Shifts in the community composition of caddisflies (Insecta: Trichoptera) in a subtropical river over three decades

Data, metadata, and R code for:Murray-Stoker, K. M., D. P. Batzer, D. Murray-Stoker, and J. V. McHugh. 2020. Shifts in the community composition of caddisflies (Insecta: Trichoptera) in a subtropical river over three decades. Ecological Entomology 45: 514-524.Abstract1. Trichoptera is an ecologically and taxonomically diverse order, and caddisfly species are under increasing pressure from anthropogenic threats to larval habitats, rivers, and streams.2. This study evaluated long-term changes in caddisfly communities of the Ogeechee River, a subtropical blackwater river in the south-eastern U.S. Coastal Plain, to understand how changes manifest as a result of ongoing human impacts. Two datasets separated by more than 30years were used, each representing a 2-year monthly quantitative sampling effort (1981–1983; 2015–2017).3. Community structure of the Ogeechee River caddisflies significantly changed, though not in ways that were predicted. The average sensitivity values of the caddisfly community declined, contrary to the expectation that increasing human impacts on a river ecosystem would promote the survival of more pollution-tolerant taxa.4. Generic richness increased in the 2010s from the 1980s, perhaps as a result of relaxed competition following declines of large, dominant taxa. The increases in various taxa have resulted in similar overall abundance metrics between time periods, although other studies of Ogeechee River invertebrates indicate that the biomass of the new taxa is far lower than that produced by the assemblages of the 1980s. Functional richness, evenness, and dispersion were higher in the 2010s, but divergence was not.5. This suggests that more nuanced monitoring efforts, focused on the threats to ecological function and the role of caddisflies (and other sensitive freshwater organisms), will be required to evaluate the changes in community structure and determine which taxa are most adversely affected.

本数据集包含以下文献的数据、元数据及R代码：Murray-Stoker, K. M.、D. P. Batzer、D. Murray-Stoker与J. V. McHugh于2020年发表的《亚热带河流中石蛾（昆虫纲：毛翅目Trichoptera）群落组成的三十年变迁》，刊载于《生态昆虫学（Ecological Entomology）》第45卷，第514-524页。
摘要
1. 毛翅目（Trichoptera）是一类生态与分类学多样性均极为丰富的类群，石蛾幼虫的栖息生境、河流与溪流正面临日益加剧的人为活动威胁，相关类群的生存压力与日俱增。
2. 本研究针对美国东南部沿海平原的亚热带黑水河流域——奥奇河（Ogeechee River）的石蛾群落展开长期变化评估，以解析人类持续活动影响下的群落响应模式。研究采用了间隔超30年的两套采样数据集：两套数据集均开展了为期2年的月度定量采样工作，采样时段分别为1981–1983年与2015–2017年。
3. 奥奇河石蛾群落的结构确实发生了显著变化，但变化趋势与此前的预测并不一致：群落整体的平均敏感性指数有所下降，这与“河流生态系统受人类活动加剧会促使耐污染类群占比提升”的预期相悖。
4. 2010年代的石蛾属级丰富度较1980年代有所提升，这或许源于大型优势类群种群衰退后，群落内竞争压力得以缓解。尽管不同类群的丰度提升使得两个时期的总体丰度指标趋于相近，但针对奥奇河无脊椎动物的其他研究显示，新增类群的生物量远低于1980年代原群落的生物量。2010年代的功能丰富度、均匀度与离散度均高于1980年代，但群落分化度并未出现显著变化。
5. 上述结果表明，若要准确评估群落结构变化并明确受负面影响最严重的类群，需开展更为精细化的监测工作，重点关注生态功能所面临的威胁，以及石蛾（及其他敏感淡水生物）所扮演的生态角色。