1,131 results on '"Defaunation"'
Search Results
2. Changes in guanaco distribution from Late Holocene to present times in Northwest Patagonia: connecting archaeological, ethnohistoric and current data.
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Moscardi, Bruno F., Vilariño, Martín, D'Abramo, Sergio L., Sosa Pfatschbacher, Luis, Bernal, Valeria, Rindel, Diego D., and Perez, S. Ivan
- Abstract
Context: The guanaco (Lama guanicoe) is one of the four species of South American camels, and is the largest native mammal inhabiting arid and semi-arid environments in South America. Although the guanaco was abundant and widely distributed in the past, currently its density and distribution range are substantially reduced, inhabiting mainly Southern Patagonia in small isolated groups. The decline in guanaco populations is most likely related to the Anthropocene defaunation process that is affecting large mammals in developing countries worldwide, but the extent and causes of these changes are not well understood. Aims: To explore both the changes in the distribution of guanaco populations in Northwest Patagonia and the environmental and anthropic factors that shaped the distribution patterns, by employing a long-term perspective spanning from the end of the Late Holocene to present times (i.e. the last 2500 years). Methods: We combine archaeological information, ethnohistorical records and current observations and apply Species Distribution Models using bioclimatic and anthropic factors as explanatory variables. Key results: Guanaco spatial distribution in Northwest Patagonia changed significantly throughout time. This change consisted in the displacement of the species towards the east of the region and its disappearance from northwest Neuquén and southwest Mendoza in the last 30 years. In particular, the high-density urban settlements and roads, and secondly, competition with ovicaprine livestock (goats and sheep) for forage are the main factors explaining the change in guanaco distribution. Conclusions: Guanaco and human populations co-existed in the same areas during the Late Holocene and historic times (16th to 19th centuries), but during the 20th century the modern anthropic impact generated a spatial dissociation between both species, pushing guanaco populations to drier and more unproductive areas that were previously peripheral in its distribution. Implications: As with many other large mammal species in developing countries, Northwest Patagonia guanaco populations are undergoing significant changes in their range due to modern anthropic activities. Considering that these events are directly related to population declines and extirpations, together with the striking low density recorded for Northwest Patagonia guanaco populations, urgent management actions are needed to mitigate current human impacts. The guanaco is the largest native mammal inhabiting arid and semi-arid South American environments, with current density and distribution ranges substantially reduced. Combined lines of evidence model how and why distribution changed in the last 2500 years in Northwest Patagonia, showing guanaco populations pushed to drier, unproductive areas of the east by recent urbanization and livestock practices. Like large mammals in developing countries worldwide, guanacos are threatened by modern human activities, so urgent measures are needed to mitigate impacts. Image by Bruno F. Moscardi and S. Ivan Perez. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Overlooked Bird Extinctions in Semideciduous Atlantic Forests.
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Cavarzere, Vagner and Silveira, Luís Fábio
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ENDEMIC species , *FIELD research , *TWENTIETH century , *CITIZEN science , *DEFORESTATION - Abstract
The semideciduous forest is a prominent yet highly degraded phytophysiognomy within the Atlantic Forest. Historically, bird species inhabiting these forests occurred throughout central and western São Paulo state, south‐eastern Brazil, until the mid‐20th century. Many of these species have not been observed again or are nearing extinction within the state's inland forest fragments. This study reviews and compares historical and recent ornithological records, using museum specimens, literature, citizen science and recent field surveys to understand these species' current lack of records. In the early 20th century, extensive deforestation occurred statewide, resulting in the current forest fragments, which are currently in various stages of regeneration, conservation and isolation. Many of these fragments lack the specific habitats some species require, or they have not been recolonised due to insufficient connectivity with other forest fragments where these species still exist (particularly in the eastern Atlantic Forest). The non‐detection of forest species in semideciduous forest fragments strongly suggests an unprecedented and largely unnoticed extinction scale. This pattern of defaunation, as predicted 30 years ago, may be prevalent across numerous Semideciduous Atlantic Forests in Brazil. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Exposing illegal hunting and wildlife depletion in the world's largest tropical country through social media data.
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El Bizri, Hani R., Oliveira, Marcela A., Rampini, Aline Pessutti, Knoop, Simon, Fa, Julia E., Coad, Lauren, Morcatty, Thais Queiroz, Massocato, Gabriel Favero, Desbiez, Arnaud L. J., Campos‐Silva, João Vitor, La Laina, Daniel Zani, Duarte, José Maurício Barbanti, Barboza, Rafael Sá Leitão, Campos, Zilca, da Silva, Marcélia Basto, Mângia, Sarah, Ingram, Daniel J., and Bogoni, Juliano A.
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HUNTING , *WILDLIFE conservation , *ANIMAL populations , *WILDLIFE crimes , *NATIVE species , *BIOMES - Abstract
Globally, illegal sport hunting can threaten prey populations when unregulated. Due to its covert nature, illegal sport hunting poses challenges for data collection, hindering efforts to understand the full extent of its impacts. We gathered social media data to analyze patterns of illegal sport hunting and wildlife depletion across Brazil. We collected data for 2 years (2018–2020) across 5 Facebook groups containing posts depicting pictures of illegal sport hunting events of native fauna. We described and mapped these hunting events by detailing the number of hunters involved, the number of species, the mean body mass of individuals, and the number and biomass of individuals hunted per unit area, stratified by Brazilian biome. We also examined the effects of defaunation on hunting yield and composition via regression models, rank–abundance curves, and spatial interpolation. We detected 2046 illegal sport hunting posts portraying the hunting of 4658 animals (∼29 t of undressed meat) across all 27 states and 6 natural biomes of Brazil. Of 157 native species targeted by hunters, 19 are currently threatened with extinction. We estimated that 1414 hunters extracted 3251 kg/million km2. Some areas exhibited more pronounced wildlife depletion, in particular the Atlantic Forest and Caatinga biomes. In these areas, there was a shift from large mammals and reptiles to small birds as the main targeted taxa, and biomass extracted per hunting event and mean body mass across all taxonomic groups were lower than in other areas. Our results highlight that illegal sport hunting adds to the pressures of subsistence hunting and the wild meat trade on Brazil's wildlife populations. Enhanced surveillance efforts are needed to reduce illegal sport hunting levels and to develop well‐managed sustainable sport hunting programs. These can support wildlife conservation and offer incentives for local communities to oversee designated sport hunting areas. [ABSTRACT FROM AUTHOR]
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- 2024
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5. The irreplaceable role of surviving megafauna in long‐distance seed dispersal: evidence from an experiment with Neotropical mammals.
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Giombini, Mariano I., Pésole, Diana, Benítez, Anuncio Daniel, Costa, Sebastián A., Fernando Foletto, L., Esteban Pizzio, C., Dip Yordanoff, Ana L., Genoveva Gatti, M., and Di Bitetti, Mario S.
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SEED dispersal , *RF values (Chromatography) , *SEED viability , *ANIMAL mechanics , *FRUGIVORES , *PALMS - Abstract
The downsizing of disperser assemblages by selective defaunation is a worldwide phenomenon thought to have important consequences in animal‐dispersed plants. Numerous large‐seeded Neotropical plants currently depend on the last megafaunal survivors, the large tapirs Tapirus spp., and medium‐sized frugivores. The extent to which medium frugivores are functionally equivalent to tapirs remains unresolved. We combined feeding trials, seed dispersal kernel modeling based on seed retention times and animal movement simulation (Levy walks), and germination experiments in a large‐seeded palm to assess the dispersal quality provided by the largest (tapirs) and two medium (foxes and howler monkeys) frugivore species in terms of dispersal distances and gut passage effects on germination. Tapirs retained the seeds in the gut for much longer (mean = 221 hours) than howlers (43 h) and foxes (22 h). Median dispersal distance by tapirs (1252 m) was 14 and 40 times larger than that by foxes (88 m) and howlers (31 m), respectively. The seed dispersal kernel of tapirs showed a 5th percentile value (291 m) larger than the 95th percentiles of foxes (285 m) and howlers (108 m). Manually depulped and gut‐passed seeds germinated in similar proportions, showing, respectively, 3.5 and 2.5–2.9 times higher values than intact fruits. Germination probability and seed viability decreased with retention time in howlers' and tapirs' gut, with howlers showing a steeper negative relationship. Such detrimental effect implies a trade‐off between germination success and dispersal distance. We conclude that tapirs may not play a unique role in germination enhancement but move seeds much further than medium frugivores, thus playing a critical role as long‐distance dispersers of many plants. This study provides important insights on palm–frugivore interactions and the potential consequences for large‐seeded plants of losing the last megafaunal representatives in the Neotropics. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Rapid urbanization declined mammals and mammal-mediated seed dispersal in a megacity, central China.
