87 



PREPARED STATEMENT OF DR. DEBORAH B. JENSEN 



Mr. Chairman, Members of the Committee, my name is Deborah Jensen, and I 

 am the Director of Conservation Science and Stewardship for The Nature Conser- 

 vancy. 



The Nature Conservancy is an international non-profit, land conservation organi- 

 zation dedicated to the preservation of biological diversity through the protection of 

 threatened species and their ecosystems. Our membership includes more than 

 730,000 individuals and over 1,100 Corporate Associates. 



For the past 40 years. The Nature Conservancy has preserved biological diversity 

 through habitat conservation. In fact, many people know us as the organization that 

 "buys land". Using a scientifically based selection process, The Nature Conservancy 

 identifies and preserves critical habitat. Typically, the land we acquire becomes a 

 part of our own preserve system that is managed for threatened and endangered 

 species. However, in some cases it is transferred to government, a university or pri- 

 vate entity dedicated to conserving the special nature of the property. 



In our efforts to secure land for the protection of biodiversity, we have worked in 

 partnership with other conservation organizations, businesses, individuals, and 

 local. State, and Federal Government agencies. Through these partnerships we have 

 helped protect more than 7.9 million acres of land in the United States, habitat for 

 literally thousands of species. We have also provided technical assistance in the 

 management of many millions of acres of land in this country and increasingly 

 abroad. 



The Nature Conservancy owns and manages 1,300 preserves nationally, with a 

 presence in all fifty States. Although our land acquisition statistics are impressive, 

 the science that drives our organization shows that to protect biological diversity we 

 must do more than merely acquire habitat. We must help conserve and manage the 

 ecological processes that are critical to the survival of rare plants and animals. Our 

 work shows that one of the biggest threats to maintaining biological diversity re- 

 sults fi-om the establishment and proliferation of non-indigenous invasive plants and 

 animals. The problems created by invasive species affect not only Nature Conser- 

 vancy preserves, but impact millions of acres of public land as well. The problem 

 is so severe, that at some locations the native biological diversity is severely threat- 

 ened. 



There are three points I want to make in my testimony today. First, The Nature 

 Conservancy views the current damage and the potential for damage created by 

 invasive species as a very serious threat to biological diversity. Second, we are ag- 

 gressively working on our own and in partnership with others to manage and con- 

 trol exotic species — and it is not cheap nor easy. Finally, there are some straight- 

 forward changes that should be made in Federal policy to help get ahead of the 

 problem. 



The CuRRE^fT Damage and Potential for Damage Caused by Invasive Species 

 IS A Very Serious Threat to Biological Diversity 



The problems associated with invasive species affect our preserves in all parts of 

 the country. Dr. John Randall, Invasive Weed Specialist for The Nature Conser- 

 vancy, surveyed land managers throughout our preserve system to determine the 

 extent of invasive plant problems on our own land. Ninety-three land managers 

 from 46 States completed the survey. Invasive plant problems were reported from 

 all 46 States but managers from California, Florida and Hawaii reported the great- 

 est number of invasive plant occurrences. Thirteen percent of the land managers re- 

 ported that weeds were their worst problem while 59 percent ranked it among their 

 top ten management concerns. 



The land managers reported a total of 197 non-native plant species. A few species 

 included in this catego^ are native to North America but are now invading beyond 

 their original ranges. The pests cited include ferns, gymnosperms and flowering 

 plants ranging from annual, biennial and perennial herbs, floating, emergent and 

 submersed aquatics, vines, shrubs, understory trees and canopv dominants. 



The threats posed by invasive plant species can be far reaching and devastating. 

 Invasive species can alter water tables, change fire regimes, suppress reproduction 

 in native species and therefore change the structure of the ecological community, 

 out-compete native species for space, change the habitat for native animal species, 

 and provide habitat for undesirable non-native animals. For example, several pre- 

 serves in the Southwestern United States have trouble with Tamarix spp an intro- 

 duced riparian tree. Preserve managers reported that Tamarix has lowered water 

 tables which has reduced or eUminated surface water habitats required by native 

 plants and animals. 



