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21. [Article] Environmental variables as predictors of fish assemblages in the Tillamook Basin, Oregon
The Tillamook and Kilchis subbasins of the Tillamook Bay watershed (Oregon Coast Range) have differences in geology and land use history and, therefore, varied environmental conditions that could affect ...Citation Citation
- Title:
- Environmental variables as predictors of fish assemblages in the Tillamook Basin, Oregon
- Author:
- Rose, Cathleen E.
The Tillamook and Kilchis subbasins of the Tillamook Bay watershed (Oregon Coast Range) have differences in geology and land use history and, therefore, varied environmental conditions that could affect fish assemblages. Fifty-two randomly selected wadeable stream reaches in these two subbasins were surveyed for stream habitat and fish assemblage composition during two summer field seasons. Data collected were used to identify environmental variables most associated with fish assemblages, determine major predictors of fish species relative abundance, and test for any differences in fish assemblages between the Tillamook and Kilchis subbasins and among three stream orders. Eleven fish species were encountered, including four salmonid species (Oncorhynchus spp.) and five species of sculpin (Cottus spp.). For three sites visited twice in both field seasons, variability in fish assemblages and environmental measurements between sample years and between early and late-summer visits to sites was low. Fish assemblages differed between the two subbasins. The assemblages in the Kilchis subbasin contained higher proportions of trout species, while the Tillamook subbasin assemblages contained higher proportions of sculpin species. A breakdown of fish assemblages by stream order showed that different fish species dominated the assemblages in different sized streams. With data from both subbasins combined, trout species composed a smaller proportion of the fish assemblages in larger streams, and sculpin species composition also varied with stream order. Results from non-metric multidimensional scaling ordinations indicated that substrate type, stream gradient, and variables related to stream size were the most highly correlated to fish species relative abundances. Multiple linear regression was used to assess the usefulness of an uncorrelated subset of the environmental variables as predictors of relative abundance of the six most common fish species. The environmental variables were good predictors of relative abundance for some species, but were less successful in predicting abundances of entirely anadromous species. These results provide valuable insight into fish-habitat relationships using a fish assemblage perspective and incorporating species, such as sculpins, for which there is little existing information. There has been recent interest in quantifying the effects of human land use on stream fish, and these data can be used in future studies to explore potential links between important environmental variables and land use practices.
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22. [Article] Seed and establishment limitation contribute to long-term native forb declines in California grasslands
This is the publisher’s final pdf. The published article is copyrighted by Ecological Society of America and can be found at: http://www.esa.org/.Citation Citation
- Title:
- Seed and establishment limitation contribute to long-term native forb declines in California grasslands
- Author:
- Brandt, Angela J., Seabloom, Eric W.
This is the publisher’s final pdf. The published article is copyrighted by Ecological Society of America and can be found at: http://www.esa.org/.
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23. [Article] Divergent Carbon Dynamics under Climate Change in Forests with Diverse Soils, Tree Species, and Land Use Histories
Accounting for both climate change and natural disturbances—which typically result in greenhouse gas emissions—is necessary to begin managing forest carbon sequestration. Gaining a complete understanding ...Citation Citation
- Title:
- Divergent Carbon Dynamics under Climate Change in Forests with Diverse Soils, Tree Species, and Land Use Histories
- Author:
- Scheller, Robert M., Kretchun, Alec M., Van Tuyl, Steve, Clark, Kenneth L., Lucash, Melissa S., Hom, John
- Year:
- 2012
Accounting for both climate change and natural disturbances—which typically result in greenhouse gas emissions—is necessary to begin managing forest carbon sequestration. Gaining a complete understanding of forest carbon dynamics is, however, challenging in systems characterized by historic over-utilization, diverse soils and tree species, and frequent disturbance. In order to elucidate the cascading effects of potential climate change on such systems, we projected forest carbon dynamics, including soil carbon changes, and shifts in tree species composition as a consequence of wildfires and climate change in the New Jersey pine barrens (NJPB) over the next 100 years. To do so, we used the LANDIS-II succession and disturbance model combined with the CENTURY soil model. The model was calibrated and validated using data from three eddy flux towers and the available empirical or literature data. Our results suggest that climate change will not appreciably increase fire sizes and intensity. The recovery of C stocks following substantial disturbances at the turn of the 20th century will play a limited but important role in this system. In areas characterized by high soil water holding capacity, reduced soil moisture may lead to lower total C and these forests may switch from being carbon sinks to becoming carbon neutral towards the latter part of the 21st century. In contrast, other areas characterized by lower soil water holding capacity and drought tolerant species are projected to experience relatively little change over the next 100 years. Across all soil types, however, the regeneration of many key tree species may decline leading to longer-term (beyond 2100) risks to forest C. These divergent responses were largely a function of the dominant tree species, and their respective temperature and soil moisture tolerances, and soil water holding capacity. In summary, the system is initially C conservative but by the end of the 21st century, there is increasing risk of de-stabilization due to declining growth and regeneration.
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This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Springer and can be found at: http://link.springer.com/journal/10533.
Citation Citation
- Title:
- Trends in cation, nitrogen, sulfate and hydrogen ion concentrations in precipitation in the United States and Europe from 1978 to 2010: a new look at an old problem
- Author:
- Lajtha, Kate, Jones, Julia
This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Springer and can be found at: http://link.springer.com/journal/10533.
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Biological invasions pose one of the greatest threats to global biodiversity, but many naturalized invaders coexist with the native community. Community ecology theory provides a framework for understanding ...
Citation Citation
- Title:
- The roles of provenance and phylogeny in recruitment, community assembly, and species coexistence in invaded California grasslands
- Author:
- Brandt, Angela J.
Biological invasions pose one of the greatest threats to global biodiversity, but many naturalized invaders coexist with the native community. Community ecology theory provides a framework for understanding the mechanisms by which invaders might coexist with native species or exclude them from the community, thus informing management practices to maximize their effectiveness at conserving native biodiversity. Differences in functional or phylogenetic similarity of invaders to native residents can affect invasion success and the probability they will coexist with natives. For example, functionally dissimilar species may not compete strongly and distantly related species may share fewer natural enemies. Furthermore, environmental heterogeneity can promote species coexistence by providing the opportunity for a greater number of coexistence mechanisms to operate, thereby mitigating the potential for species invasions to lead to native extinction. My thesis examines how provenance (i.e., native origin) and phylogenetic relatedness of plant species affect community dynamics and species interactions in the invaded California grasslands. To do this I have assembled two unique community data sets, one spanning 48 years across a 1000-ha site and one spanning 7 years along a 500-km latitudinal transect. I show that native and exotic species abundance and diversity is highly variable in both time and space, but these provenance group responses are rarely negatively correlated (Chapter 2). Thus, exotic species do not generally appear to exclude natives from communities. Long-term abundance patterns further suggest that the system remains in a state of transience, and populations of several native species are declining at local scales (Chapter 3). Recruitment limitation due to the build-up of plant litter associated with exotic grasses may be generally responsible for these declines, but habitat suitability, land-use history, and community composition also affect native recruitment. Across the grasslands, disturbance and resource supply can interact to affect both species and phylogenetic diversity (Chapter 4). Disturbance in particular can increase diversity, likely by increasing opportunities for colonization by removing plant litter that previously limited recruitment. Both phylogeny and provenance can also affect biotic interactions, such as with communities of soil organisms (Chapter 5). Thus, I have shown that spatio-temporal heterogeneity, alterations to the biotic environment mediated by exotic invasion, and phylogenetic relationships among species are all important considerations when evaluating impacts of invasion and designing management strategies to conserve native biodiversity, especially in light of anthropogenic influence on disturbance regimes and resource supply.
