Impacts of tropical forest disturbance on species vital rates

Abstract

Tropical forests are experiencing enormous threats from deforestation and habitat degradation. Much knowledge of the impacts of these land-use changes on tropical species comes from studies examining patterns of richness and abundance. Demographic vital rates (survival, reproduction, and movement) can also be affected by land-use change in a way that increases species vulnerability to extirpation, but in many cases these impacts may not be manifested in short-term changes in abundance or species richness. We conducted a literature review to assess current knowledge and research effort concerning how land-use change affects species vital rates in tropical forest vertebrates. We found a general paucity of empirical research on demography across taxa and regions, with some biases toward mammals and birds and land-use transitions, including fragmentation and agriculture. There is also considerable between-species variation in demographic responses to land-use change, which could reflect trait-based differences in species sensitivity, complex context dependencies (e.g., between-region variation), or inconsistency in methods used in studies. Efforts to improve understanding of anthropogenic impacts on species demography are underway, but there is a need for increased research effort to fill knowledge gaps in understudied tropical regions and taxa. The lack of information on demographic impacts of anthropogenic disturbance makes it difficult to draw definite conclusions about the magnitude of threats to tropical ecosystems under anthropogenic pressures. Thus, determining conservation priorities and improving conservation effectiveness remains a challenge.

Interactive impacts of climate change and land‐use change on the demography of montane birds

“…This is unfortunate because (1) climate change and land‐use change do not operate independently, but have combined effects on species, and (2) demographic vital rates are the ultimate determinants of species’ persistence and extinction risk (Karr 1990, Korfanta et al 2012). Understanding how these rates respond to anthropogenic pressures is imperative for effective conservation, especially because abundance‐based metrics can conceal serious anthropogenic impacts on population viability (Cossett et al 2018). However, demographic data are rarely collected in the field, because doing so requires well‐targeted, sustained, and replicated effort over multiple years.…”

Shifts in the demographics and behavior of bearded pigs (Sus barbatus) across a land‐use gradient

“…A thorough survey of hunting practices in the area would also help clarify the contribution of this threat to observed trends (e.g., Luskin et al, 2014). Behavior and demography must be considered when contemplating species long-term resilience in human-modified landscapes (Cosset et al, 2018) and for improving the effectiveness of conservation initiatives (Berger-Tal et al, 2011).…”

“…The final hypothesis serves as an empirical test, at the landscape level, of Hancock et al's (2006) modeling prediction that group formation in nomadic foragers is more advantageous when resources are randomly and patchily distributed. This research helps reveal the subtler effects of land-use change on large mammals-important functional groups in tropical forests (Terborgh et al, 2001)-and is designed to help generate management recommendations based more closely on the life-history traits of keystone species (Berger-Tal et al, 2011;Cosset, Gilroy, & Edwards, 2018). Despite restricted areas of low-intensity historical logging for ironwood (Eusideroxylon zwageri) the habitat is considered pristine and undisturbed (Ewers et al, 2011).…”

Variation in behavioral traits of two frugivorous mammals may lead to differential responses to human disturbance

“…A question arises as to why species respond differently; specifically, how the behavioral adaptations of species determine their responses to human disturbance (Vazquez & Simberloff, 2002). The differential response of animal species to a disturbance is likely to at least partly be a consequence of their behavioral differences (Cosset, Gilroy, & Edwards, 2019). The niche breadth of a species may govern how it responds to a disturbance: Under such conditions, the species with the narrowest niche breadth (the more specialized species) may be more negatively affected by disturbance than the species with the larger niche breadth (the more generalist species); the latter may even benefit from that disturbance, known as the “specialization‐disturbance hypothesis” (Vazquez & Simberloff, 2002).…”