Search

Riparian habitats are biodiversity hotspots, however, despite their protection (e.g. in Natura 2000 sites) they are drastically transformed, particularly in more developed countries. The least inventoried, monitored and protected are submontane drainages composed of lowland and mountain habitats and species. Effective evaluation and monitoring of riparian habitat quality and species richness in submontane valleys is difficult and time consuming, but could be overcome by using indicator species. In this work, we verify if Goosander Mergus merganser could be considered as indicators of submontane valleys' naturalness and biodiversity. Data about Goosander occurrence in the Raba drainage (Polish Carpathians) were compared with several environmental variables and information about species richness of selected riparian animals. Goosander distribution and abundance depended on "naturalness" variables (high share of alluvia and scarps in river channels and forests on river banks), but association with hydrogeomorphology and the vicinity of humans was not found. Goosander abundance was found to be significantly correlated with bird species richness (both forest- and river-dwellers) and the presence of aquatic mammals (beavers and otters), but not with a richness of fish. Moreover, Goosander allows a high prediction accuracy to be achieved for the presence of aquatic animals (otters, beavers, woodpeckers and river-dwelling birds), among others, species annexed in EU directives. The correlation of Goosander abundance with the richness of riparian vertebrates, as well as with natural riparian habitats makes this bird a good candidate for an umbrella and flagship species. Moreover, using Goosanders as indicators would be a valuable method for preliminary valorization and further monitoring of habitats and species in Natura 2000 sites of Polish Carpathians. The utility of this species as bioindicator in other parts of the Carpathians should be verified after saturation of available areas by its populations. [ABSTRACT FROM AUTHOR]

Background: Thermal gradients along changes in elevation in mountainous environments are reflected by different biotas. Although there have been studies of elevation variation in bat assemblages in summer, winter changes in the same gradients remain unknown. Methodology/Principal Findings: The objective of this study was to document changes in the species composition of bats hibernating in caves along a temperate elevational gradient. We studied 70 caves between from 300 m to 1,930 m altitude along a slope of the Carpathian Mountains in southern Poland. We recorded changes in bats, including species richness, abundance, altitudinal distribution and dominance during consecutive winters between 2003 and 2009. Similarity of dominance of faunal structure was assessed by using the Bray-Curtis similarity index. We used the generalised additive model and rarefaction to study the variation in species richness, and generalized additive mixed models to examine the effect of abiotic factors on the qualitative and quantitative structure of bat assemblages. During 351 surveys we recorded 13,856 hibernating bats from 15 species. Species richness peaked around mid-elevation (1,100–1,400 m a.s.l.) with richness declining at both higher and lower elevations. Based on the results of a cluster analysis, we could distinguish among four altitudinal zones that differed in species richness and dominance structure. Conclusions/Significance: This is the first study documenting changes in species richness and variation of structure of bats hibernating in caves along an elevational gradient. The most surprising and key finding is the fact that changes in the structure of assemblages of hibernating bats along the altitudinal gradient occurred in jumps, forming zones similar to those observed in the vegetation zones. Moreover, species richness and dominance structure of assemblages of hibernating bats in the mountains depended not only on location above sea level, but also on local geomorphologic conditions which strongly affected the microclimate of the caves. [ABSTRACT FROM AUTHOR]