Data from: Long-term species loss and homogenization of moth communities in Central Europe

1. As global biodiversity continues to decline steeply, it is becoming increasingly important to understand diversity patterns at local and regional scales.
2. Changes in land use and climate, nitrogen deposition and invasive species are the most important threats to global biodiversity. Because land use changes tend to benefit a few species but impede many, the expected outcome is generally decreasing population sizes, decreasing species richness at local and regional scales, and increasing similarity of species compositions across sites (biotic homogenization). Homogenization can be also driven by invasive species or effects of soil eutrophication propagating to higher trophic levels. In contrast, in the absence of increasing aridity, climate warming is predicted to generally increase abundances and species richness of poikilotherms at local and regional scales.
3. We tested these predictions with data from one of the few existing monitoring programs on biodiversity in the world dating to the 1960s, where the abundance of 878 species of macro-moths have been measured daily at seven sites across Hungary.
4. Our analyses revealed a dramatic rate of regional species loss and homogenization of community compositions across sites. Species with restricted distribution range, specialized diet, or dry grassland habitat were more likely than others to disappear from the community.
5. In global context, the contrasting effects of climate change and land use changes could explain why the predicted enriching effects from climate warming are not always realized.

1. 随着全球生物多样性（biodiversity）持续急剧下降，理解局地与区域尺度的多样性格局变得愈发重要。
2. 土地利用变化、气候变化、氮沉降（nitrogen deposition）以及入侵物种（invasive species）是威胁全球生物多样性的最主要驱动因素。由于土地利用变化往往仅惠及少数物种，却会抑制多数物种的存续，其预期结果通常表现为种群规模缩减、局地与区域尺度的物种丰富度（species richness）下降，以及不同样点间物种组成相似性的提升（即生物均质化（biotic homogenization））。生物均质化也可由入侵物种或土壤富营养化波及更高营养级（trophic levels）的效应所诱发。与之相反，在未出现干旱加剧的情况下，气候变暖预计总体上会提升变温动物（poikilotherms）在局地和区域尺度的种群丰度与物种丰富度。
3. 本研究借助全球少数可追溯至20世纪60年代的生物多样性长期监测项目之一的数据，对上述预测展开检验：该监测项目在匈牙利境内7个样点每日记录了878种大型蛾类（macro-moths）的种群数量。
4. 我们的分析结果显示，区域物种丧失速率极快，且各样点间的群落组成呈现出显著的均质化趋势。分布范围狭窄、食性特化或依赖干旱草原生境的物种，相较于其他物种更易从群落中消失。
5. 从全球视角来看，气候变化与土地利用变化的对立效应，或可解释为何气候变暖预期的群落富集效应并非总能得以实现。