Engl. > Rhizophora stylosa Griff > Ceriops tagal (Perr.) C. B. Rob. > B. sexangula (Lour.) Poir. Pearson correlation analysis revealed that the niche breadth of each population was significantly correlated with the importance value of the population in the whole sample (R1 = R2 = 0.771, R3 = 0.644, p

Abstract Background Small coastal wetlands are vital sites for wintering waterbirds. Identifying important habitats is critical for managing waterbirds effectively. The Vourkari inlet is a small coastal wetland located near the capital Athens, within the most urbanized and industrialized area of Greece. We aimed at identifying the most important habitats for waterbirds at the Vourkari inlet during winter. Methods Data about habitat use and availability were collected for 14 waterbird species and for seven habitat classes. Habitat selection (Manly’s selection ratio), overlap indices (Pianka’s niche overlap index) and null models were calculated. Results All the studied waterbird species selected available habitats nonrandomly. Shallow waters (0–2 m), were used by 13 waterbirds and selected by five waterbirds. Pools and channels were used and selected by 10 species. Mud was used by nine species and selected by six species. Mud with rocky substrate was used by nine species and selected by eight species. Medium (2–4 m) and deep (4–6 m) open water habitats were used by seven species and selected by four species. Halophytic vegetation was used by six species and selected by two species. Several habitats were selected by nationally important populations: mudflat habitats (i.e., mud, mud with rocky substrate and pools and channels) by Common Redshanks (Tringa totanus), halophytic vegetation by Little Egrets (Egretta garzetta), shallow waters by Common Shelducks (Tadorna tadorna) and medium and deep waters by Sandwich Terns (Thalasseus sandvicencis), whilst shallow waters and mudflat habitats were preferred by a possibly internationally important population of Mediterranean Gulls (Ichthyaetus melanocephalus). Although overlap in habitat use between species was generally low, null models indicated habitat sharing and a lack of competition. Conclusions Waterbirds coexisted in the absence of competition for habitats at Vourkari, where they mostly used and preferred shallow water and mudflats. Small coastal wetlands are numerous, both in Greece and worldwide, therefore our findings would be useful as a basis for comparisons, both temporal at the inlet and spatial with other sites, that would help assess the importance of habitats and improve management strategies to benefit waterbirds, especially in areas with similar Mediterranean-type habitats and climate.

Understanding predator-prey relationships is fundamental to develop effective conservation plans. Between 2015 and 2018, we combed 21 transects, each 7km long, searching for Iberian Lynx Lynx pardinus scat within the province of Madrid in central Spain. In order to minimise inherent subjectivity of visual identification as much as possible, we performed a double specific nested polymerase chain reaction (PCR) followed by a primer extension assay addressed to two Iberian Lynx diagnostic single nucleotide polymorphisms. Forty-six scat samples were positively identified as belonging to Iberian Lynx through genetic analysis. From these, we extracted remains of consumed prey, which we determined to the lowest possible taxonomic level, mainly through hair identification. Identified prey was divided into four types: lagomorphs, small mammals, birds, and ungulates. The species’ diet composition was described based on the frequency of occurrence (FO) of each prey and niche breadth, and also compared with prior knowledge of the species using four prior studies as a comparative reference through the calculation of the niche overlap value. The FO of lagomorphs (39%) was the lowest, while the FO of small mammals (54%) was the highest recorded to date. The niche breath (0.36) was higher than recorded in prior studies, but still showing the specialist character of the Iberian Lynx. Niche overlap was low (C = 0.49), showing differences in trophic niche between the population in our study area and the one studied in southern Spain. This indicates that the Iberian Lynx is adept at switching its main prey, an ability that has previously been firmly rejected. It is, however, capable of adapting to alternative prey more often than recorded to date, which could be a behavioural response to the patchy distribution of European Rabbit Oryctolagus cuniculus in the study area.

Abstract One of the most important resources for reproduction in frogs is the acoustic space since the advertisement call, which is mostly used to attract females, may suffer interference when the acoustic space is widely filled. Other important resources are calling sites and adequate climatic conditions. We analyzed herein three dimensions of the acoustic niche of anurans (advertisement calls, calling period, and calling sites). We recorded 11 calling species of frogs in a tropical community. Species richness was negatively related to temperature, and daily activity was positively related to humidity. We also observed a greater niche overlap than expected by chance in calling periods. These results indicate that the climatic conditions should act as an environmental filter, synchronizing the calling period. The calling site was not shared among species, and no clear pattern of substrate use was observed. Regarding the acoustic dimension, we observe a phylogenetic signal in the dominant frequency of advertisement calls. Hierarchical cluster analysis also indicated a congruence between acoustic distances and phylogenetic relationships. Therefore, the dominant frequency of advertisement calls was constrained by phylogenetic relationships, indicating that it affects the partitioning and use of acoustic resources, an important dimension in reproductive activity in anurans.

Understanding habitat and spatial overlap in sympatric species of urban areas would aid in predicting species and community modifications in response to global change. Habitat overlap has been widely investigated for specialist species but neglected for generalists living in urban settings. Many corvid species are generalists and are adapted to urban areas. This work aimed to determine the urban habitat requirements and spatial overlap of five corvid species in sixteen European cities during the breeding season. All five studied corvid species had high overlap in their habitat selection while still having particular tendencies. We found three species, the Carrion/Hooded Crow, Rook, and Eurasian Magpie, selected open habitats. The Western Jackdaw avoided areas with bare soil cover, and the Eurasian Jay chose more forested areas. The species with similar habitat selection also had congruent spatial distributions. Our results indicate that although the corvids had some tendencies regarding habitat selection, as generalists, they still tolerated a wide range of urban habitats, which resulted in high overlap in their habitat niches and spatial distributions.

