Littoral microcrustacea in Lake 302S in the Experimental Lakes Area of Canada: acidification and recovery

摘要: Summary 1 The littoral microcrustacean community (Cladocera and Copepoda) was examined from 1989 to 1991 in a lake experimentally acidified pH 4.5, 1992 1997 during the early stages of recovery. 2 Cladoceran abundance declined significantly (pH 4.5), but species richness did not change. Acantholeberis curvirostris, Simocephalus serrulatus, Latona spp. (Latona setifera, L. parviremis), all chydorid Cladocera markedly while at 4.5. The cyclopoid copepods low Ceriodaphnia calanoid were absent. 3 Recovery subsequently monitored as incrementally changed target 5.1 1993, 5.8 1994–97. Species remained unchanged. Chydorid cladocerans 1992, only Chydorus cf. brevilabris increased substantially 1993 1996. Non-chydorid again then gradually (mainly due Ophryoxus gracilis) 1994–96. All minnows recolonized lake. copepod Leptodiaptomus minutus present numbers 1997. 4 The zone Lake 302S has yet shown consistent signs recovery acidification.