ORCID Profile
0000-0001-6557-3043
Current Organisation
Oregon State University
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Publisher: Cold Spring Harbor Laboratory
Date: 14-04-2021
DOI: 10.1101/2021.04.13.439662
Abstract: Introduced large herbivores have partly filled ecological gaps formed in the late Pleistocene, when many of the Earth’s megafauna were driven extinct. However, surviving predators are widely considered unable to influence introduced megafauna, leading them to exert unusually strong herbivory and disturbance-related effects. We report on a behaviorally-mediated trophic cascade between cougars ( Puma concolor ) and feral donkeys ( Equus africanus asinus ) at desert wetlands in North America. In response to predation of juveniles, donkeys shifted from nocturnal to almost exclusively diurnal, thereby avoiding peaks in cougar activity. Furthermore, donkeys reduced the time they spent at desert wetlands by 87%: from 5.5 hours a day to 0.7 hours at sites with predation. These shifts in activity were associated with increased activity and richness of other mammal species and reduced disturbance and herbivory-related effects on these ecologically-distinct wetland ecosystems, including 49% fewer trails, 35% less tr led bare ground, and 227% more canopy cover. Cougar predation on introduced donkeys rewires an ancient food web, with erse implications for modern ecosystems.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 06-12-2019
Abstract: Habitat fragmentation caused by human activities has consequences for the distribution and movement of organisms. Betts et al. present a global analysis of how exposure to habitat fragmentation affects the composition of ecological communities (see the Perspective by Hargreaves). In a dataset consisting of 4489 animal species, regions that historically experienced little disturbance tended to harbor a higher proportion of species vulnerable to fragmentation. Species in more frequently disturbed regions were more resilient. High-latitude areas historically experienced more disturbance and harbor more resilient species, which suggests that extinction has removed fragmentation-sensitive species. Thus, conservation efforts to limit fragmentation are particularly important in the tropics. Science , this issue p. 1236 see also p. 1196
Publisher: Elsevier BV
Date: 07-2021
Publisher: The Royal Society
Date: 09-2018
DOI: 10.1098/RSOS.181228
Publisher: The Royal Society
Date: 10-2016
DOI: 10.1098/RSOS.160498
Abstract: Terrestrial mammals are experiencing a massive collapse in their population sizes and geographical ranges around the world, but many of the drivers, patterns and consequences of this decline remain poorly understood. Here we provide an analysis showing that bushmeat hunting for mostly food and medicinal products is driving a global crisis whereby 301 terrestrial mammal species are threatened with extinction. Nearly all of these threatened species occur in developing countries where major coexisting threats include deforestation, agricultural expansion, human encroachment and competition with livestock. The unrelenting decline of mammals suggests many vital ecological and socio-economic services that these species provide will be lost, potentially changing ecosystems irrevocably. We discuss options and current obstacles to achieving effective conservation, alongside consequences of failure to stem such anthropogenic mammalian extirpation. We propose a multi-pronged conservation strategy to help save threatened mammals from immediate extinction and avoid a collapse of food security for hundreds of millions of people.
Publisher: Wiley
Date: 24-07-2022
Abstract: Introduced large herbivores have partly filled ecological gaps formed in the late Pleistocene, when many of the Earth's megafauna were driven extinct. However, extant predators are generally considered incapable of exerting top-down influences on introduced megafauna, leading to unusually strong disturbance and herbivory relative to native herbivores. We report on the first documented predation of juvenile feral donkeys Equus africanus asinus by cougars Puma concolor in the Mojave and Sonoran Deserts of North America. We then investigated how cougar predation corresponds with differences in feral donkey behaviour and associated effects on desert wetlands. Focusing on a feral donkey population in the Death Valley National Park, we used camera traps and vegetation surveys to compare donkey activity patterns and impacts between wetlands with and without cougar predation. Donkeys were primarily diurnal at wetlands with cougar predation, thereby avoiding cougars. However, donkeys were active throughout the day and night at sites without predation. Donkeys were ~87% less active (measured as hours of activity a day) at wetlands with predation (p < 0.0001). Sites with predation had reduced donkey disturbance and herbivory, including ~46% fewer access trails, 43% less tr led bare ground and 192% more canopy cover (PERMANOVA, R
No related grants have been discovered for William Ripple.