Data from: Living near the edge: being close to mature forest increases the rate of succession in beetle communities

In increasingly fragmented landscapes, it is important to understand how mature forest affects adjacent secondary forest (forest influence). Forest influence on ecological succession of beetle communities is largely unknown. We investigated succession and forest influence using 235 m long transects across boundaries between mature and secondary forest at 15 sites, sampling a chronosequence of three forest age classes (5-10, 23-29 and 42-46 years since clearcutting) in tall eucalypt forest in Tasmania. Our results showed that ground-dwelling beetle communities showed strong successional changes, and in the oldest secondary forests, species considered indicators of mature forest had re-colonised to abundance levels similar to those observed within adjacent mature forest stands. However, species composition also showed forest influence gradients in all age classes. Forest influence was estimated to extend 13 m and 20 m in the youngest and intermediate aged secondary forests, respectively. However, the estimated effect extended to at least 176 m in the oldest secondary forest. Our environmental modelling suggests that leaf litter, microclimate and soil variables were all important in explaining the spatial variation in beetle assemblages, and the relative importance of factors varied between secondary forest age classes. Mature forest beetle communities can recolonise successfully from the edge and our results provide a basis for land managers to build mature habitat connectivity into forest mosaics typical of production forests. Our results also indicate the importance of forest influence in determining potential conservation value of older secondary forest for beetles.

在日益破碎化的景观格局中，明晰成熟林对邻近次生林的影响（即森林影响效应，forest influence）具有重要意义。目前学界对森林影响效应如何作用于甲虫群落的生态演替过程仍知之甚少。本研究于塔斯马尼亚的高大桉树林中，在15个样点处设置了穿越成熟林与次生林边界的235米样线开展演替与森林影响效应的相关研究，并对皆伐后5-10年、23-29年及42-46年这3个林分年龄类别的年代序列样地进行采样。研究结果表明，地表栖居甲虫群落呈现出显著的演替变化；在最老龄的次生林中，被视作成熟林指示物种的类群已完成重新定殖，其种群丰度与邻近成熟林分中的观测水平基本一致。但在所有林分年龄类别中，物种组成均表现出森林影响效应的梯度分布特征。据估算，在最年轻和中等林龄的次生林中，森林影响效应的作用范围分别为13米与20米；而在最老龄的次生林中，该效应的估算作用范围至少可达176米。本研究的环境建模结果显示，地表凋落物、微气候与土壤变量均为解释甲虫群落空间变异的关键因子，且各因子的相对重要性随次生林林分年龄的不同而存在差异。成熟林的甲虫群落可通过林缘实现成功定殖，本研究结果可为土地管理者将成熟生境连通性融入生产林典型的森林镶嵌格局提供理论支撑。本研究结果同时表明，森林影响效应在评估老龄次生林对甲虫的潜在保护价值方面具有重要意义。