Data from: The impact of even-aged and uneven-aged forest management on regional biodiversity of multiple taxa in European beech forests

For managed temperate forests, conservationists and policymakers favour fine-grained uneven-aged management over more traditional coarse-grained even-aged management, based on the assumption that within-stand habitat heterogeneity enhances biodiversity. There is, however, little empirical evidence to support this assumption. We investigated for the first time how differently grained forest management systems affect the biodiversity of multiple above- and below-ground taxa across spatial scales.
We sampled 15 taxa of animals, plants, fungi and bacteria within the largest contiguous beech forest landscape of Germany and classified them into functional groups. Selected forest stands have been managed for more than a century at different spatial grains. The even-aged (coarse-grained management) and uneven-aged (fine-grained) forests are comparable in spatial arrangement, climate and soil conditions. These were compared to forests of a nearby national park that have been unmanaged for at least 20 years. We used diversity accumulation curves to compare γ-diversity for Hill-numbers 0D (species richness), 1D (Shannon diversity) and 2D (Simpson diversity) between the management systems. Beta diversity was quantified as multiple-site dissimilarity.
Gamma diversity was higher in even-aged than in uneven-aged forests for at least one of the three Hill-numbers for six taxa (up to 77%), while eight showed no difference. Only bacteria showed the opposite pattern. Higher γ-diversity in even-aged forests was also found for forest specialists and saproxylic beetles.
Between-stand β-diversity was higher in even-aged than in uneven-aged forests for one third (all species) and half (forest specialists) of all taxa, driven by environmental heterogeneity between age-classes, while α-diversity showed no directional response across taxa or for forest specialists.
Synthesis and applications. Comparing even-aged and uneven-aged forest management in Central European beech forests, our results show that a mosaic of different age-classes is more important for regional biodiversity than high within-stand heterogeneity. We suggest reconsidering the current trend of replacing even-aged management in temperate forests. Instead, the variability of stages and stand structures should be increased to promote landscape scale biodiversity.

针对经营型温带森林（managed temperate forests），保护学者与政策制定者普遍倾向于细粒度异龄林经营模式（fine-grained uneven-aged management），而非传统的粗粒度同龄林经营模式（coarse-grained even-aged management），其核心假设为林内生境异质性（within-stand habitat heterogeneity）可提升生物多样性。然而，支撑这一假设的实证证据却极为匮乏。本研究首次探究了不同粒度的森林经营系统如何在多个空间尺度上影响地上与地下多重类群的生物多样性。
本研究在德国最大的连片山毛榉林景观中，采集了动物、植物、真菌与细菌共15个分类单元（taxa），并将其划分为功能类群。所选林分已以不同空间粒度开展经营超一个世纪。同龄林（对应粗粒度经营模式）与异龄林（对应细粒度经营模式）在空间布局、气候与土壤条件上均具有可比性。本研究同时将上述两类经营林分与附近一处至少20年未开展经营的国家公园内的森林进行对比。我们采用多样性累积曲线（diversity accumulation curves），对比了不同经营模式下希尔数（Hill-numbers）0D（对应物种丰富度，species richness）、1D（对应香农多样性指数，Shannon diversity）与2D（对应辛普森多样性指数，Simpson diversity）的γ多样性（γ-diversity）。β多样性（Beta diversity）以多位点相异性（multiple-site dissimilarity）进行量化。
在15个分类单元中，有6个类群在至少一项希尔数指标上表现为同龄林的γ多样性高于异龄林（最高可达77%），另有8个类群未呈现显著差异；仅细菌类群呈现相反模式。此外，森林专性物种（forest specialists）与腐生甲虫（saproxylic beetles）的γ多样性同样在同龄林中更高。
受林龄级（age-classes）间生境异质性驱动，在全部类群的三分之一以及森林专性物种的一半中，同龄林的林间β多样性高于异龄林；而α多样性（α-diversity）在所有类群或森林专性物种中均未表现出定向响应。
结论与应用启示。通过对比中欧山毛榉林的同龄与异龄经营模式，本研究结果表明：相较于高林内生境异质性，不同林龄级的镶嵌格局对区域生物多样性更为重要。我们建议重新审视当前温带森林中替换同龄林经营模式的趋势，转而通过提升林分发育阶段与结构的变异性，以促进景观尺度的生物多样性保护。