In this study, we described and compared the diet, monthly feeding intensity, and condition of west coast steenbras (Lithognathus aureti) and silver kob (Argyrosomus inodorus) caught at a unique habitat in the northern Benguela. Stomach contents of 179 west coast steenbras and 114 silver kob caught from October 2020 to September 2022 were investigated. The peak in feeding intensity of west coast steenbras appeared to be opportunistic during winter and summer periods depending on food availability. The fish condition, however, peaked at the beginning (October) and at the end (April) of the austral summer spawning period, with the hepatosomatic index (HSI) at 1.5% and the condition factor (CF) at 0.022%. Seven prey taxa were found in the diet of west coast steenbras (bivalves, bony fishes, other mollusks, algae, crustaceans, cnidaria, and polychaetas) and six taxa in the diet of silver kob (bivalves, crustaceans, bony fishes, algae, starfish, and zooplankton), indicating generalist feeding behavior in both the species. The bivalves were the most important prey items in the diet of west coast steenbras (95.9% index of relative importance [IRI]). The most important prey items in the diet of silver kob were crustaceans (83.1% IRI) and bony fishes (16.0% IRI). Crustaceans were most important in the diet of small-to-medium-sized silver kob, whereas bony fishes were most important in the diet of larger silver kob (>75 cm), with significant differences of IRI% by size class. Schoener's index of niche overlap indicated a relatively low overall niche overlap (0.11) between west coast steenbras and silver kob. This allows them to coexist as their feeding habits allow them to occupy unique niches in the coastal reef and sandy habitat and reduce competition for resources., (© 2024 The Author(s). Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of Fisheries Society of the British Isles.)

The global focus on fostering harmonious interactions and promoting rational coexistence among wildlife species to uphold or reinstate biodiversity remains a prominent area of interest. We conducted a study on the sable and yellow-throated marten in Taipinggou National Nature Reserve, Heilongjiang, China, using the line transect method and infrared camera traps from 2022 to 2023. We then analyzed the overlap of their suitable habitats and niches with the aim of gaining insight into the interspecific competition between these two species. We found that the suitable habitat areas for the sable and yellow-throated marten were 55.20 km 2 and 23.28 km 2 , accounting for 24.86% and 10.48% of the total area of this study, respectively. The overlap between the suitable habitats for the sable and yellow-throated marten was 15.73 km 2 , accounting for 28.5% and 67.6% of their suitable habitat, supporting our Hypothesis 1. The first principal component (Dim1) of the niche explained 35.4% of the overall variability, which is mainly related to the environmental variables "Distance from Settlements" and "Distance from Roads". Overall, 25.5% of the total variability was explained by the second principal component (Dim2), associated with "Slope" and "Distance from Coniferous and Broadleaved Mixed Forest". The niches occupied by the sable and yellow-throated marten were both off-center of the environmental background space, with the niches of the sable being larger than those of the yellow-throated marten. Schoener's D index was 0.56, indicating a high degree of niche overlap between the sable and yellow-throated marten, supporting our Hypothesis 2. Our study is helpful in terms of formulating conservation and management policies for the sable and yellow-throated marten.

Bumblebees are important pollinators for many natural and agricultural systems in temperate regions. Interspecific and intraspecific variation in floral resource preferences have been proposed to influence bumblebee community structure. In particular, sexual dimorphism is a major source of intraspecific niche variation. Although interspecific resource partitioning is well studied, few studies have explored the intraspecific dynamics between workers and males. Here, we report a study on a total of 11 528 workers and 2220 males of 14 bumblebee species recorded over 5 years in the Hengduan Mountains of Southwest China. We first compared the potential for interspecific and intraspecific competition between workers and males using visitation records and resource partitioning indices (overlap index). We then evaluated the influence of nectar traits on flower preference, including nectar volume and the levels of hexose, sucrose and 10 essential amino acids (EAAs). We found that the niche overlap between intraspecific workers and males was higher than that between different species, and temporal overlap alone did not strongly determine diet overlap. Males of most species preferred flowers with high levels of EAAs and hexose, whereas workers of some species preferred flowers with high nectar volume and sucrose levels. This study suggests that there is floral resource partitioning among bumblebee species, and between workers and males, which may play a key role in alleviating interspecific and intraspecific competition. These findings also provide a useful guide for which kinds of plants might be most valuable for bumblebees, especially the understudied males, in this biodiversity hotspot., (© 2024 Institute of Zoology, Chinese Academy of Sciences.)

Premise: Hybridization is recognized as an important mechanism in fern speciation, with many allopolyploids known among congeners, as well as evidence of ancient genome duplications. Several contemporary instances of deep (intergeneric) hybridization have been noted, invariably resulting in sterile progeny. We chose the christelloid lineage of the family Thelypteridaceae, recognized for its high frequency of both intra- and intergeneric hybrids, to investigate recent hybrid speciation between deeply diverged lineages. We also seek to understand the ecological and evolutionary outcomes of resulting lineages across the landscape., Methods: By phasing captured reads within a phylogenomic data set of GoFlag 408 nuclear loci using HybPhaser, we investigated candidate hybrids to identify parental lineages. We estimated divergence ages by inferring a dated phylogeny using fossil calibrations with treePL. We investigated ecological niche conservatism between one confirmed intergeneric allotetraploid and its diploid progenitors using the centroid, overlap, unfilling, and expansion (COUE) framework., Results: We provide evidence for at least six instances of intergeneric hybrid speciation within the christelloid clade and estimate up to 45 million years of divergence between progenitors. The niche quantification analysis showed moderate niche overlap between an allopolyploid species and its progenitors, with significant divergence from the niche of one progenitor and conservatism to the other., Conclusions: The examples provided here highlight the overlooked role that allopolyploidization following intergeneric hybridization may play in fern diversification and range and niche expansions. Applying this approach to other fern taxa may reveal a similar pattern of deep hybridization resulting in highly successful novel lineages., (© 2024 The Author(s). American Journal of Botany published by Wiley Periodicals LLC on behalf of Botanical Society of America.)

