At that time the United States pioneered the development of serious damage to the ecological environment of the buffalo and the the number of it was serious decline.
由于当时美国的开荒者为了开发严重破坏了水牛的生态环境，水牛的数量严重下降。
2
Moreover, the new concepts of ecological optimization criterion and finite time availability are presented.
同时，还介绍了生态学优化准则及有限时间可用性等新概念。
3
Through case study, find the bronze drum can use in the locality for a long time, there is connection that can't be isolated with the local unique ecological environment and culture factor.