Fluctuations in water level and the dynamics of zooplankton: a data‐driven modelling approach

Abstract

Summary 1. The zooplankton in Lake Kinneret (Israel) have undergone large fluctuations in recent decades, which have been linked to both biotic and abiotic processes. 2. By applying a data‐driven modelling approach to a long‐term database, and focusing on key abiotic (lake‐level change) and biotic (prey abundance) variables, we attempted to identify the possible factors impacting the lake’s zooplankton community. 3. We hypothesised that changes in the predatory zooplankton (adult cyclopoids) assemblage are driven by changes in lake level during years of large changes. We further postulated that lake‐level changes would have a similar impact on the herbivorous zooplankton (cladocerans and cyclopoid copepodites) but an opposite effect on the microzooplankton. In the years of moderate changes to lake level, however, the abundance of predatory zooplankton would determine the size of the herbivore and microzooplankton populations rather than their food sources, that is, top‐down control. 4. The resulting decision trees supported the hypotheses stressing the importance of the annual rate of lake‐level change in shaping the zooplankton community in the lake. In addition, and in contrast to expectations, bottom‐up processes seem to play a role in determining zooplankton abundance.

Spatiotemporal variations of zooplankton community in a shallow tropical brackish lagoon (Sontecomapan, Veracruz, Mexico)

“…The biotic processes in aquatic ecosystems could be acting separately or in tandem with abiotic forces in structuring planktonic communities at scales relevant to organisms, populations, and ecosystems (Gal et al 2013).…”

Zooplankton: A Valuable Environmental Indicator Tool in Reservoir Ecological Management?

“…Most zooplankters including Ceriodaphnia and T. prasinus, can only take particles smaller than 20 µm [23]. Those assemblage patterns are typical in reservoirs subjected to periodic water level variations [24,25,12,13]. According to these authors, the above mentioned species evidence adaptive advantages over larger Cladocera and Copepoda, not only on account of their feeding behaviour but also because they have shorter generation times and greater tolerance to large amounts of organic matter in the water.…”

Effects of water level regulation in alpine hydropower reservoirs: an ecosystem perspective with a special emphasis on fish

“…Zooplankton responses to WLR in alpine reservoirs may be driven by bottom-up processes, but this remains unstudied because the few published studies focus on reservoirs in other climatic zones (e.g. Gal et al, 2013;Simoes et al, 2015). However, one study in a subarctic Newfoundland reservoir found that zooplankton biomass, which increased approximately 19-fold during 11 years after impoundment, was not correlated with increased nutrient or resource availability (i.e., bottomup processes) but instead with increased retention time and hence decreased washout of zooplankton (Campbell et al, 1998).…”