A comparison of present-day and pre-industrial cladoceran assemblages from softwater Nova Scotia (Canada) lakes with different regional acidification histories

摘要: We compared cladoceran assemblages in modern and pre-industrial sediments from cores taken 48 softwater lakes located four main regions of Nova Scotia (Canada) to evaluate the impacts acidification other recent environmental stressors. Lakes Kejimkujik National Park showed significant increases Holopedium relative abundances decreases Alona chydorids since times, which appear be related declines pH calcium (Ca) concentrations caused by acidic deposition. Bridgewater also a decrease Alona, as well increase macrothricid (Acantholeberis Ophryoxus) taxa that cannot explained pH, although [Ca] have been recorded. Yarmouth did not show any regional changes major species groups. Still, these significantly differed assemblages, with assemblage being lake-specific likely interactions between local stressors acting on individual lakes. Finally, Cape Breton Highlands Park, taiga plateau, received historically lower levels sulphate deposition province, recorded similar The province-wide across different acid rates suggests limnological climate warming may responsible. Overall, this study shows history is an important predictor times lakes, multiple result complex Cladocera responses some regions.