Ephemeroptera, Plecoptera and Trichoptera in springs in Trentino (south-eastern Alps)

Within the CRENODAT project (Biodiversity assessment and integrity evaluation of springs of Trentino - Italian Alps - and longterm ecological research, 2004-2008) we studied a total of 90 springs in Trentino (south-eastern Alps, Italy), 75 of which were used for statistical analysis. The springs were grouped into seven different types and represented all the available lithologies in the study area. Macrozoobenthos (Ephemeroptera, Plecoptera and Trichoptera; EPT) was collected from stones, bryophytes and sediments. We investigated which physical, chemical or environmental features were important in determining EPT assemblage metrics at sites, by calculating the Shannon-Wiener diversity index, and applying a one-way ANOVA test, ANOSIM and SIMPER analyses. Statistical results highlighted the island character of the springs, each spring having its specific history and abiotic characteristics, which select for unique community patterns. For the faunistic analyses, we considered all springs where EPT taxa were recorded; a total of 88 taxa. Highest species richness was recorded among the Trichoptera, followed by the Plecoptera and Ephemeroptera, with 52, 30 and 6 taxa respectively. Fifteen Trichoptera and three Plecoptera species were recorded as new for the Autonomous Province of Trento. Our results confirm that, in the harsh environment of the Alps, the mild and stable ecological conditions that characterize spring-fed brooks contribute to maintaining and enhancing the regional biodiversity. Springs act as refuge areas for stream biota, providing more favourable conditions during spates or droughts (common in Alpine headwaters), or for particular stages of the insect life cycles. Springs also provide specific habitats for strictly crenobiontic species.