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January 1994
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Conservation of Biological Diversity in the Great Lakes Basin Ecosystem:  Issues and Opportunities

Table Of Contents


Table 1:   Globally Significant Elements of Biodiversity in the Great Lakes Basin
Portable Document File (21KB)
Table 2:  Great Lakes Biodiversity Support Systems
Portable Document File (12KB)
Table 3:  Threats to Great Lakes Biodiversity: Stress Analysis
Table 4:  Threats to Great Lakes Biodiversity: Source Analysis
Table 5:  Conservation Tools Supported by Government Programs
Portable Document File (15KB)
Table 6:  Considerations for Project Targetting - An Illustration
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Appendix 1: References
Appendix 2: The Heritage Ranking System
Appendix 3: Types of Conservation Tools
Appendix 4: Working Locally for Strategic Value-An Illustration of Project Targeting 

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This document was prepared at The Nature Conservancy's Great Lakes Program Office. The primary authors are David Rankin and Susan Crispin. It is no exaggeration to say that without the work of many individuals this document could not have been prepared.

The primary support for this work was provided by a grant from the Great Lakes National Program Office of the United States Environmental Protection Agency (U.S. EPA), and assistance provided by U.S. EPA Region 5 under the Intergovernmental Personnel Act which allowed one of the primary authors to participate in this project. The analysis contained in this document draws from and builds on the Great Lakes Biodiversity Data System made possible by the generous support of the Joyce Foundation and the hard work of staff from state and provincial Natural Heritage programs, The Nature Conservancy, and the Nature Conservancy of Canada. The Great Lakes Protection Fund provided support for the development, management, and display of the spacial data presented in this report. We deeply appreciate the collaborative support that made this work possible.

The authors wish to thank the team of scientists and protection specialists that participated in the analysis of threats to the biodiversity resources of the basin. This team included Dennis Albert, David Braun, Kim Chapman, Don Faber-Langendoen, Robin Green, Bill McCort, John Shuey, Richard Spotts and Leni Wilsmann. Thanks also goes to the staff of the Nature Conservancy's field offices around the Great Lakes, the Midwest and New York Regional Offices, the Home Office staff, and the collection of national experts spread around the country. Through the support of this far-flung and diverse network of professionals, who provided comments on the developing materials and offered advice when it was needed the most, our jobs were made much easier.
The appendix on conservation tools draws heavily on the work of Phil Hoose and his classic book Building an Ark. We appreciate his thoughtful analysis of what can actually be done to conserve biological diversity. We also appreciate the work of Keith Monzingo who built and managed the database on element characteristics and handled the actual production of the final version of this document.

Many other individuals played a significant role in the development of this document. Peter Boyer, Bob Brander, Dale Bryson, Barry DeGraff, Bill Franz, Jim Giattina, Susan Gilbertson, Chris Grundler, Bill Horvath, Bruce Kirshner, Gary Kohlhepp, Joe Koonce, John McDonald, Jake Vanderwal, Barb West, and Charlie Wooley all provided support, advice, information and/or direction during the early stages of this analysis. Jeri Berc, Pat Collins, David Cowgill, Michael Donahue, George Francis, Arlin Hackman, Karen Holland, Michael Koutnik, Richard Laing, Diana Malley, Jerome Myszka, Laura Rose-Day, and Carl Zichella all reviewed draft portions of this document and provided valuable perspective and constructive advice. The authors have not sought, nor are we attempting to imply, any endorsement of this document by the above individuals. We are simply grateful for their involvement.

Last, and certainly not least, we wish to recognize the hard work of Kathleen Rude who helped transform the working drafts of this paper into an understandable product.

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Executive Summary

Biological diversity underpins the functional integrity of the Great Lakes basin ecosystem. This document provides a "first look" at the special biological diversity of the Great Lakes basin ecosystem and at those human activities that place it at risk. This is intended not as a definitive summary, but as a starting point for understanding and conserving Great Lakes biological diversity.

In this document, the information and methods of the Natural Heritage programs are used to identify key biodiversity resources of the Great Lakes basin ecosystem. These resources are the natural communities and species that represent the range of life native to the Great Lakes basin. The Heritage methodology provides a means of focusing action on those elements most critical to the maintenance of biological diversity.