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Zhao, Hengyue, Chen, Zhiwen, Zhang, Min, Niu, Hongyu, and Zhang, Hongmao
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SEED dispersal ,GRANIVORES ,CITIES & towns ,FOREST degradation ,INFRARED cameras - Abstract
Rapid urbanization has caused a series of environmental problems, but its influences on animal-related ecological functions (e.g., seed dispersal) have not been fully studied. Mammals are ideal models for studying the functional consequences of urbanization because they are sensitive to environmental changes. It is well known that large- and medium-sized mammals are vulnerable in fragmentation ecosystem. However, little is known about the functional responses of small mammals (e.g., rodents) to the rapid urbanization. Using infrared cameras and tagged seeds, here, we quantified mammals and mammal-mediated seed dispersal (i.e., Quercus variabilis) in 11 forest patches along city-suburb-exurban gradient in a rapidly urbanizing megacity, central China. We wanted to determine the effects of defaunation on seed dispersal in the isolated urban forests. The results showed that abundance of seed dispersers was higher in the natural exurban forests than in the city forests, while abundance of seed predators did not vary significantly along the city-suburb-exurban gradient. The percentage of seed dispersal was positively associated with the abundance seed dispersers, while the percentage of seed predation increased with the abundance of seed predators. Seed dispersers loss (e.g., small rodents) disrupted the mammal-mediated seed dispersal, possibly contributing to the degradation of urbanized forests. These results suggest that defaunation effects are obvious in the rapidly urbanizing cities, in that abundance of seed dispersers, and mammal-mediated seed dispersal are undergoing decline in the urbanized forests. In order to maintain seed dispersal and natural regeneration of urban forests, diversity of small mammals (e.g., rodents) and their ecological services should be considered in ecological-based urban planning and management. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Turnover and connectivity as drivers of mammalian persistence in highly fragmented landscapes
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Mayara Guimarães Beltrão, Maria Luisa S.P. Jorge, Ana Paula Carmignotto, Luís Fábio Silveira, and Mauro Galetti
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Beta-diversity ,Defaunation ,Landscape attributes ,Pernambuco Endemism Center ,Space use ,Ecology ,QH540-549.5 - Abstract
Pernambuco Endemism Center (PEC) stands as the Brazilian Atlantic Forest region with the most pronounced history of deforestation and forest fragmentation, attributed to early European colonization and agricultural settlement. As a result, PEC is known as the global tropical forest experiencing both the highest fragmentation levels and extinction rates. The extent of biodiversity loss and the factors associated with biodiversity persistence at PEC remain a knowledge gap. To address this gap, we evaluated how forest cover, fragmentation and other landscape features are related to the mammal’s persistence. Using baited camera traps, we sampled 21 landscapes dominated by hostile matrices in Alagoas. We examined the relationship between species composition, richness, abundance, and beta-diversity and seven predictors through Generalized Linear Models and Multiple Regressions on Distance Matrices. Our findings revealed the presence of 21 native mammals in the study area, representing nearly 78 % of the diversity expected for the PEC. Nevertheless, we also found a high proportion of species loss within each landscape (from 43 % to 76 %), and high levels of species turnover between landscapes. Considering landscapes metrics, mammals exhibited more pronounced responses to habitat fragmentation in contrast to habitat loss or other anthropogenic factors. We identified a positive relationship between connectivity and richness, while the number of patches negatively affected the abundance. Our results underscore the critical role of habitat connectivity in highly deforested and fragmented regions, where it becomes more important than forest cover. The pronounced species turnover is key in upholding regional diversity and is crucial to species persistence in the region.
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- 2024
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8. Insights from 20 years of mammal population research in Indonesia
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Ardiantiono, Irene M.R. Pinondang, Desy S. Chandradewi, Gono Semiadi, Freddy Pattiselanno, Jatna Supriatna, Johny S. Tasirin, Nurul L. Winarni, Maria Voigt, Joseph W. Bull, Tatyana Humle, Nicolas J. Deere, and Matthew J. Struebig
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Biodiversity loss ,capacity building ,defaunation ,Indonesia ,population monitoring ,Southeast Asia ,species conservation ,tropics ,General. Including nature conservation, geographical distribution ,QH1-199.5 - Abstract
Mammal populations are declining in biodiverse tropical regions. Global analyses have identified Indonesia as a hotspot of vertebrate decline, although relatively few data are available to substantiate these claims. We reviewed research articles published during 2000–2020 on 104 medium-sized to large terrestrial mammal species found in Indonesia to help inform conservation management and future research. We identified 308 peer-reviewed studies published in English or Bahasa Indonesia, with an increase in publication rate (articles published per year) over time. Studies of species distributions dominated the literature, followed by publications on abundance, species diversity and combinations of these topics. Most publications concerned single-species studies conducted at a single location and a single point in time. We identify four key issues that should be addressed by future research and conservation efforts: (1) disproportionate focus on a small number of species; (2) geographical bias towards west Indonesia (Sumatra, Kalimantan and Java–Bali), with few published studies from central (Sulawesi, Nusa Tenggara and Maluku) and east (Papua) Indonesia; (3) limitations to survey design, sampling effort and data analysis; and (4) lack of long-term wildlife population studies. We also note challenges local researchers face in publishing their studies in international journals because of language barriers and costs. Greater use of existing biodiversity data and continued capacity building for local researchers, particularly those in central and east Indonesia, are critical to effectively guide future wildlife monitoring and improve the conservation status of Indonesian mammals.
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- 2024
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9. Dispersal‐related plant traits are associated with range size in the Atlantic Forest.
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Petrocelli, Isis, Alzate, Adriana, Zizka, Alexander, and Onstein, Renske E.
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PLANT dispersal , *SEED dispersal by animals , *ENDANGERED species , *FOREST plants , *TROPICAL forests , *BROMELIACEAE - Abstract
Aim: The efficiency of animal‐mediated seed dispersal is threatened by the decline of animal populations, especially in tropical forests. We hypothesise that large‐seeded plants with animal‐mediated dispersal tend to have limited geographic ranges and face an increased risk of extinction due to the potential decline in seed dispersal by large‐bodied fruit‐eating and seed‐dispersing animals (frugivores). Location: Atlantic Forest, Brazil, South America. Taxon: Angiosperms. Methods: First, we collected dispersal‐related traits (dispersal syndrome, fruit size, and seed size), growth form (tree, climber, and other) and preferred vegetation type (open and closed) data for 1052 Atlantic Forest plant species. Next, we integrated these with occurrence records, extinction risk assessments, and phylogenetic trees. Finally, we performed phylogenetic generalised least squares regressions to test the direct and interactive effects of dispersal‐related traits and vegetation type on geographical range size. Results: Large‐seeded species had smaller range sizes than small‐seeded species, but only for species with animal‐mediated dispersal, not for those dispersed by abiotic mechanisms. However, plants with abiotic dispersal had overall smaller range sizes than plants with animal‐mediated dispersal. Furthermore, we found that species restricted to forests had smaller ranges than those occurring in open or mixed vegetation. Finally, at least 29% of the Atlantic Forest flora is threatened by extinction, but this was not related to plant dispersal syndromes. Main Conclusions: Large‐seeded plants with animal‐mediated dispersal may be suffering from dispersal limitation, potentially due to past and ongoing defaunation of large‐bodied frugivores, leading to small range sizes. Other factors, such as deforestation and fragmentation, will probably modulate the effects of dispersal on range size, and ultimately extinction. Our study sheds light on the relationship between plant traits, mutualistic interactions, and distribution that are key to the functioning of tropical forests. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Updated list of mammals of the Island of Santa Catarina, southern Brazil
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Barbara Lima-Silva, Jorge J. Cherem, Paula Ribeiro-Souza, Camila R. Ayroza, Theo C.G. Mees, Sérgio L. Althoff, Maurício T.P. Bueno, Artur Stanke-Sobrinho, José O. Silva-Júnior, José S.R. Pires, and Maurício E. Graipel
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Atlantic Forest ,defaunation ,extinct species ,inventory ,isolation ,invasive species ,Zoology ,QL1-991 - Abstract
ABSTRACT The Island of Santa Catarina is the largest island on the Brazilian coast. Within the Atlantic Forest domain, it serves as a model for investigating the decline in biodiversity within this ecosystem. This decline is associated with the loss of a large part of forest cover and mammalian species. Although the forest environment in the island has recovered more in comparison to the rest of the Atlantic Rainforest (66% versus 28%, respectively), the isolation typical of islands has hindered the recolonization of sensitive species, particularly those that are threatened. Two decades after the first publication of the mammal list of the Island of Santa Catarina, we revised past data to identify which species became extinct and which native and exotic species remain, focusing on the inclusion of Chiroptera. Through bibliographical reviews, scientific collections and field surveys, a total of 59 species of native mammals, non-volant and volants, were confirmed. Among these, eight species were determined to be extirpated, all threatened with extinction, including large ungulates and top cats, in addition to the occurrence of nine domestic and exotic invasive species. Studies employing specific methodologies and sampling techniques in inadequately assessed environments have the potential to augment species richness, particularly among rodents, marsupials, and bats.
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- 2024
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11. Drivers and spatial patterns of avian defaunation in tropical forests.
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Ferreiro‐Arias, Iago, Santini, Luca, Sagar, H. S. Sathya Chandra, Richard‐Hansen, Cécile, Guilbert, Eric, Forget, Pierre‐Michel, Kuijk, Marijke, Scabin, Andressa B., Peres, Carlos A., Revilla, Eloy, and Benítez‐López, Ana
- Abstract
Aim Location Methods Results Main Conclusions Wildlife overexploitation, either for food consumption or for the pet trade, is one of the main threats to bird species in tropical forests. Yet, the spatial distribution and intensity of harvesting pressure on tropical birds remain challenging to quantify. Here, we identify the drivers of hunting‐induced declines in bird abundance and quantify the magnitude and the spatial extent of avian defaunation at a pantropical scale.Pantropical.We compiled 2968 abundance estimates in hunted and non‐hunted sites across the tropics spanning 518 bird species. Using a Bayesian modelling framework, we fitted species' abundance response ratios to a set of drivers of hunting pressure and species traits. Subsequently, we applied our model to quantify the spatial patterns of avian defaunation across tropical forests and to assess avian defaunation across biogeographic realms, and for species captured for the pet trade or for food consumption.Body mass and its interactions with hunter accessibility and proximity to urban markets were the most important drivers of hunting‐induced bird abundance declines. We estimated a mean abundance reduction of 12% across the tropics for all species, and that 43% of the extent of tropical forests harbour defaunated avian communities. Large‐bodied species and the Indomalayan realm displayed the greatest abundance declines. Further, moderate to high levels of defaunation extended over 24% of the pantropical forest area, with distinct spatial patterns for species captured for the pet trade (Brazil, China and Indonesia) and for food consumption (SE Asia and West Africa).Our study emphasizes the role of hunter accessibility and the proximity to urban markets as major drivers of bird abundance declines due to hunting and trapping. We further identified hotspots where overexploitation has detrimental effects on tropical birds, encompassing local extinction events, thus underscoring the urgent need for conservation efforts to address unsustainable exploitation for both subsistence and trade. [ABSTRACT FROM AUTHOR]
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- 2024
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12. The Restructuring of Ecological Networks by the Pleistocene Extinction.
