Data associated with: Partial recovery of a benthic community following experimental acidification

Résumé fourni par la source

Though acid precipitation is largely a forgotten issue, freshwater ecosystems in North America continue to demonstrate impairment from the effects of historical acidification. While tThe impacts of acidification on benthic species, like the vVirile cCrayfish Faxonius virilis (Hagen, 1870) and the Slimy Sculpin Cottus cognatus Richardson, 1836, have been documented, but there are few examples in the literature documenting their recovery. Here, we describe the recovery of these benthic species following a 20-year experimental acidification of a boreal lake, comparing trends over time as well as comparing the densities of organisms in the early days of acidification (1977–1978) to with contemporary densities (2018) in the same lake and in a nearby reference lake. Virile crayfish were detected 4 years after extirpation and captured only in very low densities for the following decade. Though contemporary densities appear to have stabilized, small differences between crayfish in the early days of acidification and modern estimates amplified to lake-wide density estimates revealed that current total population density exists at approximately half~½ that of the earlier time period. Slimy Sculpin were absent from surveys for nearly 20 years following extirpation but have since recovered to densities similar to those in 1977 /and 1978, despite the continued absence of a key prey item, the opossum shrimp Mysis diluviana Audzijonyte and Väinölä, 2005. These results highlight that the recovery of aquatic communities following acidification can greatly lag behind chemical recovery and can vary by taxa, which is likely linked to differences in dispersal abilities, and that complete community recovery may require decades after chemical parameters return to pre-disturbance levels. Data includes survey data from 1977/1978 in lake 223 and from 2018 in lakes 223 and 239, as well as trap net capture data from 1983 - 2017

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