Ecology of riparian plant communities in southern Malheur National Forest
Riparian communities in the southern portion of Malheur National Forest were intensively studied with the objective of designing an approach for classifying disturbed riparian areas into units of similar potential. Not all riparian community types in this portion of the Blue Mountains were sampled d...
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| Other Authors: | , , , , |
| Format: | Master Thesis |
| Language: | English unknown |
| Published: |
Oregon State University
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| Subjects: | |
| Online Access: | https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/tb09j905r |
| Summary: | Riparian communities in the southern portion of Malheur National Forest were intensively studied with the objective of designing an approach for classifying disturbed riparian areas into units of similar potential. Not all riparian community types in this portion of the Blue Mountains were sampled due to time limitations. Some of the major community types sampled included: Baltic rush (Juncus balticus) communities; Kentucky bluegrass (Poa pratensis) communities; beaked sedge (Carex rostrata) communities; water sedge (Carex aquatilis) communities; mountain alder (Alnus incana) communities; and various willow communities (Salix geyeriana, Salix exigua ssp. exigua, Salix rigida var. mackenziana, and Salix lemmonii). Sites were selected to maximize geographic variation. Piezometers were placed at each site to determine depth to water table. Soil temperature at depths of 15 cm and 50 cm and water table depth were measured semi-weekly. Plant frequency and understory cover by species were determined using 25 cm square plot frames along three 10 m transects in each community sampled. Belt transects were run to determine tree and shrub densities. Tree cover was determined using a hand-held densiometer and the line-intercept method was used for shrub cover. Soils were described and samples were collected from each horizon for laboratory determination of percent organic carbon, soil texture, and reaction (pH). Ordinations of plant communities and plant species were calculated using the DECORANA program for detrended correspondence analysis. The first axis of ordination arranged both species and communities along a moisture gradient. This was verified by correlation analysis as well as through canonical correlation of a species matrix and an environmental matrix. Stand ordination tables combined with water table and soils data were employed in separating these communities into units of similar vegetative potential (Riparian dominance types). Use of these riparian dominance types may improve management of riparian zones in ... |
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