Wild ungulates play crucial roles in maintaining the structure and function of local ecosystems. The alpine musk deer ( Moschus chrysogaste ), white-lipped deer ( Przewalskium albirostris ), and red serow ( Capricornis rubidus ) are widely distributed throughout the Nyenchen Tanglha Mountains of Tibet. However, research on the mechanisms underlying their coexistence in the same habitat remains lacking. This study aimed to investigate the mechanisms underlying the coexistence of these species based on their dietary preferences through DNA barcoding using the fecal samples of these animals collected from the study area. These species consume a wide variety of food types. Alpine musk deer, white-lipped deer, and red serow consume plants belonging to 74 families and 114 genera, 62 families and 122 genera, and 63 families and 113 genera, respectively. Furthermore, significant differences were observed in the nutritional ecological niche among these species, primarily manifested in the differentiation of food types and selection of food at the genus level. Owing to differences in social behavior, body size, and habitat selection, these three species further expand their differentiation in resource selection, thereby making more efficient use of environmental resources. Our findings indicate these factors are the primary reasons for the stable coexistence of these species.

Sympatric bats engage in various strategies for dietary niche partitioning such as different microhabitat use; however, no previous study has yet looked at potential dietary niche partitioning in mammals foraging in a space void of any physical structure. Here, we used stable isotope ratios of carbon and nitrogen to investigate if three insectivorous bats of central Thailand, Chaerephon plicatus, Taphozous melanopogon and T. theobaldi, partition food resources when foraging in the open space of the lower boundaries of the troposphere. We quantified the isotopic dietary niches of these species and compared niche dimensions within the guild of openspace foraging bats and between this guild and the edge-foraging bat Hipposideros larvatus. Our results showed that stable isotope ratios of bats differed between wet and dry seasons. Consistently, open-space foraging bat species shared a similar isotopic composition in both seasons, which contrasted that of the edge-space foraging H. larvatus. Isotopic niche dimensions of open-space foraging bats were smaller than those of the edge-space foraging bat. Based on isotopic data, we inferred that open-space foraging bats foraged mostly on dipterans which may fly or drift to higher altitudes where these bats hunt. In contrast, H. larvatus included mostly beetles from C4food webs in their diet, highlighting that this species is an important predator of pest insects of C4crops, namely cane sugar and corn. Our study emphasizes that the unstructured aerosphere in which open-space foraging bats hunt insects may promote a large overlap in the diet of these species. We conclude that mechanisms other than trophic niche differentiation, such as the motion capacity of bat species, both in terms of covered distances and accessed altitudes may facilitate the coexistence of high-altitude foraging bats. [ABSTRACT FROM AUTHOR]

To investigate divergences of ecological spatial niche dimensions, we evaluated if lizards Tropidurus hispidus and T. semitaeniatus used or selected structural (types of microhabitat and perch heights) and thermal resources (microhabitat temperatures and levels of sunlight) in ways that could ease living in syntopy. Most T. hispidus and T. semitaeniatus used rocks, resulting in a high overlap of structural niche dimensions. The former used such microhabitats according to the environmental availability and the latter selected rocks. Tropidurus hispidus selected shadier and colder microhabitats than T. semitaeniatus that selected warmer sites with full sunlight. Tropidurus semitaeniatus occupied regions further from vegetation shelters than from rock shelters. Larger T. semitaeniatus moved farther away from shelters than smaller individuals. Tropidurus hispidus perched higher than T. semitaeniatus. Distinctions regarding the use of spatial resources effectively reduced the overlaps of ecological niche dimensions, segregating the species and easing the life in syntopy. [ABSTRACT FROM AUTHOR]

Aim: Dispersal and subsequent adaptation to local environmental and climatic conditions play major roles in the evolution and current‐day distribution of plants and animals, but their relative importance is not always easy to disentangle. The aim of this study was to provide a comprehensive phylogenetic analysis of the terrestrial orchid genus Cypripedium to better understand the role of niche evolution and historical dispersal events in driving the radiation of the genus in North America and Eurasia. Location: Northern Hemisphere. Taxon: Cypripedium (Orchidaceae). Methods: We used a relaxed molecular clock analysis to infer phylogenetic relationships among 45 Cypripedium species and to estimate divergence times. Niche modelling was used to assess the potential distribution of each species in both continents, whereas ancestral area reconstructions using BioGeoBEARS were used to estimate changes in historical biogeography. Subsequently, the ancestral state of niche conditions was assessed for each species using maximum likelihood methods and we tested for phylogenetic signal in the evolution of niche conditions using Blomberg's K and Pagel's λ. A mantel test was used to test for a correlation between phylogenetic distances and niche overlap in Cypripedium. Results: We found that Cypripedium originated in Central America and underwent multiple dispersal events between North America and Eurasia after long‐distance seed dispersal or dispersal via the Bering land bridge. The mountainous area of Southwest China provided refuge areas for Cypripedium orchids during episodes of increased glaciation. Our results further showed that Cypripedium has gradually increased its tolerance to seasonal temperature changes, providing evidence for significant niche evolution through time. No significant correlation between current niches and phylogenetic relatedness was observed. Main conclusions: Our study provides clear evidence that repeated dispersal and adaptation to increased cooling after the Eocene−Oligocene Transition has contributed to the radiation of Cypripedium in the Northern Hemisphere. [ABSTRACT FROM AUTHOR]