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Pires, Mathias Mistretta
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BIOLOGICAL extinction , *PLEISTOCENE Epoch , *FOOD chains , *SPECIES diversity , *NUTRIENT cycles , *ECOSYSTEMS , *CONTINENTS , *HERBIVORES - Abstract
Most terrestrial large mammals went extinct on different continents at the end of the Pleistocene, between 50,000 and 10,000 years ago. Besides the loss in species diversity and the truncation of body mass distributions, those extinctions were even more impactful to interaction diversity. Along with each extinction, dozens of ecological interactions were lost, reorganizing species interaction networks, which attained species-poor configurations with low functional redundancy. Extinctions of most large herbivores impacted energy flow and the rates of nutrient cycling, reconfiguring ecosystem-level networks. Because large mammals have high mobility, their loss also shortened seed-dispersal distance and reduced nutrient diffusivity, disrupting spatial networks. This review examines the recent advances in understanding how different types of ecological networks have been restructured by megafaunal extinctions and how this reorganization affected ecosystem functions. Megafaunal extinctions resulted in the loss of multiple ecological interactions in terrestrial systems. Interaction loss reshaped different types of ecological networks including food webs and spatial networks. The reorganization of ecological networks changed how terrestrial ecosystems are structured and function. [ABSTRACT FROM AUTHOR]
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- 2024
- Full Text
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13. Ground‐dwelling mammal and bird diversity in the southern Annamites: Exploring complex habitat associations and the ghost of past hunting pressure.
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Nguyen, An, Tilker, Andrew, Le, Duy, Niedballa, Jürgen, Pflumm, Luisa, Pham, Xuan Hoan, Le, Van Son, Luu, Hong Truong, Tran, Van Bang, Kramer‐Schadt, Stephanie, Sollmann, Rahel, and Wilting, Andreas
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MAMMAL diversity , *BIRD diversity , *BROADLEAF forests , *POPULATION viability analysis , *CONIFEROUS forests , *HABITATS , *ROADKILL , *BIRD classification - Abstract
The Langbian Plateau, a biodiversity hotspot in the southern Annamites of Viet Nam, has undergone extensive hunting pressure. However, the limited information on the effects of overexploitation on the current status and community composition of wildlife hinders effective conservation efforts, including the implementation of targeted patrols to reduce snaring. In this study, we conducted a camera‐trapping survey across the Langbian Plateau, consisting of a broadleaf evergreen and coniferous habitat mosaic. We recorded 46 ground‐dwelling mammals and birds, including several threatened Annamite endemics. Using multi‐species Royle‐Nichols model and landscape covariates, we found higher richness in broadleaf evergreen forest located in more remote and less rugged areas. We then used species responses to covariates to predict species distribution and identify high‐priority areas for conservation. Furthermore, we constructed diversity profiles that indicated higher biodiversity in broadleaf evergreen forest compared to the coniferous forest. Finally, we used a dissimilarity index to assess the level of defaunation, revealing 16% of the community had been lost, with higher levels of defaunation for threatened and larger‐sized species. Our findings provide insights into the status, distribution, and occurrence of the ground‐dwelling mammal and bird communities in the Langbian Plateau, and can help stakeholders design more effective conservation strategies to protect existing populations. [ABSTRACT FROM AUTHOR]
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- 2024
- Full Text
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14. Global disparity of camera trap research allocation and defaunation risk of terrestrial mammals
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Badru Mugerwa, Jürgen Niedballa, Aimara Planillo, Douglas Sheil, Stephanie Kramer‐Schadt, and Andreas Wilting
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Camera trap research ,conservation ,defaunation ,monitoring ,research geographic bias ,terrestrial mammals ,Technology ,Ecology ,QH540-549.5 - Abstract
Abstract Quantifying and monitoring the risk of defaunation and extinction require assessing and monitoring biodiversity in impacted regions. Camera traps that photograph animals as they pass sensors have revolutionized wildlife assessment and monitoring globally. We conducted a global review of camera trap research on terrestrial mammals over the last two decades. We assessed if the spatial distribution of 3395 camera trap research locations from 2324 studies overlapped areas with high defaunation risk. We used a geospatial distribution modeling approach to predict the spatial allocation of camera trap research on terrestrial mammals and to identify its key correlates. We show that camera trap research over the past two decades has not targeted areas where defaunation risk is highest and that 76.8% of the global research allocation can be attributed to country income, biome, terrestrial mammal richness, and accessibility. The lowest probabilities of camera trap research allocation occurred in low‐income countries. The Amazon and Congo Forest basins – two highly biodiverse ecosystems facing unprecedented anthropogenic alteration – received inadequate camera trap research attention. Even within the best covered regions, most of the research (64.2%) was located outside the top 20% areas where defaunation risk was greatest. To monitor terrestrial mammal populations and assess the risk of extinction, more research should be extended to regions with high defaunation risk but have received low camera trap research allocation.
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- 2024
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15. Enhancing Sheep Rations: Optimal Ammoniated Palm Fronds Utilization with Lerak Fruit (Sapindus Rarak) and Probiotic Supplementation
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Essy Laura, Mardiati Zain, and Fauzia Agustin
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ammoniated ,defaunation ,in vivo digestibility ,probiotics ,sapindus rarak ,Agriculture - Abstract
This study aimed to assess the impact of lerak fruit and probiotic supplementation on varying levels of ammoniated palm fronds in sheep rations, as well as to determine the optimal inclusion rate of ammoniated palm fronds in the presence of lerak fruit and probiotics. Employing an experimental approach, a Latin Square Design was utilized, with four sheep as rows, four periods as columns, and four rations as treatments. Treatments included: A) 50% field grass + concentrate, B) 20% field grass + 30% ammoniated palm fronds + 50% concentrate + lerak fruit + probiotics, C) 10% field grass + 40% ammoniated palm fronds + 50% concentrate + lerak fruit + probiotics, and D) 0% field grass + 50% ammoniated palm fronds + 50% concentrate + lerak fruit + probiotics. Results indicated significant differences (P0.05) were observed in the digestibility of dry and organic matter. These findings suggest that supplementation with up to 40% ammoniated palm fronds in sheep rations, probiotics, and lerak fruit yielded comparable digestibility and livestock performance as the control. This study provides valuable insights into optimizing sheep rations with alternative feed ingredients, contributing to enhanced animal nutrition practices.
- Published
- 2024
- Full Text
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16. Constraints on avian seed dispersal reduce potential for resilience in degraded tropical forests.
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Hatfield, Jack H., Banks‐Leite, Cristina, Barlow, Jos, Lees, Alexander C., and Tobias, Joseph A.
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FOREST regeneration , *FOREST degradation , *TROPICAL forests , *SEED dispersal , *FOREST resilience , *LANDSCAPE assessment , *SECONDARY forests - Abstract
Seed dispersal is fundamental to tropical forest resilience. Forest loss or degradation typically leads to defaunation, altering seed transfer dynamics and impairing the ability of forested habitats to regenerate or recover from perturbation. However, the extent of defaunation, and its likely impacts on the seed dispersers needed to restore highly degraded or clear‐felled areas, remains poorly understood in tropical forest landscapes.To quantify defaunation of seed‐dispersing birds, we used field survey data from 499 transects in three forested regions of Brazil, first comparing the observed assemblages with those predicted by geographic range maps, and then assessing habitat associations of frugivores across land cover gradients.We found that current bird assemblages have lower functional diversity (FD) than predicted by species range maps in Amazonia (4%–6%), with a greater reduction in FD (28%) for the Atlantic Forest, which has been more heavily deforested for a longer period.Direct measures of seed dispersal are difficult to obtain, so we focused on potential seed transfer inferred from shared species occurrence. Of 83 predominantly frugivorous bird species recorded in relatively intact forests, we show that 10% were absent from degraded forest, and 57% absent from the surrounding matrix of agricultural land covers, including many large‐gaped species. Of 112 frugivorous species using degraded forest, 47% were absent from matrix habitats. Overall, frugivores occurring in both intact forest and matrix habitats were outnumbered by (mostly small‐gaped) frugivores occurring in both degraded forest and matrix habitats (23 additional species; 64% higher diversity).These findings suggest that birds have the potential to disperse seeds from intact and degraded forest to adjacent cleared lands, but that direct seed transfer from intact forests is limited, particularly for large‐seeded trees. Degraded forests may play a vital role in supporting natural regeneration of small‐seeded tree species as well as providing a 'stepping‐stone' in the regeneration pathway for large‐seeded trees. We propose that both intact and degraded forests will support the restoration potential of tropical forest landscapes, and that bird‐assisted seed dispersal can be enhanced by maintaining buffer zones of degraded or secondary forests around remaining intact forest patches. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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17. Global disparity of camera trap research allocation and defaunation risk of terrestrial mammals.
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Mugerwa, Badru, Niedballa, Jürgen, Planillo, Aimara, Sheil, Douglas, Kramer‐Schadt, Stephanie, and Wilting, Andreas
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MAMMAL populations ,WILDLIFE monitoring ,BIODIVERSITY monitoring ,ENDANGERED species ,LOW-income countries - Abstract
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- 2024
- Full Text
- View/download PDF
18. Updated list of mammals of the Island of Santa Catarina, southern Brazil.
- Author
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Lima-Silva, Barbara, Cherem, Jorge J., Ribeiro-Souza, Paula, Ayroza, Camila R., Mees, Theo C. G., Althoff, Sérgio L., Bueno, Maurício T. P., Stanke-Sobrinho, Artur, Silva-Júnior, José O., Pires, José S. R., and Graipel, Maurício E.
- Abstract
The Island of Santa Catarina is the largest island on the Brazilian coast. Within the Atlantic Forest domain, it serves as a model for investigating the decline in biodiversity within this ecosystem. This decline is associated with the loss of a large part of forest cover and mammalian species. Although the forest environment in the island has recovered more in comparison to the rest of the Atlantic Rainforest (66% versus 28%, respectively), the isolation typical of islands has hindered the recolonization of sensitive species, particularly those that are threatened. Two decades after the first publication of the mammal list of the Island of Santa Catarina, we revised past data to identify which species became extinct and which native and exotic species remain, focusing on the inclusion of Chiroptera. Through bibliographical reviews, scientific collections and field surveys, a total of 59 species of native mammals, non-volant and volants, were confirmed. Among these, eight species were determined to be extirpated, all threatened with extinction, including large ungulates and top cats, in addition to the occurrence of nine domestic and exotic invasive species. Studies employing specific methodologies and sampling techniques in inadequately assessed environments have the potential to augment species richness, particularly among rodents, marsupials, and bats. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
19. Influence of two defaunating agents and defaunation intervals on milk profile and selected serum parameters in lactating dairy goats in Egypt.
- Author
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Saber, M., Abdel-Salam, A. B., Abdelrahman, H. A., and Mousa, S. A.
