Dolines as microhabitat relief feature and their importance for Eurasian lynx (Lynx lynx) ecology

Automatic methods for detecting and delineating relief features allow remote and low-cost mapping, which has an outstanding potential for large-scale spatial analysis and calculation of morphometric characteristics of karst depressions in remote, forested and hard to cross areas. Besides geomorphology, detection methods can be also useful for wildlife ecology and similar research. We applied a filled-DTM (digital terrain model) method using LiDAR (Light Detection and Ranging) data to automatically detect dolines and other karst depressions in a rugged terrain of the Dinaric Mountains, Slovenia. For the dolines we calculated basic morphometric and morphological characteristics such as surface area, diameter, depth, slope, ruggedness and others.
To demonstrate its applicability for wildlife research, we applied it 1) in a preliminary study (Menišija plateau and Logatec-Begunje plain test area, NW Dinaric Mountains) in combination with GPS-telemetry data to assess the selection of these features by the Eurasian lynx (Lynx lynx) and 2) to analyse what characteristic are typical for those dolines where lynx killed ungulates (whole Dinaric Mountains of Slovenia).
In preliminary study we found that lynx selected for habitats in the vicinity of karst depressions, among which they preferentially used larger karst depressions. Lynx also regularly killed ungulate prey near these features. For whole Dinaric Mountains 202 kill sites were identified, among which 32.2% (n=65) were located inside dolines or in their close vicinity. Analysing the characteristics of those dolines where lynx kill sites were identified, we found that also these dolines were larger than mean and median surface area, depth, and diameter of all dolines in the Dinaric Mountains. The median with standard error of surface area of the dolines where the lynx caught its prey is 1,141.4 ± 703.2 m², has diameter of 38.8 ± 11.3 m, and is 5.2 ± 1.9 m deep. The maximum slope in these dolines ranges from 20.4 to 56.3°, which could indicate the formation of smaller walls, rocky outcrops and karren fields. Morphometric and morphological characteristics of dolines could influence success of lynx hunting.
Habitat selection for karst depressions and high proportion of killed ungulate inside or in close vicinity of dolines illustrate that karstic features could play an important role in the ecology of lynx

Key words: Karst depressions, GIS, LiDAR, geomorphology, Eurasian lynx (Lynx lynx), kill sites, microhabitat characteristics, Dinaric mountains, telemetry, spatial ecology