Environmental determinants of lake macrophyte communities in Baikal Siberia

Abstract

We investigated whether environmental filtering or dispersal-related factors mostly drive helophyte and hydrophyte species richness and community composition in 93 lakes situated in Baikal Siberia. Using partial linear regression and partial redundancy analysis, we studied (1) what are the relative roles of environmental variables, dispersal variables, spatial processes and region identity (i.e., river basins) in explaining variation in the species richness and species composition of helophytes and hydrophytes across 93 Siberian lakes, and (2) what are the differences in the most important explanatory variables driving community variation in helophytes versus hydrophytes? We found that, for both species richness and species composition, environmental variables clearly explained most variation for both plant groups, followed by region identity and dispersalrelated variables. Spatial variables were significant only for the species composition of hydrophytes. Nutrient-salinity index, a proxy for habitat trophic-salinity status, was by far the most significant environmental determinant of helophytes and hydrophytes. Our results indicate that environmental factors explained the most variation in both species richness and species composition of helophytes and hydrophytes. Nevertheless, dispersal-related variables (i.e. spatial and dispersal) were also influential but less important than environmental factors. Furthermore, the dispersal-related variables were more important for hydrophytes than for helophytes. Most brackish permanent lakes were mostly located in the steppe biomes of southern Transbaikalia. This characteristic along with the oldest age, the largest distances to both river and settlements and the lowest temperatures in the study region distinguished them from freshwater, drained and more nutrient-rich floodplain lakes.

Macroecology of macrophytes in the freshwater realm: Patterns, mechanisms and implications

“…This has been shown, for example, for aquatic macrophyte communities in hundreds of US lakes (Capers et al, 2010;Mikulyuk et al, 2011;Alahuhta and Heino, 2013), for Fennoscandian and Siberian lakes (Alahuhta et al, , 2020b, and for plant species richness variation in European lakes Viana et al, 2014). However, joint effects of environment and space often override pure environmental effects due to strong geographical structuring of key water quality and hydromorphology variables, or because spatially-explicit environmental variables were missing from the studies (Mikulyuk et al, 2011;O'Hare et al, 2018;Alahuhta et al, 2020b). In addition, spatial factors have often explained significant variation in lake macrophyte communities (Capers et al, 2010;Mikulyuk et al, 2011).…”

“…In lakes, environmental filtering is typically more important than spatial processes in explaining plant community variation, especially in glacial-originated lakes. This has been shown, for example, for aquatic macrophyte communities in hundreds of US lakes (Capers et al, 2010;Mikulyuk et al, 2011;Alahuhta and Heino, 2013), for Fennoscandian and Siberian lakes (Alahuhta et al, , 2020b, and for plant species richness variation in European lakes Viana et al, 2014). However, joint effects of environment and space often override pure environmental effects due to strong geographical structuring of key water quality and hydromorphology variables, or because spatially-explicit environmental variables were missing from the studies (Mikulyuk et al, 2011;O'Hare et al, 2018;Alahuhta et al, 2020b).…”

Sedimentary DNA identifies modern and past macrophyte diversity and its environmental drivers in high‐latitude and high‐elevation lakes in Siberia and China

“…Because only some macrophytes prefer high ion concentrations, the overall macrophyte richness is reduced compared to Siberian lakes. Several other studies from different geographic areas covering shorter conductivity gradients also find that conductivity is significantly related with macrophyte richness and note decreased richness with increasing lake conductivity, as exemplified in alpine lakes (Hinden et al 2005) and in Baikal Siberia lakes (Alahuhta et al 2020). Our study also finds that moderate conductivity has a positive effect on macrophyte richness, whereas eutrophic to hypertrophic conditions favor only a few saline‐tolerant species such as the submerged Stuckenia (in our data putatively ASV Stuckenia sp.…”

Community stability and seasonal biotic homogenisation emphasize the effect of the invasive tropical tanner grass on macrophytes from a highly dynamic neotropical tidal river

“…Within an ecosystem without barriers for dispersal, environmental filtering of species is the predominant factor. Characteristics such as nutrient concentrations (Lacoul and Freedman 2006 ) and salinity are important drives of macrophyte communities (Alahuhta et al 2020 ) and, in this sense, precipitation is expected to be a key factor shaping macrophyte communities (Pavão et al 2017 ), given it can directly control nutrient load, physico-chemical characteristics, and also affect species’ dispersion particularly in environments with seasonal differences in rainfall and with geographic features that highlight effects of rain in hydrology.…”