Vulnerability estimation of wetland plant communities to deer grazing in the Ozegahara mire

尾瀬ヶ原の湿原植生を構成する主要な群落について，構成種の種特性や食痕の確認頻度から，シカの採食圧に対する脆弱性の評価を行った．低層湿原や低木林・河畔林の群落は，シカの採食影響を受けやすい中・大型の広葉草本または低木を多く含み，食痕の確認頻度が高かったのもこれらの生活形をもつ種であった．このことは，低層湿原や低木林・河畔林で過去との種組成の違いが大きいという，既発表研究の結果と合致していた．また，構成種の積算優占度が大きい群落ほど食痕がみられた種数も多く，シカによく利用されていると推定された．これらのことから，尾瀬ヶ原においては低層湿原や低木林・河畔林の群落で保全対策の優先度が高いと判断された．Vulnerability of wetland vegetation on the Ozegahara mire was assessed for each representative plant community based on the plant species traits of the component species and frequency of browsing trace in each species. The low-moor communities included rich species of middle to large herbs and shrubs, as same as the shrub community and the riparian forest community. Frequency of browsing trace was also higher in the middle to large herbs and shrub species. These facts corresponded to the result of former study that indicated the low-moor, shrub and riparian forest communities had significant difference in species composition compared to the data from 50 years ago. Furthermore, number of browsed species was larger in the communities which had large cumulative dominance of palatable species in the herb and shrub layer, reflecting preferential use by deer. These results showed that low-moor communities, shrub community, and riparian forest community had higher vulnerabilities than the high-moor communities. Therefore, we concluded that these communities had higher conservation priority to protect from deer grazing in the Ozegahara mire