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We examine land use planning outcomes over a 30-year period in the Portland, OR-Vancouver, WA (USA) metropolitan area. The four-county study region enables comparisons between three Oregon counties subject ...
Citation Citation
- Title:
- How Well has Land-Use Planning Worked Under Different Governance Regimes? A Case Study in the Portland, OR-Vancouver, WA Metropolitan Area, USA
- Author:
- Kline, Jeffrey D., Thiers, Paul R., Ozawa, Connie P., Yeakley, J. Alan, Gordon, Sean N.
- Year:
- 2014
We examine land use planning outcomes over a 30-year period in the Portland, OR-Vancouver, WA (USA) metropolitan area. The four-county study region enables comparisons between three Oregon counties subject to Oregon’s 1973 Land Use Act (Senate Bill 100) and Clark County, WA which implemented land use planning under Washington’s 1990 Growth Management Act. We describe county-level historical land uses from the mid-1970s to the mid-2000s, including low-density residential and urban development, both outside and inside of current urban growth boundaries. We use difference-in-differences models to test whether differences in the proportions of developed land resulting from implementation of urban growth boundaries are statistically significant and whether they vary between Oregon and Washington. Our results suggest that land use planning and urban growth boundaries now mandated both in Oregon and Washington portions of the study area have had a measurable and statistically significant effect in containing development and conserving forest and agricultural lands in the Portland-Vancouver metropolitan area. Our results also suggest, however, that these effects differ across the four study-area counties, likely owing in part to differences in counties’ initial levels of development, distinctly different land use planning histories, and how restrictive their urban growth boundaries were drawn.
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27. [Article] Floodplains: Balancing Nature and Human Needs
For countless years, the interaction between climatic conditions and water flow has forged the rolling hills and rivers in the metroscape. The floods that forced a deluge of water down the Columbia River ...Citation Citation
- Title:
- Floodplains: Balancing Nature and Human Needs
- Author:
- Shandas, Vivek, Merrick, Meg
- Year:
- 2008
For countless years, the interaction between climatic conditions and water flow has forged the rolling hills and rivers in the metroscape. The floods that forced a deluge of water down the Columbia River between 13 and 17 thousand years ago established the fertile and absorptive landscape of the Willamette Valley. The lush vegetation controlled the regional climate and stabilized the soils, while the thirsty wetlands reduced flood potential, provided habitat, and purified the water. Over geological time, these natural processes have created ideal conditions for humans. The Pacific Northwest was home to some of the most densely populated communities of Native Americans, due partly to mild climate, plentiful water, and abundant sources of food and shelter. In the 19th century, Anglo settlers flooded the region for the same amenities, which continues to create ideal conditions for all that the region is known for today, including hiking, kayaking, and sailing - not to mention the provision of climate, topography, and fertile soils for growing some of the world?s best wines! Land surveys from the 1860s suggest that the current form of the metroscape started to take shape at the end of the 19th century. The conifers, alders, and maples that covered the region were slowly removed to make way for new urban settlements, and wetlands were drained to create farms and agricultural areas. In this atlas, we journey 140 years into the past to examine how and where the metroscape has changed. Our aim is to illustrate historic flooding of the region, and ponder what changes might mean to its future.
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Differentiates between the concepts of world cities and international cities, asserting that study of international cities offers greater opportunities for research and analysis of major urban regions ...
Citation Citation
- Title:
- The International City Hypothesis: An Approach to the Recent History of U.S. Cities
- Author:
- Abbott, Carl
- Year:
- 1997
Differentiates between the concepts of world cities and international cities, asserting that study of international cities offers greater opportunities for research and analysis of major urban regions of the latter 20th century. The world city model emphasizes hierarchy and status based on influence and power. The international city model emphasizes numerous indicators that demonstrate a broader range of international connections, including foreign tourists, new immigration, sister-city affiliations, and multinational corporation offices. They may function as production centers, gateway cities, or transactional cities. At present, statistical data are thin, and the topic invites research by urban historians.
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This study delineates and characterizes the distribution of montane meadows in the Willamette National Forest, identifies encroachment patterns in relation to topographic features and proximity to trees ...
Citation Citation
- Title:
- Meadow classification in the Willamette National Forest and conifer encroachment patterns in the Chucksney-Grasshopper meadow complex, Western Cascade Range, Oregon
- Author:
- Dailey, Michele Meadows
This study delineates and characterizes the distribution of montane meadows in the Willamette National Forest, identifies encroachment patterns in relation to topographic features and proximity to trees in the Chucksney-Grasshopper meadow complex, and examines tree species and age distributions in relation to distance from forest edges or isolated tree clusters in the West Middle Prairie meadow. The Willamette National Forest covers approximately 6780 km² and intersects two main physiographic provinces comprised of the Cascade Crest Montane Forests and Subalpine/Alpine regions to the east, and the Western Cascades Montane, Lowland, and Valley regions to the west. Tree species commonly found in the study area include firs, cedar, pine, larch, spruce, and hemlock. Non-forested openings, including meadows, are distributed throughout the study area. Matched Filtering analysis was applied to Landsat ETM+ imagery acquired in September 2002 and combined with ancillary data that delineates stand replacing fire and harvest disturbances that occurred between 1972 and 2004 to create a vegetation classification of the Willamette National Forest that identifies meadows. The meadow classification was then combined with data depicting topographic position, slope, aspect, and elevation. Chi-squared statistics were applied to determine if meadows were significantly concentrated in areas characterized by these physical factors. In the western extent of the Willamette National Forest, meadows are concentrated on steep, south and east facing ridges between 1000 and 2000m in elevation. In the eastern extent of the Willamette National Forest, meadows are concentrated in valleys between 500 and 1000 meters in elevation and occur on both gentle and steep, east and south facing slopes. The vegetation classification provides a consistent and comprehensive dataset of meadow distribution in the Willamette National Forest. The Chucksney-Grasshopper meadow complex is contained by the Chucksney Mountain roadless area and comprised of approximately 8 distinct meadows located 27 kilometers northeast of Oakridge in the Willamette National Forest. The meadows occur on mostly south and east facing steep slopes near the ridgeline, and host varied dry and mesic plant communities. Herbaceous cover for three snapshots in time was classified using aerial photographs taken in 1947, 1972, and 2005 to determine conifer encroachment into the meadows. Chi-squared statistics were applied to determine if encroachment patterns were associated with slope, aspect, or proximity to tree cover. Encroachment occurred significantly closer to existing trees in all meadows suggesting the ameliorating effects of forest create conditions favorable for seedling establishment. Encroachment was also significant on steep, south and east facing slopes in some meadows, but also on gentle, west facing slopes in other meadows indicating a complex interaction of land use history, physical, and biological factors. The encroachment history analysis provides the preliminary framework for a model that can be used to identify meadows at risk for invasion. The West Middle Prairie of the Chucksney-Grasshopper complex, also known as Meadow 4, is a 21 hectare meadow characterized by a dry meadow community at the northern boundary, a mesic forest-meadow mosaic towards the southern boundary, and a rock garden at the western boundary. This meadow underwent mechanical tree removal in 1964 and a prescribed burn in 1996 to thwart conifer invasion. Four transects intersecting burned and unburned areas at the forest edge and through isolated tree clusters were sampled to determine the distribution of tree species and ages relative to their position in the transect. Data imply Pinus contorta invasion was promoted by the 1996 burns and that seedling establishment has occurred progressively from forest edges as well as simultaneously in a band along the forest edge. These findings suggest the prescribed burn was not adequate to control invasion and such management methods should be reviewed in the context of on-going research into alternate eradication measures. This research also supports other work that suggests initial seedling establishment accelerates subsequent seedling establishment and that eradication of early invaders is important for efficient management. This study can inform meadow habitat maintenance and restoration in three ways: it provides and inventory of meadows in the Willamette National Forest, a framework for a tool to predict which meadows are at risk for invasion and therefore are potential targets for action, and finally a report on past maintenance efforts and observation of invasion patterns at a fine scale.
