Uncommon Ground

Climate change and biodiversity loss in the Cape Floristic Region


Jasper Slingsby is the lead author on a recent paper in the Proceedings of the National Academy of Sciences describing some of the work he, John Silander, and others did as part of our recently concluded Dimensions of Biodiversity project. Here’s the abstract. Follow the links below to find the full paper and a story about it in UConn Today.

Prolonged periods of extreme heat or drought in the first year after fire affect the resilience and diversity of fire-dependent ecosystems by inhibiting seed germination or increasing mortality of seedlings and resprouting individuals. This interaction between weather and fire is of growing concern as climate changes, particularly in systems subject to stand-replacing crown fires, such as most Mediterranean-type ecosystems. We examined the longest running set of permanent vegetation plots in the Fynbos of South Africa (44 y), finding a significant decline in the diversity of plots driven by increasingly severe postfire summer weather events (number of consecutive days with high temperatures and no rain) and legacy effects of historical woody alien plant densities 30 y after clearing. Species that resprout after fire and/or have graminoid or herb growth forms were particularly affected by postfire weather, whereas all species were sensitive to invasive plants. Observed differences in the response of functional types to extreme postfire weather could drive major shifts in ecosystem structure and function such as altered fire behavior, hydrology, and carbon storage. An estimated 0.5 °C increase in maximum temperature tolerance of the species sets unique to each survey further suggests selection for species adapted to hotter conditions. Taken together, our results show climate change impacts on biodiversity in the hyperdiverse Cape Floristic Region and demonstrate an important interaction between extreme weather and disturbance by fire that may make flammable ecosystems particularly sensitive to climate change.

Slingsby, J.A., C. Merow, M. Aiello-Lammens, N. Allsopp, S. Hall, H.K. Mollman, R. Turner, A.M. Wilson, and J.A. Silander, Jr.  2017. Intensifying postfire weather and biological invasion drive species loss in a Mediterranean-type biodiversity hotspot. Proceedings of the National Academy of Sciences USA (early edition) doi: 10.1073/pnas.1619014114

The new game of Russian roulette for fire-prone ecosystems, UConn Today, 17 April 2017

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