5 Special-Status Plants, Lichens, and Fungi, and Plant Communities
Hydroelectric projects potentially affect botanical resources (i.e., terrestrial and aquatic plants, lichens and fungi, and plant communities) in a variety of ways, as outlined in the Project Effects Matrix (Part I). Potential effects are due to three categories of project operations:
- land disturbance and maintenance (e.g., installation and upkeep of transmission line corridors);
- fluctuations in instream flows (e.g., flow alterations related to project operations); and
- impoundment of water (e.g., changes in reservoir elevations due to Project operations).
Land disturbance due to operations and maintenance of project facilities (i.e., powerhouses, roads, and transmission line corridors) can have an effect on presence and abundance of both special-status and non-native invasive species’ populations. Disturbance can also affect the quality and extent of certain special habitats, such as wetland communities. Changes to flow patterns, including altered flow regimes and impoundment of water, can affect riparian and wetland communities, can alter distribution of populations of special-status species, and affect the distribution of non-native invasive species populations along a reach or at the perimeter of a reservoir.
The basic approach to assessing floristic changes to the landscape due to hydroelectric project effects is to survey for the presence/absence, distribution, and extent of the “target” species—i.e., special-status vascular plants, lichen and fungi, and non-native invasive plants. Key elements and references for inventorying vary by taxonomic group and geographic region, but the general approach remains the same. The initial step involves an assessment of the habitat types present in the project area and identification of the special-status or non-native invasive species that are most likely to be present in the project area based on geographic distributions and species-habitat associations. The species that are determined likely to occur in the project area become the “target species” for subsequent field surveys. A comprehensive floristic survey of areas potentially affected by the project is then performed following the guidelines and protocol outlined by local agencies (e.g., in California, CDFG 2000). The timing of the field surveys should be determined by the periods in which the target species are identifiable (for many vascular plants positive identification is only possible when they possess flowers or fruits). Although all potentially affected areas should be surveyed, extra attention is typically given to sites that appear to provide highly suitable habitat for one or more of the target species. For bryophytes, lichens, and fungi, the process is similar, though survey efforts may be less comprehensive and more focused on only suitable habitats and substrates. Again, the local, most appropriate keys are used (e.g., for mosses in British Columbia, Schofield 1992 or for fungi in the United States, Arora 1986) and protocols follow the guidelines established by local or federal agencies (e.g., the USDA Forest Service Northwest Forest Plan’s Survey and Manage Guidelines for surveying for bryophytes, lichens and fungi).
Similarly, the basic approach to assessing potential effects to riparian vegetation or wetlands is to provide baseline information on the composition and structure of the habitat. For riparian vegetation, there are multiple methods used to characterize the vegetation, which are either transect (e.g., Greenline method) or plot-based (Cagney 1993, Winward 2000). The particulars of the system (i.e., alluvial versus non-alluvial) and species focus (e.g., cottonwood versus alders) help to dictate which methods will be more appropriate. For wetland communities, the basic approach is to characterize the site based on the following:
- species composition (i.e., via a full floristic survey);
- species assemblages or ecological zones (e.g., by defining palustrine emergent versus scrub-shrub wetland types [Cowardin et al. 1979] or riparian plant associations such as those described in various USDA Forest Service [e.g., Kovalchik 1987, McCain and Christy 2005] or other publications [e.g., Grossman et al. 1997, Sawyer and Keeler-Wolf 1995]); and
- hydrological and soil conditions (e.g., based on Cowardin et al. 1979, USACE 1987 definitions)
Typically, there is no need to formally delineate the site, as boundaries are not so important as the general condition or health of the site. However, if it is determined that the project is likely to impact wetlands, the regulatory agencies may require formal jurisdictional delineation of wetlands to aid in determining the level of mitigation required.
Upon completion of basic inventories of species composition and distribution, effects are primarily analyzed by comparing baseline data with some sort of standard or reference condition, as described below. In addition, some effects of hydroelectric projects require further, more focused field studies (e.g., tree cores to assess age-structure of riparian vegetation). These approaches are also described below.
The following references are recommended for additional information on special-status plants, lichens, and fungi and plant communities:
Arora, D. 1986. Mushrooms demystified: a comprehensive guide to the fleshy fungi.
Cagney, J. 1993. Riparian management: greenline riparian-wetland monitoring. Technical Reference 1737-8 USDI Bureau of Land Management, Denver, Colorado.
CDFG (California Department of Fish and Game). 2000. Guidelines for assessing effects of proposed projects on rare, threatened, and endangered plants and natural communities. The Resources Agency, Sacramento, California.
CNPS (California Native Plant Society). 2001. California Native Plant Society botanical survey guidelines. California Native Plant Society Sacramento, California.
Cowardin, L. M., V. Carter, F. C. Golet, and E. T. LaRoe. 1979. Classification of wetlands and deepwater habitats of the United States. U.S. Department of the Interior, Fish and Wildlife Service, Office of Biological Services, Washington, D. C. and available with Northern Prairie Wildlife Research Center Online, Jamestown, North Dakota. https://www.npwrc.usgs.gov/resource/1998/classwet/palustri.htm.
Derr, C., R. Helliwell, A. Ruchty, L. Hoover, L. Geiser, D. Lebo, and J. Davis. 2003. Survey protocol for survey and manage category A & C lichens in the Northwest Forest Plan area, Version 2.1. USDA Forest Service and USDI Bureau of Land Management, Survey and Manage Program of the Northwest Forest Plan. https://www.or.blm.gov/surveyandmanage/sp.htm.
Grossman, D. H., D. Faber-Langendoen, A. S. Weakley, M. Anderson, P. Bourgeron, R. Crawford, K Goodin, S. Landaal, K. Metzler, K. Patterson, M. Pyne, M. Reid, and L. Sneddon. 1998. International classification of ecological communities: terrestrial vegetation of the United States. Volume I. The National Vegetation Classification System: development, status, and applications. The Nature Conservancy, Arlington, Virginia.
Kovalchik, B. L. 1987. Riparian zone associations: Deschutes, Ochoco, Fremont, and Winema National Forests. Technical Paper 279-87. USDA Forest Service, Pacific Northwest Region, Region 6 Ecology.
McCain, C., and J. A. Christy. 2005. Field guide to riparian plant communities of northwestern Oregon. Technical Paper R6-NR-ECOL-TP-01-05. Prepared by USDA Forest Service, Pacific Northwest Region.
McCune, B., and L. Geiser. 1997. Macrolichens of the Pacific Northwest. Oregon State University Press, Corvallis and USDA Forest Service.
Sawyer, J. O., and T. Keeler-Wolf. 1995. A manual of California vegetation. California Native Plant Society, Sacramento, California.
Schofield, W. B. 1992. Some common mosses of British Columbia. Revised edition. University of British Columbia Press, Vancouver, Canada.
USACE (U. S. Army Corps of Engineers). 1987. Corps of Engineers wetlands delineation manual. Technical Report Y-87-1. USACE, Environmental Laboratory, Waterways Experiment Station, Vicksburg, Mississippi.
Winward, A. H. 2000. Monitoring the vegetation resources in riparian areas. General Technical Report RMRS-GTR-47. USDA Forest Service, Rocky Mountain Research Station, Ogden, Utah.