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，保护主义者与政策制定者更倾向于采用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，支撑该假设的实证证据仍较为匮乏。本研究首次探究了不同经营粒度的森林管理系统如何在多空间尺度上影响地上与地下多个类群（taxa）的生物多样性。
研究团队在德国最大的连片山毛榉林景观中，对动物、植物、真菌与细菌共15个类群进行了采样，并将其划分为功能群（functional groups）。所选林分均已采用不同空间经营粒度的管理模式超过一个世纪。同龄林（粗粒度经营）与异龄林（细粒度经营）在空间布局、气候与土壤条件上均具有可比性。同时，研究还将上述林分与附近一处至少20年未开展人工经营的国家公园森林进行了对照。研究采用多样性累积曲线（diversity accumulation curves），对比了不同经营系统下希尔数（Hill-numbers）0D（物种丰富度（species richness））、1D（香农多样性指数（Shannon diversity））与2D（辛普森多样性指数（Simpson diversity））对应的γ多样性（gamma diversity）；β多样性（beta diversity）则通过多站点相异性（multiple-site dissimilarity）指标进行量化。
结果显示，在6个类群中，至少有一项希尔数对应的γ多样性在同龄林中更高（最高可达77%），另有8个类群未表现出显著差异；仅细菌类群呈现相反的变化趋势。森林专性类群（forest specialists）与腐生甲虫（saproxylic beetles）类群同样表现出同龄林γ多样性更高的特征。
林间β多样性方面，三分之一的所有类群以及半数的森林专性类群在同龄林中更高，这一现象由林龄级（age-classes）间的环境异质性驱动；而α多样性（alpha diversity）则未在所有类群或森林专性类群中表现出明确的方向性响应。
研究总结与应用启示：通过对比中欧山毛榉林的同龄与异龄林经营模式，本研究结果表明，相较于高林内生境异质性，不同林龄级构成的镶嵌格局对区域生物多样性更为重要。研究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，转而应提升林分发育阶段与结构的多样性，以促进景观尺度的生物多样性保护。