Ábrahám Levente: Biomonitoring a Dráva folyó magyarországi szakasza mentén 2000-2004 - Natura Somogyiensis 7. (Kaposvár, 2005)
Horváth, Gy., Molnár, Dániel - Csonka, Gergely: Population dynamics and spatial pattern of small mammals in protected forest and reforested area - Kisemlősök populációdinamikája és térbeli mintázata védett erdei és újraerdősödő területen
HORVÁTH ET AL.: POPULATION DYNAMICS AND SPATIAL PATTERN 193 Trapping protocol and monitoring For population level monitoring the small mammals were captured using live-trapping, and the method of capture-mark-recapture was applied. One trapping session included five nights, this period being long enough, in case of sufficient number of captures and recaptures, for population sizes to be estimated using various models, as the shortness of the period allows the population to be considered to be closed. For capturing the animals, plastic box-type live traps were used in both areas, earlier tested by HORVÁTH et al. (1996) and HORVÁTH (1996). A trapping grid covering 1 hectare and consisting of 11 by 11 trap stations 10 m apart was used in both the protected alder gallery forest (Grid A) and the neighbouring regrowing plot (Grid В ). Bacon and mixed grains with aniseed extract and vegetable oil added, were used as bait. Traps were checked twice each day, (at 7 00 and at 19 00 ), thus each session yielded 9 checkings. In both years, monitoring was done in three trapping periods: in July, August and October in 2003, and in July, September and October in 2004. From the number of traps in the two grids and the number of sampling nights, our sampling covered 3630 trap-nights a year, that is a total of 7260 trap nights for the two years covered in the present study. Captured animals were marked individually according to BEGON (1979), and we also recorded the sex (in females: gravidity or lactation, too), age and body mass. Ages were determined based on body mass and overall appearance. Statistical methods Our capture data were recorded based ion a Manly-Parr diary of captures. Three capture parameters were specified: total number of captures, total number of recaptures, number of known individuals). Small mammal species percentages were calculated for the different sampling plots and for the sampling periods. Capture data of the strictly protected area and the regrowing plot were compared using homogeneity G-tests (ZAR 1996). As trapping sessions lasted for 5 nights, the populations can be considered to be closed, without any births, deaths emigration or immigration. For the estimation of population size we applied the MARK (Соосн and WHITE 1998) software used primarily for testing and modelling survival and capture probabilities, and the program also includes the CAPTURE application that was designed earlier for estimating sizes and densities of closed populations, here operating as a submenu. The various estimators for closed populations running within that consider the constancy or temporal dependence of capture probability, the reaction of individuals to being trapped, and also the possible change of capture probability due to individual characteristics of the animal. Based on the 5-day periods, we could perform population size estimations for the 2004 data only. For the analysis of spatial distribution of individuals and populations we recorded the coordinates of trap stations and captures, based on which it was possible to analyse the spatial distribution of the various species both statistically and graphically, using the new Biotas 2.0 program. For analysing the distribution of individuals within the population, the nearest neighbour method, and the evaluation of spatial relationship between the populations was done by calculating the degree of association (Yates-correction % 2value). Changes in the space use of the frequent species were evaluated using the higher amount of capture data from 2004, by charting together the monthly capture values in the two areas, emphasising the spatial arrangement occurring after the autumn peak density.
