Retention-tree groups in clear-cuts: Do they constitute ‘life-boats’ for spiders and carabids?
Retention-tree groups in clear-cuts: Do they constitute ‘life-boats’ for spiders and carabids?
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清晰的保留树群：它们是否构成蜘蛛和步甲动物的“救生艇”？
DOI：
10.1016/j.foreco.2006.04.025
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发表时间：
2006
影响因子：
3.7
通讯作者：
R. O’Hara
中科院分区：
文献类型：
--
作者：
K. Matveinen;J. Niemelä;H. Rita;R. O’Hara
保留绿树的目的是在采伐木材的同时保持生物多样性，但对其效率的了解仍然有限。绿化树的保留可以作为生物的“救生艇”，保持结构特征，或在收获的景观中创建踏脚石。本研究的目的是确定是否较大的保留树组建立在皆伐保持森林物种比小的。我们提出了假设不同的栖息地亲和组的蜘蛛和步甲，并测试了他们在芬兰东部的11个保留树组，0.09- 0.55公顷的大小（47-385树每树组）。虽然一些分析的物种响应预期，我们没有找到明确的支持的假设，（1）物种需要森林和/或（中）潮湿的栖息地应该更丰富的大型保留树组，（2）物种需要（半）开放和/或（中）干燥的栖息地应该更常见的小型保留树组，（3）在所有保留木组中，无论大小，对光照强度和水分无差异的物种应捕获相同数量的物种。然而，许多森林物种和/或物种需要（中）潮湿的栖息地的平均数量下降了3年后，在所有保留树组，而许多物种的（半）开放和/或（中）干燥的栖息地的平均数量增加了3年后，伐木。此外，物种组成从处理前的一年蜘蛛。我们的结论是，绿树保留是合理的，因为（1）保留树组倾向于保持一些森林物种，从而减轻了皆伐的影响，至少在短期内，（2）他们提供枯木，大古树，和其他结构特征，（3）在我们的生态知识中存在差距，值得采取预防原则。然而，由于建立保留树群会产生经济成本，因此应仔细评估其与旨在保持生物多样性的其他方法相比的生态效益。
Green-tree retention aims at maintaining biodiversity while harvesting timber, but knowledge of its efficiency is still limited. Green-tree retention may function as a ‘life-boat’ for organisms, maintain structural features, or create stepping-stones in the harvested landscape. The aim of this study is to determine whether larger retention-tree groups established in clear-cuts maintain forest species better than smaller ones. We posed hypotheses for different habitat affinity groups of spiders and carabids, and tested them in Eastern Finland with 11 retention-tree groups, 0.09–0.55ha in size (47–385 trees per tree group). Although some of the analysed species responded as expected, we did not find unambiguous support for the hypotheses that (1) species requiring forest and/or (medium-) moist habitat should be more abundant in larger retention-tree groups, (2) species requiring (semi-) open and/or (medium-) dry habitat should be more common in smaller retention-tree groups, and (3) species indifferent with respect to light intensity and moisture should be caught in equal numbers in all retention-tree groups irrespective of their size. However, the mean numbers of individuals of many forest species and/or species requiring (medium-) moist habitat decreased over the 3 years after logging in all retention-tree groups, whereas the mean numbers of many species of (semi-) open and/or (medium-) dry habitat increased over the 3 years after logging. Furthermore, species composition changed from the pre-treatment year for spiders. We conclude that green-tree retention is justified because (1) retention-tree groups tend to maintain some forest species, thereby mitigating the effects of clear-cutting, at least in the short term, (2) they provide dead wood, large old trees, and other structural features, and (3) there are gaps in our ecological knowledge that warrant the adoption of the precautionary principle. However, as there are economic costs associated with the establishment of retention-tree groups, their ecological benefits as compared to other approaches aimed at maintaining biodiversity should be assessed carefully.