Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
PLoS One. 2013 Apr 24;8(4):e62825. doi: 10.1371/journal.pone.0062825. Print 2013.
The increasing demand for forest-derived bio-fuel may decrease the amount of dead wood and hence also the amount of available substrate for saproxylic ( = dead-wood dependent) organisms. Cut stumps constitute a large portion of dead wood in managed boreal forests. The lichen flora of such stumps has received little interest. Therefore, we investigated which lichens that occur on stumps in young (4-19 years), managed forests and analyzed how species richness and occurrence of individual species were related to stump and stand characteristics. We performed lichen inventories of 576 Norway spruce stumps in 48 forest stands in two study areas in Central Sweden, recording in total 77 lichen species. Of these, 14 were obligately lignicolous, while the remaining were generalists that also grow on bark, soil or rocks. We tested the effect of characteristics reflecting successional stage, microclimate, substrate patch size, and the species pool in the surrounding area on (1) total lichen species richness, (2) species richness of obligately lignicolous lichens and (3) the occurrence of four obligately lignicolous lichen species. The most important variables were stump age, with more species on old stumps, and study area, with similar total species richness but differences in occupancy for individual species. Responses for total lichen species richness and species richness of obligately lignicolous lichens were overall similar, indicating similar ecological requirements of these two groups. Our results indicate that species richness measurements serve as poor proxies for the responses of individual, obligately lignicolous lichen species.
对森林生物燃料的需求不断增加，可能会减少枯木的数量，从而减少可供腐生（依赖枯木）生物利用的基质数量。砍伐的树桩是管理的北方森林中枯木的主要组成部分。这些树桩上的地衣植物群很少受到关注。因此，我们调查了在年轻（4-19 年）、管理的森林中的树桩上发生的哪些地衣，并分析了物种丰富度和个别物种的出现与树桩和林分特征的关系。我们对瑞典中部两个研究区的 48 个林分中的 576 个挪威云杉树桩进行了地衣清查，总共记录了 77 种地衣物种。其中，14 种是专性木质地衣，而其余的是在树皮、土壤或岩石上生长的非专性地衣。我们测试了反映演替阶段、小气候、基质斑块大小和周围地区物种库的特征对（1）总地衣物种丰富度、（2）专性木质地衣物种丰富度和（3）四种专性木质地衣物种出现的影响。最重要的变量是树桩的年龄，老树桩上的物种更多，而研究区域的总物种丰富度相似，但个别物种的占有率不同。总地衣物种丰富度和专性木质地衣物种丰富度的响应总体上相似，表明这两个群体具有相似的生态需求。我们的结果表明，物种丰富度测量不能很好地替代个别专性木质地衣物种的响应。
