The abundance of both flower-visiting insects and flowering plants in semi-natural grasslands in temperate zones has declined as a result of overbrowsing by deer. The construction of deer fences is an effective method for biodiversity conservation because these fences prevent the invasion of deer. However, few studies have elucidated the biodiversity conservation effects of deer fences in semi-natural grasslands. Here we investigated the effects of the construction of deer fences on the diversity of butterflies, bumblebees, and flowering plants on the Kirigamine Plateau, Nagano Prefecture, Japan, which is covered by semi-natural grassland. The number of species of flowering plants inside the deer fences was higher than that outside the deer fences. The numbers of individuals and species of flower-visiting butterflies and bumblebees also tended to be higher inside the deer fences than outside the deer fences. On the other hand, there tended to be no difference in the number of individuals and species of non-flower-visiting butterflies inside and outside the deer fences. The diversity of flowering plants, butterflies, and bumblebees within the fenced areas was not substantially affected by the size of the fenced-off area. Our findings suggested that the construction of deer fences can contribute to the conservation of both flower-visiting insects and flowering plants in semi-natural grassland.

温带地区半自然草原上访花昆虫和开花植物的丰度由于鹿的过度浏览而减少了。建造鹿栅栏是保护生物多样性的有效方法，因为这些栅栏可以防止鹿的入侵。但是，很少有研究阐明半自然草地中鹿栅栏对生物多样性的保护作用。在这里，我们调查了鹿栏栅的建设对日本长野县雾谷高原上被天然草覆盖的蝴蝶，大黄蜂和开花植物多样性的影响。鹿围栏内的开花植物种类数量多于鹿围栏外的种类。赏花蝴蝶和大黄蜂的个体和种类的数量也往往比鹿围栏内的要多。另一方面，在鹿篱笆内外的非访花蝴蝶的数量和种类没有差异。围栏区域内的开花植物，蝴蝶和大黄蜂的多样性基本上不受围栏区域大小的影响。我们的研究结果表明，建造鹿栅栏可以促进半天然草原上访花昆虫和开花植物的养护。鹿栅栏内外的非访花蝴蝶的数量和种类没有差异。围栏区域内的开花植物，蝴蝶和大黄蜂的多样性基本上不受围栏区域大小的影响。我们的研究结果表明，建造鹿栅栏可以促进半天然草原上访花昆虫和开花植物的养护。鹿栅栏内外的非访花蝴蝶的数量和种类没有差异。围栏区域内的开花植物，蝴蝶和大黄蜂的多样性基本上不受围栏区域大小的影响。我们的研究结果表明，建造鹿栅栏可以促进半天然草原上访花昆虫和开花植物的养护。