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30. [Article] Studies to facilitate reintroduction of golden paintbrush (Castilleja levisecta) to the Willamette Valley, Oregon
Golden paintbrush (Castilleja levisecta Greenman) historically inhabited the prairies of the Willamette Valley, Oregon. However, this Pacific Northwest endemic is currently restricted to eleven sites in ...Citation Citation
- Title:
- Studies to facilitate reintroduction of golden paintbrush (Castilleja levisecta) to the Willamette Valley, Oregon
- Author:
- Lawrence, Beth A.
Golden paintbrush (Castilleja levisecta Greenman) historically inhabited the prairies of the Willamette Valley, Oregon. However, this Pacific Northwest endemic is currently restricted to eleven sites in the Puget Trough of Washington and British Columbia. Recovery criteria call for the establishment of new populations throughout the species historic range, including the Willamette Valley. In order to facilitate reintroduction to this region, we examined: (1) habitat characteristics of potential C. levisecta recovery sites in the Willamette Valley and compared them to remaining populations in the Puget Trough, (2) a suite of ecological and genetic factors likely to contribute to reintroduction success using common garden experiments, and (3) how the performance of this rare hemiparasite was affected by the availability of different host combinations in the greenhouse and in the field. Potential C. levisecta reintroduction sites in the Willamette Valley had distinct vegetation communities and soil characteristics compared with remaining populations in the Puget Trough. This disparity was likely related to regional differences in geology, climate, ocean proximity, and land-use history. Many of the species indicative of remaining populations in the Puget Trough were native pereimials, while those of potential reintroduction sites in the Willamette Valley were introduced annuals. Soil characteristics of C. levisecta sites were also distinct among the two ecoregions. Puget Trough sites were located on sandy soils with generally high levels of magnesium and sulfur, while Willamette Valley sites were found on silty-clay soils with high concentrations of potassium and phosphorous. Differences in soil texture, and magnesium and potassium concentrations were associated with plant community divergence among the two regions. Decisions regarding seed source and recovery site selection are especially difficult in portions of a species range that are uninhabited, as no reference populations exist with which to compare ecological information. Using common garden experiments, we tested hypotheses about how C. levisecta transplants would perform in relation to the ecological similarity between seed source and introduction site, the effective population size and genetic diversity of seed sources, and the habitat quality of the recovery site. We observed significant variation in performance measures among source populations and common garden sites. Plant community characteristics, including the abundance of nonnative species and the similarity in community structure between source populations and common garden sites, helped explain the variation in these performance measures. Exotic species cover at common garden sites was associated with a reduction in performance of first year C. levisecta transplants. Survival of second year transplants increased with increasing similarity in plant functional groups between source and common garden sites, supporting the idea of a "home-habitat advantage." These results indicate that high quality prairies, dominated by native perennial species with low nonnative abundance, should be targeted for recovery sites. We recommend using plant material from Whidbey Island, WA, whose three populations represented in our study consistently performed well. Rare, parasitic plants pose an interesting challenge to restoration practitioners. We examined how the performance of C. levisecta was affected by the availability of different host combinations in the greenhouse and in the field. Castilleja levisecta individuals were grown with two grass individuals (Festuca roemeri; Poaceae), two non-grass hosts (Eriophyllum lanatum; Asteraceae), one individual of each of these species, or without a host. Our greenhouse results provide little support for the complimentary diet hypothesis, which states that parasites grown with multiple host species perform better than individuals grown alone or with a single host. Castilleja levisecta individuals grown with two different species performed better than those co-planted only with F. roemeri, but did not differ from E. lanatum or no-host treatments. In the field, vole activity had indirect effects on C. levisecta survival mediated through host species. Vole tunneling and C. levisecta mortality were strongly associated with host treatments including E. lanatum. Field survival was significantly higher among no-host C. levisecta individuals than those grown with E. lanatum or mixed host treatments. We do not suggest coplanting C. levisecta with E. lanatum in the field. Although no-host C. levisecta individuals had the greatest first year field survival, we suspect that perennial host plants will be beneficial to future survival. Therefore, we recommend planting C. levisecta in the Willamette Valley, OR with F. roemeri.
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The purpose of this study was to: (1) evaluate land use and vegetation history of the Willamette Floodplain Research Natural Area; (2) characterize present day vegetation; (3) evaluate the relation of ...
Citation Citation
- Title:
- Ecological survey and interpretation of the Willamette Floodplain Research Natural Area, W.L. Finley National Wildlife Refuge, Oregon
- Author:
- Streatfeild, Rosemary Welch
The purpose of this study was to: (1) evaluate land use and vegetation history of the Willamette Floodplain Research Natural Area; (2) characterize present day vegetation; (3) evaluate the relation of vegetation to environment, and (4) establish a baseline dataset for future trend analysis in order that response of different plant species to fire frequencies may be assessed. I used historical records, aerial photographs, interviews, and literature to ascertain land use and vegetation history. I assumed that the RNA had been maintained as prairie by periodic aboriginal burning. Fire ignited by settlers continued as a management tool into the late 19th century. Grazing was a major disturbance in the late 19th and early 20th centuries, and plowing or some other soil disturbance on the raised elongated mounds may have occurred. With removal of livestock grazing in the early 1960s and only a sporadic burning program, shrub cover increased markedly over the past several decades. I surveyed vegetation in the summer of 1991 in 36 random permanent plots. 1 classified species cover with two-way indicator species analysis, identifying two major communities. One is dominated by tall dense Rosa eg'lanteria, Hypericum perforatum, and many alien weedy species located on slightly elevated mounds, and the other is dominated by shorter but also dense Rosa eglanteria, Deschampsia cespitosa, and many species with wetland affinity on intermounds. Monotypic patches of Spiraea douglasii also occur on intermounds. Species composition strongly correlates with raicrotopography related to an indirect soil moisture index based on wetland status of individual species. Composition correlates less strongly with year since last burn. I confirmed vegetation-environment relations by null hypothesis analysis, tested by multi-response permutation procedure. Vegetation significantly differs on mounds vs. intermounds and vegetation significantly reflects burning history. I ordinated floristic data by non-metric scaling. I also tallied nested frequency data as a baseline for future trend analysis in order to assess change in vegetation in response to fire frequency. Frequency change of Rosa eglanteria will best be detected by change in a 0.01 m2 plot size, Holcus lanatus by a 0.10 m2 plot, and remaining species by a 1.00 m2 plot.
