Spatial distribution and interactions were analysed for three cooccurring populations of the rodents Clethrionomys glareolus (Schreber, 1780), Microtus agrestis (Linnaeus, 1761) and Apodemus agrarius (Pallas, 1771). The study was conducted in three 1-ha plots located in forests of southern Poland, in an industrial region (Silesia). Rodents were captured by the CMR method from October 1977 to October 1981. The study areas differed in the degradation of plant communities and the degree of industrial pollution. It has been found that C. glareolus showed a higher degree of aggregation, less frequently changed the points of capture, and was most permanently attracted to them, as compared with the other species. All the rodent species tended to avoid one another at trapping points, especially C. glareolus and M.agrestis. There were differences in the values of various indices among particular plots, which can be related to the degree of plant cover degradation.[Department of Vertebrate Ecology, Institute of Ecology P. A. Sci., Dziekanów, 05-092 Łomianki, Poland] INTRODUCTIONSmall rodents living in mixed forests usually form multispecies communities. They have relatively similar food and habitat requirements. The distribution of individual species was analysed by many authors (Turcek, 1960; Koplin & Hoffman, 1968;Chełkowska, 1969;Flint, 1977;Dienske, 1979; Kovalevskij & Korenberg, 1980;Bashenina, 1981;Andrzejewski & Simonides, 1982, and others), but so far it is not clear how individual species occupy the habitat when they co-occur, and how they interact.The purpose of this paper is to analyse differences in the distribution of co-occurring populations of C. glareolus (Schreber, 1780), M. agrestis (Linnaeus, 1761) and A. agrarius (Pallas, 1771), to find whether or not they interact, and to determine the effect of habitat on their spatial structure. (2) Plot S -at Szczygłowice, at a distance of about 10 km from plot A, close to a pit-coal mine, in Tilio-Carpinetum with Carex brizoides and Pteridium aquilinum.This was a fertile, moist site with no heavily submerged areas like those in plot A.(3) Plot P -at Jankowice near Pszczyna, about 60 km distant from the other plots, in a large forest complex. This plot was covered by Tilio-Carpinetum with Carex brizoides and Pteridium aquilinum, and by Calamagrostio villosae-Pinetum. This was the least polluted and least degenerated habitat.The degradation of plant communities on the study plots was estimated by Dr. S. Wika and Dr. S. Cabala using a 5-degree scale of Celiński and Wika (1980). This scale is based on changes in species composition, such as disappearance of characteristic plant species and appearance of non-typical, ruderal forms, and also on dying trees, leaf fall, absence of seeds, etc. Wika and Cabala also prepared a detailed botanical characteristic of the study plot«. On this basis, several) indices characterizing plant cover of the study plots were calculated. Also the coverage of earth surface by fallen trees and dry branches was estimated. The data on industri...

No abstract

The variability in the mandible dimensions has been investigated in bats of the genus Plecotus Geoffroy, 1818 from Central Europe. The material consisted of 100 individuals of P. auritus and 100 individuals of P. austriacus. The variability in the mandible length appeared to be relatively low in both species (Cv = 3.41-3.99), whereas that in the height of the ramus mandibulae was slightly higher (Cu = 4.93-8.62). For both species the common values of the measurements of the mandible length are found in 10.8-11.0 mm classes, which contain 4 per cent of P. auritus and 18 per cent of P. austriacus. As to the height of the ramus mandibulae, the common range for both species falls to the 3.2 mm class (3 per cent of P. auritus and 4 per cent of P. austriacus). A complete separation of both species can be done by simultaneous comparison of two dimensions using the diagram of their correlation considering morphological characteristics of the mandible. This method may find practical application in indentifying fossil materials or those in owl pellets.

No abstract