Graduate Thesis Or Dissertation

 

SoilPaddock.pdf Public Deposited

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  • Although terrestrial lichens and bryophytes are common in upland plant communities of the Blue Mountains in northeast Oregon, research on cryptogam communities in this region is wanting. Studies have shown that lichens and bryophytes can reduce soil erosion and increase soil fertility in other semiarid habitats of North America. Understanding the particular roles terrestrial lichens and bryophytes play in their ecosystems and how they react to anthropogenic disturbances is part of making sound management decisions. Managers in the Blue Mountains are now dealing with heavy fuel loads in forested habitats that were impacted by mountain pine beetles, western spruce budworm infestations, Douglas fir dwarf mistletoe, and drought from the 1970's into the 1990's. To better understand how cryptogam communities respond to fuels reduction treatments in insect impacted Abies grandis classified forests of the central Blue Mountains, we compared species composition of logged and burned stands to stands that have not been treated in forty years. We found early colonizing species to be much more frequent in treated sites (logged and burned) while later seral species occurred more often in untreated stands. Because untreated stands had more microsite heterogeneity (coarse woody debris as well as bare soils) there was generally a higher diversity of species than in treated sites. A comparison of the composition of cryptogam communities in these degraded forests to 'healthy' stands in the central Blue Mountains is difficult because unaffected stands are scarce and literature on such communities previous to the insect epidemics is lacking. To get a better idea of the potential that exists for terrestrial lichen and bryophyte community composition, this research was expanded to other common upland habitats in the area. In total 53 sites in five different plant community types were investigated (Abies grandis, Pinus ponderosa, Pinus contorta, Poa secunda grasslands, and Artemisia rigida steppe). Lichen and bryophyte composition and environmental characteristics were compared across sites using multivariate analyses. This research has provided some basic information on community composition in upland habitats of the Blue Mountains. Soil characteristics had the strongest correlation to community composition. Habitats with sparsely vegetated, shallow, rocky soils (bunchgrass, Artemisia rigida, Pinus ponderosa) had very different cryptogam presence than those with deep soils covered by coarse woody debris and denser vegetation (Abies grandis and Pinus contorta forests). While investigating dry bunchgrass habitat of the region an unattached form of Grimmia ovalis was found on many sites with shallow soils and sparse vegetation. Although this moss is commonly known on rock in western North America, it has not yet been reported as unattached in North America. It has, however, been recorded from Africa and Venezuela. Unattached mosses, or moss balls, form when a force, such as frost heaving, cleaves a moss clump from a substrate. That same force, or another, will rotate the clump exposing alternating sides to growth. The formation of moss balls in northeast Oregon are likely created by freeze thaw cycles. More research on their biology and habitat is needed to verify this theory.
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  • description.provenance : Submitted by Amanda Hardman (hardmana@onid.orst.edu) on 2008-01-15T23:53:28Z No. of bitstreams: 4 HardmanThesisFinal.pdf: 3036758 bytes, checksum: b1393714c6a4a3a2b06519d167149a50 (MD5) SoilPaddock.pdf: 31218 bytes, checksum: 89d918a86f4de6a3786f3104156b9191 (MD5) StarkSoil.pdf: 635059 bytes, checksum: 63787e666c9f4bf7960227b525afa508 (MD5) VagrantGrim.pdf: 871938 bytes, checksum: 9d712408f11a586328c6a88f344c486e (MD5)
  • description.provenance : Approved for entry into archive by Julie Kurtz(julie.kurtz@oregonstate.edu) on 2008-01-23T18:25:15Z (GMT) No. of bitstreams: 4 HardmanThesisFinal.pdf: 3036758 bytes, checksum: b1393714c6a4a3a2b06519d167149a50 (MD5) SoilPaddock.pdf: 31218 bytes, checksum: 89d918a86f4de6a3786f3104156b9191 (MD5) StarkSoil.pdf: 635059 bytes, checksum: 63787e666c9f4bf7960227b525afa508 (MD5) VagrantGrim.pdf: 871938 bytes, checksum: 9d712408f11a586328c6a88f344c486e (MD5)
  • description.provenance : Made available in DSpace on 2008-01-28T18:42:01Z (GMT). No. of bitstreams: 4 HardmanThesisFinal.pdf: 3036758 bytes, checksum: b1393714c6a4a3a2b06519d167149a50 (MD5) SoilPaddock.pdf: 31218 bytes, checksum: 89d918a86f4de6a3786f3104156b9191 (MD5) StarkSoil.pdf: 635059 bytes, checksum: 63787e666c9f4bf7960227b525afa508 (MD5) VagrantGrim.pdf: 871938 bytes, checksum: 9d712408f11a586328c6a88f344c486e (MD5)
  • description.provenance : Approved for entry into archive by Laura Wilson(laura.wilson@oregonstate.edu) on 2008-01-28T18:42:01Z (GMT) No. of bitstreams: 4 HardmanThesisFinal.pdf: 3036758 bytes, checksum: b1393714c6a4a3a2b06519d167149a50 (MD5) SoilPaddock.pdf: 31218 bytes, checksum: 89d918a86f4de6a3786f3104156b9191 (MD5) StarkSoil.pdf: 635059 bytes, checksum: 63787e666c9f4bf7960227b525afa508 (MD5) VagrantGrim.pdf: 871938 bytes, checksum: 9d712408f11a586328c6a88f344c486e (MD5)

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