PNW 98 Session - Full Abstracts
Full Abstract
1) Contact Author: Jess C. Mace
2) Institution:Pacific University - Biology Department
3) Mailing Address: 2416 Main St. #2 Forest Grove, Or. 97116
4) Phone #:(503) 359-5002
5) Email: macejc@pacificu.edu
6) Presenter: Jess C. Mace
7) Paper or Poster: poster
8) Equipment needs other than standard slide and overhead projector: none
9) Contributed session 1st choice:Monitoring
10) Contributed session 2nd choice:Bioassessment
11) Do you want your oral or poster presentation judged for a student award (yes or no)?: Yes
12) Would you like to be a judge for Student Awards (yes or no)?:No
13) Keywords:enhancement project, mitigated wetland, vegetational study
14) Authors:
15) Affiliation/institution:
16) Abstract Title:
A Comparison and Vegetational Study of Claremont Mitigated Wetland -
Spring, 1997 Vs. Fall, 1997.
17) Abstract Text:
Unavoidable wetland impacts due to the Claremont housing development in
Beaverton, Oregon lead to the in-kind, off-site mitigation of 6.6 acres
approximately 0.5 miles upstream along Bronson creek. The goals of this
mitigation are to replicate hydrology, hydric soils, and native vegetational
characteristics of a natural wetland system. Monitoring at Claremont began
in Spring, 1995, and has continued into a fifth year monitoring study.
Seasonal fluctuations in vegetation cover are measured using four north-
south transects (T1-T4) and a single east-west transect (T5). Quadrats
are established every 5 m. along T1 - T4 and every 25 m. along T5.
Hydrology was measured in conjunction with vegetational sampling using
peizometers and staff guages to measure both ground water and surface flow.
A comprehensive species list was collected and present taxa were assigned
as wetland indicator status (OBL, FAC, or WEED). Total species presence
increased during seasonal monitoring, from 38 (Spring, 1997) to 41 (Fall,
1997) while average percent cover over each transect was variable.
Fluctuations in percent cover by species has decreased in third year
monitoring, due to the system reaching maximum cover capacity. Competition
by non-native species, as well as loss of obligate and facultative wetland
species, is recorded using grid mapping. This mitigation can then be
assessed for its goals of species survival, diversity, and maximum total
cover. Only long term monitoring such as this can provide trends in
vegetative growth and hydrological changes with both mitigated and natural
wetland systems.
18) Comments/Requests: