Publications by authors named "Owen S Middleton"

Since prehistory, humans have altered the composition of ecosystems by causing extinctions and introducing species. However, our understanding of how waves of species extinctions and introductions influence the structure and function of ecological networks through time remains piecemeal. Here, focusing on Australia, which has experienced many extinctions and introductions since the Late Pleistocene, we compared the functional trait composition of Late Pleistocene (130,00-115,000 years before present [ybp]), Holocene (11,700-3,000 ybp), and current Australian mammalian predator assemblages (≥70% vertebrate meat consumption; ≥1 kg adult body mass).

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Article Synopsis
  • Introduced large herbivores, like feral donkeys, have partly replaced extinct megafauna and negatively impact ecosystems due to a lack of predator control.
  • This study documents the first instance of cougars preying on juvenile feral donkeys in the Mojave and Sonoran Deserts, affecting their behavior and the surrounding desert wetlands.
  • Feral donkeys showed significantly reduced activity and disturbance in areas with cougar predation, indicating that protecting apex predators can positively influence ecosystem dynamics involving introduced species.
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American black bears are considered dependent on high-elevation forests or other montane habitats in the drylands of western North America. Black bear sign, including that of cubs, was observed throughout the summers of 2015, 2016, and 2018 along a perennial desert river in the Sonoran Desert of Arizona. We analyzed the contents of 21 black bear scats, collected from May to October of 2016 and 2018.

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Carnivorous mammals play crucial roles in ecosystems by influencing prey densities and behaviour, and recycling carrion. Yet, the influence of carnivores on global ecosystems has been affected by extinctions and range contractions throughout the Late Pleistocene and Holocene (approx. 130 000 years ago to the current).

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