With ongoing climate change at global scale we are currently losing biodiversity at an unprecedented rate. The insurance hypothesis and associated research, however, suggest that biodiversity has a major stabilising effect in ecosystems. In this situation, it is crucial to develop a better understanding of natural processes of maintaining biodiversity for employing them in conservation practice. In forest ecosystems, spatial species and size diversity are important aspects of α-diversity at woodland community and species population level. Both aspects of spatial diversity stem from complex relationships between tree interaction, disturbances and subsequent waves of colonisation by tree seedlings of various species. Using point process statistics, particularly the mark mingling function and the mark variogram, we studied the processes causing spatial correlations of species and size diversity. We found that spatial species dispersal and conspecific size distributions are key drivers of spatial species-size correlations and that a combination of simple random size-labelling techniques applied to mark variograms is instrumental in efficiently diagnosing them. If size ranges differ between species, spatial size diversity is largely a function of spatial species mingling. The existence of these correlations is crucial to conservation because they imply that conservation efforts can be rationalised: It is possible to focus on only one of the two tree diversity aspects. Interestingly, in multi-species forest ecosystems, although general species diversity is high, spatial species-size correlations can be diluted, because some of the many species populations may have similar size distributions.

随着全球范围内不断变化的气候变化，我们目前正在以前所未有的速度丧失生物多样性。但是，保险假说和相关研究表明，生物多样性在生态系统中具有主要的稳定作用。在这种情况下，至关重要的是要更好地了解维持生物多样性的自然过程，以便将其用于保护实践。在森林生态系统中，空间物种和大小多样性是林地群落和物种种群水平上α多样性的重要方面。空间多样性的两个方面都源于树木之间的相互作用，干扰和各种树木幼苗随后的定居浪潮之间的复杂关系。使用点过程统计信息，尤其是标记混合功能和标记变异函数，我们研究了引起物种与大小多样性空间相关的过程。我们发现，空间物种散布和同种大小分布是空间物种-大小相关性的关键驱动力，并且将简单的随机大小标记技术应用于标记变异函数的组合有助于有效诊断它们。如果物种之间的大小范围不同，则空间大小多样性很大程度上取决于空间物种的混合。这些相关性的存在对保护至关重要，因为它们暗示了保护工作可以合理化：可以仅关注两个树木多样性方面之一。有趣的是，在多物种的森林生态系统中，尽管一般物种的多样性很高，但可以稀释空间物种与大小的相关性，