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Piñon pine and juniper woodlands in the southwestern United States are often represented as an expanding and even invasive vegetation type, a legacy of historic grazing, and culpable in the degradation of western rangelands. A long-standing emphasis on forage production, in combination with recent hazard fuel concerns, has prompted a new era of woodland management with stated restoration objectives. Yet the extent and dynamics of piñon-juniper communities that predate intensive Euro-American settlement activities are poorly known or understood, while the intrinsic ecological, aesthetic, and economic values of old-growth woodlands are often overlooked. Historical changes in piñon-juniper stands include two related,...
The southwestern willow flycatcher (SWFL; Empidonax traillii extimus) is an endangered songbird whose habitat has declined dramatically over the last century. Understanding habitat selection patterns and the ability to identify potential breeding areas for the SWFL is crucial to the management and conservation of this species. We developed a multiscaled model of SWFL breeding habitat with a Geographic Information System (GIS), survey data, GIS variables, and multiple logistic regressions. We obtained presence and absence survey data from a riverine ecosystem and a reservoir delta in south-central Arizona, USA, in 1999. We extracted the GIS variables from satellite imagery and digital elevation models to characterize...
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Predicting suitable habitat and the potential distribution of invasive species is a high priority for resource managers and systems ecologists. Most models are designed to identify habitat characteristics that define the ecological niche of a species with little consideration to individual species’ traits. We tested five commonly used modelling methods on two invasive plant species, the habitat generalist Bromus tectorum and habitat specialist Tamarix chinensis, to compare model performances, evaluate predictability, and relate results to distribution traits associated with each species. Most of the tested models performed similarly for each species; however, the generalist species proved to be more difficult...
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Submersed aquatic vegetation (SAV) communities are highly productive ecosystems that provide significant ecological benefits to coastal areas, including essential calories for wintering waterfowl. However, the potential effects of sea-level rise is posing new questions about the future availability of SAV for waterfowl and other coastal wildlife. Of primary concern is the fact that rising seas have the potential to increase salinities in fresh and brackish marshes on the Gulf of Mexico’s coast, changing the distribution and composition of SAV communities, and affecting valuable waterfowl habitat and food resources. Not enough is known about the relationship between salinity and SAV to predict how this important...
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The ascii grids represent regional probabilities that groundwater in a particular location will have dissolved oxygen (DO) concentrations less than selected threshold values representing anoxic groundwater conditions or will have dissolved manganese (Mn) concentrations greater than selected threshold values representing secondary drinking water-quality contaminant levels (SMCL) and health-based screening levels (HBSL) for water quality. The probability models were constrained by the alluvial boundary of the Central Valley to a depth of approximately 300 meters (m). We utilized prediction modeling methods, specifically boosted regression trees (BRT) with a Bernoulli error distribution within a statistical learning...
Pi�on pine and juniper woodlands in the southwestern United States are often represented as an expanding and even invasive vegetation type, a legacy of historic grazing, and culpable in the degradation of western rangelands. A long-standing emphasis on forage production, in combination with recent hazard fuel concerns, has prompted a new era of woodland management with stated restoration objectives. Yet the extent and dynamics of pi�on-juniper communities that predate intensive Euro-American settlement activities are poorly known or understood, while the intrinsic ecological, aesthetic, and economic values of old-growth woodlands are often overlooked. Historical changes in pi�on-juniper stands include two related,...
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Description of Work In collaboration with 23 local and state agencies, beach-specific models were developed at 43 beaches throughout the Great Lakes region, and data were collected at 6 more beaches for future predictive model development. A predictive modeling workshop was hosted by USGS with instructors from USGS, USEPA, and Wisconsin DNR and included training on the use of USGS-developed data aggregation tools and USEPA’s Virtual Beach. Relevance & Impact Over 56 beaches across the Great Lakes region, in addition to those currently being monitored, will be included in this effort to help meet goals for healthier beaches. Key Findings Analyses were completed for a suite of pathogens at 12 Great Lakes beaches....
Pi�on pine and juniper woodlands in the southwestern United States are often represented as an expanding and even invasive vegetation type, a legacy of historic grazing, and culpable in the degradation of western rangelands. A long-standing emphasis on forage production, in combination with recent hazard fuel concerns, has prompted a new era of woodland management with stated restoration objectives. Yet the extent and dynamics of pi�on-juniper communities that predate intensive Euro-American settlement activities are poorly known or understood, while the intrinsic ecological, aesthetic, and economic values of old-growth woodlands are often overlooked. Historical changes in pi�on-juniper stands include two related,...
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Understanding species?environment relationships is important to predict the spread of non-native species. Yellow toadflax (Linaria vulgaris Mill.) is an invasive perennial recently found in the Flat Tops Wilderness of the White River National Forest on the western slope of the Colorado Rocky Mountains. We hypothesized yellow toadflax occurrence could be predicted from easily measured site characteristics. We used logistic regression with stepwise selection to generate a model to predict yellow toadflax occurrence on a particular plot based on that site?s physical characteristics. The experimental design was a paired-plot study in two locations using circular 1,018-m2 plots. Sixty-eight plots that did not contain...
    map background search result map search result map Predicting yellow toadflax infestations in the Flat Tops Wilderness of Colorado Modelling invasion for a habitat generalist and a specialist plant species Assessing the Potential Impact of Sea-Level Rise on Submersed Aquatic Vegetation and Waterfowl in the Northern Gulf of Mexico Enhance Great Lakes beach recreational water quality decision making Probability distribution grids of dissolved oxygen and dissolved manganese concentrations at selected thresholds in drinking water depth zones, Central Valley, California Predicting yellow toadflax infestations in the Flat Tops Wilderness of Colorado Modelling invasion for a habitat generalist and a specialist plant species Assessing the Potential Impact of Sea-Level Rise on Submersed Aquatic Vegetation and Waterfowl in the Northern Gulf of Mexico Probability distribution grids of dissolved oxygen and dissolved manganese concentrations at selected thresholds in drinking water depth zones, Central Valley, California Enhance Great Lakes beach recreational water quality decision making