Habitat type as strongest predictor of the body size distribution of Chydorus sphaericus (O. F. Müller) in small water bodies

Abstract

Chydorus sphaericus, a cladoceran characterized by a wide range of distribution, is often numerous in various water habitats. Its body size is a consequence of environmental characteristics and physiology. The aim of the study focused on the distribution of body size and densities of C. sphaericus in relation to environmental conditions represented by: (i) habitat types (elodeids, helophytes, and the open water); (ii) specific pond types (forest and field); (iii) pond size (surface area); (iv) the presence/lack of fish; and (v) physicochemical factors. Similar to large daphnids, in the case of the examined small water bodies, fish presence was responsible for a reduction of the body size of C. sphaericus in the zone of open water. More abundant crustacean communities and the presence of larger specimens were found among macrophytes, which indicated that aquatic vegetation offered optimal growth conditions as well as an effective refuge against fish predation. These facts reflect the necessity for maintaining a varied mosaic of habitats even in small water bodies such as the examined ponds. We found that not only the abundance of C. sphaericus but also its body size can be used as an bioindicator of environmental conditions as it preferred small and eutrophic ponds, particularly those with complex macrophyte cover (such as elodeids). Furthermore, the abundance pattern of zooplankton dominant species was affected by elodeids and fish presence as well as by the area of the ponds.

Impact of Habitat Complexity on Body Size of Two Spider Species, Alopecosa cuneata and A. pulverulenta (Araneae, Lycosidae), in River Valley Grasslands

“…The importance of structurally complex habitat as a refuge from predators especially confirmed research on water organisms. For example, the study of Chydorus sphaericus species belonging to Crustacea revealed that larger specimens occurred among macrophytes, and the smallest ones were in the open water zone, which indicated that vegetation was a significant refuge against predators [65].…”

The response of hydrophyte growth forms and plant strategies to river restoration

“…Furthermore, widened channels are expected to have larger areas with direct sunlight (due to reduced shading from riparian trees) and low water depth, which probably positively affected hydrophyte growth as also noted by Makkay et al (2008). Due to the importance of elodeid species as habitats and refuges for macroinvertebrates and fish (Strayer & Malcom, 2007;Basińska et al, 2014), the positive effect of widening on elodeids could potentially also have cascading ecological effects. Instream measures in our study comprised, among others, bolder replacement and gravel additions to increase salmonid spawning areas.…”

“…For example, the partial loss of aquatic macrophytes (Steffen et al, 2013) not only has severe consequences for macrophyte diversity but might also have cascading ecological effects due to the macrophytes' importance as habitat for other organism groups (Heck Jr. & Crowder, 1991;Strayer & Malcom, 2007;Basińska et al, 2014). Furthermore, aquatic macrophytes also function as ecosystem engineers (Asaeda et al, 2010;O'Hare et al, 2011) and influence river processes such as metabolism and nutrient cycling (Tabacchi et al, 1998).…”

Two microcrustaceans affect microbial and macroinvertebrate‐driven litter breakdown

“…Chydorus sphaericus is one the most common benthic cladoceran species (Giere, ), and has been reported living in the littoral zones of lakes among macrophyte vegetation and on benthic substrates that are rich in organic material (e.g. Giere, ; Basińska et al ., ), as well as in the water column in the open water zone of eutrophic lakes and ponds (Vijverberg & Boersma, ). Therefore, this taxa is probably better adapted to detrital food sources compared to large‐bodied pelagic cladocerans (Vijverberg & Boersma, ).…”

“…This is misleading since many cladocerans such as Chydorus sphaericus (Chydoridae) and cyclopoid copepods have been reported as living among macrophytes, organic rich benthos, and water column of lentic ecosystems (e.g. Giere, ; Basińska et al ., ). They perform diel vertical migrations concentrating near the bottom during the day and on the surface at night (Lauridsen et al ., ; Casper & Thorp, ; Semyalo, Nattabi & Larsson, ; Wallace et al ., ).…”