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51. [Article] Comparing vegetation and soils of remnant and restored prairie wetlands in the northern Willamette Valley
Native prairies of the Willamette Valley are considered among the rarest of Oregon's ecosystems (Clark and Wilson, 2001). As a result of agriculture conversion, urban development and cessation of native ...Citation Citation
- Title:
- Comparing vegetation and soils of remnant and restored prairie wetlands in the northern Willamette Valley
- Author:
- Taylor, Sara M.
Native prairies of the Willamette Valley are considered among the rarest of Oregon's ecosystems (Clark and Wilson, 2001). As a result of agriculture conversion, urban development and cessation of native burning, Willamette Valley prairies have become highly fragmented and invaded by non-native species, leaving little room for native plant diversity. Even though wetland prairie conservation and restoration has been a priority for many government agencies there is a need for research on what restoration techniques and management are necessary for increasing native species richness and abundance in remnant and restored wet prairie sites. In this research project, two studies were conducted. In the first study, data were collected on species presence and abundance from three 100m² randomized plots within three remnant wet prairies (Green Mountain, Gotter Prairie South, Knez) and three restored wet prairies (Hutchinson, Gotter Prairie North, Lovejoy) to answer the following research question, 'Are there differences between remnant and restored prairie plant communities with respect to the diversity and abundance of native species?' Analysis of variance and multivariate ordination techniques were used to assess the ecological differences between uncultivated, minimally-managed remnant wet prairies and newly-restored, highly managed wet prairies. Data on soils collected from agricultural sites (Westbrook, Zurcher, Gotter Prairie Ag), as well as the remnant and restored wet prairies mentioned above, were also used to compare soil quality and processes with the remnant and restored wetlands. Restored wet prairie had 23% higher native species cover than remnant prairie (p-value=0.089, N=6). Remnant and restored sites did not differ in native species richness (p-value=0.949, N=6). The relatively high per cent cover of native species at restored sites, (significant at the 10% level), suggests that land managers have successfully restored agricultural properties with an abundance of native species. The lack of significant difference in native species richness between remnant and restored sites also suggests that land managers have also been able to restore native plant diversity into former agricultural properties equivalent to some of the best intact remnant prairies within the Northern Willamette Valley in a short period of time (8 years or less). However, a non-metric scaling (NMS) ordination of the species matrix separated the remnant sites from the restored sites, suggesting that community composition distinguishes restored sites from remnants. The NMS results, which include environmental data in the analysis, also suggest that there is a positive correlation of percent soil moisture and percent soil organic matter associated with the remnant prairies and a positive correlation of management practices such as yearly chemical use, mowing, and clean crops, associated with the restored prairies. The location of Gotter Prairie North restoration within the ordination, between the remnant and restored sites, suggests an intermediate plant composition and soil quality. This could be attributed to intensive weed suppression and soil organic matter build up over time (8 years) in comparison to younger restored sites (3 and 4 years). Indicator species analysis identified many species with high indicator values (IVs) in the remnant prairies; Holcus lanatus, Deschampsia cespitosa, Carex densa and Phalaris arundinacea being the highest. The use of fire as a management tool produced only one species with a high IV (Camassia quamash). In the second study, three seeding treatments (Grass first, Grass and Forb together, Forb first) were compared within a 4 hectare experimental wet prairie unit to answer the research question „Which of the three seeding treatments used leads to the highest native species abundance and species richness?‟ Results from an analysis of variance indicated significant differences between treatments in native species richness for 2009 and 2010 (p-values=0.002 & 0.004 respectively) at the 5% level and native species abundance in 2010 only (p-value=0.099) at the 10% level. The Grass and Forb and Forb first treatments were highest in native species richness for 2009 and 2010, whereas the Grass and Forb and Grass first treatments were highest in native species abundance in 2010. A NMS ordination suggests that Juncus tenuis is one of the dominant species, in all seeding treatments, after one year of growth.
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52. [Article] Using a species-centered approach to examine patterns and drivers of avian species richness in the Rogue Basin, Oregon
The combined effects of habitat loss, degradation, and fragmentation pose a serious threat to Earth's biodiversity, imperiling even relatively common species. 'Habitat' is necessarily a species-specific ...Citation Citation
- Title:
- Using a species-centered approach to examine patterns and drivers of avian species richness in the Rogue Basin, Oregon
- Author:
- Halstead, Katherine E.
