Influences of habitat type and environmental variables on littoral macroinvertebrate communities in a large lake system

Abstract

The community structure of littoral macroinvertebrates was explored by multivariate analyses in three basins of the large Lake Saimaa system (eastern Fin land). The basins differed in trophic status and degree of human influence. It was hypothesized that the structure of littoral invertebrate communities is influenced by lake trophic status, as is the case in profundal communities. Three littoral habitat types with different substrate (stony, sandy and vegetated shores) were sampled from the shoreline to a depth of 1.5-3 meters. The habitat type was found to be largely deter mined by the slope of the shore and the wind exposure. Each habitat type supported fairly characteristic fauna, and detrended correspondence analysis grouped the inverte brate assemblages by habitat type rather than by basin. Within each habitat type, canonical correspondence analysis indicated that species composition changed along the trophic gradient. In the vegetated littoral zone, the greatest change in community structure occurred within the macrophyte beds, varying from the outer edge of macro phytes to the shoreline. Two alternative or complementary explanations are given for this horizontal gradient. First, a horizontal gradient of abiotic characteristics results in a change of community composition. Second, the macrophyte beds may form a hori zontal transition zone in predation, from invertebrate predation inshore to fi sh preda tors offshore. On the stony and sandy shores, the magnitude of wave action was also important in structuring the communities. As each habitat type harbors characteristic

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

“…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.…”

Influência da heterogeneidade ambiental sobre os atributos da comunidade de Chironomidae em lagoas de inundação neotropicais

“…Todas essas características nas lagoas contribuem para o aumento da heterogeneidade ambiental, alterando a estrutura dos ambientes, que é um fator determinante na distribuição das comunidades (downes et al, 2000;toLonen et al, 2001). Os ambientes mais complexos sustentam maior diversidade e riqueza de espécies que os ambientes mais simples (wiLLiaMs, 1964;BeLL et al, 1991;downes et al, 2000;shosteLL & wiLLiaMs, 2007), pois quanto maior a heterogeneidade ambiental, maior é a disponibilidade de nichos e de recursos alimentares (tews et al, 2004; townsend et al, 2006).…”

“…Nesse sentido, a estrutura do ambiente é um importante fator que influencia a distribuição das comunidades (MacaRthuR & MacaRthuR, 1961;downes et al, 2000;toLonen et al, 2001) e determina diferenças na diversidade, onde ambientes fisicamente mais complexos sustentam maior riqueza de espécies que aqueles mais simples (wiLLiaMs, 1963;BeLL et al, 1991;downes et al, 2000;shosteLL & wiLLiaMs, 2007). Essa maior diversidade de espécies em relação à heterogeneidade ambiental está relacionada à maior disponibilidade de nichos e recursos alimentares, possibilitando assim a coexistência de um maior número de espécies em uma mesma área (scognaMiLLo et al, 2003;tews et al, 2004;townsend et al, 2006).…”

Are the effects of an invasive crayfish on lake littoral macroinvertebrate communities consistent over time?

“…The study sites had comparable key habitat features (substratum particle size, slope; Bjurström et al, 2010;Ruokonen et al, 2014), and water quality (Hertta environmental database, Finnish Environment Institute), all of which are known to shape the structure of littoral communities (Tolonen et al, 2001).…”

“…Benthic macroinvertebrates were sampled using a system powered by a water pump operated from a boat (Tolonen et al, 2001). A scuba diver cleaned a framed area of bottom (0.25 m 2 ) sucking up the sample to a sieve of mesh size 0.5 mm (see Ruokonen et al, 2014 for a more detailed description).…”