Michael L. Bowman

Prior to creating durable habitats, existing terrestrial and aquatic habitats must be accurately assessed to determine their existing condition. In many instances, mapped geological information is one of the important components supporting natural resources assessment. This type of information has played a key role in several projects in Maryland and Virginia in which I've been involved. Geological information can be applied across a wide spatial scale of assessment and habitat creation activities. Examples of regional-scale assessments that relied on mapped geological information include--

• The delineation of ecoregions and subecoregions,
• The Maryland Synoptic Stream Chemistry Survey, and
• The Maryland Critical Loads Study.

At the local or site-specific scale, the following projects have relied in part on mapped geological data:

• Stream restoration,
• Habitat assessment, and
• The Western Maryland Watershed Liming Project.

Each of these efforts either provided an assessment of existing conditions or incorporated an assessment as one of its elements. The ultimate focus of all of these projects was to determine or restore habitat quality for native biota.

Lindsay McClelland

In a fundamental sense, geology is the foundation upon which terrestrial ecosystems are built. In recognition of the importance of geology to ecosystems, the National Park Service (NPS) Inventory and Monitoring Program, established to support NPS ecosystem management, includes geologic map data as a basic component of the multilayered geographic information systems being developed for the parks. Park natural-resource managers will be able to combine digital surficial and bedrock geologic-map data with topography, vegetation maps, soils maps, and wildlife inventories. The NPS is in the process of identifying, acquiring, and digitizing all available geologic maps of national parks through agreements with the Association of American State Geologists and the USGS.

In the Mid-Atlantic region, two geologic mapping projects in national parks should particularly be highlighted. Along the C&O Canal from Washington, D.C., to Cumberland, Md., Scott Southworth is generating a 180-mile-long strip map that illustrates the region's primary geologic provinces from the Coastal Plain into the Appalachians. This map will provide a fundamental tool for comparing geological changes with biological variation through the length of the park. In Shenandoah National Park, Ben Morgan and his colleagues are mapping dramatic debris flow deposits that have had major effects on stream ecosystems in the park. Continuing work will focus on surficial geology with direct links to a number of park ecological issues.

Geologic mapping data from Art Schultz and Scott Southworth in Great Smoky Mountains National Park is being eagerly sought by park ecologists. The terrain in the park is steep, and vegetation is junglelike, making ground access challenging. By combining topography and slope direction with bedrock and surficial geology, ecologists will target areas that have a high potential for harboring threatened and endangered species.

Lucy McCartan and colleagues are developing mapping techniques to characterize the geochemistry of bedrock over broad regions. As this approach is refined, and if it includes targeted analyses of the complex data for land managers, it could be a powerful technique in better understanding the geochemical basis for ecosystems and the potential for external threats to those ecosystems.

Several geologic environments from the Mid-Atlantic region are known for supporting distinct ecosystems that often include rare and (or) endemic plants and animals. Geologic mapping enables land managers to target these unusual environments for special attention. Where ecologists have identified unusual assemblages, geologic mapping will help them understand why they have developed at a particular site and will provide key data for their effective management.

• Limestone and the associated karst environments are characterized by distinctive hydrologic regimes and cave systems. Cave ecosystems are particularly fragile because of their vulnerability to pollution and often include endemic and rare species, particularly bats and invertebrates. From the land manager's perspective, detailed geologic mapping in karst areas is most effective if it provides locations of cave openings, losing streams, springs, and fracture systems to help determine the controls on subsurface water flow. Note that, to protect caves and their ecosystems from damage and vandalism, Federal law prohibits revealing locations of cave openings to the public. Cave locations should be provided to land managers but not published in electronic or paper map products. USGS projects near two national parks--Buffalo National River, Arkansas (led by Mark Hudson), and Ozark Scenic Riverways, Missouri (led by Rich Harrison)--are addressing key land-management issues by assessing subsurface flows of pollutants.

• The soils that develop over limestone are often thin and differ substantially from the region's typical acid clays. Limestone cliff faces provide dry, chemically distinct environments similar to those found in semiarid to arid parts of the West. These support very different plant communities, including endemics such as tall blazing-star (Liatris aspersa) (Terwilliger, 1991).

• Serpentinite-dominated systems, rich in magnesium and iron but impoverished in many chemical components that most plants need to prosper, create unusual ecological communities.

• Shale barrens develop on steeply sloping sites, where the shale flakes at the surface reduce water infiltration, and mass-wasting limits tree growth to scrub pine-oak (Pinus virginiana/Quercus prinus). Especially if south-facing, these environments tend to be hot and dry, with a characteristic assemblage of endemic plants, including Virginia endangered species Millboro leatherflower (Clematis viticaulis), shale barren rockcress (Arabis serotina), and Kate's Mountain Clover (Trifolium virginicum) (Terwilliger, 1991).

