Species- and trait-based responses of carabids to rotation and closer-to-nature forestry in a temperate forest under changing climate

European temperate forests are managed by various silvicultural practices that can impact ground beetles (Coleoptera: Carabidae) in terms of species composition and abundance. However, the responses at the assemblage or community level may not provide sufficient insight into how individual species react to forest management. We examined the species- and trait-based mid-term (2014–2018) responses of the eight most common carabid species in a managed oak-hornbeam forest in Hungary. The studied forestry treatments included preparation cutting, clear-cutting, green tree retention, gap cutting, and undisturbed control plots. Species responses varied across forestry treatments and years, but clear-cutting consistently had a negative impact on multiple species, particularly on Abax parallelepipedus, Aptinus bombarda, and Carabus hortensis. In contrast, the abundance of Carabus coriaceus and Carabus ullrichii declined after an initial burst in the newly established treatments. Functional traits also influenced the responses; forest specialists and spring and autumn breeders were negatively affected by clear-cutting and retention, followed by an overall decline in their abundance. Notwithstanding, habitat generalists and species without a defined breeding season exhibited more stable abundance trends over the years. These declines may be linked to phenological shifts driven by climate change. Spring breeders may have extended their activity period, leading to increased competition with autumn breeders in late summer and autumn when tenerals of spring breeders emerge. Although our study presents mid-term trends, we believe that it provides a further understanding of the responses of carabid species in managed temperate forests.

欧洲温带森林通过多种营林措施进行经营，此类措施会对步甲 (ground beetles, Coleoptera: Carabidae) 的物种组成与种群丰度造成影响。然而，仅从类群或群落层面分析得到的响应结果，可能不足以揭示单一物种对森林经营措施的具体反应机制。本研究针对匈牙利一片经营型栎-鹅耳枥林中的8个最常见步甲物种，分析了其基于物种和功能性状的中期（2014–2018年）响应特征。本次研究涉及的营林处理措施包括：抚育采伐、皆伐、保留活立木、林隙采伐以及未受干扰的对照样地。不同步甲物种的响应随营林措施与研究年份存在差异，但皆伐对多数步甲物种始终产生负面影响，尤其对Abax parallelepipedus、Aptinus bombarda以及Carabus hortensis的影响更为显著。与之相反，Carabus coriaceus和Carabus ullrichii的种群丰度在新实施的处理措施中经历初始激增后出现下降。功能性状同样会影响步甲的响应模式：森林专性物种以及春季、秋季繁殖型物种均受到皆伐与保留活立木措施的负面影响，其种群丰度随后出现整体下降。尽管如此，栖息地广适性物种以及无明确繁殖季的物种，其种群丰度在研究年间呈现出更为稳定的变化趋势。此类丰度下降可能与气候变化驱动的物候转变有关。春季繁殖型物种可能延长了其活动周期，导致在夏末与秋季（此时春季繁殖型物种的新羽化个体开始出现）与秋季繁殖型物种的种间竞争加剧。尽管本研究仅揭示了中期变化趋势，但我们认为其有助于进一步理解经营型温带森林中步甲物种的响应机制。