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A recent report entitled The Conservation of Biological Diversity in the Great 

 Lakes Ecosystem: Issues and Opportunities, produced by The Nature Conservancy's 

 Great Lakes Program, documents that invasive fish and invertebrate species, such 

 as the sea lamprey (petromyzon marinus), the alewife (Alosa psuedoharengus), the 

 Eurasion river ruffe (Gymnocephalus cernus) and zebra mussel {Dreissena 

 polymorphs) pose a significant problem to the Great Lakes ecosystem. The report 

 states that these species have the insidious impact of causing a dramatic change in 

 the community structvu-e of the Great Lakes. The zebra mussel for example, is caus- 

 ing some shift;s in phytoplankton composition (microscopic plant communities), 

 which, in conjunction with increased grazing and predation from introduced 

 zooplankton and higher fishes, is causing shifts in the entire lake food web. 



In some cases, introduced animals and plants combine to reinforce a bad situa- 

 tion. In Hawaii for example, feral pigs {Sus scrofa) consume the fruit of introduced 

 common guava and strawberry guava (Psidium guajava and P. cattleianum) and 

 disperse the seeds throughout their range. The feral pigs contribute to the success- 

 ful propagation of the plants by disturbing soil and providing a location for exotic 

 plant establishment. The exotic plants exclude native vegetation from their original 

 habitat. This interaction contributes significantly to the decline of threatened and 

 endangered native plants. 



The Conservancy is concerned about the eventual impact of invasive species in 

 areas where they are not yet present. In Oregon, concern over the spread of leafy 

 spurge {Euphorbia esula) from Montana and Idaho (where it has had a major nega- 

 tive impact on the quality of rangeland) has stimulated discussion and preparation 

 for quick response when it first appears in the State. Control of invasive plants, in 

 general, is at the top of the Oregon Chapter's Stewardship Strategic Plan. 



The Nature Conservancy's problem with exotics is small when compared to the 

 problem on other public and private land. The Forest Service has identified invasive 



Slant problems on 6.5 million acres of land it manages. Eighty-eight National Parks 

 ave recognized invasive alien plants as a significant threat. Some reports have sug- 

 gested that invasive plants are spreading at a rate of 2,000 acres per day, with a 

 significant portion of the impact concentrated in the Intermountain West. Clearly, 

 this "biological wildfire" impacts everyone. 



II. The Nature Conservancy is Working On Its Own and in Partnership with 



Others to Manage Invasive Species 



The Nature Conservancy is working aggressively to manage exotic species on our 

 own land. It is extremely difficult to document the financial resources The Nature 

 Conservancy dedicates exclusively to the management of invasive species. In most 

 cases, management involves significant inputs of both professional and volunteer 

 labor to physically or mechanically remove or manage exotic species. The Conser- 

 vancy has used a variety of management control techniques in its arsenal of weap- 

 ons. For example, at our Pine Butte Swamp Preserve in Montana we have used her- 

 bicides to control a serious and growing problem with leafy spurge {Euphorbia 

 esula). Chemical control has not been effective in stopping leafy spurge from spread- 

 ing and we are now exploring the release of a biocontrol agent {Apthona nigriscutis) 

 to manage the problem. 



Blowing Rocks Preserve, Florida — A Case Study 



The efforts of our Florida Chapter to restore the Blowing Rocks Preserve are a 

 good illustration of our institutional commitment to controlling exotic species. This 

 case study documents a worst case example of the effort and resources required to 

 restore an area besieged by invasive plants. Although most areas of the country do 

 not require this level of intense involvement it is important to note that three 

 states — California, Hawaii and Florida — are extremely vulnerable to invasions of 

 non-natives. Since these States possess high levels of biological diversity, we are 

 particularly active in our efforts to control invasive species in those States. 



The Blowing Rocks Preserve is a 73 acre site on a barrier island in Sc itheast 

 Florida with a mile of shoreline on the Atlantic Ocean and the Indian River Lagoon. 

 It is an important nesting site for the federally endangered leatherback sea turtle 

 {Dermochlys coriacea), as well as the federally threatened loggerhead {Caretta 

 caretta) and green {Chelonia mydas) sea turtles. When The Nature Conservancy ac- 

 quired the property in 1968 it was dominated by non-native plant species that 

 threatened the native vegetation. In particular, the Australian pine {Casuarina 

 eg uiseti folia) had severely altered the dynamic dune ecosystem at the beach. Of 

 grave concern was the possibility that the shading of the trees lowered the beach 

 temperature which in turn may have altered the sex ratio of incubating sea turtle 

 eggs buried in the sand (encouraging the production of more males, which is not 



