The use of littoral mesohabitats and their macroinvertebrate assemblages in the ecological assessment of lakes

-The macroinvertebrate fauna of twenty-one ponds (thirteen temporary and eight permanent) located in four protected areas in Central Italy were studied in March, May and June 2002, with the aim to bring out relationships between environmental variables and the functional characteristics (functional feeding groups, habits and resistance to drought) of communities. Macroinvertebrates were collected in three mesohabitat types (macrophyte beds, littoral sediments, central sediments). Overall, the functional attributes of temporary and permanent pond communities did not differ greatly. However, at the mesohabitat scale, collector-gatherers, burrowers and permanent residents capable of passive dispersal were more abundant in sediments. Scrapers and shredders, sprawlers and climbers, swimmers and divers, and organisms capable of active dispersal which lack drought resistance were more abundant in macrophyte beds. Although hydroperiod is the main driving factor affecting community structure, our results suggest that it remains an unimportant factor in controlling functional traits, which appeared to be more influenced by substratum types. Moreover, the positive relationship between taxonomic and functional diversity metrics indicates that an increase in taxonomic richness induces a satisfactory partitioning of the ecological resources among taxa, thus maintaining the ecological complexity of the ponds regardless of their hydroperiod length.

Section: Sampling and Laboratory Methodsmentioning

confidence: 99%

Functional characteristics of macroinvertebrate communities in Mediterranean ponds (Central Italy): Influence of water permanence and mesohabitat type

Bazzanti

Bella

Grezzi

2009

“…Habitat complexity also influences the composition of the freshwater assemblages (Heino, 2000;Tolonen et al, 2001;White and Irvine, 2003). Coffman (1995Coffman ( , 1989 proposed ecological heterogeneity as one of the main factors influencing chironomid species richness.…”

Section: Spatial Variability: Hydromorphological and Physicochemical mentioning

confidence: 99%

Environmental factors – spatial and temporal variation of chironomid communities in oceanic island streams (Azores archipelago)

Raposeiro

Costa

Hughes

2011

-Freshwater systems on volcanic oceanic islands have very particular characteristics as a result of their geological origins, relatively small size, distances from source areas for colonizers, and distinct catchment morphology. These factors result in freshwater communities that are clearly distinct from continental systems. Chironomid spatial and temporal distribution was investigated in chironomid assemblages at 21 sites across the Azores Archipelago. Results using PERMANOVA, a permutational multivariate analysis of variance, indicated significant longitudinal differences in assemblages but none between islands or over time.Links between hydromorphological and physicochemical variables and the community assemblage were assessed using DISTLM, a linear model for distance-based multivariate analysis. The percentage of variation explained by hydromorphological factors (31%) was slightly higher than that explained by physicochemical (28%) factors. Descriptors of land use (forest area, scrub area, natural area of catchment) and stream slope were found to be the best environmental predictors of chironomid assemblages in Azores. Physicochemical variables such as temperature, pH, nitrite, iron and conductivity were the principal drivers of change in chironomid composition in stream locations. Headwater sites, characterized by lower temperature, acid to neutral pH values, low conductivity, nutrient and metal concentrations were dominated by Rheocricotopus atripes. Mid-section sites, located in agricultural areas were dominated by Thienemanniella clavicornis. Urbanized lower reaches were characterized by higher temperature, pH, conductivity and nutrient levels and were dominated by Cricotopus sp. These results give essential information that allows us to predict the response of different chironomid species to hydromorphological and physicochemical gradients across the archipelago's streams contributing providing the basis for the development of tools for the implementation of the Water Frame Directive.

“…(Cyr & Downing 1988, Kornijów & Gulati 1992, Cattaneo et al 1998, Cheruvelil et al 2000, White & Irvine 2003. The general view of Peeters et al (2004) that biotic factors are more important at a local scale and environmental factors determine distribution of species at larger scales may explain our results.…”

Section: Discussionmentioning

confidence: 51%

Macroinvertebrate communities in sediment and plants in coastal Mediterranean water bodies (Central Iberian Peninsula).

Sahuquillo

Poquet

Rueda

et al. 2007

Sediment and plant-associated macroinvertebrates were sampled in six shallow water bodies along the central part of the coast of Mediterranean Spain. The size of ponds, salinity and hydroperiod were highly variable. Seventy-one taxa were recorded, some of them were endemic or uncommon species, evidencing the important contribution of these ponds to biodiversity. Crustaceans and gastropods of biogeographical interest were found in the most primeval site. Correspondence analysis showed that macroinvertebrate assemblages responded to environmental variables such as salinity, temporality and eutrophication. The brackish water fauna was dominated by crustaceans, while oligochaeta and insect larvae were abundant in freshwater conditions. Oligochaetes were abundant at localities with high trophic level, whereas localities with semi-permanent waters were dominated by chironomids. The density of macroinvertebrates was clearly related with trophic state but we did not find significant relationships between density and salinity or water permanence. For plant associated samples our results showed negative relationships between species richness and temporality or salinity, contrary to sediment samples, where the Oligochaeta/Chironomidae ratio in sediments and the percentage of sensitive taxa (Ephemeroptera, Odonata, Trichoptera) were useful indices, and were dependent on pond typology. This study emphasizes the broad ecological variety of ponds found in these wetlands and their importance for biodiversity. Some ponds act as permanent biodiversity reservoirs in fluctuant marshes with seasonal dryness, calling for more attention on their ecological relevance for management strategies.