Local climatic effects on colonisation and extinction drive changes in mountain butterfly communities

Aim: The capacity of cool refugia to protect cold-adapted species against climate change may depend on both their initial climatic conditions and how quickly these change. We test how local climatic conditions influence mountain butterfly communities via their effects on colonisation and local extinction.

Location: Four mountain ranges in Central Spain.

Methods: We used Community Temperature Index (CTI), based on the climatic niches of constituent species (Species Temperature Index, STI), to estimate thermal affinities for butterfly communities sampled in 1984-2005 to 2017-2022. We related CTI to local temperature, estimated using the model Microclima, and tested for changes to local temperature and CTI over time. We used standard deviation in CTI (CTISD) and species richness to detect effects of colonisation and local extinction on community change. Finally, we tested for differences in thermal affinity and thermal niche breadth (STISD) between species undergoing local extinction or colonisation at each site.

Results: CTI was positively related to local temperature in both periods. However, there were regional differences in rates of change in CTI and local temperature. CTI increased overall, even though temperatures decreased at many sites; and CTI increases were greatest in historically cool sites. Neither CTISD nor species richness changed overall, suggesting that communities experienced equivalent numbers of colonisations and extinctions. Colonising species had warmer thermal affinities than those undergoing local extinction, and species with broader thermal niches increased their occupancy most over time.

Main conclusions: Local climatic conditions influenced changes to community composition based on species thermal tolerances, resulting in the loss of communities where species with cool thermal affinities predominated, and a narrower range of community thermal affinities overall. Our results suggest that a regional perspective to identifying climate change refugia is needed to provide a wide range of local climate conditions and rates of change to help adapt conservation to climate change.

Methods
This dataset contains all data needed for the main statistical analysis and figures of the paper. It contains the data related to community composition using the Community Temperature Index (CTI), estimated species richness corrected using Sample Coverage with iNEXT R package and the fine-scale modelled temperature maxima in the study sites using Microclima R package. 

The data comes from our field surveys in 2020 to 2022 (recent survey) compared to historical data processed from data presented in the following original sources: 

Baz, A. (1987). Abundancia y riqueza de las comunidades forestales de mariposas (Lepidoptera: Rhopalocera) y su relación con la altitud en el Sistema Ibérico Meridional. Graellsia, 43, 179–192.

Gutiérrez-Illán, J., Gutiérrez, D., & Wilson, R. J. (2010). The contributions of topoclimate and land cover to species distributions and abundance: Fine-resolution tests for a mountain butterfly fauna: Determinants of butterfly distribution and abundance. Global Ecology and Biogeography, 19(2), 159–173. https://doi.org/10.1111/j.1466-8238.2009.00507.x

Sánchez-Rodríguez, J. F., & Baz, A. (1995). The effects of elevation on the butterfly communities of a Mediterranean mountain, Sierra de Javalambre, central Spain. Journal of the Lepidopterists’ Society, 49(3), 192–207.
Viejo, J. L., & Martín, J. (1988). Las mariposas del Macizo Central de Gredos (Lepidóptera: Hesperioidea et Papilionoidea). Actas de Gredos, Boletin Universitario 7, 81–93

研究目的：凉爽型气候变化避难所对冷适应物种的气候保护潜力，可能同时取决于其初始气候条件与气候变化速率。本研究旨在探究局地气候条件如何通过影响物种定居与局地灭绝过程，进而作用于山地蝴蝶群落。

研究区域：西班牙中部的四个山脉。

研究方法：本研究基于组成物种的气候生态位（即物种温度指数（Species Temperature Index, STI））构建群落温度指数（Community Temperature Index, CTI），用以估算1984-2005年至2017-2022年期间采样的蝴蝶群落的热偏好性。将群落温度指数与通过Microclima模型估算的局地温度进行关联，并检验局地温度与群落温度指数随时间的变化趋势。本研究采用群落温度指数的标准差（CTISD）与物种丰富度，以分析定居与局地灭绝过程对群落变化的影响。最后，针对各调查样地中发生局地灭绝或成功定居的物种，检验其热偏好性与热生态位宽度（STISD）的差异。

研究结果：两个调查时期内，群落温度指数均与局地温度呈正相关关系。但不同区域的群落温度指数与局地温度变化速率存在显著差异。尽管多数样地的温度出现下降，整体群落温度指数仍呈上升趋势，且在历史上为凉爽环境的样地中，群落温度指数的增幅最为显著。群落温度指数标准差与物种丰富度均未发生整体变化，表明群落内的定居与灭绝事件数量大致相当。成功定居的物种相比发生局地灭绝的物种，具有更高的热偏好性；而热生态位更宽的物种，其种群占有率随时间提升最为明显。

主要结论：局地气候条件通过物种的热耐受性影响群落组成变化，最终导致以冷适应物种为主的群落逐渐消失，且整体群落的热偏好性范围趋于收窄。本研究结果表明，在识别气候变化避难所时需采用区域视角，以保障多样的局地气候条件与变化速率，助力气候变化适应性保护工作的开展。

数据集说明：本数据集包含本论文核心统计分析与图表绘制所需的全部数据，涵盖基于群落温度指数（CTI）的群落组成相关数据、通过iNEXT R包以样本覆盖度校正后的物种丰富度数据，以及通过Microclima R包建模得到的研究样地精细尺度最高温度数据。

本数据集的数据来源包括2020-2022年的野外实地调查（近期调查），以及从以下原始文献中整理得到的历史观测数据：
1. Baz, A. (1987). 伊比利亚南部山地森林蝴蝶群落（鳞翅目：蝶亚目）的丰度与物种丰富度及其与海拔的关联. Graellsia, 43, 179–192.
2. Gutiérrez-Illán, J., Gutiérrez, D. & Wilson, R. J. (2010). 地形气候与土地覆盖对物种分布与丰度的贡献：山地蝴蝶类群的高分辨率检验. Global Ecology and Biogeography, 19(2), 159–173. https://doi.org/10.1111/j.1466-8238.2009.00507.x
3. Sánchez-Rodríguez, J. F. & Baz, A. (1995). 海拔对西班牙中部地中海山地哈瓦拉姆布雷山脉蝴蝶群落的影响. Journal of the Lepidopterists’ Society, 49(3), 192–207.
4. Viejo, J. L. & Martín, J. (1988). 西班牙格雷多斯中央地块的蝴蝶（鳞翅目：弄蝶总科与凤蝶总科）. Actas de Gredos, Boletin Universitario 7, 81–93.