DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 3-4/2012 str. 35 <-- 35 --> PDF |
We evaluated the capture results of the four typical small mammal species in respect of the two areas separated by the dirt road as well. The mean capture numbers of the two separated forest sites showed that the four examined species used the two sites equally therefore the variance analysis gave no significant result in the comparison of the capture proportions of the two areas separated by a dirt road (Kruskal-Wallis ANOVA: H = 0.362–1.881, n.s.). Furthermore, using Ivlev’s habitat preference calculation we examined the habitat usage of the two forest sites compared to the whole forest area covered by the six transects. In case of the two Apodemus species we revealed the same habitat preference (Fig. 4): in 2001 the woodland between River Drava and the dirt road (Site A) was preferred both species, while the two mice avoided this woodland in 2002. In case of the bank vole we observed contrary habitat use with the two Apodemus species in 2001 and 2002. The result of area preference calculation from the two years capture data suggested a strategy leading towards the spatial segregation of the bank vole and the two mice species. The common shrew, with the increase of its area occupation rate in 2002–2003, preferred significantly the area lying close to the river which justified the shrew’s presence associated with wet areas (Fig. 4). Spatial association and movement distance – Prostorna povezanost i udaljenost kretanja We analysed the habitat use and the overlap of the four examined species with reference to the grid defined by the trap stations of the transects. All significant spatial association values were positive in all cases (Table 2) which referred to a considerable spatial overlap and common habitat usage. There was significant positive association between yellow-necked mouse and bank vole on the dirt road-river terrace area in 2001. The same positive association appeared in 2002 between the two species as well, also between dirt road and the river terrace, however we could not show any significant association between these species in 2003. In case of the striped filed mouse and the bank vole, there was significant association between dirt road and the river terrace or rather the road and Drava, but considering the whole area we did not receive a significant value. In 2003 it was a significant positive association between the species in case of the area lying between the dirt road and Drava. Between yellow-necked mouse and common shrew we received significant positive spatial association for the whole area in 2002, however, when examining the two areas separately we could prove a significant positive association only between the road and the river terrace. There was a significant positive association between the striped field mouse and the common shrew in the area between the dirt road and River Drava (A) in 2003 (Table 2). Regarding the analysis of the association, it is important to look back at the results of the preference of the two forest-sites separated by a dirt road. Although the bank vole used the two forest areas with opposite preference in 2001 and 2002 which suggested that the species avoids the sites used by the two competing mice, but concerning the interspecific spatial association, its spatial segregation was successful only against the striped field mouse in 2001; in 2002 the vole’s significant spatial overlap was observed with both Apodemus species, which fact was reflected for this year by the significant association values as well. We evaluated the movement distances of the three frequent rodents in the analysis of spatial distribution of the fragmented floodplain forest. Based on the three sampling years the movement distances of striped field mouse had the greatest standard deviation, the average movement distance of the species showing an increasing tendency between 2001 and 2003. The most balanced and largest average movement distances were recorded for the yellow-necked mouse while the smallest |