破碎栖息地中物种灭绝机制

栖息地毁坏既会直接降低物种多度,又会间接地降低物种迁移繁殖力,同时还会改变原有的种间平衡.尽管已有研究表明栖息地毁坏是物种灭绝的主要原因之一,但是尚未揭示破碎的栖息地中物种灭绝的驱动机制.通过元胞自动机模拟了物种灭绝对栖息地毁坏空间异质性响应的基础上,进一步研究了栖息地毁坏和种间竞争对物种灭绝的影响.结果发现:强物种的灭绝主要来自栖息地毁坏,而弱物种的灭绝,在随机毁坏下,主要由栖息地毁坏与种间竞争共同决定,而在边缘毁坏下则主要由种间竞争所引起的.栖息地毁坏与种间竞争共同引起的物种灭绝的时间非常短,而栖息地毁坏或种间竞争所引起的物种灭绝时间则较长.

The driving forces of species extinction in fragmented habitat

Habitat fragmentation can reduce not only species abundance directly due to occupied patches being destroyed, but also the effective colonization rates indirectly. Moreover, habitat fragmentation can change the equilibrium among competitors. Previous studies to date consider habitat fragmentation to be the major cause of species loss. However, most analyses have been limited to the studies of consequences of habitat destruction. They do not reveal the driving mechanism. In this paper, we have studied the effects of habitat destruction and competition on species extinction in fragmented habitat. The results show that: the extinctions of superior competitors come from habitat destruction. However, the extinctions of inferior competitors decide by both habitat destruction and inter-competition under random destruction, and mainly by interspecific competition under edge destruction. The extinction time is much shorter when affected by habitat destruction and interspecific competition, while it is longer when affected by habitat destruction or interspecific competition. So, random destruction is more unfavorable for inferior competitors, and edge destruction is more unfavorable for superior competitors. Aggregated exploitation should be taken to decrease impacts on superior competitors, while random and disaggregate exploitation should be taken to decrease impacts on poor competitors.