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Nest site preference of forest dormouse Dryomys nitedula (Pallas) in the north-western corner of the distribution range

Juškaitis R., Balčiauskas L., Šiožinytė V.

Polish Journal of Ecology

2012

Vol. 60, nr 4

815--826

Lithuania is situated in the very north-western corner of the large distribution range of the forest dormouse Dryomys nitedula and it might be considered that dormouse habitats should be both different and sub-optimal in this area in comparison to central parts of the range. The aims of the present study were to analyse which vegetation parameters determine nest site preference of D. nitedula and to compare these with nest site preferences of other dormouse species. The population of D. nitedula was studied from 2001 to 2011 using nestboxes set up in a grid system, with regular control of the nestboxes and ringing of dormice captured. During entire study period, 97 individuals were marked with rings and the total number of dormouse captures was 440. Vegetation parameters (the composition of the overstorey and understorey, the numbers and cover of different tree and shrub species, absence of vegetation etc.) were evaluated quantitatively in areas of 2500 m2 around 58 nestboxes at this study site. During the period 2001–2002, the abundance of D. nitedula was relatively high, with the dormice using the entire area of the study site, showing a preference for nest sites with a more diverse overstorey and understorey. However, no significant correlations were found between indices of nestbox use and other vegetation parameters in this period. During the period 2003–2011, when the dormouse abundance was lower but stable, dormice used only part of the study site area, in this preferring nest sites with a better developed and diverse understorey (especially with young rowan, lime and aspen trees), with more abundant mature oak, lime and black alder trees and a higher percentage of raspberry and bramble cover, as well as overgrown clearings. D. nitedula avoided nest sites with higher total number of mature trees (especially Scotch pine and Norway spruce), as well as areas with higher percentage of bilberry cover and open areas (rides, presence of stumps). In general, a well-developed and diverse understorey was the main habitat component which determined nest site preference of D. nitedula in the very northwestern corner of its range. Thus, D. nitedula retains its main habitat requirement which is characteristic also for other parts of its large range. Vegetation parameters determining nest site preference of D. nitedula are rather similar to nest site preference of the common dormouse Muscardinus avellanarius. However, D. nitedula may live in less rich habitats probably because their diet includes more food of animal origin.

Selection of nesting and foraging habitat by the Lesser Spotted Eagle Aquila Pomarina (Brehm) in the Knyszyńska Forest (NE Poland)

Mirski P.

Polish Journal of Ecology

2009

Vol. 57, nr 3

581-587

To manage conservation issues, it is essential to recognize the factors determining the occurrence of endangered species. This study examined the foraging habitat and nest site preferences of the Lesser Spotted Eagle Aquila pomarina (Brehm) in the Knyszyńska Forest (NE Poland). This is a large (839 km[^2]) protected (Landscape Park Puszcza Knyszyńska, NATURA 2000) forest complex composed mainly with coniferous and mixed wood stands with meadows in river valleys inside the complex and arable lands outside it. The research was carried out on a study plot of 440 km[^2], in the breeding seasons of 2006 and 2007. Nest site characteristics, such as distance to open areas, settlements and watercourses were measured and compared with random points. The habitat composition of hunting territories was recorded and compared to habitat availability on the whole study plot, and the birds. hunting effort was assessed. The eagles showed a preference for nesting close to open spaces (potential hunting grounds) and watercourses (like rivers and streams), but avoided proximity to human settlements. As hunting grounds, the birds highly preferred grasslands and avoided arable lands. Time spent hunting on grasslands comprised over 95% of the observed hunting activities and grasslands were significantly positively selected both in the whole study plot and within a 2 km-radius from nest. The results suggest that the conservation of the Lesser Spotted Eagle should focus especially on meadows and pastures adjacent to large forest complexes.