The network of state and provincial Natural Heritage programs has identified 131 elements within the Great Lakes basin that are critically imperiled (22), imperiled (30), or rare (79) on a global basis. Of these globally significant elements, 31 are natural ecological community types; the rest are individual species, subspecies or varieties, including 49 plants, 21 insects, 12 mollusks, nine fish, five birds, three reptiles and one mammal. Additionally, 12 natural community types are recognized that, while not globally rare, form major components of the basin's landscape and support a wealth of biological diversity that is important to the basin's ecological integrity.
Actual numbers of globally significant species and communities in the basin may be higher, given that some areas and taxa have not yet been thoroughly inventoried. In particular, invertebrate groups, northern reaches of the basin and open-water aquatic systems have received the least attention, and undoubtedly support additional species and communities of global significance.

Of the 131 elements of global significance, nearly half (47%) occur exclusively or predominantly within the basin, or have many of their best examples here. Of the critically imperiled elements, fully 77% belong to this category. The global existence of these communities and species depends upon their survival in the Great Lakes basin. They define the unique biological character of the Great Lakes ecosystem and underscore the importance of preserving its biological diversity.

Human activities have altered and will continue to impact the Great Lakes ecosystem and the biological diversity it sustains. To protect this biodiversity, the ecological processes that sustain key elements need to be safeguarded. Stresses which threaten those processes must be identified, evaluated and then addressed.
To guide this process, seven broad systems are identified that support the basin's biological diversity. They are: open lake, coastal shore, coastal marsh, lakeplain, tributary and connecting channel, inland terrestrial and inland wetland. Of these, the coastal shores, lakeplains and coastal marshes support the greatest amount of biological diversity that is unique to or dependent upon the Great Lakes ecosystem.
Next, 16 stresses that directly threaten key biodiversity elements of these systems are identified and evaluated on the basis of the severity and scope of their impacts. These stresses include: toxics, alterations of nutrient inputs, acidification, salinization, alteration of lake levels/natural fluctuations, alteration of stream flow, alteration of water tables, temperature changes, disruption of longshore transport, sedimentation, fire suppression, habitat destruction, changes in forage base, increased competition, disease and increased predation/grazing.

This analysis suggests that stresses having the greatest impacts on biological diversity include habitat destruction and alteration of physical processes such as lake level dynamics, stream flows and groundwater regimes. Altered species interactions, particularly competition pressure from exotic species, also emerge as important stresses. These stresses have greater impacts because they affect multiple systems and tend to be less reversible than stresses in other categories.

A variety of human activities are evaluated to determine which contribute most to the stresses identified. These activities include: agriculture, air emissions, development, exotic species, in-place pollutants, mining, solid waste disposal, recreation, resource management, water discharges and water level management. This analysis suggests that the greatest sources of stress to Great Lakes biodiversity are development, water level management and agriculture. Other sources may become more important as additional information on the biological diversity of aquatic systems and the northern basin becomes available.

Conservation actions aimed at protecting the biological diversity of the Great Lakes basin must strategically address these key sources of stress. First, efforts need to focus on protecting ecological systems that are most important to the basin's biological diversity. They must also concentrate on key sources of stress, and do so sustainably in a variety of socioeconomic settings that represent the diversity of challenges present in the basin. Integral to all actions is an ever-growing understanding of what these key species and communities need to survive.
Four major types of strategic activity are recommended to protect biological diversity in the basin:

  • Developing strategically coordinated, locally-based projects that collectively address the most significant systems and stresses;
  • Improving the basic and applied science necessary for biodiversity conservation;
  • Increasing awareness of the basin's biological diversity and of methods to conserve that diversity;
  • Increasing the support of regional institutions, both governmental and private, for the protection of biological diversity.

The Nature Conservancy remains committed to the conservation of biological diversity. Our protection efforts in the Great Lakes basin ecosystem will include a series of large-scale, sustainable, locally driven protection initiatives focused on the basin's special biodiversity features. The Conservancy will continue to seek and build partnerships that directly support biodiversity conservation goals in these project areas. The Conservancy will also improve methods of sharing our knowledge and of learning from the work of others. Finally, the Conservancy will support inventory work to increase knowledge of biodiversity resources, especially of aquatic systems and northern areas of the basin, and will support research to better understand ecological processes that are essential to targeted biodiversity elements.



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