当代生物多样性剧减与古—中生代之交生物绝灭的对比

Comparison of Modern Biodiversity Variation with Paleozoic-Mesozoic Biotic Crisis

18世纪以来人类活动对环境造成了强烈破坏 ,给生物多样性带来了巨大损失 .为了了解生物多样性的变化趋势 ,利用“绝灭物种统计法”、“种 -区曲线法”和化石记录对 4 0 0年以来的生物多样性和古—中生代之交的生物绝灭进行了分析 .当代生物多样性剧减表现为物种的快速绝灭 (从 8× 1 0 4种 /Ma增大到 1 .2× 1 0 6种 /Ma) ,而属的绝灭几乎为 0 ;古—中生代之交生物绝灭的初始阶段也表现为物种的快速绝灭 (从 4 0种 /Ma增大到 1 5 0种 /Ma) ,并且这个阶段的属的绝灭速率远低于绝灭高峰阶段的相应值 (即 6 6属 /Ma远小于 4 6 5属 /Ma) ,可见当代生物多样性剧减相当于二叠—三叠系之交生物绝灭的初始阶段 .

Since the 18th century the earth environment was extremely destroyed by anthropogenic activity, associated with the sharp decrease of biodiversity. In order to understand the trend of biodiversity variation, authors compare the biodiversity variation within recent 400 years with the biotic crisis occurring at the transitional period of Paleozoic-Mesozoic. Current biodiversity, evaluated by means of 'statistic of extinction species' and 'species-area curve', is characterized by a high species extinction rate ranging from 8×10~4 species to 1.2×10~6 species per million year, but nearly by zero of genus extinction. Similarly, the initial phase of the Paleozoic-Mesozoic mass extinction, calculated from the previously reported fossil records, was also distinguishable by a high species extinction rate ranging from 40 to 150 species per million year and a low extinction rate of genus, 66 genera per million year, which is far less than 465 genera per million year representative of the peak phase of Permian-Triassic mass extinction. Modern biodiversity variation is thus comparable with the initial phase of the Permian-Triassic mass extinction.