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Until recently, few have questioned the notion that the separation of uses in land use zoning is inherently correct. Many observers of the city are now suggesting that zoning, as it has been practiced ...
Citation Citation
- Title:
- Patterns of Time, Place, and Culture: Land Use Zoning in Portland, Oregon, 1918-1924
- Author:
- Merrick, Meg
- Year:
- 1998
Until recently, few have questioned the notion that the separation of uses in land use zoning is inherently correct. Many observers of the city are now suggesting that zoning, as it has been practiced in this country over the last 80 years, has created cities that are fractured and function poorly. Others propose that zoning should be reconsidered as a remedy for urban dysfunction. They suggest that the whole notion of zoning be rethought. The purpose of this study is to uncover some of the underlying rationales and methodologies that set the model for zoning. This study examines the rationales behind the classification and location of land use zones in a fast-growing area of Portland, Oregon, for its first zoning ordinance through history, culture, and geography. Between 1919 and 1924, two ordinances were prepared using two very different methodologies. The first of these was designed by nationally known consultant, Charles H. Cheney, using the latest scientific methods. After its rejection in the polls, a second ordinance was developed by a prominent group of realtors in conjunction with the city planning commission using more intuitive methods. This “realtors’ code” (MacColl 1979) was approved by the Portland electorate in 1924. Some fifty years later, the Portland planning commission would identify zoning as having played a significant role in the deterioration of the Buckman neighborhood in the study area. The comparison of the rationales and methods behind the locations of zone boundaries in both ordinances against the locations of actual uses in the study area, reveals the powerful influences of social Darwinism, laissez-faire attitudes, and newly developing social science methods on the association of zoning with the separation of uses and the land use patterns that were created.
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33. [Article] A history of the Portland waterfront between southwest Clay and Washington streets, its land use and legal problems
Between 1845 and 1980 the Portland waterfront between southwest Washington and Clay Streets, east of Front Street, metamorphosed from wilderness to trade center, to highway, to inner-city vacant lot. No ...Citation Citation
- Title:
- A history of the Portland waterfront between southwest Clay and Washington streets, its land use and legal problems
- Author:
- Carter, Jeffrey G.
- Year:
- 1981
Between 1845 and 1980 the Portland waterfront between southwest Washington and Clay Streets, east of Front Street, metamorphosed from wilderness to trade center, to highway, to inner-city vacant lot. No place in Portland has more graphically illustrated the rapidly changing forces of the modern age in which the city has grown. For much of its history this stretch of waterfront was mired in law suits. The struggles centered on public versus private ownership. Originally dedicated as public property, but left unimproved by the city, the waterfront was usurped by private investors. Eventually, private owners allowed their property to decay prompting the public to encourage improvements. The legal battles even became reversed as private investors sought to force the sale of the waterfront to the city. Through all the confusion of legal battles this stretch of waterfront played a central role in the development and identity of Portland. It has finally become, undisputed public territory. The tension and greed of private investment have been replaced by the lack of municipal funds for aesthetic improvement and have left this stretch of land, a potentially fine and important urban park, a vacant lot.
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34. [Article] The Histories of New York City’s Parks
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35. [Article] Restructuring of land and community in the remote rural west : the case of Wallowa County, Oregon
Since at least the 1970s, rural areas in the western United States, as elsewhere across the country and world, have been subject to social, economic, and political forces that have resulted in novel demographic ...Citation Citation
- Title:
- Restructuring of land and community in the remote rural west : the case of Wallowa County, Oregon
- Author:
- Abrams, Jesse
Since at least the 1970s, rural areas in the western United States, as elsewhere across the country and world, have been subject to social, economic, and political forces that have resulted in novel demographic and land tenure trends when compared to previous decades. Collectively, these processes of restructuring have created material effects in the form of diversifying patterns of land ownership, use, and economic relations and at the same time have precipitated social conflict regarding the legitimacy of various claims on rural space. In this case study, I examine in detail the manifestation of these interrelated material and symbolic dynamics within one particular community, Wallowa County, Oregon, as it experiences a wave of new rural landowners and associated changes in land access and use. I pay particular attention to the categories of "amenity-oriented" and "production-oriented" landowners, as well as year-round and seasonally-resident landowners, because these categories are situated at the center of local discourse regarding land tenure and use dynamics. Methods for this study include key informant interviews with 70 individuals, a mail-administered survey of 209 Wallowa County landowners, review of secondary data sources, and direct observation as a member of the Wallowa County community. This case study includes a land tenure and use history of Wallowa County, a review of pertinent quantitative land ownership and use data, and analyses of the symbolic (discursive), material (land use), and political dimensions of restructuring in Wallowa County. I discuss ways in which observed patterns of land tenure and use reflect complex influences, based ultimately in class, culture, livelihood, and associated identities and environmental ideologies. I pay particular attention to the contradictory nature of narratives of land ownership, rurality, and nonhuman nature and the ways in which these affect land uses and land use politics. I close with a series of recommendations for rural communities experiencing amenity-driven property turnover.
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The forest alpine tundra ecotone (FTE, also known as alpine treeline or subalpine parkland), is a conspicuous feature of mountain landscapes throughout the world. Climate change-driven increases in temperature ...
