Habitat fragmentation, as a result of habitat loss and degradation, is widely considered to be a major threat to biodiversity. Our study focused on the distribution, diversity and abundance of butterflies on 22 isolated plots, mainly consisting of wet grassland. The plots were surrounded by deciduous mixed forests and located in an agglomeration area close to Lake Zurich, Switzerland. In addition to vegetation parameters, we assessed structural connectivity, adapted to least cost distances, using digital surface and terrain models. The resulting mixed-effects models revealed on plot level that (1) Molinia meadows had a significantly positive effect on rarefied Simpson butterfly diversity, (2) structural connectivity had a highly significant negative impact on rarefied Simpson butterfly diversity, whereas (3) plot size showed a significant positive impact, and (4) higher butterfly abundance was strongly related to blossom density. Across plot level, Molinia meadows had a higher rarefied butterfly species richness and rarefied Simpson butterfly diversity than any of the other habitat types evaluated. Among the endangered target species, the preferences of the Alcon Blue Phengaris alcon alcon were consistent with (1) to (3), while those of the Marsh Fritillary's E. aurinia aurinia were not. (2) is discussed with regards to the predominant influence of habitat type, vegetation and plot size, relativizing the effect of structural connectivity on butterfly communities in presumably resilient metapopulations. Ongoing targeted maintenance measures in the study area provide a promising basis for the sustainable conservation of local butterfly communities in isolated wet grassland plots.

由于生境丧失和退化造成的栖息地破碎被广泛认为是对生物多样性的主要威胁。我们的研究集中在22个孤立地带上蝴蝶的分布，多样性和丰富度，这些地区主要由湿草地组成。该地块被落叶混合森林所包围，位于瑞士苏黎世湖附近的一个集聚区。除植被参数外，我们还使用数字地面和地形模型评估了适应于最小成本距离的结构连通性。由此产生的混合效应模型在情节水平上显示：（1）Molinia草甸对稀有Simpson蝴蝶多样性具有明显的积极影响；（2）结构连通性对稀有Simpson蝴蝶多样性具有非常显着的负面影响，而（3）地块大小显示出显着的积极影响，（4）较高的蝴蝶丰度与开花密度密切相关。在整个样地水平上，与其他评估的栖息地类型相比，Molinia草甸的稀有蝴蝶物种丰富度和稀有的Simpson蝴蝶多样性。在濒临灭绝的目标物种中，爱尔康蓝的偏好Phengaris alcon alcon与（1）至（3）一致，而沼泽贝母的E. aurinia aurinia则与之不符。（2）讨论了关于栖息地类型，植被和样地大小的主要影响，并阐明了结构连接性对可能具有弹性的种群中蝴蝶群落的影响。研究区域内正在进行的有针对性的维护措施为在偏远的湿地草地上可持续保护本地蝴蝶群落提供了有希望的基础。