Distribution of Trichoptera communities in the Hozgargantacatchment (Los Alcornocales Natural Park, SW Spain)

Abstract

The distribution of Trichoptera of the Hozgarganta River (Los Alcornocales Natural Park, SW Spain) in relation with environmental factors was examined.Three groups of species were recognised according to the altitudinal gradient. In the headwaters the caddisflies Rhyacophila fonticola, Lepidostoma hirtum, Silonella aurata, Allogamus gibraltaricus, Hydropsyche infernalis and Diplectrona felix predominated; in the constrained section of the tributaries Polycentropus kingi, Chimarra marginata, Hydropsyche iberomaroccana, R. fonticola and Tinodes sp. prevailed; finally, in the main channel H. iberomaroccana, C. marginata, Hydropsyche lobata, Leptocerus lusitanicus and Rhyacophila munda were the most important species. A direct ordination analysis (CCA) was used to describe assemblage changes among sites and corroborated that conductivity and temperature were the variables that best explained Trichoptera distribution.The temporal analysis showed changes in the Trichoptera diversity and richness in permanent stretches, as well as variations in the structure of the communities according to the season. We identified autumn-winter species (H. infernalis, H. siltalai, H. lobata, R. fonticola and R. munda) and summer ones (Ithytrichia sp, Oxyethira unidentata, Mystacides azurea and Setodes argentipunctellus). In the basin we distinguished permanent, intermittent and ephemeral reaches with similar caddisfly richness and diversity, however the species composition associated with each one was different.

Life cycle phenology, secondary production, and trophic guilds of caddisfly species in a lake-outlet stream of Patagonia

“…Likewise Miserendino and Brand (2007) report discharge and POM as important variables in determining caddisfly community composition. Our results also showed differences in the community structure in each season, with clear differences in autumn-winter and summer assemblages, this is in agreement with observations by Ruiz García et al (2006) at headwater Mediterranean streams. However, only part of the seasonal variation in our data was explained by the RDA, other factors such as competition and predation could account for the unexplained variance in density data (Huryn and Wallace 2000;Allan and Castillo 2007).…”

Life history strategies and production of caddisflies in a perennial headwater stream in Patagonia

“…According to our results (RDA analysis), seasonally dynamic variables such as water temperature, discharge, and detritus availability were the main predictors of caddisfly assemblage variation at our study site. These variables are commonly identified as determinants of temporal patterns of aquatic insects in perennial streams, draining deciduous forest (Miserendino & Pizzolón, 2003, 2004Hughes, 2006;Ruiz García et al, 2006;Miserendino & Brand, 2007). As stated by Lytle & Poff (2004) when the timing of floods and droughts is sufficiently predictable among years, the life history strategy of organisms is generally synchronized.…”

High Variability Is a Defining Component of Mediterranean-Climate Rivers and Their Biota

“…Nevertheless, macroinvertebrates are by far the most investigated group and studies on seasonal changes have focused on whole communities as well as the composition of particular taxonomic groups (e.g., Plecoptera [67]; Trichoptera [68]; or Chironomidae [69]). …”