Climate change will lead to extreme droughts, but it is difficult to predict how this will affect crop pests. In particular, it is unclear how interactions between natural enemies and pests will be influenced. In the field, bird cherry‐oat aphids (Rhopalosiphum padi (L.)) have been observed to reside close to, or below the ground surface during dry conditions. We hypothesized that this will increase the niche overlap between R. padi and ground‐dwelling predators such as carabid beetles and wolf spiders and that aphid numbers will therefore decline during dry conditions. A fully factorial mesocosm experiment was conducted testing the combined effects of drought and predator presence on aphid position and abundance on barley (Hordeum vulgare) plants. In support of our hypothesis, we found that (a) aphids moved below ground during dry conditions, (b) predators reduced aphid numbers, but only during dry conditions, and (c) predators reduced the proportion of aphids below ground in dry conditions. This increased predation effect during dry conditions was, however, compensated for by a corresponding increase in aphid performance on the plants and so the net effect of drought on aphid numbers ended up being neutral. Thus, pests can be affected by drought in complex ways via a combination top‐down and bottom‐up mechanisms. Predicting how pest populations will be affected by droughts in the future is thus a formidable research challenge. [ABSTRACT FROM AUTHOR]

Resource competition is an important interaction that can structure ecological communities, but is difficult to demonstrate in nature, and rarely demonstrated for large mammals including marsupials. We analysed 10 years of population survey data to investigate resource competition between bare-nosed wombats (Vombatus ursinus) and eastern grey kangaroos (Macropus giganteus) at two sites to assess whether resource competition is occurring. At one site, wombat abundance was reduced by increased mortality from mange disease, whereas at the other site, kangaroo abundance was reduced primarily by culling. We used the modified Lotka–Volterra competition (LVC) models to describe the mechanism of resource competition and fitted those models to the empirical data by maximum likelihood estimation. We found strong negative relationships between the abundance of wombats and kangaroos at each site, and resource competition was also mechanistically supported by the modified LVC models. The estimated competition coefficients indicate that bare-nosed wombats are a slightly superior competitor of eastern grey kangaroos than vice versa, and that intraspecific competition is almost twice as strong as interspecific competition. In addition, this study facilitated the calculation of the transmission rate associated with mange disease at one site (0.011), and the removal rate owing to culling, the introduction of a predator species, and drought at the other site (0.0006). Collectively, this research represents a rare empirical demonstration of resource competition between large mammals and contributes new insight into the ecology of two of Australia's largest grazing marsupials. [ABSTRACT FROM AUTHOR]

Aim: The plant species sharing ancestors now disjunctly distributed in eastern Asia (EAS) and eastern North America (ENA) have long been a biogeographic puzzle. Species within the EAS–ENA disjunct genera are presumed to exhibit niche conservatism, the tendency of closely related species to be more ecologically similar, reflecting lineages' common evolutionary history. However, the hypothesis has not been well examined at the species level. Location: EAS and ENA. Time period: Current. Major taxa studied: Species within the EAS–ENA disjunct genera. Methods: We compiled data on climate, species occurrence, growth form, and phylogeny to examine niche conservatism. We first built a phylogenetic tree to select intercontinental congeneric pairwise species and obtained their divergence times. We then quantified the observed niche overlaps with Schoener's D, which has a 0–1 range, based on species occurrence and climate of species' native ranges. To obtain projected distributions, each species' niche was projected to the non‐native region using ensemble ecological niche models. Projected‐related niche overlaps were then calculated using projected distributions and the corresponding climatic conditions. Results: Average observed niche overlaps of congeneric pairwise species were relatively small:.124,.211 and.109 for all, herbaceous and woody species, respectively. Both observed and projected‐related niche overlaps had significant negative relationships with divergence times of intercontinental congeneric pairwise species, with niche overlap for herbaceous species being higher than that for woody plants when controlling for divergence times. Main conclusions: We conclude that the significant negative relationships between niche overlap and divergence times of congeneric pairwise species confirm niche conservatism among species of EAS–ENA disjunct plants and that the extent of niche conservatism is slightly different for herbaceous and woody plants. These findings suggest the potential role of allopatric speciation in EAS, and could help to understand the evolutionary history and the Asian‐bias diversity pattern of the EAS–ENA disjunct plants. [ABSTRACT FROM AUTHOR]

Copyright of Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales is the property of Academia Colombiana de Ciencias Exactas, Fisicas y Naturales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Phytophthora cinnamomi is among the most destructive plant pathogens that affect many host plants in different ecosystems. Economically important hosts of this pathogen include avocado (Persea americana), and this oomycete may cause large-scale destructive epidemics. This study analyzed the potential geographic distribution of P. cinnamomi (pathogen) and avocado (host), and distribution of the pathogen in relation to multiple hosts in the Americas. Niche overlap between hosts and pathogen were also evaluated, using a multistep process of ecological niche modelling and the MaxEnt algorithm. Niche similarity among pathogen populations in different hosts and related niche similarity were also examined. As a complement, a tool was designed to visualize the risk of this pathogen in avocado. Results showed that the pathogen was randomly distributed in the avocado niche environmental space, but the niche of the pathogenwas narrower than that of its principal host. The niche of the pathogen was largely a function of the host niches. Areas with potential to grow avocado could present low risk of P. cinnamomi, but given the invasiveness of this pathogen, they may be affected in the future.

