L. Forró szerk.: Miscellanea Zoologica Hungarica 13. 2000 (Budapest, 2000)

Horváth, Gy.; Pintér, V.: Small mammal fauna of two abandoned field habitats, and a spatio-temporal analysis of four rodent populations

rounding fields, and found six different species in two different habitats. AdamczewskaAndrzejewska et al. (1981) studied the demography of populations in a small mammal community with a very similar composition to that found in our abandoned field sample areas. M. arvalis, A. agrárius and A. flavicollis were reported as dominant species of the various cultivated sample lands. The population size of M. arvalis grew from spring to autumn (Adamczewska-Andrzejewska et al. 1981), while the populations of the other species within the community exhibited considerable differences in their maxima which, in addition, did not overlap. This phenomenon appeared also in our studies: we recorded the demographic maximum for M. arvalis in late summer (August-September), which finding corresponds to those reported by Butet and Leroux (1994). Similarly to the formerly cited Polish data, population maxima of the different species were not synchronous; besides the drop in M. arvalis numbers in autumn, the abundance of the Apodemus species, especially of A. agrárius, remained considerably growing for a while. It was possible to test the density-dependence of Lloyd's aggregation index in both habitats, based on data of 8 and 5 months, respectively. Our results are in correspondance with Polish data from trapping in cultivated fields (Mackin-Rogalska 1981). We could record the decrease of the aggregation index as a function of growing population size in M. arvalis and A. agrárius. In two cases in A. sylvaticus these parameters were negatively correlated in the form of a linear trend. We deem it important from a conservational aspect to study near-natural open habitats existing in various phases of succession. From the point of view of landscape ecology, these mosaic-like habitat fragments are crucial for the survival of the native small mammal populations and communities. Acknowledgement This project was supported by the Hungarian Scientific Research Found OTKA for Gy. Horváth (No. F021184). References Adamczewska-Andrzejewska, K. (1981): Population structure of Microtus arvalis (Pall.) against the background of a community of rodents in crop fields. — Pol. ecol. Stud. 7(2): 193-211. Adamczewska-Andrzejewska, K., Bujalska, G. & Mackin-Rogalska, R. (1979): The differentiation and spatial distribution of a rodent community in agrocenosis. — Polonaise des Sciences 27(9): 731-737. Adamczewska-Andrzejewska, K., Bujalska, G. & Mackin-Rogalska, R. (1981): Changes in numbers of Microtus arvalis (Pall.), Apodemus agrárius (Pall.) and Apodemus flavicollis (Melch.) of chosen crop fields. — Pol. ecol. Stud. 7(2): 175-192. Babiska-Werka, J., Gliwicz J. & Goszczyski, J. (1979): Synurbization processes in population of Apodemus agrárius. II. Habitats of the striped field mouse in town. —Acta theriol. 24: 405—415. Begon, N. (1979): Investigating animal abundance: capture-recapture for biologists. — Edward Arnold London, pp. 96. Boonstra, R. & Krebs, C. J. (1978): Pitfall trapping of Microtus townsendii. — J. Mammal. 59(1): 136-148. Butet, A. & Leroux, A. (1994): Spatial and Temporal Density Fluctuations in Common Vole Populations in a Marsh in Western France. — Pol. ecol. Stud. 20(3-4): 137-146.