铁矿开采对褐马鸡种群的影响

在山西五鹿山自然保护区的核心区就铁矿开采对褐马鸡(Casoptilon mantchuricum)种群的影响进行了调查。将铁矿周围的栖息环境分为<50 m、50-100 m和>100 m 3个分布带。开采前期,3个分布带中都可以遇见褐马鸡;开采初期,在<50 m分布带中已经看不到褐马鸡的踪迹,50-100 m分布带中的数量也有所减少,而在>100 m的分布带中褐马鸡的数量却有所增加,这表明由于铁矿开采的影响,褐马鸡从距铁矿较近的<50 m和50-100 m的分布带中,被迫转移到>100 m的分布带中活动。在铁矿开采3年以后,<50 m和50-100 m分布带中的遇见数都降至0,而>100m分布带中遇见的个体与开采初期相比,也有所下降。在开采初期,由于铁矿的数量较少,对褐马鸡种群活动综合影响并不显著,其种群密度并未发生明显变化。随着铁矿数量的增多和开采时间的延长,原来许多的觅食地,如林缘灌丛和地表草本都遭到破坏,而且铁矿开采的嘈杂声和爆破声此起彼伏,严重影响了褐马鸡正常的觅食活动。与开采初期相比,这种限制作用愈益显著,褐马鸡种群密度和空间分布也发生较大变化。研究结果表明,褐马鸡已不能适应铁矿开采带来的不良影响,在一些铁矿开采时间较长和数量较多的局部区域,褐马鸡已无法生存。

Effects of iron mine exploitation on the population of brown eared pheasant

Brown eared pheasant, Crossoptilon mantchuricum, is a globally threatened species of pheasant that is native to China. Following research in 1997, effects of iron mine exploitation on this species were studied again in Wulushan Nature Reserve of Shanxi Province in the spring of 2000, aiming at further un- derstanding the current status of habitats and population dynamics. Before exploitation, brown eared pheasants were observed in all three buffer zones, i. e. <50 m, 50 - 100 m, >100 m. Early after ex- ploitation began, the species was not found in the <50 m buffers, and there was a small decrease on number in the 50 - 100 m buffers, and an increase in the >100 m buffers. The results indicate that iron mine exploitation caused brown eared pheasants in the <50 m and 50 - 100 m buffers to move to the > 100 m buffers. After 3 years, brown eared pheasants did not occur in either the <50 m or the 50 - 100 m buffers. Compared with early after exploitation began, there was also a decrease in >100 m buffers. At the beginning of exploitation, because there were few iron mines, the effects on activities of brown eared pheasants were not great and population density did not change markedly. However, with increase in the number of iron mines and long-term exploitation many feeding sites were damaged, and this, com- bined with the effect of noise and explosives from mining, restricted normal feeding activities directly. Consequently population density and ranging pattern changed greatly. The results indicate that iron mines are an important factor determining habitat use by brown eared pheasants. The species has not accommo- dated to habitat change caused by iron mine exploitation.