On the role of natural water level fluctuation in structuring littoral benthic macroinvertebrate community composition in lakes

Abstract

We used traditional hydrologic endpoints and extracted novel water-level fluctuation (WLF) characteristics through principal components analysis (PCA), to determine the relationship between WLF and rocky littoral benthic macroinvertebrate (BMI) richness in 16 boreal lakes. Yearly WLF amplitude (maximum minus minimum water levels) ranged from 35.9 cm to 157.5 cm. Using PCA we derived a new variable D80-D210 (31 March minus 01 August) as a surrogate for change in mean water level and potential habitat squeeze (loss). Analyses of BMI richness with several physicochemical variables, including water quality (8), habitat variability (4), lake and basin morphology (6), land classification (28), water temperature (8), hydrology (9), and PCA axes (10) resulted in only three significant relationships. We found a classic species-area relationship, as BMI richness increases with increasing lake area (r 2 5 0.38 linear , r 2 5 0.69 unimodal ). Similarly, as littoral slope increases macroinvertebrate richness decreases (r 2 5 0.32 linear ). Most importantly, lower water levels, quantified using D80-D210, have higher macroinvertebrate richness (r 2 5 0.38 linear ). Together these results suggest that a habitat squeeze in littoral areas is the direct result of lower mean water levels and that relatively small changes in natural WLF can be associated with changes in BMI communities.

Water‐level fluctuations regulate the structure and functioning of natural lakes

“…Sampling was confined to stony substrata as they are easy and relatively economical to sample and their communities are known to respond to human‐induced pressure, including water‐level regulation (Brauns et al ., ; Aroviita & Hämäläinen, ; Donohue et al ., ; Tolonen & Hämäläinen, ; White et al . ). In addition, lakes with total phosphorus concentrations in excess of 100 μg L −1 or with alkalinity less than 10 mg CaCO 3 L −1 were excluded from the study.…”

Water level fluctuation and sediment–water nutrient exchange in Great Lakes coastal wetlands

“…Water level fluctuations in aquatic ecosystems are naturally occurring phenomena that can influence a number of ecological processes, including ecosystem metabolism and biomass accumulation (Hudon, 1997;James and Havens, 2005), sediment biogeochemistry (Akatsuka and Mitamura, 2011;Furey et al, 2004;Kelley et al, 1985;McGowan et al, 2005), and survival of sessile organisms (White et al, 2010). Human influence has often modulated, and sometimes exacerbated, water level fluctuations through river regulation, water withdrawals, and climate change, thereby impacting these ecological processes.…”

Quantifying ecological responses to amplified water level fluctuations in standing waters: an experimental approach

“…These natural fluctuations tend to be gradual and predictable in nature (White et al . ), are essential for the survival of some species and can support both the biodiversity and productivity of littoral regions (e.g. Coops & Hosper ).…”