Quantification of environment-driven changes in epiphytic macroinvertebrate communities associated to Phragmites australis

Abstract

The epiphytic macroinvertebrate communities associated with the Common Reed, Phragmites australis (Cav.) Trin. ex Steudel, were examined seasonally from summer 2004 to spring 2005 in eleven coastal lagoons of the Llobregat Delta (NE Spain) following the method proposed by Kornijów & Kairesalo (1994). The aims of the study were to: 1) characterise and quantify changes in epiphytic macroinvertebrate communities along environmental gradients; 2) assess the contribution of elements of the epiphytic compartment to structuring the community; 3) define the optima and tolerances of selected epiphytic macroinvertebrate taxa for the most relevant ecological factors responsible for assemblage composition; and 4) identify possible epiphytic species assemblages that would allow a lagoon’s typology to be established, as well as their representative indicator species. Communities showed statistically significant seasonal variation, with two faunal peaks: one in summer, with high chironomid densities, and the other in winter, with high naidid densities. These peaks showed a clear response to the influence of environmental factors. Salinity explained the highest percentage of total variance (36%), while trophic variables (nutrients, phytoplanktonic chlorophyll-a, and total organic carbon) and epiphyton biomass (19.2 and 4% of total variance explained, respectively) were secondary. Three different epiphytic macroinvertebrate species assemblages could be defined. These assemblages were directly linked to conductivity conditions, which determined the rate of survival of certain taxa, and to the existence of a direct connection with the sea, which permitted the establishment of "brackish-water" species. In spite of the existence of these species assemblages, the species composition and biomass of epiphytic macroinvertebrates and epiphyton differed substantially between lagoons; both elements were subject to changes in the environment, which finally determined the site-to-site variation in the density and composition of the macroinvertebrate population

Patterns of salinity regime in coastal lakes based on structure of benthic invertebrates

“…Understanding of the mutual relationships between the composition and distribution of biological communities and changing environmental conditions at the local or regional level is one of the major challenges of ecological research [ 28 ]. Partitioning of diversity measures enables us to understand better the mechanisms that shape the structure of communities along environmental gradients [ 8 ], such as salinity in coastal lakes [ 45 ].…”

“…Besides, both physical and biological processes can proceed differently in transitional zones, so groups of benthic fauna react differently, too the benthic macrofauna plays a major role in the food cycle, decomposition of detritus, and as a source of food for higher trophic levels, and some species of this group are sensitive indicators of changes in marine habitats [ 27 ]. Also, in estuaries, colonized by marine and freshwater organisms, changes in the structure of benthic fauna reflect environmental changes [ 8 , 18 , 28 ]. This applies to assessment of the role of hydrodynamic factors on sedimentation rate and resuspension of sedimented particles [ 29 ], as well as spatial changes in physico-chemical properties of water [ 30 , 31 ] observed a close relationship between the rate and direction of water flow and the distribution of macrofauna.…”

Spatial distribution of epiphytic chironomid larvae in a shallow macrophyte-dominated lake: effect of macrophyte species and food resources

“…ex Steud.) are mostly affected by nutrients, epiphytic chlorophyll-a, periphyton biomass, reed density and total organic carbon (Cañedo-Argüelles and Rieradevall 2009;Tarkowska-Kukuryk 2011). Nevertheless, the determinants governing spatial distribution of chironomid species between macrophytes in clear-water lakes are still not well recognised.…”

Chironomidae larvae in hypersaline waters of the Crimea: diversity, distribution, abundance and production

“…All this leads to the conclusion that the physiological capabilities do not define the upper level of salinity at which Chironomidae naturally inhabit water bodies, and the biotic environment (algal concentration and composition) is just as important. Both elements -salinity and microalgae developmentare changing in the water bodies and determine the site-to-site and temporal variability of chironomid larva composition and density in hypersaline waters, as was shown for brackish waters (Cañedo-Argüelles & Rieradevall 2009). Hypersaline water bodies in Crimea are characterized by high variability; many of them are partially temporal or dry completely.…”