Bäcklund Sofia, Jönsson Mari, Strengbom Joachim, Frisch Andreas, Thor Göran
Department of Ecology, Swedish University of Agricultural Sciences, P.O. Box 7044, SE-750 07 Uppsala, Sweden.
The Swedish Species Information Centre, P.O. Box 7007, SE-750 07 Uppsala, Sweden.
PLoS One. 2016 Jan 22;11(1):e0147004. doi: 10.1371/journal.pone.0147004. eCollection 2016.
With an increasing demand for forest-based products, there is a growing interest in introducing fast-growing non-native tree species in forest management. Such introductions often have unknown consequences for native forest biodiversity. In this study, we examine epiphytic lichen species richness and species composition on the trunks of non-native Pinus contorta and compare these to the native Pinus sylvestris and Picea abies in managed boreal forests in northern Sweden across a chronosequence of age classes. Overall, we recorded a total of 66,209 lichen occurrences belonging to 57 species in the 96 studied forest stands. We found no difference in species richness of lichens between stands of P. contorta and P. sylvestris, but stands of P. abies had higher total species richness. However, species richness of lichens in stands of P. abies decreased with increasing stand age, while no such age effect was detected for P. contorta and P. sylvestris. Lichen species composition progressively diverged with increasing stand age, and in 30-year-old stands all three tree species showed species-specific assemblages. Epiphytic lichen assemblages in stands of 30-year-old P. contorta were influenced by greater basal area, canopy closure, and average diameter at breast height, P. abies stands by higher branch density and canopy closure, and stands of P. sylvestris by greater bark crevice depth. Differences in lichen species richness and composition were mainly explained by canopy closure and habitat availability, and the greater canopy closure in mature P. abies stands promoted the colonization and growth of calicioid lichen species. Our results indicate that the non-native P. contorta have similar species richness as the native P. sylvestris. The main difference in lichen species richness and composition is between P. abies and Pinus spp. in managed forests of boreal Sweden.
随着对林产品需求的不断增加，在森林经营中引入速生非本地树种的兴趣日益浓厚。此类引入往往会给本地森林生物多样性带来未知的后果。在本研究中，我们调查了非本地扭叶松树干上的附生地衣物种丰富度和物种组成，并将其与瑞典北部经营的北方森林中不同年龄阶段的本地欧洲赤松和欧洲云杉进行比较。总体而言，我们在96个研究林分中记录了总共66209次地衣出现情况，属于57个物种。我们发现扭叶松林分和欧洲赤松林分之间地衣物种丰富度没有差异，但欧洲云杉林分的总物种丰富度更高。然而，欧洲云杉林分中地衣的物种丰富度随着林分年龄的增加而降低，而扭叶松和欧洲赤松则未检测到这种年龄效应。地衣物种组成随着林分年龄的增加而逐渐分化，在30年生的林分中，所有三种树种都表现出特定物种的组合。30年生扭叶松林分中的附生地衣组合受更大的基部面积、树冠郁闭度和胸高平均直径影响，欧洲云杉林分受更高的树枝密度和树冠郁闭度影响，欧洲赤松林分受更大的树皮裂缝深度影响。地衣物种丰富度和组成的差异主要由树冠郁闭度和栖息地可用性来解释，成熟欧洲云杉林分中更大的树冠郁闭度促进了钙皮类地衣物种的定殖和生长。我们的结果表明，非本地扭叶松的物种丰富度与本地欧洲赤松相似。在瑞典北部经营的森林中，地衣物种丰富度和组成的主要差异存在于欧洲云杉和松属之间。