- Subjects
- *
GOATS , *SODIUM dodecyl sulfate , *MILKFAT , *GOAT breeds , *MILK , *BREEDING - Abstract
Impact of defaunation (removal of protozoa from the rumen) on animal health and productivity is still controversial. This study quantified the effects of defaunation intervals using two defaunating agents; sodium lauryl sulfate (SLS) and dioctyl sodium sulfosuccinate (DSS), on serum and milk profiles in lactating goats. Ten apparently healthy female Egyptian native breed lactating goats were assigned into two experimental groups. The administration of both defaunating agents was carried out daily for the first three days of the experiment then once weekly for three consecutive weeks. The research samples were collected before defaunation, 7, 14, and 21 days post defaunation. Milk parameters were determined using milk lactometer and selected serum parameters were measured using specific kits. Generally, defaunation resulted in a significant decrease in milk fat, solid not fat, and salt%, with significant increment in serum calcium (Ca) and inorganic phosphorous (P). Serum Ca and albumin decreased significantly at 14 days than 21 days post defaunation. Serum inorganic P decreased significantly due to DSS than SLS and at 14 days than 7 days post defaunation. Milk profile was significantly undesirably influenced by using DSS more than SLS, and at time point of 14 days post defaunation. Defaunation using DSS or SLS for 14–21 days has a dramatically negative influence on milk profile. It is recommended not to use DSS for treatment of rumen bloat or indigestion in dairy goats. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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- View/download PDF
20. Landscape Influence on Leaf-Nosed Bats (Chiroptera: Phyllostomidae) and Potential of Arthropod Consumption in Brazilian Atlantic Forests.
- Author
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Oliveira, Sérgio L., Faria, Deborah M., and Cassano, Camila R.
- Abstract
Understanding the effects of habitat loss on communities is essential for biodiversity conservation and maintenance of ecosystem services. Considering that bats are efficient consumers of arthropods, including insects of economic interest, knowledge on how local and landscape factors influence bat assemblages may provide the basis for enhancement of key ecosystem functions, such as natural control for arthropods. Based on the species richness (total and insectivorous) and on the defaunation index (DI), defined as the loss or depletion of an animal species attribute, we investigated how the landscape can influence patterns of leaf-nosed bats and their potential of arthropod consumption in the Brazilian Atlantic Forest. We calculated species richness and DI using a compilation of bat records in the Atlantic Forest over 20 years (focal assemblages) and IUCN's potential occurrence polygons (reference assemblages used in DI). We quantified the vegetation cover, the dominant type and the heterogeneity of the matrix within circular landscapes around each sampling site of focal assemblages. One hundred and four assemblages were included in the analyses, most of them in the southeast of the Atlantic Forest, with agriculture as the dominant non-natural matrix. We found a negative effect of matrix heterogeneity on DI, and a positive effect of forest cover on the richness of insectivorous bats. The results highlight the importance of forest remnants in fragmented landscapes in the Brazilian Atlantic Forest for the maintenance of leaf-nosed bats and their potential for arthropod consumption. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
21. Guidelines for a Post-speciesist Epistemology in the Age of Anthropocene
- Author
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Ferrari, Héctor Ricardo, Anzoátegui, Micaela, and Weir, Lucy, editor
- Published
- 2023
- Full Text
- View/download PDF
22. Global Forest Biodiversity: Current State, Trends, and Threats
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Leuschner, C., Homeier, J., Lüttge, Ulrich, Series Editor, Cánovas, Francisco M., Series Editor, Pretzsch, Hans, Series Editor, Risueño, María-Carmen, Series Editor, and Leuschner, Christoph, Series Editor
- Published
- 2023
- Full Text
- View/download PDF
23. The late-Quaternary megafauna extinctions: Patterns, causes, ecological consequences and implications for ecosystem management in the Anthropocene
- Author
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Jens-Christian Svenning, Rhys T. Lemoine, Juraj Bergman, Robert Buitenwerf, Elizabeth Le Roux, Erick Lundgren, Ninad Mungi, and Rasmus Ø. Pedersen
- Subjects
defaunation ,prehistoric Homo sapiens ,megafauna extinctions ,Pleistocene climate ,trophic rewilding ,Evolution ,QH359-425 - Abstract
Across the last ~50,000 years (the late Quaternary) terrestrial vertebrate faunas have experienced severe losses of large species (megafauna), with most extinctions occurring in the Late Pleistocene and Early to Middle Holocene. Debate on the causes has been ongoing for over 200 years, intensifying from the 1960s onward. Here, we outline criteria that any causal hypothesis needs to account for. Importantly, this extinction event is unique relative to other Cenozoic (the last 66 million years) extinctions in its strong size bias. For example, only 11 out of 57 species of megaherbivores (body mass ≥1,000 kg) survived to the present. In addition to mammalian megafauna, certain other groups also experienced substantial extinctions, mainly large non-mammalian vertebrates and smaller but megafauna-associated taxa. Further, extinction severity and dates varied among continents, but severely affected all biomes, from the Arctic to the tropics. We synthesise the evidence for and against climatic or modern human (Homo sapiens) causation, the only existing tenable hypotheses. Our review shows that there is little support for any major influence of climate, neither in global extinction patterns nor in fine-scale spatiotemporal and mechanistic evidence. Conversely, there is strong and increasing support for human pressures as the key driver of these extinctions, with emerging evidence for an initial onset linked to pre-sapiens hominins prior to the Late Pleistocene. Subsequently, we synthesize the evidence for ecosystem consequences of megafauna extinctions and discuss the implications for conservation and restoration. A broad range of evidence indicates that the megafauna extinctions have elicited profound changes to ecosystem structure and functioning. The late-Quaternary megafauna extinctions thereby represent an early, large-scale human-driven environmental transformation, constituting a progenitor of the Anthropocene, where humans are now a major player in planetary functioning. Finally, we conclude that megafauna restoration via trophic rewilding can be expected to have positive effects on biodiversity across varied Anthropocene settings.
- Published
- 2024
- Full Text
- View/download PDF
24. Social and ecological drivers of illegal bird hunting in the Indawgyi wetland ecosystem in Myanmar.
- Author
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Htay, Thazin, Htoo, Kyaw Kyaw, Røskaft, Eivin, Ringsby, Thor Harald, and Ranke, Peter Sjolte
- Subjects
- *
FOWLING , *BIRD conservation , *AGRICULTURAL conservation , *WETLANDS , *POISONS , *BIRD classification , *DRIVERS' licenses - Abstract
Hunting and illegal bird killing are major concerns for avian conservation globally. Unsustainable bird hunting in wetland habitats, particularly those located along important flyways, has contributed to avifauna defaunation and species endangerment. Since wetlands are primary habitats for migratory birds and are associated with anthropogenic landscapes, a comprehensive understanding of bird harvesting, and its drivers is fundamental to reduce threats to current avifauna. In this study, we examined the distribution of illegal bird hunting and its socioecological drivers in the Indawgyi wetland ecosystem in Myanmar by integrating data from bird surveys, household surveys, and market surveys. We found that illegal bird hunting using nets, traps, and poisonous substances is prevalent in areas close to water and during the migration season. People who had negative attitudes toward avian species were more likely to engage in bird hunting, primarily because of the conflicts between bird conservation and crop production. Socioeconomic needs were not the major driving factors of bird killing. We therefore suggest sustainable management interventions promoting coexistence by integrating bird conservation and agricultural production, accompanied by increasing awareness to improve avian conservation in an internationally important wetland in Myanmar. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
25. Situating defaunation in an operational framework to advance biodiversity conservation.
- Author
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Poulsen, John R, Maicher, Vincent, Malinowski, Halina, and DeSisto, Camille
- Subjects
- *
BIODIVERSITY conservation , *ANIMAL communities , *BIOLOGICAL extinction , *ANIMAL species , *ECOSYSTEMS , *ANIMAL populations , *DEFORESTATION - Abstract
Anthropogenic pressures are causing the widespread loss of wildlife species and populations, with adverse consequences for ecosystem functioning. This phenomenon has been widely but inconsistently referred to as defaunation. A cohesive, quantitative framework for defining and evaluating defaunation is necessary for advancing biodiversity conservation. Likening defaunation to deforestation, we propose an operational framework for defaunation that defines it and related terms, situates defaunation relative to intact communities and faunal degradation, and encourages quantitative, ecologically reasonable, and equitable measurements. We distinguish between defaunation , the conversion of an ecosystem from having wild animals to not having wild animals, and faunal degradation , the process of losing animals or species from an animal community. The quantification of context-relevant defaunation boundaries or baselines is necessary to compare faunal communities over space and time. Situating a faunal community on the degradation curve can promote Global Biodiversity Framework targets, advancing the 2050 Vision for Biodiversity. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
26. Enhancing ecological connectivity through biodiversity offsets to mitigate impacts on habitats of large mammals in tropical forest environments.