Our challenge is to link the different disciplines necessary to put geologic maps to work addressing ecological issues. The incorporation of the Biological Resources Division (formerly the National Biological Service) into the USGS provides an excellent opportunity to build key parts of that linkage.

Michael E. Slattery

Recent reorganization of the Maryland Department of Natural Resources (DNR) resulted in the genesis of Heritage and Biodiversity Conservation Programs (HBCP), an interdependent set of programs with a unified mission--to provide for the long term conservation of the full array of native ecosystems, natural communities, and species that constitute the biological integrity of Maryland, for the benefit of this and future generations. Maryland's biological heritage and natural diversity are diminishing, along with the integrity of ecological functions that are the underpinnings of our natural world. Along with this loss of diversity, elements of the very fabric of natural history and culture that Marylanders so cherish, indeed that support human life and spiritual well-being, are significantly impoverished.

DNR has had many biodiversity-related successes in its past. However, those successes have been hard fought, somewhat sporadic, and often opportunity driven. HBCP's aim is pursue the conservation of biodiversity in a systematic, strategic way. To accomplish this, we need to answer four questions. (1) What living things and ecosystems should we conserve and protect? (2) Where should we protect those resources in order to get the greatest return on our investment of time and energy? (3) How should we manage those resources once conservation and protection measures have been put in place? (4) Are we succeeding in the achievement of our mission? The answers to these questions must be rooted in good science. The scientific information considered must be understandable to a wide variety of public and private decisionmakers. The application of that information must result in meaningful conservation measures on the ground.

In order to most efficiently answer the first and second questions, HBCP has shifted its emphasis to concentrate on ecological community-oriented approaches, as opposed to more traditional species-oriented approaches. Specifically, we have chosen to focus on plant community alliances to guide our conservation efforts. This is not to say that we will disregard the importance of rare species conservation. We will look to rare species data to differentiate between otherwise similar examples of community types and further refine our conservation priorities geographically.

A community type is an assemblage of species that recurs under similar habitat conditions and disturbance regimes, which are classified in a standard system. A plant community alliance is the smallest scale level at which recurring assemblages of plants are discernible on the landscape. Plant community alliances have unique ecological functions, some identifiable and some presumed, which are unique to that community alliance and which have inherent conservation value. Protecting and conserving communities are efficient strategies for conserving the full range of ecological functions existing in a given landscape, which support the diverse and interconnected community of living things (biological diversity). This is especially necessary for the protection of more common species and those we know very little about. It is commonly referred to as the "coarse filter" approach to conservation.

Identifying and classifying plant community alliances require extremely sophisticated botanical assessment, as well as some understanding of the physical environment with which living organisms interact. The functional relationships between biotic and abiotic ecosystem components must be considered. The nuances of variation between plant community alliances are a result of sometimes subtle, and sometimes not so subtle, differences in surface and shallow subsurface geology and hydrology, among other abiotic variables.

So, community ecologists and other conservation ecologists rely heavily on geologic maps and other information to perform their life's work. Geology is an important consideration for planning fieldwork and is used extensively by field ecologists in their work to traverse remote areas with few landmarks. It helps us to key in on unique features when we hunt for certain rare species with very specific habitat requirements. For example, the State endangered green salamander is known to occur only in Pottsville Formation sandstone outcrops in Garrett County's wilder forests, and several rare small mammal species occur with regularity in western Maryland forests with limestone talus substrates. Geologic features also define some of our most unique and biologically diverse natural community types, such as our limestone caves, sandstone glades, shale barrens, and xeric dunes. The limits of Maryland's relic short and tall grass prairies and oak savannahs at Soldier's Delight, which are now the focus of a major restoration initiative, are determined largely by the extent of serpentine soils.

Geologic maps and information are critical in many ways to the conservation of biological diversity in Maryland. Of primary importance at the moment are the implications this information may have for future iterations and refinement of the classification of plant community alliances. The classification is necessary to develop baseline inventories of natural communities and important habitats to be used in setting conservation priorities. A conservation planning process will make extensive use of such information to identify a core network of lands representative of Maryland's diverse natural communities and native species. The process will geographically assemble and arrange ecologically targeted areas that, presumably, act collectively in the landscape to provide a full range of ecological niches supportive of our diverse and interconnected communities of living things. We can then work systematically to promote and facilitate the conservation and protection of those areas. From this perspective, geologic information plays a critical role in this vision of creating a durable and self-sustaining habitat that supports the full complement of Maryland's natural diversity.

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Last modified 15 April 1998
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