Characteristics, Main Impacts, and Stewardship of Natural and Artificial Freshwater Environments: Consequences for Biodiversity Conservation

Abstract

In this overview (introductory article to a special issue including 14 papers), we consider all main types of natural and artificial inland freshwater habitas (fwh). For each type, we identify the main biodiversity patterns and ecological features, human impacts on the system and environmental issues, and discuss ways to use this information to improve stewardship. Examples of selected key biodiversity/ecological features (habitat type): narrow endemics, sensitive (groundwater and GDEs); crenobionts, LIHRes (springs); unidirectional flow, nutrient spiraling (streams); naturally turbid, floodplains, large-bodied species (large rivers); depth-variation in benthic communities (lakes); endemism and diversity (ancient lakes); threatened, sensitive species (oxbow lakes, SWE); diverse, reduced littoral (reservoirs); cold-adapted species (Boreal and Arctic fwh); endemism, depauperate (Antarctic fwh); flood pulse, intermittent wetlands, biggest river basins (tropical fwh); variable hydrologic regime—periods of drying, flash floods (arid-climate fwh). Selected impacts: eutrophication and other pollution, hydrologic modifications, overexploitation, habitat destruction, invasive species, salinization. Climate change is a threat multiplier, and it is important to quantify resistance, resilience, and recovery to assess the strategic role of the different types of freshwater ecosystems and their value for biodiversity conservation. Effective conservation solutions are dependent on an understanding of connectivity between different freshwater ecosystems (including related terrestrial, coastal and marine systems).

Diatom Species Richness in Swiss Springs Increases with Habitat Complexity and Elevation

“…Thus, while plants as well as meso-and macrofauna typically show strongly decreasing diversity towards higher elevations in the Alps [75,76] and other mountains [34], we found weakly increasing species richness for diatoms. The lack of a richness decrease, in spite of increasing environmental harshness with elevation, might be due to the "azonal" character of spring habitats that often act in many ways as refugia for different organisms including diatoms [77,78]. Weak elevational richness patterns have also been found in other microorganisms such as bacteria [6].…”

Jumping into the grids: mapping biodiversity hotspots in groundwater habitat types across Europe

“…Groundwater communities consist of distantly related taxa, thus they are characterized by high taxonomic disparity. High endemicity and high taxonomic disparity would determine several phylogenetic lineages to become extinct (Galassi et al 2009, Cantonati et al 2020, sometimes before being discovered (Mammola et al 2019b), due to anthropogenic disturbance. In spite of this, records are still scanty and the groundwater biodiversity remains underestimated (Racovitzan shortfall; Ficetola et al 2019), despite some taxonomic groups are even richest in the underground.…”

Environmental variables driving species composition in subarctic springs in the face of climate change

“…Spring ecosystems are important hotspots of biodiversity (Scarsbrook et al, 2007;Cantonati et al, 2012;Ilmonen et al, 2012;Cantonati et al, 2020). These islet-like systems may be critical for maintaining a high biodiversity because of the specific and stable habitat conditions they provide: high water quality, thermal constancy, and low seasonal variability (Odum, 1971;Hobbie, 1984;Callaghan, 2005;Wrona et al, 2005;Audorff et al, 2011;Cantonati et al, 2012;Glazier, 2012).…”

“…These islet-like systems may be critical for maintaining a high biodiversity because of the specific and stable habitat conditions they provide: high water quality, thermal constancy, and low seasonal variability (Odum, 1971;Hobbie, 1984;Callaghan, 2005;Wrona et al, 2005;Audorff et al, 2011;Cantonati et al, 2012;Glazier, 2012). These factors result in distinct species composition and higher species richness, often including highly specialized organisms, and higher incidence of rare and red-listed species than in surrounding areas with disparate environmental conditions (Rosenzweig, 1995;Cantonati et al, 2009;Gerecke et al, 2011;Tomaselli et al, 2011;Cantonati et al, 2012;Cantonati et al, 2020). Additionally, helocrenic -or seepage -springs are characterized by diffuse outflow and low water current velocity, as well as gentle sloping and rare flooding events, all of which provide a more conducive environment for the establishment of a wide variety of plant species, diatoms, and benthic invertebrates (Rosenzweig, 1995;Cantonati et al, 2009;Gerecke et al, 2011;Ilmonen et al, 2012;Spitale et al, 2012).…”