- Author
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Sales Rosa, Josianne Claudia, Campos, Pedro Bueno Rocha, Nascimento, Caroline Bianca, Souza, Barbara Almeida, Valetich, Rebeca, and Sánchez, Luis Enrique
- Subjects
- *
ENVIRONMENTAL impact analysis , *TROPICAL forests , *HABITATS , *ECOLOGICAL impact , *FRAGMENTED landscapes , *ENVIRONMENTAL degradation - Abstract
Habitat loss and fragmentation are ecological impacts of development projects known to have severe effects on mammals' populations. Here, we study the role of connectivity assessment in Environmental Impact Assessment, focusing on its contribution to determining appropriate mitigation, in particular, biodiversity offsetting. For that purpose, we analysed the dispersal of large mammals in a region potentially influenced by a mine located in the Atlantic rainforest in Brazil and anticipate the long-term outcomes of restoration offsets by modelling a 30-year post-offset scenario. Results show that: (i) offsets enhance ecological connectivity and are used as an alternative habitat for the animals dispersed due to habitat loss and fragmentation; (ii) the location of restoration areas should be carefully planned to maximize their contribution to increase ecological connectivity and enhance habitat quality. The reviewed case suggests that best practices to incorporate connectivity analysis in environmental impact assessment include: (i) monitoring biodiversity to quantify losses and gains; (ii) modelling offset areas alternatives for both protection and restoration; and (iii) conducting rigorous analysis of project alternatives, aiming at impact avoidance. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
27. Assessing conservation status of remnant mammal populations in a Neotropical cloud forest
- Author
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Hoskins, Hannah, Reid, Neil, and Montgomery, William
- Subjects
conservation ,defaunation ,Honduras ,mammals ,deforestation ,habitat loss - Abstract
Neotropical cloud forests are some of the most biodiverse and yet threatened ecosystems. Terrestrial mammals play key roles delivering numerous ecosystem services within such systems including seed dispersal and nutrient cycling. Yet like the habitat in which they reside, some mammal species are also highly threatened; sensitive to deforestation and hunting. Protected areas are a cornerstone of conservation policy and National Parks have notionally one of the highest status designations, yet in many instances such designation may not be effective in conserving biodiversity. This study assessed the efficacy of Cusuco National Park in preserving Neotropical cloud forest mammal fauna in northwest Honduras, Central America. A comprehensive list of all non-volant mammal species was assembled, reflecting a highly biodiverse ecosystem. The park’s more protected core zone was more biodiverse with high mammal abundance than its less protected buffer zone. Species Distribution Models (SDMs) suggested that anthropogenic pressures were the principal driving factors in determining species ranges throughout the park rather than local environmental variation. General Additive Models (GAMs) were used to assess temporal trends in mammal populations revealing all groups, most notably large hunted species, declining dramatically in recent years with near complete mammalian defaunation of the park predicted as early as the mid-2020s. Analysis of camera trapping surveys indicated that large mammalian species detections were negatively associated with proximity to scientific research stations. Additionally smaller species were negatively associated with proximity to survey transects used for monitoring and surveillance of mammal tracks and signs. These results suggest a need for conservationists to be mindful of the impact of their activities on the systems they aim to protect. Analysis of satellite imagery captured widespread deforestation within the park with the highest rates of loss in recent years. Under ‘business-as-usual’ it is predicted that 20% of forest within the park will be lost by 2040. Areas of greatest forest cover are most likely to be lost especially in the northeast of the park’s buffer zone. Spatial predictions of the probability of both mammal occurrence and deforestation risk should empower government, law enforcement, forest managers and conservation organisations to target conservation resource investment into enforcing legal protections in-and-around villages associated with greatest risk of illegal activities.
- Published
- 2020
28. The Violent Narrowing of Animal Life.
- Author
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Weis, Tony
- Subjects
- *
LIVESTOCK productivity , *ENVIRONMENTAL degradation , *LIVESTOCK growth , *CLIMATE change , *HABITATS , *LOW-calorie diet - Abstract
Mainstream environmentalism has long prioritized wild animals and their habitats while paying little attention to the explosive growth of global livestock production and consumption. However, this blind spot to livestock is changing quickly, in large part because of the rising general awareness of the resource and emissions intensity of animal-based foods and how it relates the interwoven crises of climate change and biodiversity loss. This paper considers both the fertile ground for animal advocacy to be found in the mounting scientific evidence about environmental inefficiencies of animal-based foods, and the need to be attentive to the risks it bears. The principal danger of efficiency-centred narratives is that if they are largely focused on climate change and biodiversity loss, the goal of reducing relative associated impacts can appear in a way that helps to further stoke the growth of industrially produced birds, which should be understood in relation to the already well-established poultrification of global livestock supply and demand. This paper highlights the importance of challenging this partial lens and response, and stresses the need to connect macro-scale environmental concerns to critical reflection about the ways that animal lives are organized in industrial livestock production. The concern for declining wild animal populations among environmentalists is a key lever for this, as industrial livestock can be shown to bear on the loss and fragmentation of habitats while at the same condemning a large and growing share of all birds and mammals to a short and agonizing existence. What emerges is an indelible image of a pathological mode of production that is violently narrowing how other animals get to inhabit the earth. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
29. Responses of ground-dwelling birds and mammals to local environmental variables and human pressure in an Amazonian protected area.
- Author
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Brocardo, Carlos R., Rosa, Dian C. P., Castro, Arlison B., Rosa, Clarissa, Torralvo, Kelly, Pequeno, Pedro, Magnusson, William E., and Fadini, Rodrigo F.
- Subjects
GAME & game-birds ,LEAF area index ,PROTECTED areas ,MAMMALS ,WILDLIFE management ,UNGULATES - Abstract
Vertebrates play key roles as seed dispersers, herbivores, and top predators in tropical ecosystems. Therefore, obtaining population estimates for these species and understanding the factors that affect them are essential for wildlife management since changes in their populations have consequences for entire ecosystems. Vertebrate abundances in tropical forest may be related to habitat characteristics, resource seasonality, and human pressure. However, how ecological variables and human pressure concurrently influence animal abundances is not well understood. We investigated the associations between the number of records of vertebrates (ground-dwelling birds and medium- and large-sized mammals) and habitat features, food availability, and human pressure in a sustainable protected area in the Brazilian Amazon of western Pará, Brazil. Our study design included the recording of animals at 38 camera trap stations, sampling of environmental variables (canopy cover, leaf area index, tree height, and local altitude) and food resources (fruit or prey biomass), and measurement of a hunting pressure proxy (distance from human settlements). Our results indicated that groups responded in different ways: omnivorous mammals were affected positively by local altitude, canopy openness, and leaf area index; game birds were affected positively by local altitude and leaf area index; ungulates were affected negatively by local altitude and positively by food resources; and large rodents were affected only by food resources (positively). In contrast, insectivorous mammals and mesopredators were not affected by any variable we tested. Surprisingly, no groups responded to distance from human access, although the low number of records of large species, such Tapirus terrestris and Dicotyles tajacu, suggests that the sampled area may suffer from significant hunting pressure. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
30. The total dispersal kernel: a review and future directions.
- Author
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Rogers, Haldre S, Beckman, Noelle G, Hartig, Florian, Johnson, Jeremy S, Pufal, Gesine, Shea, Katriona, Zurell, Damaris, Bullock, James M, Cantrell, Robert Stephen, Loiselle, Bette, Pejchar, Liba, Razafindratsima, Onja H, Sandor, Manette E, Schupp, Eugene W, Strickland, W Christopher, and Zambrano, Jenny
- Subjects
Defaunation ,dispersal vector ,frugivore ,mathematical modeling ,seed dispersal ,seed dispersal effectiveness ,total dispersal kernel ,total effective dispersal kernel ,wind ,Plant Biology - Abstract
The distribution and abundance of plants across the world depends in part on their ability to move, which is commonly characterized by a dispersal kernel. For seeds, the total dispersal kernel (TDK) describes the combined influence of all primary, secondary and higher-order dispersal vectors on the overall dispersal kernel for a plant individual, population, species or community. Understanding the role of each vector within the TDK, and their combined influence on the TDK, is critically important for being able to predict plant responses to a changing biotic or abiotic environment. In addition, fully characterizing the TDK by including all vectors may affect predictions of population spread. Here, we review existing research on the TDK and discuss advances in empirical, conceptual modelling and statistical approaches that will facilitate broader application. The concept is simple, but few examples of well-characterized TDKs exist. We find that significant empirical challenges exist, as many studies do not account for all dispersal vectors (e.g. gravity, higher-order dispersal vectors), inadequately measure or estimate long-distance dispersal resulting from multiple vectors and/or neglect spatial heterogeneity and context dependence. Existing mathematical and conceptual modelling approaches and statistical methods allow fitting individual dispersal kernels and combining them to form a TDK; these will perform best if robust prior information is available. We recommend a modelling cycle to parameterize TDKs, where empirical data inform models, which in turn inform additional data collection. Finally, we recommend that the TDK concept be extended to account for not only where seeds land, but also how that location affects the likelihood of establishing and producing a reproductive adult, i.e. the total effective dispersal kernel.
- Published
- 2019
31. Low species turnover of upland Amazonian birds in the absence of physical barriers.
- Author
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Rutt, Cameron L., Cooper, W. Justin, Andretti, Christian B., Costa, Thiago V. V., Stouffer, Philip C, Vargas, Claudeir F., Luther, David A., and Cohn‐Haft, Mario
- Subjects
- *
BIOTIC communities , *UPLANDS , *BIRD communities , *URBAN growth , *BIRD surveys , *HABITATS , *SPECIES diversity - Abstract
Aim: One of the oldest and most powerful ways for ecologists to explain distinct biological communities is to invoke underlying environmental differences. But in hyper‐diverse systems, which often display high species richness and low species abundance, these sorts of community comparisons are especially challenging. The classic view for Amazonian birds posits that riverine barriers and habitat specialization determine local and regional community composition. We test the tacit, complementary assumption that similar bird communities should therefore permeate uniform habitat between major rivers, regardless of distance. Location: Upland (terra firme) rainforests of central Amazonia. Methods: We conducted intensive whole‐community surveys of birds in three pairs of 100‐ha plots, separated by 40–60 km. We then used dissimilarity indices, cluster analysis, and ordination to characterize differences among the six avian communities. Results: In all, we detected 244 forest‐dependent birds, with an average of 190 species (78%) per plot. Species turnover was negligible, no unique indicator species were found among plot pairs, and all documented species were already known from a complete inventory at one of the three sites. Main Conclusions: Our study corroborates the classic biogeographical pattern and suggests that turnover contributes little to regional avian diversity within upland forests. Using a grain size of 100 ha, this implies that upland birds perceive the environment as uniform, at least over distances of ~60 km. Therefore, to maximize both local species richness and population persistence, our findings support the conservation of very large tracts of upland rainforest. Our analyses also revealed that the avifauna at Reserva Ducke, encroached by urban sprawl from the city of Manaus, shows the hallmarks of a disturbed community, with fewer vulnerable insectivores. This defaunation signals that even an enormous preserve (10 × 10 km) in lowland Amazonia is not insulated from anthropogenic degradation within the surrounding landscape. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
