Ấn phẩm:
Lichen Response to the Environment and Forest Structure in the Western Cascades of Oregon
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We sought major gradients in epiphytic macrolichen community composition at a landscape scale in the western Oregon Cascades. These gradients form a context for understanding likely effects of forest management, air pollution, and climate change on an important part of the biota. We also compared lichen community composition in different forest age classes to describe lichen colonization, succession, and the association of species with stands of different ages. Variation in lichen community composition was well described by nonmetric multidimensional scaling (NMS) with 83.4% of the variation accounted for. The strongest gradient (rotated to axis 1; r2 = 0.46) was related to climate as expressed by elevation and annual temperature, and air quality. Axis 2 (r2 = 0.23) was related to north-south position and the richness of epiphytic macrolichens. Axis 3 (r-2 = 0.15) was associated with air quality and also represented forest age, with old growth and young forest stands occupying opposite ends of the axis. Species richness did not differ significantly between age classes. However, the abundance of chlorolichens, cyanolichens, forage lichens, nitrophilous lichens, species in the Cladonia/Sphaerophorus group, Usnea spp., old-growth associated lichens, and listed (Survey-and-Manage species, and
Oregon Natural Heritage Program's threatened species) lichen species all differed significantly among forest age classes. Indicator Species Analysis (ISA) found significant indicators for each forest age class.
Habitat models have become increasingly popular and powerful tools in ecology, conservation biology, and land management. We used a nontraditional modeling approach, Nonparametric Multiplicative Regression (NPMR) to build habitat models for selected lichen species in the western Cascades of Oregon. We selected the following target species based on their ecological significance in forests of western Oregon, because they were formerly listed as Survey-and-Manage species under the Northwest Forest Plant, or because little was known about their distributions: Alectoria sarmentosa, A. vancouverensis, Hypogymnia duplicata, H. oceanica, Lobaria oregana, Nephroma occultum, Platismatia norvegica, Pseudocyphellaria rainierensis, Ramalina thrausta, Sticta weigelii, U. cavernosa and Usnea longissima. Using NPMR to build these models allowed us to accommodate the complex, nonlinear responses of these species to multiple interacting environmental variables. Models for infrequent species performed more poorly compared to models for more common species, however all models made better predictions of species occurrences than predictions from a naive model based solely on the frequency of a species in a data set.
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Martin, Erin P.
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Oregon State University
Năm xuất bản
2006
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Địa y -- Sinh thái học -- Oregon, Western , Địa y -- Ảnh hưởng thời tiết -- Oregon, Western , Thực vật học -- Bệnh lý học