Citation Citation
- Title:
- Patterns of tree establishment and vegetation composition in relation to climate and topography of a subalpine meadow landscape, Jefferson Park, Oregon, USA
- Author:
- Zald, Harold Samuel James
The forest alpine tundra ecotone (FTE, also known as alpine treeline or subalpine parkland), is a conspicuous feature of mountain landscapes throughout the world. Climate change-driven increases in temperature are believed to result in FTE movement and tree invasion of subalpine meadows, which have been documented throughout the Northern Hemisphere across a wide range of geographic locations, climatic regimes, forest types, land use histories, and disturbance regimes. Climate-driven FTE movement may have numerous ecological effects such as: positive temperature feedbacks, increased net primary productivity and carbon storage, and declines of plant populations and species. The magnitude of these ecological effects is highly uncertain, but will be largely determined by the rates and spatial extent of FTE movement and meadow invasion. FTE movement and meadow invasion are often considered at global or regional spatial scales in relation to climate, yet they are fundamentally driven by tree regeneration processes that are influenced by a variety of climatic and biophysical factors at micro site, landscape, and regional scales. Much of the research on the FTE has not taken a landscape approach incorporating multi-scale processes. For example, species distribution models used to project climate change effects on future species distributions and plant biodiversity in mountainous landscapes rely on species distribution data that is often sparse and incomplete across FTE landscapes. This dissertation attempts to overcome many of the limitations in FTE research by taking a landscape approach to develop a greater understanding of past spatiotemporal patterns of tree invasion, current spatial patterns of vegetation composition and structure, and potential future patterns of climate-driven tree invasion in the FTE. The setting for this research is Jefferson Park, a 260 ha subalpine parkland landscape in the Oregon High Cascades, USA. This study uses field plots, remotely sensed imagery, airborne Light Detection and Ranging (LiDAR), and simulation modeling to: 1) predictively map current fine-scale species distributions, vegetation structure, and tree ages; 2) reconstruct patterns of tree invasion over the last fifty years in subalpine meadows in relation to climatic conditions, landforms, microtopography, and seed dispersal limitations; and 3) develop a statistical model that projects future patterns of tree invasion into subalpine meadows under different climate scenarios in Jefferson Park. In chapter two, I generated fine-scale spatially-explicit predictions of current vegetation composition, structure, and tree ages in the Jefferson Park study area. Objectives of this chapter were threefold: 1) to characterize spatial patterns of tree ages, vegetation composition, and vegetation structure in a FTE landscape in the Oregon Cascades using predictive mapping; 2) determine how vegetation composition and structure were associated with gradients of environmental factors derived from multispectral satellite imagery and Light Detection and Ranging (LiDAR) data; and 3) determine if predictive mapping characterizations of tree age, vegetation composition, and vegetation structure were improved by the inclusion of LiDAR data. Predictive mapping of vegetation attributes was accomplished using gradient analysis with nearest neighbor imputation; integrating field plots, multispectral SPOT 5 satellite imagery, and LiDAR data. Vegetation composition was best described by SPOT 5 imagery and LiDAR-derived topography, while vegetation structure was best described by LiDAR-derived vegetation heights. Predictions of species occurrence were most accurate for tree species, moderate for shrub species and vegetation groups, and highly variable for graminoid species. Tree age, which was the most accurately predicted vegetation structure variable, indicates the study area was largely un-forested in 1600, gradually invaded by trees from 1600 to the 1920's, and rapidly invaded from the 1920's to 1980. Predictive mapping of vegetation structure variables such as basal area and stand density were subject to large amounts of error, possibly resulting from scale incompatibilities between vegetation patterns and plot size, and/or heterogeneous FTE landscapes where forest structure does not develop along consistent trajectories with stand age. This study suggests integrating multispectral satellite imagery, LiDAR data, and field plots can accurately predict fine-scale spatial characterizations of species distributions and tree invasion in the FTE. This study also indicates that sample design can influence spatial patterns of model uncertainty, which needs to be considered if predictive mapping of vegetation and sensitive ecosystems is a component of inventory and monitoring programs. In chapter three, I focused on quantifying spatiotemporal patterns of subalpine parkland tree invasion in Jefferson Park over the past five decades in relation multi-scale climatic and biophysical controls. LiDAR data provided previously unavailable fine-scale spatial characterizations of microtopography and vegetation structure. I utilized LiDAR, georeferenced field plots, and tree establishment reconstructions to quantify spatiotemporal patterns of tree invasion in relation to late season snow persistence, landform types, fine-scale topographic variability, distances from potential seed sources, and climate variation within 130 ha of the subalpine parkland landscape of Jefferson Park. Tree occurrence (i.e. tree presence in 2 m plots and grid cells) occurred in 7.75% of study area meadows in 1950 and increased to 34.7% in 2007. Landform types and finer-scale patterns of topography and vegetation structure influenced summer snow depth, which influenced temporal and spatial patterns of tree establishment. Tree invasion rates were higher on debris flow landforms, which had lower summer snow depth than glacial landforms, suggesting potentially rapid treeline responses to disturbance events. Tree invasion rates were strongly associated with reduced annual snow fall on glacial landforms, but not on debris flows. Tree establishment was spatially constrained to micro sites with high topographic positions and close proximity to overstory canopy, site conditions associated with low summer snow depth. Seed source limitations placed an additional species-specific spatial constraint on where trees invaded meadows. Climate and topography had an interactive effect, with trees establishing on higher topographic positions during both high snow/low temperature and low snow/high temperature periods, but had greater than expected establishment on lower topographic positions during low snow/high temperature periods. Within the context of larger landform types, topography and proximity to overstory trees constrained where trees established in the meadows, even during climate periods with higher temperatures and lower snowfall. Results of this study suggest large scale climate-driven models of vegetation change may overestimate treeline movement and meadow invasion, because they do not account for biophysical controls limiting tree establishment at multiple spatial scales. In chapter four, I used field data and analyses from chapter 3 to parameterize a spatially and temporally explicit statistical model of fine-scale tree invasion within 130 ha of the Jefferson Park study area. The model incorporated both the climatic and biophysical controls found in chapter 3 to influence tree invasion. The model was used in two ways: (1) to spatially project patterns of tree invasion from 1950 to 2007 in response to historical climate; and (2) to project future tree invasion of the study area from 2007 to 2064 under six different annual snowfall scenarios. Modeling addressed the following questions: (1) Can fine-scale (2 m pixel size) patterns of historical tree invasion be accurately predicted? (2) How sensitive is future tree invasion (and therefore meadow persistence) to different future snowfall scenarios? (3) Are non-climatic factors such as landforms and biotic interactions associated with different spatial patterns of tree invasion? From 1950 to 2007, simulated historical meadow area declined from 82% to 65% of the study area. Model outputs of historical area, spatial distributions, and spatial clustering of tree invasion generally agreed with independent validation, and suggest biotic interactions due to young tree establishment facilitation are important on glacial landforms but not debris flows. Simulations of future scenarios indicated meadow declined to 36 to 43% of the study area by 2064. Projected meadow area declined with reduced annual snow fall, but not under prolonged high and low snow fall periods. Meadows persisted under all future scenarios in 2064. This model suggests subalpine meadows may significantly decline under climate warming, but will still persist in 2064. Micro sites and recruitment limitation may be equally or more important factors than climate change in influencing subalpine landscape change, suggesting local high-elevation persistence of subalpine meadows under future climate warming.
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37. [Article] Vegetation response to prescribed fire in mountain big sagebrush ecosystems at Lava Beds National Monument, California
Anthropogenic land use alterations such as livestock grazing and fire suppression have greatly altered sagebrush grasslands of the Great Basin, facilitating invasion of exotic annuals, increases in woody ...Citation Citation
- Title:
- Vegetation response to prescribed fire in mountain big sagebrush ecosystems at Lava Beds National Monument, California
- Author:
- Ellsworth, Lisa M.