32. How Does Changing Environment Influence Plant Seed Movements as Populations of Dispersal Vectors Decline?
- Author
-
Hernandez, Jonathan O., Naeem, Muhammad, and Zaman, Wajid
- Subjects
PLANT dispersal ,SEED dispersal ,EXTREME weather ,LIFE history theory ,PLANT diversity ,PHYTOGEOGRAPHY - Abstract
Plants differ widely in their ability to find tolerable climatic ranges through seed dispersal, depending on their life-history traits and habitat characteristics. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic review on seed dispersal mechanisms was conducted to elucidate plant seed movements amid changing environments. Here, the highest relative count of studies was found in Spain (16.47%), followed by Brazil (14.12%), and the USA (14.12%). The megadiverse, hotspot countries (e.g., Philippines, Vietnam, Myanmar, India, and Indonesia) and Africa (Tanzania, South Africa, Democratic Republic of the Congo) have very low to no data about the reviewed topic. The effects of land use changes, habitat degradation/disturbances, climate, and extreme weather conditions on seed dispersal mechanisms and agents had the highest share of studies across topics and countries. Plant diversity and distribution of anemochorous, endozoochorous, epizoochorous, hydrochorous, myrmecochorous, and ornithochorous species are seriously affected by changing environments due to altered long-distance seed dispersal. The fruit types commonly associated with endozoochory and ornithochory are species with achene, capsule, drupe, fleshy, and nut fruits/seeds, whereas achene, capsule, samara/winged seeds are associated with anemochory. The present review provides a summary of evidence on how plants are affected by climate change as populations of dispersal vectors decline. Finally, recommendations for further study were made based on the identified knowledge gaps. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
33. Seagrass ecosystem multifunctionality under the rise of a flagship marine megaherbivore.
- Author
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Christianen, Marjolijn J. A., Smulders, Fee O. H., Vonk, Jan Arie, Becking, Leontine E., Bouma, Tjeerd J., Engel, Sabine M., James, Rebecca K., Nava, Mabel I., de Smit, Jaco C., van der Zee, Jurjan P., Palsbøll, Per J., and Bakker, Elisabeth S.
- Subjects
- *
ECOSYSTEM services , *NUTRIENT cycles , *SEAGRASSES , *GREEN turtle , *ADAPTIVE natural resource management , *ECOSYSTEMS , *POSIDONIA , *OVERGRAZING - Abstract
Large grazers (megaherbivores) have a profound impact on ecosystem functioning. However, how ecosystem multifunctionality is affected by changes in megaherbivore populations remains poorly understood. Understanding the total impact on ecosystem multifunctionality requires an integrative ecosystem approach, which is especially challenging to obtain in marine systems. We assessed the effects of experimentally simulated grazing intensity scenarios on ecosystem functions and multifunctionality in a tropical Caribbean seagrass ecosystem. As a model, we selected a key marine megaherbivore, the green turtle, whose ecological role is rapidly unfolding in numerous foraging areas where populations are recovering through conservation after centuries of decline, with an increase in recorded overgrazing episodes. To quantify the effects, we employed a novel integrated index of seagrass ecosystem multifunctionality based upon multiple, well‐recognized measures of seagrass ecosystem functions that reflect ecosystem services. Experiments revealed that intermediate turtle grazing resulted in the highest rates of nutrient cycling and carbon storage, while sediment stabilization, decomposition rates, epifauna richness, and fish biomass are highest in the absence of turtle grazing. In contrast, intense grazing resulted in disproportionally large effects on ecosystem functions and a collapse of multifunctionality. These results imply that (i) the return of a megaherbivore can exert strong effects on coastal ecosystem functions and multifunctionality, (ii) conservation efforts that are skewed toward megaherbivores, but ignore their key drivers like predators or habitat, will likely result in overgrazing‐induced loss of multifunctionality, and (iii) the multifunctionality index shows great potential as a quantitative tool to assess ecosystem performance. Considerable and rapid alterations in megaherbivore abundance (both through extinction and conservation) cause an imbalance in ecosystem functioning and substantially alter or even compromise ecosystem services that help to negate global change effects. An integrative ecosystem approach in environmental management is urgently required to protect and enhance ecosystem multifunctionality. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
34. The empty forest three decades later: Lessons and prospects.
- Author
-
Bogoni, Juliano A., Percequillo, Alexandre R., Ferraz, Katia M. P. M. B., and Peres, Carlos A.
- Subjects
BIODIVERSITY ,RESOURCE exploitation ,EROSION - Abstract
The “Empty Forest” paradigm published three decades ago inspired studies on biodiversity erosion. Evidence to date continues pessimistic regarding the fate of wildlife. This calls for a more proactive approach by several societal actors to realign systems of resource exploitation with the goals of the Convention on Biological Diversity. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
35. Savanna vegetation increase triggers freshwater community shifts.
- Author
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Demare, Guillaume, Spieler, Marko, Grabow, Karsten, and Rödel, Mark‐Oliver
- Subjects
- *
COMMUNITIES , *SAVANNAS , *FRESH water , *AMPHIBIAN larvae , *LIFE history theory , *ECOSYSTEMS - Abstract
Tropical savannas are globally extensive and ecologically invaluable ecosystems. As most ecosystems however, they are subject to serious anthropogenic stress. Defaunation, and especially the loss of large mammals, is pervasive in tropical savannas and known to trigger wide‐ranging ecological effects, from vegetation changes to the loss of ecosystem function. Despite what is currently known about the terrestrial consequences of defaunation, and the potential cross‐ecosystem influence of large mammals, virtually no research has investigated associated effects on small adjacent water bodies. This research gap persists because (1) tropical savannas have been historically neglected, (2) the ecological value of small water bodies (e.g. ponds) is only recently being recognized, and (3) empirical baseline data are often lacking. In this paper, we compared a rare pre‐change dataset with newly collected data on 213 freshwater assemblages, to investigate community structure and composition before and after a major defaunation event. Our research focused on a diverse species assemblage of amphibian larvae (i.e. tadpoles) in temporary savanna ponds. We found that pond vegetation cover increased from 16.0% to 45.6% post‐defaunation, that is, a near three‐fold increase. Such habitat changes seemed to have benefitted those species that use vegetation during reproduction (e.g. the leaf‐folding Afrixalus spp.), while others have declined. Interestingly, we found a strong correlation between tadpole community shifts and other freshwater organisms, which indicates that habitat changes have affected a wide variety of aquatic organisms. Given that organisms inhabiting temporary aquatic habitats often have complex life histories with terrestrial adult life stages, we propose that the terrestrial effects of defaunation have indirectly led to distinct aquatic communities, in addition to direct habitat effects. These results shed new light on the potential role of large‐bodied mammals in shaping adjacent ecosystems, and raise important questions concerning the functioning of temporary aquatic systems in the Anthropocene. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
36. Frugivory and Seed Dispersal
- Author
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Corlett, Richard T., Del-Claro, Kleber, editor, and Torezan-Silingardi, Helena Maura, editor
- Published
- 2021
- Full Text
- View/download PDF
37. The role of trophic interactions in shaping tropical tree communities
- Author
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Hazelwood, Kirsten, Paine, C. E. Timothy, Vallejo-Marin, Mario, and Dent, Daisy
- Subjects
577.34 ,Negative Density Dependence ,Janzen-Connell ,Tropical Trees ,Tree Recruitment ,Defaunation ,Cocha Cashu ,Hunting ,Trophic Interactions ,Dispersal ,Fungal Pathogens ,Tree Communities ,Insect Herbivores ,Neotropics ,Seedlings ,Rainforests ,Forestry ecology ,Sustainable development ,Ecosystems - Abstract
Tropical rainforests contain exceptionally high biodiversity and account for >30% of the world's carbon fixed by photosynthesis. Consequently, there are compelling reasons to deepen our understanding of the mechanisms that maintain these highly diverse forests and of the potential long-term threats to their preservation. An important process shaping tropical plant communities is negative density dependence (NDD). NDD occurs when plant performance is negatively impacted by increased neighbourhood density. Reduced performance at high neighbourhood density is thought to arise through ecological interactions between plants and their natural enemies. Thus in a healthy ecosystem, trophic interactions play vital roles as mechanisms driving NDD and are important as dispersers facilitating escape from NDD mortality. However, interruption to ecological processes caused by human activities, such as hunting, can perturb NDD interactions and cause cascading effects throughout an ecosystem. In my thesis I investigate the role of dispersal and mortality in NDD dynamics of tropical tree communities, as well as investigating local and global impacts of removing ecological interactions in tropical rainforests. In my thesis, I begin by addressing the presence and variation in strength of NDD among tree species and ontogenetic stages, the mechanisms driving NDD, and the role of trophic interactions in this process. The Janzen-Connell hypothesis predicts that host-specific natural enemies drive NDD by selectively reducing conspecific density, and increase diversity by suppressing competitive exclusion, thus allowing heterospecifics to persist. In chapters 2 and 3 of this thesis, I show that mortality driven by conspecific NDD is prevalent at the early life stages, and this effect is considerably stronger during the year after germination. Furthermore, this process is driven exclusively by host-specific fungal pathogens, which cause mortality selectively among conspecifics and drive diversity. As seedlings age beyond their first year, NDD interactions become less impacted by conspecifics but are impacted by closely related neighbours or by general neighbourhood density, representing changes in the mechanism driving NDD as seedlings age, and a decline in host-specificity of natural enemies. Equally, relative growth rates (RGR) are reduced under high neighbourhood density irrespective of species identity. Results suggest insect herbivores are the strongest driver of reduced RGR but not mortality under increased neighbourhood density. As a consequence of stronger inter than intra-specific NDD effects on RGR, insects had no impact on seedling diversity in the short term. This study supports assertions that regionally rare species experience stronger NDD than common species, accounting for the high variability in species relative abundance in the tropics. In the second part of my thesis, I address the role of large vertebrate dispersers in shaping tropical tree communities and the consequences of defaunation for tree assemblage and carbon storage. Dispersal allows seeds to escape NDD and persist to reproductive maturity and is therefore vital for the maintenance of diversity. Vertebrates disperse the seeds of more than 70% of neo-tropical tree species. However, many large vertebrates are becoming scarce due to widespread hunting. The decline of large vertebrates and their role as dispersers is predicted to alter tree community composition. Additionally, large vertebrates are responsible for the dispersal of large-seeded species, which are linked to species with high wood density. With wood density positively associated with carbon storage, there is a potential cascading influence of defaunation on global carbon storage. We investigate the consequences of declining large vertebrate mortality agents in chapter 3, and the consequences of declining large vertebrate dispersers in chapters 4 and 5. Although community composition is altered in a defaunated forest, species dispersed by extirpated fauna do not appear to drive this. In fact we find that many species thought to be heavily reliant on extirpated fauna manage to persist. Although it is thought that the simultaneous loss of seed predation from large terrestrial vertebrates may create compensatory effects, we found little support for this, with an absence of large terrestrial vertebrates driving only temporary changes to species diversity. Neither a loss of large frugivores or large-seeded species lead to declines in species with high wood density, but we detect a worrying decline in large stemmed species, which has negative implications for carbon storage. Overall, my thesis highlights the importance of NDD and trophic interactions, particularly fungal pathogens, at the early life stages in shaping tropical tree communities and in maintaining diversity. I provide evidence that the removal of trophic interactions among larger natural enemies and dispersers does not impact community assemblage in the directional manner found in previous studies. I provide evidence for the variability in response to trophic interactions among species and ontogenetic stages. I show disproportionate relative importance among natural enemies and dispersers in the maintenance of tropical tree assemblage, with implications for conservation and for assessing the consequences for tree diversity under the influence of degradation.