The combined effects of habitat loss, degradation, and fragmentation pose a serious threat to Earth's biodiversity, imperiling even relatively common species. 'Habitat' is necessarily a species-specific concept, and investigations of bird diversity relationships and subsequent efforts to prioritize conservation areas, are challenged by the difficulty of estimating complex habitat gradients for multiple species across broad spatial scales. Technologies such as fine-resolution remote sensing combined with enhanced species distribution modeling techniques hold promise for more accurate assessments of multi-species habitat distributions. In this research, I focused on forest bird species which utilize and/or are highly associated with threatened Oregon white oak and California black oak (Quercus garrayana and Q. kelloggii) vegetation types in the Rogue Basin of southwest Oregon. I created individual species distribution models (SDMs) for 48 bird species as a function of fine-resolution (30 x 30 m) remotely sensed land cover and other environmental variables using boosted regression tree (BRT) models. I then 'stacked' SDMs for spatially explicit regional estimates of multi-species avian richness. In my first chapter, I examined the potential for site-level species richness to be influenced by local vegetation and environmental conditions (e.g. the "local vegetation heterogeneity hypothesis") or by landscape-level dispersal potential (e.g. the "regional species pool hypothesis"). I summarized 'stacked' SDMs for indices of 1) habitat amount at a local scale relevant bird territory use and 2) habitat amount at a broad scale relevant to forest bird dispersal, and ask whether local- or landscape-scale habitat amount is relatively more important to site-level bird species richness. I hypothesized that greater importance of either habitat amount metric would indicate greater influence of local or landscape drivers to local richness. I found evidence that for a large pool of bird species with diverse habitat associations, landscape-scale habitat amount may be relatively more important to local (i.e., territory level) richness of forest birds than is local habitat amount. In contrast, for more specialized (i.e., oak-associated) guilds, local-scale habitat may be considerably more important than amount of habitat within the surrounding landscape. My results suggest the importance of local- and landscape-scale processes in structuring bird communities, supporting both 'local vegetation heterogeneity' and 'regional species pool' hypotheses. In my second chapter, I examined the relationships between landownership, oak vegetation distribution, and bird diversity, with the objective of determining which of five primary landownership types contribute most strongly to bird species habitat in the Rogue Basin. I asked whether individual bird species distributions and estimated richness are 'additive' or 'redundant' among land ownership types, hypothesizing that differences among owners will be apparent and related to the amount of oak-dominant vegetation held by each owner regionally. I found that estimated local mean species richness of oak-associated birds in private non-industrial (PNI) ownerships is approximately double that of other Rogue Basin public and private ownerships examined. This result may be driven by disproportionate PNI ownership of limited oak cover types, and/or by hypothesized variation in management goals and activities among owners which influence local vegetation structure. Relatively greater importance of territory-scale habitat to local oak-associated species richness suggests management for these species should maximize site-level habitat amount and quality. The importance of private non-industrial owners to oak-associated avian richness validates current focus on engaging private landowners in bird-focused oak conservation and restoration. Overall, my research links efforts to conserve avian habitat with efforts to understand multi-scale drivers of bird diversity, using a novel methodology that embraces the complexity of species' habitat gradients.
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Spatially explicit maps of habitat relationships have proven to be valuable tools for conservation and management applications including evaluating how and which species may be impacted by large scale ...
Citation Citation
- Title:
- The use of remote sensing for characterizing forests in wildlife habitat modeling
- Author:
- Vogeler, Jody C.
Spatially explicit maps of habitat relationships have proven to be valuable tools for conservation and management applications including evaluating how and which species may be impacted by large scale climate change, ongoing fragmentation of habitat, and local land-use practices. Studies have turned to remote sensing datasets as a way to characterize vegetation for the examination of habitat selection and for mapping realized relationships across the landscape. Although the use of remote sensing in wildlife studies has increased in recent years, the use of these datasets is still limited and some data sources and methods are yet to be explored. The overall goal of this dissertation was to look at the state of the wildlife ecology discipline in the use of geospatial data for habitat mapping, and to advance this area through the fusion of remote sensing tools for the mapping of previously difficult to characterize forest metrics for inclusion in avian cavity-nester habitat models. Chapter 2 reviewed over 60 years of selected wildlife literature to examine the wildlife ecology disciple through historic trends and recent advances in the use of remote sensing for habitat characterization focusing on aspects of scale and the use of available technology. We discuss commonly used remote sensing data sources, point out recent advances in the use of geospatial data for characterizing forest wildlife habitat (the use of lidar data and the creation of spatially explicit habitat prediction maps), and provide future suggestions for increased utilization of available datasets (secondary lidar metrics and time series Landsat data). In chapters 3 and 4 we explored the use of remote sensing for characterizing forest components previously difficult to map across landscapes at scales relevant to local wildlife habitat selection. Chapter 3 found promise in the fusion of lidar structure and Landsat time series disturbance products in the modeling and mapping of post-fire snag and shrub distributions at fine scales and at size/cover thresholds relevant for habitat mapping applications for many wildlife species. The study was conducted within the 2003 B&B Fire Complex in central Oregon. Using 164 field calibration plots and remote sensing predictors, we modeled the presence/absence of snag classes (dbh ≥40cm, ≥50cm, and ≥75cm) and woody shrub cover resulting in 10m output predictive grid maps. Remote sensing predictors included various lidar structure and topography variables and Landsat time series products representing the pre-fire forest, disturbance magnitude, and current forest conditions. We were able to model and map all habitat metrics with acceptable predictive performance and low-moderate errors. The utility of these snag and shrub metrics for representing important nesting habitat features for a cavity-nesting species of conservation concern, the Lewis's Woodpecker (Melanerpes lewis), was demonstrated in Chapter 4. We were able to model nesting habitat with good accuracies according to multiple performance measures and then map realized relationships for this species of conservation concern in an identified source habitat type, providing a potential resource for local scale conservation and management efforts and adding to the regional knowledge of habitat selection for the Lewis's Woodpecker. To our knowledge, these chapters represent first attempts to fuse lidar and time series Landsat disturbance metrics in a post-fire landscape and for the mapping of snag and shrub distributions at scales relevant to avian cavity nesting habitat.
