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Global biodiversity and ecosystem function are the result of complex networks of interactions and feedbacks between animals and their environments, which in turn are affected by the interactions and feedbacks between animals and the organisms they host. Understanding these complex networks, including the main drivers of and responses to ecological and environmental changes and their global implications, requires adopting a systems-based perspective. We advocate for this approach by characterizing a framework centered around bats, a globally-distributed mammalian order, and their dual roles as both inhabitants of ecosystems and as habitats themselves. Like other organisms, bats interact with habitats by providing ecosystem services that impact the survival and distribution of other species, and may be affected by such factors as land use change, climate change, fluctuations in food availability, and hunting pressure. Habitat conditions (e.g. food availability, temperature, etc.) can affect the physiological condition of individuals, which in turn can affect the prevalence and/or virulence of hosted organisms and potential pathogens (e.g. ectoparasites, bacteria, viruses, fungi, and protozoa). In addition, the interactions among individuals (e.g. co-roosting, migration, etc.) influence the habitat connectivity for their hosted organisms (e.g. opportunities for dispersal). Bats have a unique relationship with infectious disease, both biological and cultural. With this in mind, when applied to bats this framework has special importance to how we understand and apply the One Health concept, whereby healthy natural environments foster both human and animal health, which in turn also promotes healthy environments. By leveraging a hierarchical approach among these different levels of biological organization, we can arrive at a clearer picture of the specific threats facing bats—as well as the risk of pathogen spillover to humans and other domesticated and wild animals generated by disrupting this delicate balance—and identify possible measures to mitigate adverse impacts. Thus, to understand these complex interactions and their implications for conservation, ecosystem health, and human health, we need a new ecological framework that recognizes that changes in habitats not only affect macrofauna and the ecosystem services they provide, but also have the potential to cascade through the diversity and evolution of the organisms they host. This review provides a case study for the application of this framework, which is extensible to other organisms with their own unique relationships with habitats and as habitats.
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Cascading impacts of large-carnivore extirpation in an African ecosystem
The world’s largest carnivores are declining and now occupy mere fractions of their historical ranges. Theory predicts that when apex predators disappear, large herbivores should become less fearful, occupy new habitats, and modify those habitats by eating new food plants. Yet experimental support for this prediction has been difficult to obtain in large-mammal systems. Following the extirpation of leopards and African wild dogs from Mozambique’s Gorongosa National Park, forest-dwelling antelopes (bushbuck, Tragelaphus sylvaticus ) expanded into treeless floodplains, where they consumed novel diets and suppressed a common food plant (waterwort, Bergia mossambicensis ). By experimentally simulating predation risk, we demonstrate that this behavior was reversible. Thus, whereas anthropogenic predator extinction disrupted a trophic cascade by enabling rapid differentiation of prey behavior, carnivore restoration may just as rapidly reestablish that cascade.
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- PAR ID:
- 10109391
- Date Published:
- Journal Name:
- Science
- ISSN:
- 0036-8075
- Page Range / eLocation ID:
- eaau3561
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1126/science.aau3561