Anthropogenic land use alterations such as livestock grazing and fire suppression have greatly altered sagebrush grasslands of the Great Basin, facilitating invasion of exotic annuals, increases in woody species, and losses of native species. Much of the current research surrounding wildland and prescribed fire in sagebrush dominated ecosystems has focused on a persistent belief that fire in sagebrush systems results in a loss of native flora and a trend toward dominance by exotic annuals. Fire was historically the dominant disturbance throughout the sagebrush steppe and the plant species that comprised these communities possess a variety of adaptations facilitating survival to the fire regime. In order to restore ecosystems, land managers will need to reintroduce natural ecosystem processes, including natural disturbance processes. To describe the response of these plant communities to fire, I examined the plant community response, seedbank response, and reproductive and density responses of three native bunchgrasses (Pseudoroegneria spicata, Achnatherum therberianum, and Elymus elymoides) as well as one native forb (Calochortus macrocarpus) following spring and fall prescribed fires at Lava Beds National Monument. Fires were applied to three Artemisia tridentata ssp. vaseyana (Mountain Big Sagebrush) plant communities with different land use and fire histories. These communities were different in composition ranging from a dominance of exotic annuals to dominance by native grasses, shrubs, and trees. Little is known about how prescribed fire affects the soil seed bank in sagebrush-dominated ecosystems. To address this, we quantified the emergence of Bromus tectorum (cheatgrass) seedlings as well as emergence of seedlings of functional groups (native forbs, bunchgrasses, and shrubs) in a seedbank germination study. At the invasive dominated site (Gillems Camp), we found 91% fewer B. tectorum seedlings germinated in spring burned sites than in controls immediately following spring prescribed burns. However, soils collected one-year following fire had 40% more B. tectorum germinants (8017 germinants/m [superscript 2]) than unburned controls (5132 germinants/m [superscript 2]). Following fall burns at this site there was a similar response, with a 56% immediate reduction in B. tectorum (as compared to unburned control) and a 59% increase in B. tectorum and 58% increase in exotic forb germinants one year following fires. There was an increase in native forb germination following spring burns (94%) and fall burns (45%) at a site dominated by native plants (Fleener Chimneys). Native bunchgrass seed germination declined following spring fire in sites dominated by sagebrush and native understory vegetation (79%), and in sites where Juniperus occidentalis (western juniper) and other woody species dominated (Merrill Caves) (71%). In invasive-dominated sites (Gillems Camp), there was a decrease in B. tectorum cover following both spring (81% decrease) and fall fires (82% decrease), and little native vegetation composition change. Shrub cover, made up predominantly of Chrysothamnus nauseosus, decreased following spring (95% decrease) and fall (93% decrease) fires. At the sagebrush, native understory site (Fleener Chimneys), there was a reduction in native bunchgrass cover (64% decrease), and an increase in native forbs (168% increase) following spring burns, with no changes following fall fires. At the juniper- woody dominated site (Merrill Caves), fire treatments resulted in a decrease in woody plant cover, with no immediate postfire differences seen in the herbaceous plant community. Density of bunchgrass species (Pseudoroegneria spicata, Achnatherum therberianum, Elymus elymoides) did not change following either spring or fall prescribed fire treatments. Fire enhanced flowering was not seen in C. macrocarpus following spring or fall burns at the native or juniper dominated sites. There was increased reproductive effort in native bunchgrass species following fires in all communities studied. Following spring fires at invasive dominated sites, there was a 245% increase in reproductive culms of P. spicata. Following fall fires in native dominated sites, we saw a 974% increase in reproductive culms of P. spicata and a 184% increase in reproductive culms of A. therberianum. Following fall fires at juniper-dominated sites, we saw in an increase in reproductive culms of P. spicata (678% increase), A. thurberianum (356% increase), and Elymus elymoides (209% increase). These results suggest that implementing prescribed fire in order to restore the natural disturbance regime in these fire-adapted ecosystems is beneficial to restoration and preservation of the native biota.
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38. [Image] Upper Klamath Basin bull trout conservation strategy : part 1, a conceptual framework for recovery, final
EXECUTIVE SUMMARY This document presents the framework of a plan to reverse the decline of bull trout (Salvelinus confluentus) populations in the Klamath Basin. If successful, we expect bull trout ...Citation Citation
- Title:
- Upper Klamath Basin bull trout conservation strategy : part 1, a conceptual framework for recovery, final
- Author:
- Light, Jeffrey
- Year:
- 1996, 2008, 2005
EXECUTIVE SUMMARY This document presents the framework of a plan to reverse the decline of bull trout (Salvelinus confluentus) populations in the Klamath Basin. If successful, we expect bull trout to recover to a level where they will have a reasonable chance of long-term viability. The work is the collective effort of fish biologists, foresters, other natural resource management professionals, and local landowners representing a diverse array of interests and organizations. Together, these individuals have worked for several years to gather information pertaining to the distribution and status of Klamath bull trout populations and threats to their persistence. The members of the Bull Trout Working Group share the common desire to restore bull trout populations while at the same time sustaining their respective land use interests in the Klamath Basin. This approach provides incentives to all the interested parties to seek agreement on solutions, encouraging cooperative work on an otherwise ambitious and daunting task. The following few pages summarize the plan. Each area is covered again in greater detail in the body of the document. The goals established by the Bull Trout Working Group for this recovery plan are to (1) Secure existing bull trout populations, and (2) Expand the populations to some of their former range and numbers. We pursue these goals with a three step approach of assessment, implementation, and evaluation. We begin with a review of the distribution and status of bull trout generally, then specifically within the Klamath Basin. Next we present available data and interpretations supporting our conclusions regarding the type, magnitude, and extent of physical and biological factors or concerns that may hamper bull trout persistence. Land and fish management activities that contribute to these problem situations are then identified. This is followed by a blueprint for stepwise development and implementation of practical solutions. Finally, a monitoring plan is proposed to measure the success of the recovery efforts. The Klamath Basin Bull trout populations represent a valuable biological resource. These populations exist at the southern edge of the species' distribution, and have distinctive genetic character. In the Upper Klamath River Basin, bull trout are presently found as resident forms in eight isolated headwater streams within six small drainages. (4Headwater streams' in this document refers to very small streams, rather than rivers which are the headwaters for larger rivers). These streams occur in three general locations: they are tributaries of the Sprague River, of the Sycan River and of Upper Klamath Lake. Together, the known populations occupy approximately 23 miles (37 km) of perennial streams. Formerly, bull trout may have occurred in the mainstems of these systems (Gilbert 1897. Dambacher et al. 1992, Roger Smith, ODFW, pers. coram. 1994). In addition to existing populations, other populations are known to have recently occupied nearby streams (Cherry and Coyote creeks, the Upper Sycan River). Estimated current population sizes in each drainage range between 133 and 1,293, indicating that populations are low enough to warrant concern. These population sizes are smaller than the minimum viable population sizes predicted by conservation biology theory. A substantial risk of extirpation via natural disturbance cycles and stochastic events exists for such small populations. Streams that are presently inhabited by bull trout are typically small and spring-fed with steep gradients. They originate in the higher elevations of mountains within the Upper Klamath Basin and flow through forests where land uses range from wilderness and national parkland to commercial forestry and grazing. Eventually, these tributaries or their mainstem receiving waters leave the forest and flow through broad sagebrush-covered valleys or marshes where they widen and flatten. Here livestock grazing and agriculture are the dominant land uses. An assessment of the current situation regarding Klamath Basin bull trout was performed using existing and new information on life history, distribution, habitat requirements by lifestage, environmental requirements, exotic species interactions, angling pressure, land use interactions, habitat fragmentation, population fragmentation and many other factors. Basin-specific information on each of these factors was collected and analyzed, complemented by a thorough review of the literature. Past, present and possible future distributions of bull trout were examined. Particular emphasis was placed on determining the nature and extent of biotic interactions, because this potential agent of bull trout decline has not been thoroughly addressed in other works. Analysis of the assembled information resulted in the identification of several specific natural and anthropogenic factors which are thought to limit the distribution and persistence of bull trout. Habitat quality and quantity are affected by land use to some degree in all currently inhabited bull trout streams except upper Sun Creek. Generally, habitat conditions vary from fair to good in existing bull trout streams. We identified several land uses that have reduced habitat quality. Principal among the abiotic factors of concern is fine sediment loading from (1) road erosion, (2) stream bank and adjacent ground disturbance by livestock, and (3) Bull Trout Document - Final - - 6 - 26-Jan-96 stream-adjacent hillslope erosion from logging. Second among the abiotic factors of concern is elevated temperature. Other concerns include diminished large woody debris (LWD) recruitment, declining bank integrity, low flows, changes in stream morphology, and blocked or hindered fish passage. The relative importance of each of these factors or concerns differs by watershed, or by location within a watershed. In most cases, information on specific issues and their locations is available with sufficient resolution to allow land managers to develop action plans to address them. Possible exceptions may include Deming Creek, where Watershed Analysis has not yet been performed. Based on the assessment results to date, the following strategy was developed to address limiting factors and concerns. Competitive and genetic interactions with non-native brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta) were found to be important biotic factors currently threatening the persistence of bull trout in the Klamath Basin. This conclusion was based on the almost pervasive presence of these exotic competitors and the significance of their negative interactions as determined from the literature and from local observations in headwater streams. Temperature may be a significant issue, especially for juvenile rearing, although the temperature tolerances of bull trout are not well understood. Habitat fragmentation and alteration appear to have been major issues in the past, resulting in population fragmentation, particularly at lower elevations and in larger streams where bull trout may have ranged historically. These final two factors appear less important than exotic competitors or temperature for bull trout in the current limited ranges in headwater streams, though they are important in mainstems and larger tributaries. They will need to be addressed if large scale restoration is undertaken. With the exceptions of temperature and fine sediment, brook trout have habitat requirements and environmental tolerances similar to bull trout, and they thrive in many Klamath Basin headwater streams while bull trout do not. Brown trout pose a competitive threat similar to that posed by brook trout, but the mechanisms of displacement and the areas where they occur differ. Even in environments unaltered by land management, such as Sun Creek within Crater Lake National Park, exotic trout are displacing bull trout. This conclusion is consistent with findings throughout the west, where competition with exotic species has clearly had a major effect on bull trout range, resulting in widespread declines in bull trout distribution. Changes in habitat may have altered competitive interactions between bull trout and other salmonids, both directly and indirectly. Since changes in environmental factors can exacerbate competition issues in sensitive populations, habitat condition remains a concern. Near-term, mid-term, and long-term strategy for Recovery of Bull Trout Populations Our approach to recovery of the Klamath basin's bull trout populations is a two-phase effort corresponding to near- and mid-term objectives, and an examination of possible long-term recovery objectives. It entails securing and maintaining existing populations followed by expansion into former headwater and downstream habitats, and ultimately the possibility of connecting tributaries with mainstem linkages. Assessment, research and monitoring needs associated with each phase were identified (see main body of text). Specific project details such as funding, work schedules, participant responsibilities, specific actions, implementation methods and costs are not presented but are to be developed collectively by the Bull Trout Working Group. Phase 1: Securing existing populations This phase of the recovery plan focuses on the six small drainages where bull trout populations are known to exist today. Here we wish to prevent further decline of individual populations as a step toward securing the viability of the Klamath Basin metapopulation(s).1 This is accomplished by addressing biotic and abiotic factors that threaten the persistence of these populations. The most immediate threat is the continued presence of non-native salmonids. Localized areas of habitat degradation or alteration from sediment inputs and shade removal are an additional serious concern. It may be feasible to isolate bull trout populations above barriers, followed by eradication of brook and brown trout within each isolated stream reach. This approach will be tested early in Phase 7, with particular attention to unforeseen consequences on the ecology of the test streams. Assuming it is viable, this approach will become the focus of Phases 1 & 2, in parallel with habitat enhancement efforts. Habitat enhancement is generally feasible, particularly in areas where roads or livestock are the issues. Where needed, such habitat enhancement efforts are expected to be completed as part of Phases 1&2. It will be necessary to understand the distribution of genetic variation among existing sub-populations of bull trout in order to embark on a well 1 For an understanding of metapopulation considerations, see the body of the text, in particular the section on 'Metapopulations and sub-populations' on page 60. Bull Trout Document - Final - - 7 - 26-Jan-96 directed range expansion program. Baseline data would be essential for genetic monitoring activities and for the development of stocks for establishing new sub-populations in subsequent phases. If successful, the actions taken in Phase 1 are expected to eliminate the direct threats to existing bull trout sub-populations posed by non-native salmonids. Parallel efforts to improve the in-stream physical environment to ensure habitat is suitable for bull trout are expected to eliminate proximate environmental threats to existing bull trout sub-populations. This effort will require that abiotic limiting factors and concerns be addressed via land management activities, most of which fall within the realm of forest land management. Timber harvest and regeneration, roads (construction, use, and maintenance), and livestock grazing programs are considered. Immediate actions may take the form of road erosion abatement, including road abandonment and revegetation. Some of these actions can be accomplished when a particular unit is harvested, while others may be pursued as independent restoration activities (e.g., livestock management plans, culvert replacements). Presently, no in-stream fish habitat improvement projects have been proposed, and none are foreseen for stream reaches affected by this phase of the recovery plan. Most of the concerns related to livestock are focused within the riparian zone. Some riparian locations are much more sensitive than others, for example the large meadow in Long Creek. Actions to address these concerns will vary by landowner and location, and may range from complete riparian exclosure to short-term grazing to continuous but moderate access. The preferred actions will depend on the success of these various strategies in bringing about the desired response of the channel and fish habitat, and can be expected to change as recovery of riparian areas progresses. Effectiveness monitoring will be invaluable for measuring the success of these efforts, and in adapting our management strategy during