The challenge posed by newly discovered cryptic species: disentangling the environmental niches of long-eared bats
Correspondence: Marianne Rutishauser, Division of Conservation Biology, Institute of Ecology and Evolution, Baltzerstrasse 6, CH - 3012 Bern, Switzerland.
The discovery of cryptic species poses new challenges for species conservation. Species distributions and conservation status have to be re-evaluated, and the ecological requirements within the species complex have to be re-assessed to recommend adequate conservation guidelines. The recent discovery in Central Europe of the cryptic bat species Plecotus macrobullaris (Kuzjakin 1965) calls for a new appraisal of all three Plecotus species in that area.
Using mostly DNA-identified records, we investigated the environmental niches (ecological niche factor analysis) of the three long-eared bat species at the landscape scale and modelled their potential distributions. Discriminant analysis was used for interspecific niche comparisons.
The occurrence of all three species was best explained by proximity to rural settlements and warm summer temperature. Plecotus auritus (Linnaeus, 1758) was positively associated with transition zones from forests to other habitats within heterogeneous landscapes; Plecotus austriacus (J. Fischer, 1829) was more frequently found in orchards and vineyards. Plecotus macrobullaris was linked mostly with deciduous forests. P. auritus had the broadest niche, with occurrence predicted in most forested regions throughout Switzerland. The slightly narrower niche of P. macrobullaris mainly encompassed areas in the Central and Southern Alps. P. austriacus showed a very narrow niche and was predicted mainly in the lowlands, with its habitat requirements overlapping those of P. macrobullaris. Although a range overlap was predicted between P. austriacus and P. macrobullaris, current observations suggest a mostly parapatric distribution in Switzerland.
The projected distributions confirm previous knowledge for P. auritus, but shed new light on the other two species. In contrast to the newly discovered P. macrobullaris, which is actually widespread in the Southern Alps of Switzerland, P. austriacus is restricted to warmer cultivated lowlands and thus may have suffered from recent major land use changes. We suggest reclassifying P. austriacus to a higher conservation status.