We employed sequential aerial photographs from 1939 to 1981 to document establishment and exponential spread of Spartina patens on Cox Island, the only recorded Oregott locality for this east coast species. Spartina patens, growing in distinctive circular patches, now occupies more than 3000 m 2 with no diminished expansion rate. Eight marsh communities are aggregated into four generalized marsh types: Low Marsh, Middle Marsh, High Marsh, and Transition Marsh. Spartina patens invades the Deschampsia caespitosaScirpus maritimus community, the most open (7.7 percent "bare ground") of the Middle Marsh communities. Spartina patch elevation ranges from 1.83 to 2.05 m above MLLW comparable to its indigenous east coast tidal position. Proximate expansion of individual circular patches is by clonal growth. The role of seed and vegetative propagule dispersal in establishment of new colonies has not been determined. Once established, S. patens inOregon performs comparably to its performance in Delaware and New England as shown by its general growth form, average above-ground live biornass of 329 gdw mL above-ground dead biomass of 411 gdw m a, and a below-ground to above-ground biomass ratio of 4.80.

ABSTRACT/Wetland environmental characteristics are examined to determine their spatial and temporal relationships. Two very different Oregon freshwater wetlands provided a range of wetland types. Resutts are evaluated to determine the possible use of environmental characteristics in defining wetlands and their boundaries. Representative physical, hydrological, and edaphic properties were periodically measured in microplots along upland/wetland transects. A multivariate approach is stressed in the data analysis; correlation, cluster analysis, and principal components analyses were used. The results indicate the environmental characteristics change in a quantifiable manner both spatially and temporally. The controlling mechanism is moisture, spatially in terms of the upland/wetland transect and temporally with respect to seasonal response. These changes do not correlate well with vegetation. Several hypotheses are offered as an explanation. Correlation within environmental characteristics is variable but definite patterns are discernible. These data suggest both single and combinations of environmental characteristics that could serve as "keys" in wetland identification and boundary determination. However, before extensive use is made of this information additional long-term monitoring of wetland environmental characteristics will be required.

Any project construction or operation that may potentially impact a threatened or endangered (T and E) plant or animal species or plant community will require notification to the appropriate federal or state agency. Mitigation measures may be required by the agencies to avoid or reduce impacts to these T and E species. Introduction Activities that involve federally threatened or endangered species on public land must comply with Section 7 of the Endangered Species Act of 1973, as amended. This Act is promulgated by the U.S. Fish and Wildlife Service (USFWS). Section 7 requires federal agencies, in consultation with the USFWS, to ensure "that any action authorized, funded, or carried out …. is not likely to jeopardize the continued existence of any listed species or result in the destructive or adverse modification of (critical) habitat." It should be noted, however, that individuals or private industry may also be required to consult with other federal or state agencies (i.e., Bureau of Land Management [BLM], U.S. Forest Service [FS]) or Tribal Councils regarding non-listed species if such agencies have classified certain species as sensitive or as "species of concern". Mitigation measures may be required by these agencies to avoid or reduce impacts to T and E species or to species of concern. Mitigation measures for protected plant species may include avoiding or minimizing impacts through project design changes or route realignments, or transplanting individuals or populations outside the impact area. For raptors (birds of prey), impacts can usually be avoided by restricting work activities within a buffer zone (usually 0.5 mile from active nests) during the nesting season. For various animals, monitoring any "taking" during work activities may be required. For aquatic species, mitigation measures may be taken to minimize direct impacts (e.g., injury, mortality) and indirect or secondary impacts (e.g., reduction in water quality, spawning habitat removal) during construction activities. P. 297^