- Published
- 2018
38. Loss of endangered frugivores from seed dispersal networks generates severe mutualism disruption.
- Author
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Lamperty, Therese and Brosi, Berry J.
- Abstract
Many tropical seed-dispersing frugivores are facing extinction, but the consequences of the loss of endangered frugivores for seed dispersal is not well understood. We investigated the role of frugivore endangerment status via robustness-to-coextinction simulations (in this context, more accurately described as robustness-to-partner-loss simulations) using data from the Brazilian Atlantic Forest biodiversity hotspot. By simulating the extinction of endangered frugivores, we found a rapid and disproportionate loss of tree species with dispersal partners in the network, and this surprisingly surpassed any other frugivore extinction scenario, including the loss of the most generalist frugivores first. A key driver of this pattern is that many specialist plants rely on at-risk frugivores as seed-dispersal partners. Moreover, interaction compensation in the absence of endangered frugivores may be unlikely because frugivores with growing populations forage on fewer plant species than frugivores with declining populations. Therefore, protecting endangered frugivores could be critical for maintaining tropical forest seed dispersal, and their loss may have higher-than-expected functional consequences for tropical forests, their regeneration processes, and the maintenance of tropical plant diversity [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
39. Long‐term monitoring shows that drought sensitivity and riparian land use change coincide with freshwater mussel declines.
- Author
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Lopez, Jonathan W., DuBose, Traci P., Franzen, Alex J., Atkinson, Carla L., and Vaughn, Caryn C.
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FRESHWATER mussels ,DROUGHT management ,DROUGHTS ,LAND use ,SPECIES diversity ,ATMOSPHERIC temperature ,BIVALVES - Abstract
Freshwater mussels (Bivalvia: Unionoida) are globally imperilled and are the subjects of wide‐ranging conservation initiatives. This study combined traditional species‐monitoring surveys with a novel functional trait classification scheme and publicly available environmental data to assess potential environmental drivers of declining mussel abundance and species richness.Surveys to document mussel abundance and assemblage composition in south‐east Oklahoma, United States were conducted on the Glover, Mountain Fork and upper Little rivers. Present day survey results (2015–2021) were compared with those from previous studies (1993–1999, 2010) to document long‐term changes in the species and functional composition of mussel assemblages and concurrent changes in climate and land use.Mussel catch per unit effort declined by 71.5% between historical and present day surveys. Species richness declined by 44.4% over this same period. Using a novel classification of mussel drought sensitivity, it was found that the declines were associated with a disproportionate loss of drought‐sensitive taxa (67.0% decline) – those classified as drought‐tolerant did not decline in abundance. Mussel declines coincided with the loss of open surface waters (such as streams, ponds and lakes) and riparian wetlands, increased local air temperatures and longer and more intense hydrological drought.These findings indicate that for a complete understanding of the causes and consequences of mussel declines, conservation biologists must not only monitor the species composition and abundance of threatened organisms, but also consider functional traits. The results further underscore the importance of long‐term monitoring for long‐lived organisms owing to the decadal time scales over which climate and land use change occur. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
40. Climate‐driven divergent long‐term trends of forest beetles in Japan.
- Author
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Evans, Maldwyn J., Barton, Philip, Niwa, Shigeru, Soga, Masashi, Seibold, Sebastian, Tsuchiya, Kazuaki, and Hisano, Masumi
- Subjects
- *
BEETLES , *PRECIPITATION anomalies , *CONIFEROUS forests , *MIXED forests , *SPECIES diversity , *FOREST biodiversity , *ANIMAL population density , *ECOSYSTEMS - Abstract
Concerning declines in insect populations have been reported from Europe and the United States, yet there are gaps in our knowledge of the drivers of insect trends and their distribution across the world. We report on our analysis of a spatially extensive, 14‐year study of ground‐dwelling beetles in four natural forest biomes spanning Japan's entire latitudinal range (3000 km). Beetle species richness, abundance and biomass declined in evergreen coniferous forests but increased in broadleaf‐coniferous mixed forests. Further, beetles in evergreen coniferous forests responded negatively to increased temperature and precipitation anomalies, which have both risen over the study's timespan. These significant changes parallel reports of climate‐driven changes in forest tree species, providing further evidence that climate change is altering forest ecosystems fundamentally. Given the enormous biodiversity and ecosystem services that forests support globally, the implications for biodiversity change resulting from climate change could be profound. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
41. Forest hoverfly community collapse: Abundance and species richness drop over four decades.
- Author
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Barendregt, Aat, Zeegers, Theo, van Steenis, Wouter, and Jongejans, Eelke
- Subjects
- *
SPECIES diversity , *COMMUNITY forests , *ENDANGERED species , *NUMBERS of species , *FOREST management , *INSECT diversity - Abstract
To study insect decline, an important threat to biodiversity, long‐term datasets are needed. Here we present a study of hoverfly (Diptera: Syrphidae) abundance and diversity in a Dutch forest, surrounded by other forests, and analyse the variation in insect numbers over four decades.Between 1982 and 2021, abundance decreased by 80%. Until 1990, abundance showed a strong decrease of 10.9% per year, mainly in nationally rare species with carnivorous larvae exposed to air. From 1990, abundance stabilised, whereas from 2000, a second period of strong decline of 9.0% per year occurred, mainly in very common species.Species richness also declined strongly between 1979 and 2021: the total number of species observed in five monitoring days dropped by 44% over those 43 years. The characteristic set of dry‐forest hoverfly species disappeared over four decades.The number of nationally rare species observed at the study site declined from 19 to 9 early on, in a period (1979–1984) that coincided with intense nitrogen input and acidification caused by agriculture in the same region. The more recent decline is likely also caused by factors from outside the forest, as forest management and conditions remained constant.Continued influx of nutrients and pesticides at a regional level, as well as climate change are possible causes of the decline. Research is needed to quantify their relative effects. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
42. Status of Marine Biodiversity in the Anthropocene
- Author
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Luypaert, Thomas, Hagan, James G., McCarthy, Morgan L., Poti, Meenakshi, Jungblut, Simon, editor, Liebich, Viola, editor, and Bode-Dalby, Maya, editor
- Published
- 2020
- Full Text
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43. Collapse of Terrestrial Biodiversity
- Author
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Marques, Luiz and Marques, Luiz
- Published
- 2020
- Full Text
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44. Detangling ecosystem services: Open‐field manipulation of soil‐dwelling microarthropods provides new opportunities to investigate their effects on nitrogen cycling.
- Author
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Gergócs, Veronika, Flórián, Norbert, Tóth, Zsolt, Sipőcz, László, and Dombos, Miklós
- Subjects
- *
NITROGEN cycle , *ECOSYSTEM services , *NITROGEN fertilizers , *SANDY soils , *WHEAT , *CHERNOZEM soils - Abstract
Soil microarthropods have a pivotal role in soil nitrogen cycling in that they affect microbial decomposers. A high abundance of microarthropods may increase the mobility of inorganic nitrogen ions in the soil, mainly in nitrogen‐limited habitats. However, it is difficult to study ecological processes with small‐sized, soil‐dwelling arthropods. The effects of soil microarthropods on nitrogen cycling have mainly been studied in laboratory microcosm experiments. Therefore, we face many practical issues in investigating these effects under field conditions that remain to be resolved.We developed an open‐field mesocosm setup with growing plants. In a two‐part experiment, spring wheat and grass species were grown in chernozem and sandy soils. Leached ammonium and nitrate ions were measured with percolation lysimeters. Half of the mesocosms included natural assemblages, and the other half included less abundant Acari and Collembola assemblages. The application of nitrogen fertilization assured differences in nitrogen sources.We found a large difference in ammonium and nitrate leaching between the two soil types. In chernozem soil, the leached ion concentrations were higher in mesocosms with more abundant mite and springtail assemblages. The expected patterns were less pronounced in sandy soil. Adding nitrogen fertilizer did not modify the effects of soil microarthropods.Open‐field mesocosms are promising for studying the role of soil‐dwelling mesofauna in ecological processes. We solved the problem of keeping mesofauna abundance lower in treated plots than that in control plots. Plants successfully grew in our semi‐closed systems with functioning percolation lysimeters. The use of the equipment in the experiments in this study helped reveal that the role of soil‐dwelling microarthropods in nitrogen cycling depends on the soil type and not on the application of nitrogen fertilizer. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
45. The effect of past defaunation on ranges, niches, and future biodiversity forecasts.
- Author
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Sales, Lilian P., Galetti, Mauro, Carnaval, Ana, Monsarrat, Sophie, Svenning, Jens‐Christian, and Pires, Mathias M.
