Effects of macrophyte heterogeneity and food availability on structural parameters of the macroinvertebrate community in a Pampean stream

Abstract

Environmental heterogeneity in natural ecosystems influences several parameters at the population and community levels. In freshwater ecosystems, habitat heterogeneity can be provided by macrophyte species with different structural shapes. Previous studies suggest that aquatic plants with more complex architectures will support higher number, biomass, and taxon richness of macroinvertebrates than plants with simpler shape. We investigated the influence of macrophyte structural heterogeneity (quantified by fractal dimension) and food availability (represented by epiphytic biomass) on several parameters (number of individuals, biomass, body size distribution, taxon richness, and diversity) of the macroinvertebrate community in a Pampean stream. Four submerged macrophyte species (Egeria densa, Elodea ernstae, Ceratophyllum demersum, and Stuckenia striata) and associated macroinvertebrates were sampled in late spring, summer, and autumn.

Structural and functional responses of the oligochaete and aeolosomatid assemblage in lowland streams: a one-way-pollution-modelled ecosystem

“…Accordingly, the total abundance, diversity, and species richness of the oligochaetes and the aeolosomatids were analysed in the vegetation samples as well as the sediment. Because of the specific variation in macrophytes recorded over the study period and between sampling sites, the associated assemblages could not be compared (Warfe and Barmuta, 2006;Ferreiro et al, 2011), although such a determination was possible in the sediment samples. A Student t-test was applied to compare the samples; and when the data were not normally distributed and/or had unequal variances, they were analysed by the Mann-Whitney Rank-Sum Test.…”

Colonization by oligochaetes (Annelida: Clitellata) in decomposing leaves ofEichhornia azurea(SW.) Kunth (Pontederiaceae) in a neotropical lentic system

“…These plants are often used by invertebrates as refuge for reproduction and protection against predators (Harrison et al, 2005;Ferreiro et al, 2011). The presence of macrophytes in aquatic environments increases the habitat's complexity, providing greater richness and density of invertebrates associated with these plants in relation to those associated with the sediment (Rennie and Jackson, 2005).…”

Potential of submerged macrophytes to support food webs in lowland agricultural streams

“…Sabina River), although they were potentially an important food for Chironomidae and Leptoceridae. The higher abundances of aquatic invertebrates often associated with macrophytes (Bell et al 2013) can be related to epiphyte biomass (Ferreiro et al 2011). Here, assimilation of δ 15 N-enriched epiphytes by most consumers was very high, and corresponding enrichment of consumer δ 15 N compared to other reaches provides further evidence that they were assimilating this resource (Bergfur et al 2009).…”

“…Although epiphytes were not apparent on the P. ochreatus and O. ovalifolia assemblage sampled here, morphologically complex assemblages such as this can provide important substrate for epiphytes (Warfe and Barmuta 2006;Ferreiro et al 2011). The assimilation of grass by several invertebrates was surprising, given that aquatic invertebrates are usually thought to avoid C-4 plants (Clapcott and Bunn 2003;Jardine et al 2013).…”

“…They also have potential to contribute to food webs both directly in the form of fresh or detrital material (Jacobsen and Sand-Jensen 1994;Kornijow et al 1995) and indirectly as a substrate for periphyton (Warfe and Barmuta 2006;Ferreiro et al 2011). However, river food web studies have often examined the relative importance of either terrestrial or algal inputs as the basis for stream food webs, excluding macrophytes, possibly because early research suggested low dependence of macroinvertebrates on macrophyte carbon (Hamilton et al 1992;Bunn and Boon 1993).…”