Meeting Abstract

88-4   08:45 - 09:00  Effects of climate change and land-management practices on the persistence of an endemic Kalahari lizard: a resurvey after 50 years Martin, RN; Miles, DB*; Gilbert, AL; Kirchhof, S; McBrayer, LD; Clusella-Trullas, S; Ibargüengoytía, N; Medina, M; Sinervo, B; Pianka, ER; Huey, RB; Ohio University; Ohio University; University of Virginia; New York University, Abu Dhabi; Georgia Southern University; University of Stellenbosch; Universidad Nacional de la Comahue, Argentina; Universidad Nacional de la Patagonia, Argentina; University of California, Santa Cruz; University of Texas, Austin; University of Washington urosaurus@gmail.com

Two major threats to biodiversity are rising temperatures and changing land-use practices. Although interactions between these threats are known to accelerate species loss, most studies focus on a single threat. One impediment for conducting integrative analyses is the lack of historical data on thermal ecology and habitat occupancy of many species. Here, we examine whether five populations of a once abundant lizard (Meroles suborbitalis) persist 50 years after surveys conducted in the Kalahari semi-desert in 1960-1970, before recent climate change. Temperatures in the Kalahari have warmed and potentially have made habitats vulnerable to expanding desertification, altered thermal landscapes, and forced range shifts. In addition, much of the remaining suitable habitat is used for grazing. Whether species persist depends on access to favorable habitat that serves as an environmental buffer or refuge. Our resurveys suggest two populations became extirpated at sites with grazing, even though such sites have high thermal quality. Only one population persisted in a protected area (Kgalagadi Transfrontier Park) albeit at low numbers and in a thermal environment that is less favorable – at least during the austral summer – than those of grazed areas. A species distribution model based on climate metrics predicts that core zones of the species’ current distribution will be unsuitable by 2050 and 2070, even under optimistic climate scenarios, but that higher latitude habitats (further south) will become more suitable. However, habitats south of the Park are already degraded due to grazing by livestock and lack microhabitats serving as thermal refugia. Consequently, the threat status of M. suborbitalis may need revision, specifically to incorporate elevated extirpation risks caused by the interaction of warming environments and habitat degradation from grazing.