Abstract
Simple SummaryFew studies refer to ecological differences of genetically close and morphologically almost identical insectivorous bat species. However, this information is indispensable for effective and sustainable nature conservation strategies. This study aims at investigating differences in the spatial ecology of the long-eared bat species Plecotus auritus and Plecotus austriacus in a typical cultural landscape of Brandenburg, where the two species occur sympatrically. The reconstruction of the prey spectrum revealed that P. auritus and P. austriacus strongly overlapped in their diet. Our results suggest that resource partitioning is based on using different foraging habitats. While radio-tracked females of P. auritus were strongly associated with woodland patches resulting in small-scale activity areas of only few square kilometers, activity areas of P. austriacus encompassed a large-scale matrix of grassland habitats in the magnitude of a small town. Based on these results, we identify priority conservation needs for the two species to ensure that these differences in the spatial behavior and habitat use can be adequately taken into account for future nature conservation efforts.Movement behavior and habitat use of the long-eared bat species Plecotus auritus and Plecotus austriacus were studied in the Havelland region in Brandenburg (Germany). Data collection included mist-netting, radiotelemetry, reconstruction of prey items, and monitoring of roosting sites. Body measurements confirm a high degree of phenotypic similarity between the two species. Total activity areas (100% Minimum Convex Polygons, MCPS) of Plecotus austriacus (2828.3 ± 1269.43 ha) were up to five-fold larger compared to Plecotus auritus (544.54 ± 295.89 ha). The activity areas of Plecotus austriacus contained up to 11 distinct core areas, and their mean total size (149.7 ± 0.07 ha) was approximately three-fold larger compared to core areas of Plecotus auritus (49.2 ± 25.6 ha). The mean distance between consecutive fixes per night was 12.72 ± 3.7 km for Plecotus austriacus and 4.23 ± 2.8 km for Plecotus auritus. While Plecotus austriacus was located most frequently over pastures (>40%) and meadows (>20%), P. auritus was located mostly within deciduous (>50%) and mixed forests (>30%) in close vicinity to its roosts. Roost site monitoring indicates that the activity of P. austriacus is delayed relative to P. auritus in spring and declined earlier in autumn. These phenological differences are probably related to the species’ respective diets. Levins’ measure of trophic niche breadth suggests that the prey spectrum for P. auritus is more diverse during spring (B = 2.86) and autumn (B = 2.82) compared to P. austriacus (spring: B = 1.7; autumn: B = 2.1). Our results give reason to consider these interspecific ecological variations and species-specific requirements of P. auritus and P. austriacus to develop adapted and improved conservation measures.
Highlights
Species that share habitats as well as ecomorphological features due to adaptive convergence or phylogenetic proximity pose a challenge to conservationists and require enhanced conservation strategies [1,2]
Plecotus austriacus contained up to 11 distinct core areas, and their mean total size (149.7 ± 0.07 ha) was approximately three-fold larger compared to core areas of Plecotus auritus (49.2 ± 25.6 ha)
The principal component analysis (PCA) scatterplot shows a substantial overlap between P. auritus and P. austriacus along the two axes
Summary
Species that share habitats as well as ecomorphological features due to adaptive convergence or phylogenetic proximity pose a challenge to conservationists and require enhanced conservation strategies [1,2]. The coexistence of sympatric species is facilitated by sufficient competitiondriven ecological differentiation [8,9], in most cases through the division of limiting resources (resource partitioning). Where the niches of two species are highly similar (i.e., high degree of niche overlap), out-competing can occur if the resource in question is limited. In most cases, competing species overlap in various aspects of their biology with only minor, but still qualitative, differences in their ecological niches (e.g., roosting behavior, habitat preferences). This can complicate current approaches to define reasonable conservation measures. There are examples of co-occurring species that are primarily limited by only a single resource [14], and recent studies indicate that nature conservation measures for such species do not take this into account sufficiently
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