Researchers report historical regime shifts in the coastal wetlands of northeastern Florida. Mangroves have expanded into saltmarsh-dominated coastal wetlands along the northeast coast of Florida in recent decades, a phenomenon believed to be caused by reduced frequency of extreme cold events. The extent to which mangrove expansion is driven by anthropogenic climate change is uncertain. Kyle Cavanaugh and colleagues documented variability in mangrove abundance in northeastern Florida from the late 1700s to 2016 using a combination of remote sensing, climate data, and historical records. Between 1942 and 2013, the observed mangrove area in any given year was negatively correlated with the frequency and severity of extreme freezes during the previous decade. By combining this association with climate data, the authors modeled mangrove suitability in coastal wetlands across the region between 1850 and 2016. The model identified 6 transitions between mangrove-dominated and saltmarsh-dominated regimes, which are consistent with historical records and associated with decadal-scale fluctuations in the frequency and intensity of extreme cold events. Climate model projections indicated increasing annual minimum temperatures and mangrove suitability through the end of the 21st century, suggesting that climate change may drive the system toward persistent mangrove dominance, according to the authors.
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Article #19-02181: "Climate-driven regime shifts in a mangrove-salt marsh ecotone over the past 250 years," by Kyle C. Cavanaugh et al.
MEDIA CONTACT: Kyle C. Cavanaugh, University of California, Los Angeles, CA; tel: 703-489-4671; e-mail: kcavanaugh@geog.ucla.edu
Proceedings of the National Academy of Sciences