Human activities are significantly affecting biodiversity on a global scale. Beyond the decline in species numbers, the composition of entire species communities is undergoing profound changes. In our study, published in Nature, we highlight these shifts. Our research stands among the most extensive studies ever conducted on the subject.
Cryptic freshwater species contribute to biodiversity, but their community integration remains unclear. In a recent study published in Freshwater Biology, we examined local and regional co-occurrences of cryptic amphipod species to understand the role of phylogenetic relationships in shaping biodiversity patterns. Our findings suggest that regional overlap results from dispersal rather than phylogenetic relatedness, with sympatries occurring more frequently among species from different clades. Ultimately, spatial patterns reflect historical events like mountain formation and climatic shifts, influencing biodiversity at local and regional scales.
As part of Mara Knüsel’s impressive PhD work, we publisehd a paper in Ecography that explores how Late Pleistocene glaciation influenced the diversity and distribution of 36 groundwater amphipod species in the Alpine and peri-Alpine regions. It is based on a massive citizen science approach in collaboration with drinking water providers. The analysis, based on data from over 1,000 systematic sampling sites across Switzerland, reveals a significant impact of the Last Glacial Maximum (LGM) ice extent on the current distribution of groundwater amphipods. The findings highlight a pronounced species turnover and distinct spatial envelopes of species occurrences in zones that were formerly ice-covered, ice-free, or transitional.
The genus Niphargus, the most diverse subterranean amphipod genus in the western Palearctic, shows many cryptic species and homoplasy, necessitating molecular methods for understanding its evolution. In a new study, published in Contributions to Zoology, we used DNA-based taxonomy and traditional morphotaxonomy to study Niphargus bihorensis Schellenberg, 1940, from the Western Alps and Carpathians. The type material from Bihor County, Romania, revealed a cryptic species, N. absconditus n. sp., in the same area. Furthermore, we describe the Alpine populations as a new species, N. tizianoi n. sp. Our phylogenetic analyses suggest the N. bihorensis species complex is part of a well-supported clade with species ranging from Switzerland to Iran.
We published a study of 99 small Swiss streams in Aqua & Gas which reveals that most of these streams have significant ecological deficits, limiting their ability to serve as habitats for animals. In over 70% of the streams studied, pesticide-sensitive insect larvae and other small animals are partially missing. Statistical analyses show that these aquatic organisms are particularly affected when the stream bed structure and morphology have been altered or when the catchment area has a high proportion of agricultural land.
