DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 11-12/2017 str. 22 <-- 22 --> PDF |
value was 0.59). Decrease of the water level in the Dyje river caused the decrease of the dominance of common shrew and vice versa. Dynamics of the FR is not influenced by the flooding regime. Wood mouse responded well to changes in the MR during summer and at the beginning of autumn during the period 1982–1987. This species shows high indirect dependence on changes in the FR during summer (r = -0.77), which is also influenced by the decrease of water level in the Dyje river (r = -0.81; significance value was 0.74). The high soil moisture (high water table in forests influenced by the high flow of the Dyje river) reduced the dominance of wood mouse and drying of the lowland positively influenced its dominance. To evaluate the aggregate effect of the FR and MB in the growing season, a MLRM was used for the period 1982–1987. It follows that the model is able to explain the dominance of wood mouse according to the coefficient of determination of 67.9 % (r = 68) on the basis of mean monthly flows and MB during the summer season. Dominance (wood mouse) = 19.50 – 0.07 · monthly flow + 0.0179 · MB It means that the FR and MB can explain 67.9 % changes in the wood mouse population dominance. The proportion of other effects (factors) influencing the dominance amounts to 32.1 %. The dominance of this species increases with the decline of flow during the summer season. Similar behavior according to the multiple regression function can be also noted in yellow-necked mouse in the spring season of the period 2002–2006. Dominance (yellow-necked mouse) = –1.93 · monthly flow + 3.69 MB + 553.38. The derived regression model is able to explain the yellow-necked mouse dominance of 80.7 % (r = 0.81) on the basis of mean monthly flow and MB during the spring season 2002–2006. More than 80% of the yellow-necked mouse population prefers dry sites without the effect of floods. According to the regression model, opposite behavior expressing the dependence of the dominance of bank vole on the FR and the MB in the growing season is shown in the period 2002–2006. Dominance (bank vole) = 0.42 · monthly flow – 0.39 · MB – 65.55. The model can explain changes in the dominance from 76.6 % (r = 0.77) that is, with the increase of the FR and improvement of MB the dominance of bank vole increases. Improvement in the MB is affected by the increase of precipitation and decline of air temperature in the floodplain alluvium and higher water level in the Dyje river. The species prefers sites of higher moisture where the value of the FR factor is slightly higher than the factor of MB. During the spring season of 2002–2006, the behavior of common shrew showed dependence on the FR and the MB aggregate effect. Dominance (common shrew) = 0.39 · monthly flow – 0.87 · MB – 103.77. The derived regression model confirmed 62.9 % of dominance changes to be influenced by MB. Generally, this species prefers humid sites, which are temporarily slightly moistened by local precipitation. Discussion Rasprava Changes in the MR, namely in the level of the water table and the elimination of regular floods together with associated changes in the phytocoenosis and zoocoenosis of the floodplain forest ecosystem affected the dominance of the small terrestrial mammals. Three periods were compared in this study. The first period is from 1968 to 1972 (Zejda 1976) when flood plain forest was influenced by periodical flows, the second period is from 1982 to 1985 (Zejda 1991) when floods ceased, and the third is from 2002 to 2006 (Suchomel & Heroldová 2004; Suchomel et al. 2012) after revitalization measures were applied. Even though the data are merely correlative in nature, we believe that they reflect |