the implementation. No water diversion concerns have been identified for this phase of the plan, except for Deming Creek, where screening of irrigation ditches may be warranted. Some additional fish management actions may also be applicable in Phase 7, for example to continue to monitor compliance with existing no kill regulations in bull trout streams. Other pertinent fish management issues have been addressed already, for example the cessation of exotic trout stocking (brook, brown or non-native rainbow) in bull trout streams. Phase 2: Expanding the range of bull trout within headwater streams In Phase 2, bull trout populations are refounded in headwater streams which now support brook trout, e.g. Calahan and Cherry creeks, or possibly in creeks without fish, e.g. Sheep Creek on the North Fork Sprague. This serves to expand the number of sub-populations, increases the number of refugia, and increases the overall size of the Klamath metapopulation(s). This is a major step in the establishment of viable metapopulations; by increasing the number of sub-populations, the effect of the loss or decline of any particular sub-population is reduced, making the metapopulation(s) more resilient to natural disturbance, variations in breeding success, disease outbreaks and other stochastic factors. Phase 2 consists of two parts: Phase 2a, in which sub-populations are founded in streams which only recently lost bull trout (e.g. Cherry Creek, Coyote Creek and the upper Sycan River) and Phase 2b, in which sub-populations are founded in other suitable headwater habitat, as indicated by the presence of thriving brook trout sub-populations (e.g. Sevenmile Creek, Calahan Creek, Annie Creek, Camp Creek, Jackson Creek, Deep Creek and Corral Creek). Both parts of Phase 2 are accomplished in much the same way as Phase 7: Barriers are constructed to exclude brook trout and brown trout, then the exotic species are eradicated above the barriers. Bull trout populations are then founded with human-introduced bull trout, whether via transplantation from wild sources or from a hatchery. Care must be exercised to maintain adequate genetic diversity in the founded sub-populations as establishment of genetically healthy populations is a non-trivial task. An inherent risk in newly created sub-populations is the loss of genetic variation (founder effect), which if great enough can reduce the vigor of the population and its long-term viability. As in Phase 7, stresses from abiotic factors, such as excessive delivery of fine sediment, low flows, or warm water temperatures, need to be reduced in parallel with the removal of exotics. Streamside roads, road crossings, low flows in upper reaches, and livestock are situations of concern in many of the streams, and warm temperatures are in some. Also as in phase 7, monitoring for the presence of exotics, bull trout population parameters, and abiotic factors is an important follow-up activity to track and ensure long-term success. In addition, genetic monitoring of newly founded populations is indicated. Bull Trout Document - Final - -8- 26-Jan-96 A possible future direction after Phase 2 Once Phase 2 is complete, the Bull Trout Working Group will pause to assess the efforts completed and plan future efforts. If phases 1 and 2 are successful, there will be significant numbers of bull trout in various tributaries, but possibly little genetic exchange between them. Bull trout range may still be restricted to headwater streams. During the evaluation and reassessment of the recovery effort, the group will re-consider the long-term recovery objectives. Based on what we know now, two possible recovery objectives are likely to be considered. The first such possible objective is the establishment of natural movement corridors between adjacent headwater streams, thereby establishing complete and viable metapopulation(s) of bull trout within the Upper Klamath Basin. Connectivity between headwater streams would allow volitional movement of bull trout. Movement would allow dispersal, founding of new sub-populations, and interbreeding between sub-populations, within the local sub-basin. Establishing natural movement corridors between headwater streams may require that selected reaches of larger tributaries or even portions of mainstem rivers be restored to suitable habitat for bull trout. This would be an ambitious undertaking, which may be infeasible. It might require the elimination or exclusion of exotics, the removal of man-made barriers which prevent movement between streams, or alterations in current land use to reduce anthropogenically induced fine sediment loads, low flows, warm stream temperatures, or changes in channel morphology. The change in focus from headwater streams to larger tributaries represents an escalation in the scale and complexity of the restoration effort. Exclusion of exotics is much more difficult. Land use effects, whether from water diversions or livestock grazing are often more significant. The second possible objective of future efforts after Phase 2 is to attemp to re-establish fluvial populations of bull trout in selected mainstem rivers of the Upper Klamath Basin, in such a way as to connect the sub-populations of each metapopulation. Fluvial bull trout are far larger than stream resident bull trout, and have much higher fecundity as a result. This gives them a tremendous advantage in breeding, whether in founding new sub-populations, or augmenting existing sub-populations. By establishing a fluvial form of bull trout in the Upper Klamath Basin, overall viability of the metapopulation(s) should be greatly increased. Timeline for implementation A prototype Phase 1 implementation is likely to be completed within 2-5 years. Full implementation of Phase 1 may take many years, but the bulk of the work could be completed in 10-20 years. Further assessment work and some aspects of Phase 2 will be accomplished concurrent with Phase 1 efforts over the next several years, but may require 5-10 years before being well underway. Specific timelines for individual projects in phases 1 and 2 and the overall recovery effort will be developed by the Bull Trout Working Group. Summary and prognosis for bull trout populations in the Upper Klamath River Basin If our analysis is accurate, the Klamath Basin's native bull trout populations are imperiled, yet their future need not be bleak. They persist today as a handful of isolated sub-populations in small, headwater streams. If a fluvial life history form existed, as it may have at one time in the Wood River2, no longer occurs or is a very small (i.e., undetectable) component of the current Klamath River Basin population. Gene flow between these sub-populations has apparently ceased. Individual population sizes are small enough to be near or below minimum viable levels as defined by current theorists in conservation biology. Competition from introduced brook and brown trout is widespread, with severe long-term consequences. Habitat conditions vary from stream to stream, depending on the nature and extent of land uses around and downstream of the bull trout tributaries. Fine sediment inputs and elevated stream temperatures are the principal habitat issue. Water withdrawals, altered channels and flood plains, and other anthropogenic influences have contributed to loss of mainstem fluvial habitat, and may have ultimately resulted in habitat fragmentation, followed by isolation of the remaining populations. Together, these conditions do not bode well for the longevity of native bull trout populations. We believe concerted efforts to resolve the identified problems can achieve the goals of maintaining, and possibly restoring, Klamath bull trout populations. Further, we believe that without attention, one or more of the identified limiting factors will almost certainly spell an end to most or all of the sub-populations in the basin. 2 A 330 mm specimen was collected from Fort Creek, a tributary to the Wood River, in 1876. Cited in Cavendar 1978; Smithsonian Accession Number 16793. Bull Trout Document - Final - -9 - 26-Jan-96
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"September 8, 1999."
Citation -
Land use planning, zoning, and subdivisions are integrally tied to the land resource. The need for a land surveyor and for statutes which govern his operation when working in these areas is stressed. A ...
Citation Citation
- Title:
- Comparison of Vermont and Oregon statutory land surveyor laws
- Author:
- Norton, Robert Leon
Land use planning, zoning, and subdivisions are integrally tied to the land resource. The need for a land surveyor and for statutes which govern his operation when working in these areas is stressed. A brief history of Vermont and Oregon, illustrating the role of land surveys on settlement, is given. Statutes relative to: the registration of land surveyors, Vermont town lines, the Oregon county surveyor, Oregon subdivisions, Vermont land use, and state plane coordinate systems are discussed. Nine recommendations in these areas are made.