最新提问
我的动态
登录后查看动态
题目内容双击单词支持查询和收藏哦～
题目材料：
The decline of the heath hen began when the first Europeans arrived on the East Coast of North America. Before European settlement, Native Americans used fire to maintain a mosaic of forests, shrublands, agricultural fields, and grasslands. After European diseases decimated Native American populations, the formerly open habitats of the Northeast became largely forested, resulting in major changes to bird communities and probably reducing habitat. Although the clearing of forests by European settlers probably once again increased heath hen habitat, hunting pressure was extreme, and by 1821 the formerly common bird was rare in New England. The last reports of heath hens in Pennsylvania and New Jersey are from 1869, and it is doubtful that the heath hen survived much after that on mainland North America.
以上解析由 考满分老师提供。