Ecological (isotopic) niche refers to a surface in a two-dimensional space, where the axes correspond to environmental variables that reflect values of stable isotopes incorporated in an animal's tissues. Carbon and nitrogen stable isotope ratios (δ13C-δ15N) notably provide precious information about trophic ecology, resource and habitat use, and population dynamics. Various metrics allow for isotopic niche size and overlap assessment. In this paper, we advocate α-minimum convex polygons (MCP) - that have long been used for home range estimation – as a relevant tool for isotopic niche size, overlap, and characteristics. The method allows for outlier rejection while being suited to data that are not Gaussian in the bivariate isotopic (δ13C-δ15N) space. The proposed indicators are compared to other existing approaches and are shown to be complementary. Notably an indicator of divergence within the niche is introduced, and allows for comparisons at low (n > 6) and different sample sizes. The R code is made publicly available and will enable ecologists to perform isotopic niche comparison, contraction and expansion assessment, and overlap, based on various methods.

Neotropical savannas have undergone continuous processes of landscape transformation (e.g., agriculture, oil, gas, and hydrocarbon industry) and very little is known about the ecology and natural history of key biological groups such as terrestrial mammals while the information on behavioral aspects of mammalian species in these ecosystems is very scarce. Here, we aimed to describe the activity patterns of medium and large mammals in two savanna ecosystems in the Colombian Llanos. A set of 60 camera traps was installed in the two ecosystems for 35 days (2100 camera days). We described the activity patterns of nine predominantly nocturnal species. We found no difference in circadian distributions of mammals between ecosystems. Cuniculus paca Linnaeus 1758 and Dasyprocta fuliginosa Wagler 1832 showed patterns of exclusion probably due to competition whereas other species like Tamandua tetradactyla Linnaeus1758 and Myrmecophaga tridactyla Linnaeus 1758 displayed similar activity patterns. We highlight the importance of savannas for the conservation of these species and discuss the relevance of studies on activity patterns for mammal ecology and conservation in Neotropical savannas.

Discoglossus pictus is a North African amphibian that was introduced in southern France early the 20th century and has spread south and north along the Mediterranean coastal plains up to 170 km. In order to disentangle the conservation implications of the spread of D. pictus for sensitive native species, we examined the impact of long-term climate warming on the basis of niche overlap analysis, taking into account abiotic factors. The study area covered the distribution ranges of all genus Discoglossus species in northwestern Africa (659,784 km2), Sicily (27,711 km2), the Iberian Peninsula, and southern France (699,546 km2). Niche overlap was measured from species environmental spaces extracted via PCA, including climate and relief environmental variables. Current and future climatic suitability for each species was assessed in an ensemble-forecasting framework of species distribution models, built using contemporary species data and climate predictors and projected to 2070′s climatic conditions. Our results show a strong climatic niche overlap between D. pictus and native and endemic species in the Iberian Peninsula. In this context, all species will experience an increase in climatic suitability over the next decades, with the only exception being Pelodytes punctatus, which could be negatively affected by synergies between global warming and cohabitation with D. pictus.

A growing number of cases of the spread and establishment of non-native species outside their previously known ranges has been reported in recent years. Here we report new distributional records of Lepturges (Lepturges) limpidus Bates, 1872 (Cerambycidae) from Argentina and investigate whether these records could represent established populations. We constructed ellipsoid envelope models to characterize climatic niches of L. limpidus, identified areas of climatic suitability, investigated the status of new records as climatic outliers, and evaluated its dependency on its known hostplant as a limiting factor for the beetle distribution. Results indicate widespread climatic suitability in the Neotropical Region, and new records are not outliers with regard to the climatic profile of L. limpidus. Association with its known hostplant is non-dependent, indicating that the species might utilize different hosts plants. New records likely represent established populations, but targeted surveys should be carried out to detect new arrivals and enable the installation of mitigation and control measures.

Niche theory is significant for understanding the function of community structure, interspecific relationships, and community dynamic succession. However, there are few studies on the soil animal niche in returning farmland to forest areas on the Loess Plateau, making it challenging to comprehend the utilization of soil animal resources, the stability of the local community, and the succession process in the areas. Therefore, this study collected soil animals in five typical vegetation types: Robinia pseudoacacia (R), Hippophae rhamnoides (H), Populus simonii (P), Pinus tabulaeformis (T), and Armeniaca sibirica x Hippophae rhamnoides (M), with abandoned grassland (G) used as a control group. Then, the number of soil animal taxa, individuals, diversity, and niche were sampled and examined in the study areas during the four seasons of spring, summer, autumn, and winter using the manual sorting method and the Tullgren method. The results revealed that 3872 soil animals from 3 Phyla, 8 Classes, 22 Orders, and 49 Families were captured in the study areas. The dominant groups of soil macrofauna were Diptera larvae, Julidae, and Formicidae, and the dominant groups of meso–micro soil fauna were Oribatida, Protospira, and Collembola juveniles. Soil animals have rich nutritional function groups, with the most saprophytic soil animal groups. The individual density and taxa number of soil animals in G were lower than other vegetation on the whole. H, M, and P had a higher Shannon–Winner index than the other vegetation. Seasonal changes had different effects on macro and meso–micro soil fauna. The diversity of soil macrofauna is higher in spring and summer, and that of meso–micro soil fauna is higher in autumn and winter. Oribatida, Diptera Larvae, and Formicidae had a large niche width in the main taxa of soil animals, with universal adaptability to the environment. Cicadellidae and Culicidae had narrow niche widths and were highly dependent on resources and the environment. There were 67 pairs of highly overlapped (Oik > 0.8) taxa of soil animals and 56 pairs of moderately overlapped (0.6 < Oik ≤ 0.8) taxa, accounting for 80.39% of the total number of taxa. Soil animals had high commonality in resource utilization, intense competition, and poor community stability. As a result, we can conclude that the soil animal community in the study areas was in the stage of succession.

