Browsing by Author "Miller, David A. W."
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- Assessing global patterns in mammalian carnivore occupancy and richness by integrating local camera trap surveysRich, Lindsey N.; Davis, Courtney L.; Farris, Zachary J.; Miller, David A. W.; Tucker, Jody M.; Hamel, Sandra; Farhadinia, Mohammad S.; Steenweg, Robin; Di Bitetti, Mario S.; Thapa, Kanchan; Kane, Mamadou D.; Sunarto, Sunarto; Robinson, Nathaniel P.; Paviolo, Agustin; Cruz, Paula; Martins, Quinton; Gholikhani, Navid; Taktehrani, Atieh; Whittington, Jesse; Widodo, Febri A.; Yoccoz, Nigel G.; Wultsch, Claudia; Harmsen, Bart J.; Kelly, Marcella J. (2017-08)Aim: Biodiversity loss is a major driver of ecosystem change, yet the ecological data required to detect and mitigate losses are often lacking. Recently, camera trap surveys have been suggested as a method for sampling local wildlife communities, because these observations can be collated into a global monitoring network. To demonstrate the potential of camera traps for global monitoring, we assembled data from multiple local camera trap surveys to evaluate the interchange between fine- and broad-scale processes impacting mammalian carnivore communities. Location: Argentina, Belize, Botswana, Canada, Indonesia, Iran, Madagascar, Nepal, Norway, Senegal, South Africa, and the U.S.A. Methods: We gathered camera trap data, totalling >100,000 trap nights, from across five continents. To analyse local and species-specific responses to anthropogenic and environmental variables, we fitted multispecies occurrence models to each study area. To analyse global-level responses, we then fitted a multispecies, multi-area occurrence model. Results: We recorded 4,805 detections of 96 mammalian carnivore species photographed across 1,714 camera stations located in 12 countries. At the global level, our models revealed that carnivore richness and occupancy within study areas was positively associated with prey availability. Occupancy within study areas also tended to increase with greater protection and greater distances to roads. The strength of these relationships, however, differed among countries. Main conclusions: We developed a research framework for leveraging global camera trap data to evaluate patterns of mammalian carnivore occurrence and richness across multiple spatial scales. Our research highlights the importance of intact prey populations and protected areas in conserving carnivore communities. Our research also highlights the potential of camera traps for monitoring wildlife communities and provides a case study for how this can be achieved on a global scale. We encourage greater integration and standardization among camera trap studies worldwide, which would help inform effective conservation planning for wildlife populations both locally and globally.
- Ecological correlates of the spatial co-occurrence of sympatric mammalian carnivores worldwideDavis, Courtney L.; Rich, Lindsey N.; Farris, Zachary J.; Kelly, Marcella J.; Di Bitetti, Mario S.; Di Blanco, Yamil; Albanesi, Sebastian; Farhadinia, Mohammad S.; Gholikhani, Navid; Hamel, Sandra; Harmsen, Bart J.; Wultsch, Claudia; Kane, Mamadou D.; Martins, Quinton; Murphy, Asia J.; Steenweg, Robin; Sunarto, Sunarto; Taktehrani, Atieh; Thapa, Kanchan; Tucker, Jody M.; Whittington, Jesse; Widodo, Febri A.; Yoccoz, Nigel G.; Miller, David A. W. (2018-09)The composition of local mammalian carnivore communities has far-reaching effects on terrestrial ecosystems worldwide. To better understand how carnivore communities are structured, we analysed camera trap data for 108087 trap days across 12 countries spanning five continents. We estimate local probabilities of co-occurrence among 768 species pairs from the order Carnivora and evaluate how shared ecological traits correlate with probabilities of co-occurrence. Within individual study areas, species pairs co-occurred more frequently than expected at random. Co-occurrence probabilities were greatest for species pairs that shared ecological traits including similar body size, temporal activity pattern and diet. However, co-occurrence decreased as compared to other species pairs when the pair included a large-bodied carnivore. Our results suggest that a combination of shared traits and top-down regulation by large carnivores shape local carnivore communities globally.
- Quantifying climate sensitivity and climate-driven change in North American amphibian communitiesMiller, David A. W.; Grant, Evan H. Campbell; Muths, Erin; Amburgey, Staci M.; Adams, Michael J.; Joseph, Maxwell B.; Waddle, J. Hardin; Johnson, Pieter T. J.; Ryan, Maureen E.; Schmidt, Benedikt R.; Calhoun, Daniel L.; Davis, Courtney L.; Fisher, Robert N.; Green, David M.; Hossack, Blake R.; Rittenhouse, Tracy A. G.; Walls, Susan C.; Bailey, Larissa L.; Cruickshank, Sam S.; Fellers, Gary M.; Gorman, Thomas A.; Haas, Carola A.; Hughson, Ward; Pilliod, David S.; Price, Steven J.; Ray, Andrew M.; Sadinski, Walt; Saenz, Daniel; Barichivich, William J.; Brand, Adrianne; Brehme, Cheryl S.; Dagit, Rosi; Delaney, Katy S.; Glorioso, Brad M.; Kats, Lee B.; Kleeman, Patrick M.; Pearl, Christopher A.; Rochester, Carlton J.; Riley, Seth P. D.; Roth, Mark; Sigafus, Brent H. (2018-09-25)Changing climate will impact species' ranges only when environmental variability directly impacts the demography of local populations. However, measurement of demographic responses to climate change has largely been limited to single species and locations. Here we show that amphibian communities are responsive to climatic variability, using >500,000 time-series observations for 81 species across 86 North American study areas. The effect of climate on local colonization and persistence probabilities varies among eco-regions and depends on local climate, species life-histories, and taxonomic classification. We found that local species richness is most sensitive to changes in water availability during breeding and changes in winter conditions. Based on the relationships we measure, recent changes in climate cannot explain why local species richness of North American amphibians has rapidly declined. However, changing climate does explain why some populations are declining faster than others. Our results provide important insights into how amphibians respond to climate and a general framework for measuring climate impacts on species richness.
- Quantitative evidence for the effects of multiple drivers on continental-scale amphibian declinesGrant, Evan H. Campbell; Miller, David A. W.; Schmidt, Benedikt R.; Adams, Michael J.; Amburgey, Staci M.; Chambert, Thierry; Cruickshank, Sam S.; Fisher, Robert N.; Green, David M.; Hossack, Blake R.; Johnson, Pieter T. J.; Joseph, Maxwell B.; Rittenhouse, Tracy A. G.; Ryan, Maureen E.; Waddle, J. Hardin; Walls, Susan C.; Bailey, Larissa L.; Fellers, Gary M.; Gorman, Thomas A.; Ray, Andrew M.; Pilliod, David S.; Price, Steven J.; Saenz, Daniel; Sadinski, Walt; Muths, Erin (Springer Nature, 2016-05-23)Since amphibian declines were first proposed as a global phenomenon over a quarter century ago, the conservation community has made little progress in halting or reversing these trends. The early search for a "smoking gun" was replaced with the expectation that declines are caused by multiple drivers. While field observations and experiments have identified factors leading to increased local extinction risk, evidence for effects of these drivers is lacking at large spatial scales. Here, we use observations of 389 time-series of 83 species and complexes from 61 study areas across North America to test the effects of 4 of the major hypothesized drivers of declines. While we find that local amphibian populations are being lost from metapopulations at an average rate of 3.79% per year, these declines are not related to any particular threat at the continental scale; likewise the effect of each stressor is variable at regional scales. This result - that exposure to threats varies spatially, and populations vary in their response - provides little generality in the development of conservation strategies. Greater emphasis on local solutions to this globally shared phenomenon is needed.