有哪些信誉好的足球投注网站- 1、本文档共13页，可阅读全部内容。
- 2、有哪些信誉好的足球投注网站（book118）网站文档一经付费（服务费），不意味着购买了该文档的版权，仅供个人/单位学习、研究之用，不得用于商业用途，未经授权，严禁复制、发行、汇编、翻译或者网络传播等，侵权必究。
- 3、本站所有内容均由合作方或网友上传，本站不对文档的完整性、权威性及其观点立场正确性做任何保证或承诺！文档内容仅供研究参考，付费前请自行鉴别。如您付费，意味着您自己接受本站规则且自行承担风险，本站不退款、不进行额外附加服务；查看《如何避免下载的几个坑》。如果您已付费下载过本站文档，您可以点击 这里二次下载。
- 4、如文档侵犯商业秘密、侵犯著作权、侵犯人身权等，请点击“版权申诉”（推荐），也可以打举报电话：400-050-0827(电话支持时间：9:00-18:30)。
查看更多
Non-native plant invasions of United States National Parks
ORIGINAL PAPER
Non-native plant invasions of United States National Parks
Julia A. Allen ? Cynthia S. Brown ?
Thomas J. Stohlgren
Received: 31 March 2008 / Accepted: 24 September 2008 / Published online: 10 October 2008
Springer Science+Business Media B.V. 2008
Abstract The United States National Park Service
was created to protect and make accessible to the
public the nation’s most precious natural resources
and cultural features for present and future genera-
tions. However, this heritage is threatened by the
invasion of non-native plants, animals, and patho-
gens. To evaluate the scope of invasions, the USNPS
has inventoried non-native plant species in the 216
parks that have significant natural resources, docu-
menting the identity of non-native species. We
investigated relationships among non-native plant
species richness, the number of threatened and
endangered plant species, native species richness,
latitude, elevation, park area and park corridors and
vectors. Parks with many threatened and endangered
plants and high native plant species richness also had
high non-native plant species richness. Non-native
plant species richness was correlated with number of
visitors and kilometers of backcountry trails and
rivers. In addition, this work reveals patterns that can
be further explored empirically to understand the
underlying mechanisms.
Keywords Non-native plant species
United States National Park Service
Invasion Invasive species
Exotic plant species management
Abbreviations
USNPS United States National Park Service
US United States
NR-MAP Natural Resource Management
Assessment Program
Introduction
The United States National Park Service (USNPS)
was created to protect natural resources and cultural
features in National Parks Service lands selected for
their beauty, uniqueness, and American historical
value, and to make these resources available to the
public. However, this heritage is threatened by the
invasion of non-native plants, animals and patho
文档评论（0）