The cross-species transmission (CST) of pathogens can have dramatic consequences, as highlighted by recent disease emergence events affecting human, animal and plant health. Understanding the ecological and evolutionary factors that increase the likelihood of disease agents infecting and establishing in a novel host is therefore an important research area. Previous work across different pathogens, including rabies virus (RABV), found that increased evolutionary distance between hosts reduces the frequency of cross-species transmission and of permanent host shifts. However, whether this effect of host relatedness still holds for transmission among recently diverged hosts is not well understood. We aimed to ask if high host relatedness can still increase the probability of a host shift between more recently diverged hosts, and the importance of this effect relative to ecological predictors. We first addressed this question by quantifying the CST frequency of RABV between North American bat species within the genus Myotis, using a multi-decade data set containing 128 nucleoprotein (N) RABV sequences from ten host species. We compared RABV CST frequency within Myotis to the rates of CST between nine genera of North American bat species. We then examined whether host relatedness or host range overlap better explains the frequency of CST seen between Myotis species. We found that at the within genus scale, host range overlap, rather than host relatedness best explains the frequency of CST events. Moreover, we found evidence of CST occurring among a higher proportion of species, and CST more frequently resulting in sustained transmission in the novel host in the Myotis dataset compared to the multi-genus dataset. Our results suggest that among recently diverged species, the ability to infect a novel host is no longer restricted by physiological barriers but instead is limited by physical contact. Our results improve predictions of where future CST events for RABV might occur and clarify the relationship between host divergence and pathogen emergence.

The study of niche and interspecific relationships is one of the classical ecological theories. We set up four desertification gradients. The “Levins” and “Pianka” method were used to calculate the species’ niche breadth and niche overlap. Interspecies associations were analyzed by the ratio of variance (VR), Chi-square test, association coefficient (AC) and Ochiai index (OI). The results showed that in grasslands with different degrees of desertification, Stellera chromosome (3.90), Thermopsis lanceolate (3.52) and Aster almanacs (3.99) had larger niche widths, which were wide-area species of plant communities in the desertification area. The ecological niches of the same species in different habitats or different species in the same habitat were multi-dimensional. Niche differentiation measured by niche overlap can occur at any community succession stage. Niche width and niche overlap were not always consistent with environmental changes. Moreover, there was no linear relationship between them. The interspecific connection coefficient fluctuated greatly with the environment. The results can provide a reference for the study of plant community competition mechanism and desertification control in desertification land of the study area. We still do not know the mechanism of how the plants were preserved and how the retained plants adapted to the new environment during the desertification process. We can further study these questions in the next step.

Background: Zelkova schneideriana Hand.-Mazz., is an endangered species mainly distributed in subtropical China. Currently, little is known about its niche and interspecific association. Questions: What are the niche characteristics of Z. schneideriana and other associated species? What are the interspecific associations between these species? Study sites and dates: Z. schneideriana communities in Jiangsu, China in 2019. Methods: Twenty-one 400 m2 plots were studied for importance value, niche breadth and overlap, interspecific association of Z. schneideriana communities. Results: In 39 species of tree layer, Z. schneideriana had the greatest importance value and niche breadth. For the first 10 dominant species, a considerable difference was detected by the Levins index (1.75 - 19.84) and Shannon-Wiener index (0.77 - 3.02). Forty-four out of the 45 species pairs had the value of niche similarity indices ≤ 0.5; 38 species pairs had the value of niche overlap indices ≤ 0.5. Overall interspecific association was not a significantly negative association for variance ratio < 1. χ2 test and Spearman’s correlation coefficient further revealed that above 60 % of species pairs had negative associations, suggesting most dominant species were slightly associated with other species or even independent. Conclusions: Z. schneideriana was a constructive species. Dissimilarity in environmental requirements was found among most dominant tree species, thus decreasing competition. This is likely due to the unstable community in the early stage of succession.

Copyright of Journal of Zhejiang University (Science Edition) is the property of Journal of Zhejiang University (Science Edition) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Sebangau National Park is a major stronghold for Bornean Orangutan (Pongo pygmaeus wurmbii) ranging from 6000 - 9000 individuals. In comparison with Bornean Orangutans, very little ecological fieldwork has been conducted to investigate sun bear biology, and there have been no thorough surveys of distribution or population densities. Thus, this study aimed to investigate the basic information on niche overlap between these two endangered species, specifically to quantify their relationship within the small-scale habitat in Punggualas area, SNP. Data was collected and measured during 15 - 21 June 2019; using line transects methods. A total of 6580 m was walked along 8 consecutive transects. Bear and aging sign follow Augeri protocols. A total 18 printed mark-claw and 17 Orangutan nests was measured according to the mentioned methodology. The relationships between signs use binary logistic regressions (StatPlus for Mac) and PCA model (using R), while interspecific relationships use Co-Occurrence modeling, ESP for Windows. The results showed that there is no difference between bear sign and orangutan nest (2: 26.249; df :1, p-value: 0.001); While the results on habitat selection between transects is failed to reject the null hypothesis (2 = 0.29; df :1, p-value: 0.490). The Mann-Whitney U test, also confirmed no distinctive overlap between the Orangutan and the Sun Bear (Z: 0.84; p-value: 0.40). The co-occurrence simulations also revealed significant results (C-Score = 1.00), by means both target animals co-existed in the habitat. Obviously, the Orangutan and Sun Bear occupy the same habitat. There is no distinctive overlap between them in terms of tree species selection and having a close interrelationship in terms of feeding ground, whereas the fruiting is not available. The only distinctive difference is that the Bear sign was tend hindering waterlogged terrain. [ABSTRACT FROM AUTHOR]