- Subjects
- *
NUMBERS of species , *CLIMATE sensitivity , *CLIMATE change , *BIOLOGICAL extinction , *CONSERVATION & restoration , *FORCED migration , *BIODIVERSITY - Abstract
Humans have reshaped the distribution of biodiversity across the globe, extirpating species from regions otherwise suitable and restricting populations to a subset of their original ranges. Here, we ask if anthropogenic range contractions since the Late Pleistocene led to an under‐representation of the realized niches for megafauna, an emblematic group of taxa often targeted for restoration actions. Using reconstructions of past geographic distributions (i.e., natural ranges) for 146 extant terrestrial large‐bodied (>44 kg) mammals, we estimate their climatic niches as if they had retained their original distributions and evaluate their observed niche dynamics. We found that range contractions led to a sizeable under‐representation of the realized niches of several species (i.e., niche unfilling). For 29 species, more than 10% of the environmental space once seen in their natural ranges has been lost due to anthropogenic activity, with at least 12 species undergoing reductions of more than 50% of their realized niches. Eighteen species may now be confined to low‐suitability locations, where fitness and abundance are likely diminished; we consider these taxa 'climatic refugees'. For those species, conservation strategies supported by current ranges risk being misguided if current, suboptimal habitats are considered baseline for future restoration actions. Because most climate‐based biodiversity forecasts rely exclusively on current occurrence records, we went on to test the effect of neglecting historical information on estimates of species' potential distribution – as a proxy of sensitivity to climate change. We found that niche unfilling driven by past range contraction leads to an overestimation of sensitivity to future climatic change, resulting in 50% higher rates of global extinction, and underestimating the potential for megafauna conservation and restoration under future climate change. In conclusion, range contractions since the Late Pleistocene have also left imprints on megafauna realized climatic niches. Therefore, niche truncation driven by defaunation can directly affect climate and habitat‐based conservation strategies. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
46. Large wildlife removal drives immune defence increases in rodents
- Author
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Young, Hillary S, Dirzo, Rodolfo, Helgen, Kristofer M, McCauley, Douglas J, Nunn, Charles L, Snyder, Paul, Veblen, Kari E, Zhao, Serena, and Ezenwa, Vanessa O
- Subjects
Ecological Applications ,Biological Sciences ,Ecology ,Environmental Management ,Environmental Sciences ,Life on Land ,Good Health and Well Being ,defaunation ,ecoimmunology ,Kenya Long-term Exclosure Experiment ,rodent ,wildlife decline ,Biological sciences ,Environmental sciences - Abstract
Anthropogenic disturbances involving land use change, climate disruption, pollution and invasive species have been shown to impact immune function of wild animals. These immune changes have direct impacts on the fitness of impacted animals and, also, potentially indirect effects on other species and on ecological processes, notably involving the spread of infectious disease. Here, we investigate whether the selective loss of large wildlife can also drive changes in immune function of other consumer species. Using a long-standing large-scale exclosure experiment in East Africa, we investigated the effects of selective removal of large wildlife on multiple measures of immune function in the dominant small rodent in the system, the East African pouched mouse, Saccostomus mearnsi. We find support for a general increase in immune function in landscapes where large wildlife has been removed, but with some variation across immune parameters. These changes may be mediated in part by increased pathogen pressure in plots where large wildlife has been removed due to major increases in rodent density in such plots, but other factors such as changes in food resources are also likely involved. Overall, our research reveals that the elimination of large-bodied wildlife - now recognized as another major form of global anthropogenic change - may have cascading effects on immune health, with the potential for these effects to also impact disease dynamics in ecological communities. Lay Summary Functional Ecology
- Published
- 2016
47. The specter of empty countrysides and wetlands—Impact of hunting take on birds in Indo‐Burma.
- Author
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Yong, Ding Li, Jain, Anuj, Chowdhury, Sayam U., Denstedt, Emily, Khammavong, Kongsy, Milavong, Phonesavanh, Aung, Thiri Dae We, Aung, Ei Thinzar, Jearwattanakanok, Ayuwat, Limparungpatthanakij, Wich'yanan, Angkaew, Rongrong, Sinhaseni, Khwankhao, Le, Trong Trai, Nguyen, Hoai Bao, Tang, Punleu, Taing, Porchhay, Jones, Victoria R., and Vorsak, Bou
- Subjects
- *
FOWLING , *WETLANDS , *ATTITUDE (Psychology) , *PADDY fields , *BIRD migration , *BIRD surveys , *LANDSCAPES - Abstract
Hunting for the wild meat trade, medicines and other human uses has decimated Indo‐Burma's vertebrate biota and has led to widespread defaunation. Yet, there is surprisingly little data on how hunting impacts wild bird assemblages in different landscapes here. Based on concurrent snapshot surveys of bird hunting, food markets and hunting attitudes across six Indo‐Burma countries, we found that hunting threatens species not only in forested landscapes but also wetlands and farmlands such as orchards and paddy fields—ecosystems overlooked by past studies, with at least 47 species associated with wetlands and agricultural lands identified from market surveys across the region. High rates of mortality are suffered when hunting tools such as nets are used to exclude perceived bird pests in both aquaculture and agricultural landscapes, with over 300 individual carcasses of at least 29 identifiable species detected in one aquaculture landscape sampled in Thailand. We warn that the potentially unsustainable trapping of species for consumption and trade in Indo‐Burma, coupled with high incidental mortalities, could decimate the populations of erstwhile common and/or legally unprotected species. There is an urgent need for stronger regulatory oversight on the hunting take of wild birds and the use of hunting tools such as nets. Alongside this, conservation practitioners need to better engage with rural communities to address unsustainable hunting practices, especially outside of protected areas. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
48. What Caused Declines in Intertidal Invertebrate Populations around Fukushima Daiichi Nuclear Power Plant after the 2011 Great East Japan Earthquake, Tsunami, and Nuclear Disaster?
- Author
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Horiguchi, Toshihiro and Kodama, Keita
- Subjects
SENDAI Earthquake, Japan, 2011 ,NUCLEAR accidents ,INVERTEBRATE populations ,TSUNAMIS ,IONIZING radiation ,LIFE history theory ,NUCLEAR power plants - Abstract
We discuss possible causal factors for the decline in intertidal invertebrate populations around Fukushima Daiichi Nuclear Power Plant (FDNPP) after the 2011 Great East Japan Earthquake and subsequent tsunami and nuclear disaster on the basis of existing knowledge about the effects of radionuclides and ionizing radiation on aquatic organisms. We found a gap between effects observed in the laboratory and those observed in natural aquatic environments, and discuss possible reasons why. Considering the complexity of the environment, we conclude that it is critical to evaluate the effects of ionizing radiation combined with other biotic and abiotic environmental factors, together with the life-history traits of the species examined, for realistic assessment of population-level effects. Finally, we present possible causal factors for strange or abnormal phenomena observed in intertidal biota near FDNPP, namely declines in population densities and number of species of invertebrates, delayed recovery from these declines, and continuous sexual maturation in the rock shell population. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
49. Large mammalian herbivores modulate plant growth form diversity in a tropical rainforest.
- Author
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Souza, Yuri, Villar, Nacho, Zipparro, Valesca, Nazareth, Sérgio, and Galetti, Mauro
- Subjects
- *
FOREST biodiversity , *RAIN forests , *TREE growth , *PLANT growth , *BIOLOGICAL extinction , *HERBIVORES , *MAMMAL growth - Abstract
The world's terrestrial biomes are broadly classified according to the dominant plant growth forms that define ecosystem structure and processes. Although the abundance and distribution of different plant growth forms can be strongly determined by factors such as climate and soil composition, large mammalian herbivores have a strong impact on plant communities, thus defaunation (the local or functional extinction of large animals) has the potential to alter the compositional structure of plant growth forms in natural ecosystems.Tropical rainforests sustain a high diversity of growth forms, including trees, palms, lianas, shrubs, herbs and bamboos, all of which play important ecosystem functions. Here, we experimentally evaluate how large mammalian herbivores affect the dominance, diversity and coexistence of these major tropical forest plant growth forms, by monitoring communities of saplings on the understorey in 43 paired exclusion plots in a long‐term replicated exclusion experiment in the understorey of the Atlantic forest of Brazil.Over the course of 10 years large herbivore exclusion decreased diversity among growth forms, increased the absolute abundance of palms and trees (22% and 38% respectively) and increased the diversity of species within these two groups, to the detriment of other growth forms. Furthermore, all pairwise relationships between growth forms were positive on plots where herbivores had access, whereas several strong negative relationships emerged in plots where herbivores were excluded. This occurred despite strong background directional temporal trends affecting plant communities in both experimental treatments across the region.Synthesis. Our work indicates that the defaunation alters growth form dominance by favouring palms and trees while eroding diversity among growth forms and coexistence on a temporal scale. Large herbivore mammals promote diversity among growth forms, preventing the hyper‐dominance of trees and palms, yet without supressing the diversity of species within growth forms. We argue that large herbivore mammals affect growth forms through several non‐mutually exclusive mechanisms, including herbivory, seed dispersal and physical disturbance, as well as differential effects linked to the morphological and physiological adaptations of growth forms. We conclude that defaunation might lead to profound impacts on important ecosystem functions underpinned by growth form diversity, and result in vertical and horizontal structural simplification of tropical rainforests. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
50. Rapid colonisation post‐displacement contributes to native fish resilience.
- Author
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Alford, Samantha L. and Walters, Annika W.
- Subjects
- *
NATIVE fishes , *COLONIZATION (Ecology) , *RESTORATION ecology , *FISH diversity , *FRESHWATER fishes , *FISH populations - Abstract
Native freshwater fish are experiencing global declines. Determining what drives native fish resilience to disturbance is crucial to understanding their persistence in the face of multiple stressors. Fish colonisation ability may be one factor affecting population resilience after disturbance. We conducted displacement experiments in headwater streams in Wyoming, USA, to evaluate mottled sculpin (Cottus bairdii) and mountain sucker (Catostomus platyrhynchus) colonisation ability. Specifically, we (1) determined whether fish could colonise sites rapidly after displacement, (2) evaluated site‐level factors affecting colonisation, and (3) compared species‐level differences in movement and colonisation capabilities. Mountain sucker recovered to pre‐displacement abundances within 6–11 weeks, but mottled sculpin were still at slightly reduced abundances. For both species, the majority of colonists were unmarked new individuals and size–structure was similar to pre‐displacement size–structure. Fish colonisation was best predicted by pre‐displacement abundance and an interaction between per cent riparian cover and species identity. The slower colonisation rate of mottled sculpin may relate to movement ability as average daily movement rate and movement extent were significantly greater for mountain sucker. Our results demonstrate that colonisation is one mechanism allowing fish populations to be resilient in the face of disturbance and that species' traits provide insight into fish colonisation capabilities. Experimental approaches provide mechanistic insight into colonisation dynamics, enhancing our understanding of native fish resilience in degraded stream ecosystems and their response to restoration actions. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
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