大兴安岭呼中区紫貂生境格局变化及采伐的影响

本文根据紫貂（Martes zibellina）行为生态学特征，利用景观生态学的原理和技术，将大兴安岭呼中区紫貂生境划分成最适、一般适宜和非适宜三种类型。以其紧邻的呼中自然保护区核心区1989年的生境格局代表呼中区1970年开发前的原始生境，揭示原始生境、1989年、2000年3个时期紫貂生境格局及变化。结果表明，1970-2000年紫貂生境格局持续恶化，已极不利于紫貂的生存。适宜生境向非适宜生境呈单一方向转变，且适宜生境由沟谷两侧向远离河谷的森林腹地大幅度萎缩。生境格局变化与经营时问长短关系密切，原始状态是以适宜生境为基质的均质状态，开发至一定时期，生境格局的异质化程度增大，继续开发则异质化程度又减小，形成以非适宜生境为基质的相对均质状态。大于巢区最小面积f4km0）的生境斑块的面积百分比、斑块密度明显下降，斑块间距离显著增大。进而对导致生境格局变化的要素进行分析后发现，持续采伐是紫貂生境格局变化的主要驱动因子，采伐改变了植被条件，而植被条件的非适宜性造成了紫貂非适宜生境。1989-2000年的采伐格局也并不合理，各年伐区在研究区内均匀分布，采伐设计时没有考虑动物生境保护。但可以推断，1999年后开始逐步实施的“天然林保护工程”有利于紫貂生境的恢复，本研究强调森林采伐经营的空间格局与动物生境保护之间的关系，旨在促进决策部门将生物保护作为采伐经营政策制定的重要决策因子。

Habitat pattern change of Martes zibellina and the impact of timber harvest in Huzhong Area in Greater Hing'an Mountains, Northeast China

To better understand human impact on wild animal habitats,we selected three habitat types of Martes zibellina,representing three different successionary stages of their habitats in Huzhong Area,Greater Hing'an Mountain in northeastern China.Employing published literature about behavior ecology,aerial pho-tographs and forest stand maps,we classified the study site into three habitat types,i.e.,best-suitable,suit-able,and unsuitable.We chose the habitat pattern of the year 1989 in the core zone of Huzhong National Natural Reserve,which is adjacent to Huzhong Area and has similar natural conditions,to represent the pri-mary habitat pattern of Huzhong Area before exploitation.The result showed that,from 1989 to 2000,changes in the best-suitable-habitat was significant,decreasing from 68% to 40%,while suitable habitats de-creased from 42% to 17%,whereas unsuitable habitat increased from 21% to 39%.Suitable habitats shrank away from area close to river banks to central forests far away from rivers.Timber harvest proved to be the leading cause of habitat degradation.Our results provide a scientific basis for forest management and animal conservation.