Background: Malaria is often persistent in communities surrounded by mosquito breeding habitats. Anopheles gambiae sensu lato exploit a variety of aquatic habitats, but the biotic determinants of its preferences are poorly understood. This study aimed to identify and quantify macroinvertebrates in different habitat types with determined water physico-chemical parameters to establish those preferred by An. gambiae s.l. larvae as well as their predators and competitors. Methods: A field survey was conducted in Kibuye and Kayonjo villages located in the vicinity of the River Sezibwa, north-eastern Uganda to identify Anopheline larval habitats shared by aquatic insects. Habitats were geo-recorded and as streams, ponds, temporary pools and roadside ditches. From October to December 2017, random microhabitats/quadrats were selected from each habitat type, their water physico-chemical parameters (electrical conductivity, total dissolved solids, temperature and pH) were measured, and they were sampled for macroinvertebrates using standard dippers. All collected arthropod macroinvertebrates were then morphologically identified to family level and enumerated. Results: Principal component analysis showed that the four larval habitat types were characterized by distinct physico-chemical parameter profiles. Ponds and streams had the highest number and diversity of macroinvertebrate insect taxa and sustained few An. gambiae s.l. larvae. Anopheles gambiae s.l. were more common in roadside ditches and particularly abundant in temporary pools which it commonly shared with Dytiscidae (predaceous diving beetles) and Culex spp. Cluster correlation analysis conducted on the abundance of these taxa within quadrats suggested that An. gambiae s.l. and Dytiscidae have the most similar patterns of microhabitat use, followed by Cybaeidae (water spiders). Whilst Culex spp. co-occurred with An. gambiae s.l. in some habitats, there was only partial niche overlap and no clear evidence of competition between the two mosquito taxa. Conclusions: Ponds and streams are habitats that host the largest diversity and abundance of aquatic insect taxa. Anopheles gambiae s.l. larvae distinctively preferred temporary pools and roadside ditches, where they were exposed to few predators and no apparent competition by Culex spp. Further studies should aim to test the impact of Dytiscidae and Cybaeidae on An. gambiae s.l. dynamics experimentally. [ABSTRACT FROM AUTHOR]

The family Profundulidae is a group of small‐sized fish species distributed between southern Mexico and Honduras, where they are frequently the only fish representatives at higher elevations in the basins where they occur. We characterized their ecological niche using different methods and metrics drawn from niche modelling and by re‐examining phylogenetic relationships of a recently published molecular phylogeny of this family to gain a better understanding of its biogeographic and evolutionary history. We assessed both lines of evidence from the perspective of niche conservatism to set a foundation for discussing hypotheses about the processes underlying the distribution and evolution of the group. In fish clades where the species composition is not clear, we examined whether niche classification could be informative to discriminate groups geographically and ecologically consistent with any of the different hypotheses of valid species. The characterization of the ecological niche was carried out using the Maxent algorithm under different parameterizations and the projection of the presence on the main components of the most relevant environmental coverage, and the niche comparison was calculated with two indices (D and I), both in environmental space and in that projected geographically. With the molecular data, a species tree was generated using the *BEAST method. The comparison of these data was calculated with an age‐overlap correlation test. Based on the molecular phylogeny and on niche overlap analyses, we uncovered strong evidence to support the idea that ecologically similar species are not necessarily sister species. The correlation analysis for genetic distance and niche overlap was not significant (P > 0.05). In clades with taxonomic conflicts, we only identified Profundulus oaxacae as a geographically and ecologically distinct group from P. punctatus. All the evidence considered leads us to propose that Profundulidae do not show evidence of niche conservatism and that there are reasons to consider P. oaxacae as a valid species. Our study suggests that niche divergence is a driving evolutionary force that caused the diversification and speciation processes of the Profundulidae, along with the geological and climatic events that promoted the expansion or contraction of suitable environments. [ABSTRACT FROM AUTHOR]

Nelsonia is an extant genus of North American woodrats, in which most of the biological information remains unknown. Only N. neotomodon and N. goldmani are recognized inhabiting in similar temperate environments. Recently, a biogeographic hypothesis for the genus pointed out that Nelsonia after diverging from Repomys or Protorepomys in the Californian-Rocky Mountains in USA, the Mexican highlands in Mexico played a significant role in how the two species of Nelsonia became established in two different mountain ranges: N. neotomodon in the Sierra Madre Occidental and N. goldmani in the Transmexican Volcanic Belt. However, no other evidence exists about the biogeographic history of both species that improve the explanation about how past climate events affected their distribution, as well as whether the current environmental space occupied by both species are similar such as previous studies have argued. Therefore, this study aimed to characterize the environmental niche of both species, to test environmental differences, overlap, equivalence, and niche similarity, and lastly, to build their current niche model and paleodistribution for three past scenarios: Pliocene, Last Interglacial, and Last Glacial Maximum. The results revealed significant differences in niche centroid, low niche overlap, and no niche equivalence or similarity, suggesting niche divergence. The current niche suitability showed that the two species have small and restricted potential habitats highlighting the need to reevaluate the current international conservation category of N. neotomodon. The paleodistribution suggested that both species of Nelsonia have contractions and expansions of niche suitability in the past. [ABSTRACT FROM AUTHOR]

