Department of Biology, Plant Conservation and Population Biology, KU Leuven, B-3001 Leuven, Belgium.
Department of Biology, Plant Conservation and Population Biology, KU Leuven, B-3001 Leuven, Belgium.
Sci Total Environ. 2019 May 20;666:703-712. doi: 10.1016/j.scitotenv.2019.02.290. Epub 2019 Feb 20.
Forest conversion into agricultural land has resulted in a continuous decline in forest cover and in a reduced size and increased edge-to-core ratio of the remaining fragments. Forest edges are more directly exposed to sunlight, wind and pollutants and the resulting changes in habitat quality might have a large impact on plant and animal communities. Few studies, however, have focused on forest edge effects on mycorrhizal fungus communities. Here, we used high-throughput sequencing to study how communities of arbuscular mycorrhizal (AMF) and ectomycorrhizal fungi (EcMF), present in both the roots of the dual mycorrhizal tree Alnus glutinosa and in the soil, changed with increasing distance from the forest edge within fragmented forests embedded in an intensively managed agricultural matrix. Overall, we found 158 AMF OTUs and 275 EcMF OTUs. Soil moisture content increased with increasing distance from the forest edge, whereas soil nitrate concentration increased with increasing distance in south-facing and decreased in north-facing edges. Distance to the forest edge had a significant effect on EcMF community composition that largely overlapped with the observed changes in soil variables, especially soil moisture content. Apart from this distance effect, there were also clear effects of edge orientation on mycorrhizal diversity and community composition. While AMF OTU richness was higher at south- than at north-facing edges, the opposite pattern was found for EcMF. Community composition of both mycorrhiza types also differed significantly between south- and north-facing edges. We conclude that altered environmental conditions at forest edges cause significant changes in mycorrhizal communities, which could subsequently affect ecosystem functioning.
森林转化为农业用地导致森林覆盖面积持续减少，剩余片段的面积缩小，边缘与核心的比例增加。森林边缘更容易直接受到阳光、风和污染物的影响，导致栖息地质量的变化可能对植物和动物群落产生重大影响。然而，很少有研究关注森林边缘对菌根真菌群落的影响。在这里，我们使用高通量测序来研究在双菌根树桤木（Alnus glutinosa）的根部和土壤中存在的丛枝菌根（AMF）和外生菌根真菌（EcMF）群落如何随森林破碎化中森林边缘的距离增加而变化，这些森林嵌入在集约化管理的农业基质中。总的来说，我们发现了 158 个 AMF OTUs 和 275 个 EcMF OTUs。土壤含水量随与森林边缘的距离增加而增加，而土壤硝酸盐浓度随南缘距离增加而增加，随北缘距离增加而减少。与森林边缘的距离对 EcMF 群落组成有显著影响，这与土壤变量的观察变化有很大的重叠，特别是土壤含水量。除了这种距离效应之外，边缘方向对菌根多样性和群落组成也有明显的影响。虽然 AMF OTU 丰富度在南缘高于北缘，但 EcMF 的情况则相反。两种菌根类型的群落组成在南缘和北缘之间也有显著差异。我们得出结论，森林边缘改变的环境条件导致菌根群落发生显著变化，这可能随后影响生态系统功能。
