Data from: Diversity and composition of tropical butterflies along an Afromontane agricultural gradient in the Jimma Highlands, Ethiopia

Afromontane landscapes are typically characterised by a mosaic of smallholder farms and the biodiversity impacts of these practices will vary in accordance to local management and landscape context. Here we assess how tropical butterfly diversity is maintained across an agricultural landscape in the Jimma Highlands of Ethiopia. We used transect surveys to sample understory butterfly communities within degraded natural forest, semi-managed coffee forest (SMCF), exotic timber plantations, open woodland, croplands and pasture. Surveys were conducted in 29 one-hectare plots and repeated five times between January and June 2013. We found that natural forest supports higher butterfly diversity than all agricultural plots (measured with Hill’s numbers). SMCF and timber plantations retain relatively high abundance and diversity, but these metrics drop off sharply in open woodland, cropland and pasture. SMCF and timber plantations share the majority of their species with natural forest and support an equivalent abundance of forest-dependent species, with no increase in widespread species. There was some incongruence in the responses of families and sub-families, notably that Lycaenidae are strongly associated with open woodland and pasture. Adult butterflies clearly utilise forested agricultural practices such as SMCF and timber plantations, but species diversity declines steeply with distance from natural forest suggesting that earlier life-stages may depend on host plants and/or microclimatic conditions that are lost under agricultural management. From a management perspective, the protection of natural forest remains a priority for tropical butterfly conservation, but understanding functioning of the wider landscape mosaic is important as SMCF and timber plantations may act as habitat corridors that facilitate movement between forest fragments.

非洲山地景观通常以小农农场镶嵌体为典型特征，此类实践带来的生物多样性影响会随当地管理模式与景观背景的差异而有所不同。本研究针对埃塞俄比亚吉马高地的农业景观，探究热带蝴蝶多样性的维持机制。我们采用样带调查法，在退化天然林、半管理咖啡林（semi-managed coffee forest, SMCF）、外来用材林、开阔林地、农田与牧场中对林下蝴蝶群落进行采样。调查于2013年1月至6月间在29个1公顷样地中开展，且每个样地重复调查5次。研究发现，天然林的蝴蝶多样性（以希尔数（Hill’s numbers）衡量）高于所有农业用地样地。半管理咖啡林与外来用材林的蝴蝶个体丰度与多样性相对较高，但在开阔林地、农田与牧场中，这两项指标会急剧下降。半管理咖啡林与外来用材林的多数物种与天然林共有，且其依赖森林的物种丰度与天然林相当，并未出现广布物种占比上升的情况。不同蝴蝶科与亚科的响应模式存在一定不一致性，其中灰蝶科（Lycaenidae）与开阔林地和牧场呈现显著正相关。成虫明显会利用半管理咖啡林、外来用材林等林木覆盖的农业生境，但蝴蝶物种多样性随与天然林距离的增加而急剧降低，这表明蝴蝶的早期发育阶段可能依赖于农业管理下已丧失的寄主植物或微气候条件。从管理角度而言，保护天然林仍是热带蝴蝶保护的核心要务，但理解整体景观镶嵌体的生态功能同样至关重要——半管理咖啡林与外来用材林可作为生境廊道，促进森林片段间的物种迁移。