Benthic communities through the construction of a major reservoir and 40 years of change
Phillips, Iain D.; Pollock, Michael S.; Chivers, Douglas P.
published: Oct 1, 2016
published online: Oct 24, 2016
manuscript accepted: Oct 5, 2016
manuscript received: Feb 29, 2016
ArtNo. ESP141018804001, Price: 29.00 €
Abstract Large hydroelectric dams have proliferated across the world through the 20th century. The resulting reservoirs can impart large changes to the abiotic and biotic environments upstream and downstream through changes in thermal regime of the rivers. Most understanding of the impacts these dams have on riverine communities is derived from studies conducted long after dams are constructed, with little information on what the communities resembled prior to construction and how they may have changed through time. In the current study we provide historical community data pre-dating the construction of a large, Northern Great Plains reservoir in reference reaches of the river system and the river downstream of the dam, as well as repeated sampling 20 and 40 years after its construction. In exploring changes in the community through time we find that densities of benthic macroinvertebrates have increased significantly through time relative to reference sites and pre-dam habitats. Further, these communities have changed through time to be different downstream of the reservoir in both soft and hard sediment. Our findings indicate that although there is a notable loss in sensitive taxa such as mayflies and stoneflies, other midge taxa colonize this unique, cold water habitat and create a new community of benthic macroinvertebrates.