Aquatic molluscs in high mountain lakes of the Eastern Alps (Austria): Species-environment relationships and specific colonization behaviour |
| |
| Authors: | Robert Sturm |
| |
| Institution: | 1. Brunnleitenweg 41, A-5061, Elsbethen, Salzburg, Austria
|
| |
| Abstract: | Mountain lakes represent essential stages for aquatic species on their way colonizing habitats of more elevated regions. Despite
extensive biological and chemical study, only little has been reported about the species number and density of freshwater
molluscs in these waters. The article presented here elucidates the dispersal of aquatic gastropods and bivalves in 12 mountain
lakes that are commonly situated in the Eastern Alps, Austria. Molluscs were recorded at 120 sample points, where a total
of 13 species (8 gastropods and 5 bivalves) could be determined. Species distribution data as well as results from contemporarily
conducted physico-chemical factor recording were subject to weighted average analysis. In addition, a global marginality coefficient
indicating the particularity of a habitat inhabited by a focal species as well as a global tolerance coefficient expressing
the width of a niche occupied by this species were computed. Species-environment relationships exhibited that species number
and specific density decrease with increasing geographic altitude, declining water temperature, and decreasing amount of submerged
vegetation. Whilst waters of the montane altitude level are partly charcterized by high number of mollusc species (> 10),
lakes of the subalpine altitude level commonly bear 1 or 2 species with ≪1 ind./m2. As proposed by the results of statistics, 9 of the 13 mollusc species are characterized by a pronounced behaviour as specialists
with respect to most environmental factors. The four remaining species, Pisidium casertanum, Galba truncatula, Radix labiata, and Radix balthica, act as generalists which increases their pioneering role in the long-term occupation of the Central-alpine region. |
| |
| Keywords: | aquatic invertebrates species abundance weighted average analysis global marginality coefficient global tolerance coefficient Eastern Alps |
| 本文献已被 CNKI SpringerLink 等数据库收录！ |
|
