Sleeping threats to biodiversity conservation: Extinction debt in global plant communities

William Fowler

Publication Date:

The ability to identify ecosystems suffering delayed impacts of human activity poses a significant challenge for biodiversity conservation. Extinction debt measures the time lag of species losses in ecosystems and as such can be used to predict the magnitude and timing of future species losses without management intervention. There is an urgent need to quantify the extent and magnitude of extinction debt given we are in the midst of the sixth global extinction event. Here, we review and quantify evidence of extinction debt in the literature on plant communities, applying a formal meta-analysis of species–area relationships and extinction debt magnitude estimates. Comparing current richness with past and present habitat characteristics was found to be the most common method, but inadequate to identify species and species groups suffering extinction debt. With extinction debt detectable between 10- and 110-years following habitat fragmentation for communities with short to moderate species longevities, there is an expectation that long-lived communities have longer time lags. Our review revealed a large knowledge gap for long-lived communities and subsequently, we tested for extinction debt in a rapidly urbanising woodland system from south-west Western Australia. To test for extinction debt, we used re-measurement of plots spanning 1991–2016. For the effective management of ecosystems into the future, we discuss how a predictive restoration approach could be used to prevent future extinctions.

Resource Type:
Audio/Video, Conference Presentation, SER2019

Society for Ecological Restoration