Theme
Conserving in the face of Global Change
Speaker
David Ehlers Smith – University of KwaZulu-Natal
Authors
Robin Colyn – BirdLife South Africa
Hanneline Smit-Robinson – BirdLife South Africa
Yvette Ehlers Smith – University of KwaZulu-Natal
Colleen Downs – University of KwaZulu-Natal
Abstract
Forested regions are of global importance for a multitude of ecosystem functions and services, and are critical for biodiversity. Anthropogenic climate change compounds the negative effects of land-use change on forest persistence and forest-dependent biodiversity. Habitat loss and climate change have synergistic, additive effects and drive species’ extinctions in similar ways. Connectivity is key in conservation planning as a means of mitigating climate-change effects and facilitating species’ abilities to disperse throughout remnant habitat and track their climate niches. We hypothesised that three forest-specialised, habitat-specific and range-restricted bird species would act as efficient surrogates for promoting the connectivity and conservation of each of South Africa’s three threatened forest classes. We created ensemble models of species’ distributions and incorporated their core home- and breeding-range patches into a hybrid model of least-cost pathways and, using ecological circuit theory mapping, assessed its success in promoting connectivity for the forest class of each species. We predicted the likelihood of niche persistence for each species under future climate-change scenarios and their ability to track their climate niche. Projected habitat loss under climate-change scenarios impacted core-habitat patch distribution, size, and corridor connectivity, exacerbating habitat fragmentation, increasing resistance along least-cost paths and the severity of pinch-points and barriers along dispersal corridors. Forest systems and associated surrogate species are projected to experience the highest levels of habitat loss/contraction at mid- to high elevations. Climate-change resilience across ecosystems, and the persistence of species therein, was dependent on connectivity which facilitated a species’ ability to track specific climate niches. Our forest conservation network model promoted the persistence of our surrogate species, the ecological niche they represent and the ecosystem that provisions them, thus providing a replicable framework to aid conservation planning for future climate change.