Stability and changes in the distribution of Pipiza hoverflies (Diptera, Syrphidae) in Europe under projected future climate conditions

Climate change is now considered a significant threat to terrestrial biodiversity. Species distribution models (SDMs) are among the modern tools currently used to assess the potential impacts of climate change on species. Pipiza Fallén, 1810 is a well known aphidophagous hoverfly genus (Diptera, Syrphidae) at the European level, for which sampling has been conducted across the region, and long-term databases and geo-referenced datasets have been established. Therefore, in this work, we investigated the potential current distributions of the European species of this genus and their response to future climate change scenarios, as well as evaluated stability in their ranges and potential changes in species-richness patterns. We applied three climate models (BCC_CSM1.1, CCSM4, HadGEM2-ES) to four representative concentration pathways (RCP 2.6, RCP 4.5, RCP 6.0, RCP 8.5) for two time frames (2050 and 2070). Our results show that the distribution of most Pipiza species may slightly differ under different climate models. Most Pipiza species were predicted not to be greatly affected by climate change, maintaining their current extent. Percentages of stable areas will remain high (above 50%) for the majority of studied species. According to the predicted turnover of species, northern Europe, could become the richest in terms of species diversity, thus replacing Central Europe as the current hot spot.气候变化目前被视为对陆地生物多样性的重大威胁。物种分布模型（Species Distribution Models, SDMs）是当前用于评估气候变化对物种潜在影响的主流现代工具之一。Pipiza属（Pipiza Fallén, 1810）是欧洲区域内广为人知的食蚜蝇属（双翅目，食蚜蝇科），目前该区域已针对该属开展系统性采样调查，并建立了长期数据库与地理参考数据集。因此，本研究探究了该属欧洲物种的当前潜在分布区及其对未来气候变化情景的响应，同时评估了其分布区的稳定性以及物种丰富度格局的潜在变化。本研究针对2050年与2070年两个时间框架，采用3种气候模型（BCC_CSM1.1、CCSM4、HadGEM2-ES）与4种典型浓度路径（RCP 2.6、RCP 4.5、RCP 6.0、RCP 8.5）开展模拟分析。结果表明，多数Pipiza属物种的分布在不同气候模型下或存在细微差异；多数预测物种受气候变化影响较小，其当前分布范围将得以维持。多数研究物种的稳定区域占比仍将高于50%。基于物种周转预测结果，北欧或将成为物种多样性最丰富的区域，从而取代当前的热点区域中欧。