Potential shifts in zooplankton community structure in response to changing ice regimes and hydrologic connectivity

Abstract

Changing Arctic climate may alter freshwater ecosystems as a result of warmer surface waters, longer open-water periods, reduced wintertime lake ice growth, and altered hydrologic connectivity. This study aims to characterize zooplankton community composition and size structure in the context of hydrologic connectivity and ice regimes in Arctic lakes. Between 2011 and 2016, we sampled the phytoplankton, zooplankton, and fish communities from a set of representative lakes on the Arctic Coastal Plain (ACP) of northern Alaska to determine potential food web responses to changing Arctic ecosystems. Multivariate analyses showed that time from ice-out had a strong influence on zooplankton community structure and that seasonal succession of zooplankton differed between lakes with varying hydrologic connectivity. Trends were observed suggesting that large-bodied zooplankton (Daphnia, calanoid copepods) may be more prevalent in poorly connected lakes with low fish diversity. Large-bodied zooplankton displayed higher biomass in lakes with high occurrences of bedfast ice, while small-bodied zooplankton (Bosmina, rotifers) displayed highest biomass in deeper lakes with low occurrences of bedfast ice. Our results contribute to limited knowledge of zooplankton in remote lakes of the ACP and suggest that the anticipated changes to aquatic ecosystems in the Arctic may include energetically less efficient plankton food webs.

Interannual variability of larval fish assemblages associated with water masses in winter in the Taiwan Strait during 2007–2013

“…4; ranging from 0.01 to 0.12), giving confidence that the MDS plots are an accurate representation of the station relationships. Similar situations in the cutting of similarity were found in previous studies (Zhang et al 2018;Beaver et al 2019;Nandy and Mandal 2020).…”

Arctic roads and railways: social and environmental consequences of transport infrastructure in the circumpolar North

“…Research in central Europe has shown that road crossings negatively affect the richness and abundance of benthic macro-invertebrates (animals living on stream beds that are a food supply to birds and fish), including protected species (Gál et al 2020). In a study of Alaskan hydrological networks, the observations suggested an effect of hydrological connectivity on food web composition, with large-bodied zooplankton more prevalent in poorly connected lakes with low fish diversity (Beaver et al 2019). Fish are especially sensitive to transport infrastructure as barriers to migration, but also because of effects on habitat quality including temperature, suspended sediments, food supply and the timing and magnitude of water flow (Trombulak and Frissell 2000).…”

Classifying connectivity to guide aquatic habitat management in an arctic coastal plain watershed experiencing land use and climate change

“…Emerging research from other watersheds in Alaska highlights the role of ephemerally connected habitats in supporting shifting habitat mosaics (Brennan et al 2019) and off-channel habitats (Huntsman and Falke 2019), which ultimately result in more resilience of fish communities to land use and climate change. Fish research from ACP watersheds distinctly shows higher diversity and the presence of species with subsistence value in lakes with higher connectivity (Haynes et al 2014;Laske et al 2016;Jones et al 2017), yet shallow disconnected lakes are also shown to support very high plankton and planktivorous fish productivity (Beaver et al 2019) and even provide habitat for certain life history stages of subsistence species (Heim et al 2019). At the watershed and landscape scales, the composition of catchments with varying degrees of connectivity likely plays an important role in fish community diversity and productivity such that managing for a balance of habitat connectivity classes should be prioritized.…”