Effects of damming a large lowland river on chironomids and fish assessed with the (multiplicative partitioning of) true/Hill biodiversity measure

Abstract

The impact of a large lowland temperate zone reservoir on chironomid and fish biodiversity was investigated in the same upstream (U) and downstream (D) sites on the same sampling occasions in spring and autumn of several post-impoundment years. The true/Hill N1 diversity measure was used to construct diversity models of the impact, and partitioning of N1 to reveal the importance of ecological gradients. N1 is unique in being decomposable among multiple levels and easily comparable across ecosystems and animal groups.Chironomids were more diverse than fish in all community sets owing to their probably lower mobility, lower interspecific competition, opportunistic character and much shorter life spans than those of fish. Fish exerted consumption pressure on chironomids upstream by foraging mostly on benthic insects, but not downstream where they fed on microcrustaceans of reservoir origin or on epiphytic fauna (mainly Chironomidae).The reservoir impact on chironomids decreased their diversity in U and increased in D, while much the opposite was true in fish. In D in macroinvertebrates, the impact consisted in advancing over time intensification of seasonal development of submersed macrophytes, while in D in fish in a few species escaping from the reservoir after their populational explosions each year.Partitioning of diversity revealed that the spatial (upstream-downstream) gradient was the strongest factor of diversity change in chironomids as compared with season, and age of the impoundment. No gradient was dominant in fish. Comparisons of observed data with a null model testified to very strong intraspecific aggregation in both chironomids and fish.

Percid occupation of submersed riverine macrophytes: food resource partitioning between perch (Perca fluviatilis L.) and ruffe (Gymnocephalus cernuus L.)

“…However, during sampling in 2004 the discharge was quite different, especially in summer, when flow stabilized at a much lower level. One consequence of this phenomenon was the appearance of submersed macrophytes along a short stretch of the tailwater each year (Grzybkowska, Dukowska 2002;Głowacki et al 2011).…”

“…Dams usually affect downstream flow regimes, river-channel geomorphology, water and sediment quality, aquatic environment and biota, and thus entire aquatic ecosystems (Ward, Stanford 1980;Petts 1984;Głowacki et al 2011). The effects of damming, including the development of submerged macrophytes (Grzybkowska et al 2003), are evident downstream for many kilometers (Bednarek 2001).…”

“…In the Jeziorsko tailwater, two secondary or tertiary consumers forage among the submersed hydrophytes: perch and ruffe (Marszał et al 1996, Penczak et al 1998, Dukowska et al 2009, Głowacki et al 2011). Unlike lakes, for which abundant literature on percid foraging in the littoral and the pelagial zones exists (Diehl, Kornijów 1997;Jacobsen, Berg 1998;Perrow et al 1999;Okun, Mehner 2005;Borcherding, Magnhagen 2008), little is known about the percid diet in rivers.…”

Impact of damming on the Chironomidae of the upper zone of a tropical run-of-the-river reservoir

“…Impacts on aquatic ecosystems can be followed by shifts in the Chironomidae that have been used in biomonitoring and environmental impact assessments, from organisms to the community level (Rosenberg et al, 1986). In general, the effects of dam construction on Chironomidae are evaluated by comparing sites located upstream and downstream the reservoir and the taxonomic identification varies from family (Nichols et al, 2006) to species (Penczak et al, 2006;Glowacki et al, 2010;Grzybkowska et al, 2012) and morphospecies (Rosin et al, 2009). In some cases, authors also analyse data using tribe and subfamily level (e.g.…”

Kohonen Artificial Neural Networks and the IndVal Index as Supplementary Tools for the Quantitative Analysis of Palaeoecological Data

“…4). All these taxa are associated with a warm or intermediate temperate climate and meso/eutrophic waters with ample vegetation (Szczerkowska-Majchrzak et al, 2010;Głowacki et al, 2011). Larvae of Glyptotendipes type pallens are often found to be macrophyte miners.…”