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Title: Amphibian conservation in the face of land-use change and global warming
Author: Gonzalez del Pliego Castaneda, Pamela
ISNI:       0000 0004 6494 1133
Awarding Body: University of Sheffield
Current Institution: University of Sheffield
Date of Award: 2017
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The loss of tropical forests has caused dramatic declines in biodiversity. Yet some tropical regions are undergoing large-scale secondary forest regeneration on abandoned farmland, and these recovering forests are increasingly recognised as being important for reversing biodiversity losses. A key issue studied in this thesis is whether these secondary forests will remain valuable for biodiversity under climate change, doing so focusing on amphibians within the Tropical Andes of Colombia. First, I measured the abundance of live (e.g. bromeliads) and dead (e.g. deadwood) microhabitats used by amphibians across primary, and young (4-18 yrs) and old secondary forests (19-35 yrs), and explored whether these microhabitats provide thermally buffered microclimates. I showed that microhabitats in secondary forests recovered towards primary forest levels and served as thermal buffers that reduce exposure to extreme temperatures. One of the main species' traits determining survival at higher temperature is the thermal point at which an animal loses its ability to escape from deadly conditions (critical thermal maximum – CTmax). I measured the CTmax from 14 Pristimantis frog species to demonstrate that physiological thermal tolerance is strongly related to phylogeny, but not affected by environmental factors, suggesting low levels of environmental selection. I then used individuals' current vulnerability and showed that species' in young, but not mature, secondary forests will become more threatened under global warming because they are exposed to higher temperatures. These results underscore the value of secondary forests in offering critical, thermally buffered microhabitats, suggesting that most amphibian species could maintain their current thermal niche if temperature increase remains below +2°C. Nevertheless, c.40% of amphibians are currently threatened with extinction, and c.25% are data deficient (DD) and may also be at risk. Using a global trait database and a fully sampled phylogeny, I predicted the threatened status of global DD species. I found that between almost half of DD species are threatened, mainly across Southeast Asia and the Neotropics, suggesting that DD species require urgent conservation.
Supervisor: Edwards, David P. ; Freckleton, Robert P. ; Scheffers, Brett R. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available