Collins SL, Knapp AK, riggs JMB, Blair JM, Steinauer EM
S. L. Collins, Division of Environmental Biology, National Science Foundation, Arlington, VA 22230, USA. A. K. Knapp, J. M. Briggs, J. M. Blair, Division of Biology, Kansas State University, Manhattan, KS 66506, USA. E. M. Steinauer, Department of.
Science. 1998 May 1;280(5364):745-7. doi: 10.1126/science.280.5364.745.
Species diversity has declined in ecosystems worldwide as a result of habitat fragmentation, eutrophication, and land-use change. If such decline is to be halted ecological mechanisms that restore or maintain biodiversity are needed. Two long-term field experiments were performed in native grassland to assess the effects of fire, nitrogen addition, and grazing or mowing on plant species diversity. In one experiment, richness declined on burned and fertilized treatments, whereas mowing maintained diversity under these conditions. In the second experiment, loss of species diversity due to frequent burning was reversed by bison, a keystone herbivore in North American grasslands. Thus, mowing or the reestablishment of grazing in anthropogenically stressed grasslands enhanced biodiversity.
由于栖息地破碎化、富营养化和土地利用变化，全球生态系统中的物种多样性已经下降。如果要阻止这种下降，就需要恢复或维持生物多样性的生态机制。在原生草原上进行了两项长期田间试验，以评估火灾、添加氮以及放牧或割草对植物物种多样性的影响。在一项试验中，火烧和施肥处理下物种丰富度下降，而割草在这些条件下维持了多样性。在第二项试验中，北美草原的关键食草动物野牛扭转了因频繁火烧导致的物种多样性丧失。因此，在人为压力大的草原上进行割草或重新引入放牧可提高生物多样性。