South American rodents of the genus Ctenomys (tuco-tucos) occupy the underground environment, present high specificity to loose and friable soils and have restricted mobility, with a generally fragmented distribution. We use species distribution models (SDMs) in two Ctenomys species from the Atlantic coast and continental areas of Argentina. We develop SDMs using Maxent software for Ctenomys australis and Ctenomys talarum, which coexist in a narrow coastal landscape with restricted distributions. We model the potential distributions of both species using, first, bioclimatic variables (Group 1), and second, Landsat 8 bands and granulometric layers (Group 2). According to the known distributions of the species, the Group 2 variables showed the greatest accuracy for inferring their potential distributions. The most important variables for predicting habitat suitability were, primarily, the majority of granulometric variables and some Landsat 8 bands such as the bands 4 and 5, related to the vegetation cover. We also analyze the level of overlapping niches between these two species, and we found that there is a certain degree of geographical overlap between them, and also present ecologically similar niches, despite the fact that the characteristics of their habitats differ in certain aspects. We conclude that in tuco-tucos species, their potential distributions are better predicted by variables that consider the particular characteristics of soils and cover vegetation, since they are specialized species of substrates. Also, a higher spatial resolution allows a better performance of the Ctenomys species models, which was expected for species with restricted distributions. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

European honey bees have been introduced across the globe and may compete with native bees for floral resources. Compounding effects of urbanization and introduced species on native bees are, however, unclear. Here, we investigated how honey bee abundance and foraging patterns related to those of native bee abundance and diversity in residential gardens and native vegetation remnants for 2 years in urbanized areas of the Southwest Australian biodiversity hotspot and assessed how niche overlap influenced these relationships. Honey bees did not overtly suppress native bee abundance; however, complex relationships emerged when analysing these relationships according to body size, time of day and floral resource levels. Native bee richness was positively correlated with overall honeybee abundance in the first year, but negatively correlated in the second year, and varied with body size. Native bees that had higher resource overlap with honey bees were negatively associated with honey bee abundance, and resource overlap between honey bees and native bees was higher in residential gardens. Relationships with honey bees varied between native bee taxa, reflecting adaptations to different flora, plus specialization. Thus, competition with introduced bees varies by species and location, mediated by dietary breadth and overlap and by other life-history traits of individual bee species. [ABSTRACT FROM AUTHOR]

Copyright of Biotropica is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Biological invasion is one of the important reasons for the decline of freshwater biodiversity in China and even in the world. The Pearl river basin is one of the most threatened areas in China by biological invasion. Over the past four decades, mrigal carp Cirrhinus mrigala and rohu Labeo rohita have invaded the Pearl river. They potentially pose a huge threat to a well-known economic species, native mud carp Cirrhinus molitorella. However, little is known about the likely habitat distributions of these two invasive species, which limits our management of them. In this study, we detected the stable isotope ratios of nitrogen and carbon for fish and quantified their niche overlap with nicheROVER in R. The result showed that the individuals of two invasive species had a higher probability to be found in niche region of native C. molitorella (i.e., 65 % for C. mrigala and 74 % for L. rohita). Moreover, to increase understanding of their habitat distributions and potential range of spread, the existing habitats data of these three fish species obtained from previous literatures and the high-resolution bioclimatic parameters from WorldClim were analyzed via Maxent model. The results stressed that niche overlap was high among species, which could have an impact on local biodiversity in future. Furthermore, the visualization of habitat distributions could help show the dynamic habitat changes of invasive and native species over time, while also provide new insights into the subsequent prevention and control for invasive species in other river regions around the world. • Studying the niche overlap between fish species via nicheROVER. • Maxent can visualize the habitat distributions of fish in rivers. • Unknown invasive species may also cause serious harm to environments. [ABSTRACT FROM AUTHOR]

40% of the land global surface and deliver significant ecosystem services. These regions are the most sensitive, prone to suffer the effects of climate and distribution changes, so estimates on projected range shifts are crucial to complement traditional approaches to biodiversity conservation and sustainability. Shrubs of the Monte Desert dominate the largest temperate dryland in South America. Our goal is to assess the spatial distribution and niche overlap of three native shrubs (Larrea cuneifolia (LC), L. divaricata (LD), and L. nitida (LN)), under present climate conditions, to retrodict their potential past distribution, and anticipate their predicted range under future climate scenarios. We used ecological niche modeling that were projected to the past (LGM and Mid Holocene) and future (2050 and 2070) under two scenarios of greenhouse gas emissions and two model of global circulation. All species have high niche overlap (67–89%), but showed species-specific responses, highlighting the need to develop mitigation measures particularly for LD and LN in the face of climate change and land use pressures. Global South deserts are being highly degraded and information on future potential ranges of endemic species can support the development of sustainable conservation and management plans. • Drylands are threatened by the effects of climate changes. • Monte desert plants suffer climatic uncertainty and are prone to range shifting. • Ecological niches of three creosote bush Larrea species resulted species-specific. • Two species would severely reduce range by 2070 and a third one will remain stable. • Mitigation measures in the face of climate change and land use pressures are needed. [ABSTRACT FROM AUTHOR]