The role of gap dynamics for the regeneration of the natural spruce forests in the Harz Mountains

在中欧，只有几个已知的地方可以在自然或接近自然的云杉林中研究自然干扰后的植被再生；布罗肯山的斜坡就是一个例子。虽然是单显性的，但布罗肯山的云杉林是独特的，因为它们含有本土的云杉基因型。此外，草本层的物种相对较少，无性繁殖的物种比例很高。基于林间隙动态对树木和草本层的再生与其他森林类型同样重要的假设，该项目试图测试四个主要假设。对于树层，将检验林隙是否促进了杉木异域基因型的建立，以及本土基因型的比例是否由于强烈的环境选择而随着林隙年龄的增长而增加。对于草本层再生，我们验证了丰富的无性系种桃金娘（Vaccinium myrtillus）、山菖蒲（Calamagrostis villosa）和三角杉（Trientalis europaeus）的生殖生殖能力在间隙中增强，无性系大小随着间隙年龄的增加而增加的假设。为了实现这一目标，该项目采用了地理信息系统、树木年代学和分子遗传学方法。利用航拍照片，根据年龄对间隙进行分层，并对目标物种的物种组成和种群结构进行采样。在田间观察的基础上，将对云杉的生长、抗冻性和营养再生能力以及目标草本植物的无性系生长进行试验。

In Central Europe only few places are known where vegetation regeneration after natural disturbances can be studied in natural or near-natural Picea abies forests; one example are the slopes of Mt. Brocken. Although being mono-dominant, the spruce forests at Mt. Brocken are unique because they contain autochthonous Picea abies genotypes. In addition, the herb layer is comparably species-poor with a high proportion of clonally reproducing species. Based on the assumption that gap dynamics are equally important for regeneration of the tree and herb layer as in other forest types, the project seeks to test four main hypotheses. For the tree layer, it will be tested whether gaps promote the establishment of allochthonous genotypes of Picea abies and whether the proportion of autochthonous genotypes increases with gap age due to strong environmental selection. For herb layer regeneration the hypotheses are tested that generative reproduction is enhanced in gaps for the abundant clonal species Vaccinium myrtillus, Calamagrostis villosa and Trientalis europaeus and that clone size increases with gap age. To attain its goal the project employs GIS, dendrochronology and molecular genetic approaches. Using aerial photographs, gaps will be stratified according to age and sampled for species composition and population structure of target species. The field observations will be supplemented by experiments on establishment, frost hardiness and vegetative regeneration capacity of spruce as well as on clonal growth of target herbs.