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Mat-forming ectomycorrhizal (EcM) fungi represent a prevalent constituent of many temperate forest ecosystems and create dramatic changes in soil structure and chemistry. EcM mat soil have been shown to ...
Citation Citation
- Title:
- Characterization of fungal and bacterial communities associated with mat-forming ectomycorrhizal fungi from old-growth stands in the H.J. Andrews Experimental Forest
- Author:
- Hesse, Cedar N.
Mat-forming ectomycorrhizal (EcM) fungi represent a prevalent constituent of many temperate forest ecosystems and create dramatic changes in soil structure and chemistry. EcM mat soil have been shown to have increased microbial respiration rates and have been hypothesized to harbor unique assemblages of fungi and bacteria. The objectives of this dissertation were to characterize and examine the fungal and bacterial communities associated with EcM mats in old-growth forests of the H.J. Andrews Experimental Forest located in the Oregon Cascades. Additionally, this work assessed the application of traditional, emerging, and novel molecular sampling techniques for determining microbial communities of environmental samples. This research investigated the microbial communities associated with two common EcM mat genera found in old-growth Douglas fir stands in the Pacific Northwest; Piloderma (Atheliales, Basidiomycota) and Ramaria (Gomphales, Basidiomycota). Soil samples were collected from Piloderma and Ramaria mats and surrounding non- mat soil for molecular analysis of nucleic acids. First, a comparative study was conducted to determine the most appropriate rDNA molecular sampling technique for microbial community characterization. Two next-generation sequencing methods, Roche 454 pyrosequencing and Illumina-based environmental sequencing, the latter developed by the author, were compared to a more traditional sequencing approach, i.e., Sanger sequencing of clone libraries. These findings informed the subsequent sampling of the fungal ITS and bacterial 16S rDNA fragment with 454 pyrosequencing to determine the microbial communities within mat and non-mat soils. Second, this work utilized a pyrosequencing approach to explore fungal community structure in EcM mat and non-mat soils. This work concluded that differences in microbial communities do exist between Piloderma mat, Ramaria mat, and non-mat soils, but the differences are largely quantitative with relatively few distinct taxonomic shifts in microbial constituents. Piloderma, Ramaria and Russula, in addition to being the dominant taxa found on mycorrhizal root tips, were found to be the most abundant taxa in bulk soils within their respective mat types or non-mat sample. The background fungal communities within the EcM mats in this study exhibited considerable taxonomic overlap with the exception of Piloderma vs. non-mat comparisons; Russula species dominated nonmat soils but tended to be excluded or significantly underrepresented in Piloderma mats. Lastly, this study explored the bacterial communities associated with Piloderma and Ramaria mats using lower- coverage 454-Jr pyrosequencing. Bacterial communities exhibited significant structure as a function of mat-type, soil horizon and pH, but this finding should be interpreted with respect to the nonrandom distribution of Piloderma-mats in the O- horizon and the Ramaria-mats in the A-horizon, and the tendancy for EcM mats to be more acidic than surrounding soils. Nonetheless, the total microbial (bacterial and fungal) community was typically dominated by the mat-forming taxa, or Russula, in the case of non-mat soils. While the presence of Piloderma mats did enrich or restrict some bacterial groups, soil pH was also found to be a significant driver of bacterial richness and taxonomic diversity. Fungal and bacterial richness were also found to be positively related to one another, regardless of soil horizon or EcM mat type. This work, taken together, contributes to the understanding of hyperdiversity and heterogeneity of microbial communities of temperate forest soils and highlights the potential for fungal and bacterial communities to be influenced by the presence of EcM mats.