COS 74-5
Multiple year legacy of a climate episode on a trophic subsidy
Climate extremes and climate episodes may result in persistent changes to trophic subsidies, as impacted donor communities reset and recover to a pre-disturbance state. However, the legacy effects of these severe climate events on trophic subsidies are not well known. In 2011, an episodic drought impacted Everglades coastal rivers in South Florida (U.S.). This drought likely altered Everglades marsh floodplain fish communities that function as important seasonal prey subsidies to a large bodied river predator, common snook. Thus, our research objectives were to 1) track the crash and recovery of the donor marsh floodplain community and 2) document how changes in the donor community dynamics influenced trophic subsidies to river fishes. From 2010 to 2013, we sampled the abundances and diets of fishes within the Everglades floodplain-river interface monthly.
Results/Conclusions
Our results show that one year after the drought in 2012, marsh floodplain subsidies dominated by sunfishes were largely absent. Two years after the drought, allochthonous sunfish biomass entering the coastal river tripled relative to pre-drought conditions, but were packaged differently, such that the average body size of sunfish prey doubled. Despite the increased magnitude of sunfish biomass entering the system, the consumption of floodplain biomass did not differ from pre-disturbance conditions. With increases in the frequency and intensity of climate extremes and climate episodes like droughts, we may expect the year to year predictability of trophic subsidies to decrease, likely altering their influence on community and ecosystem dynamics.