TREELANDS – Trees as Islands – on the phylogenetic isolation of trees in mixed forests

混交林是营林经营的核心工具之一。在生物多样性探索中，针叶树比例的增加是森林土地利用强度的一个主要决定因素。然而，推动不同进化环境中树木树冠多样性的生态机制仍然知之甚少。随着系统发育隔离对目标树种及其居住者的影响是多方面的：一是通过改变树冠和树叶的特征，二是随着进化距离的增加而与邻近树种隔离。在这里，我们检验了寄主树的系统发育隔离影响中欧四种主要树种--樟子树、栎树、樟子松和云杉--节肢动物群落的假设。我们将结合冠层节肢动物雾化样本、陆地激光扫描、小气候测量、树叶测量和创新条形码方法来测试四个研究领域的八项预测。首先，我们将研究系统发育隔离是通过隔离直接影响昆虫群落，还是通过冠层结构的变化间接影响昆虫群落。第二，我们将研究系统发育隔离对树内变异的影响，第三，这种变异对昆虫群落的影响。第四，我们将研究系统发育隔离对草食性、不同行会的多样性和物种内变异的影响。这将使我们能够首次测试以前来自橡树的结果在多大程度上可以推广到其他树种，并使我们能够更深入地了解森林土地利用梯度混合成分背后的生态机制。

Mixing trees in production forests is one of the core tools of silvicultural forest management. In the Biodiversity Exploratories the increasing proportion of conifers is a major determinant of the land-use intensity in the forests. However, the ecological mechanisms driving the diversity in the canopy of trees embedded in different evolutionary neighbourhoods is still poorly understood. The neighbourhood to tree species with an increasing evolutionary distance as the phylogenetic isolation can affect the target tree and it inhabitants in many ways: first by changing the crown and leaf characteristic, second via isolation from neighbour with increasing distance. Here we test the hypothesis that phylogenetic isolation of a host tree affects the arthropod communities for the four major tree species in Central Europe, Fagus sylvatica, Quercus petrae, Pinus sylvestris and Picea abies. We will combine canopy arthropod fogging samples, Terrestrial Laserscanning, microclimate measurements, Leaf measurements and innovative barcoding methods to test eight predictions in four research fields. First, we will investigate if phylogenetic isolation affects insect communities directly via isolation or indirectly by changes in crown structures. Second we will study the effects of phylogenetic isolation on within tree variation and third the effects of this variation on insect communities. Fourth, we will study the effect of phylogenetic isolation on herbivory, diversity of different guilds and within species variation. This will allow us to test for the first time how far previous results from oaks can be generalised to other tree species and give a deeper insight into the ecological mechanisms behind the mixing component of the land use gradient in forests.