Treesearch

Island ecosystems provide habitat for many endemic species that may be threatened by nonnative species introductions. We examined nonnative freshwater turtle occurrences and diets to examine potential predation effects on native species in Kawai Nui Marsh, Oahu, Hawaii. No freshwater turtles are native to the Hawaiian Archipelago. The Pond Slider (Trachemys scripta) and Chinese Softshell (Pelodiscus sinensis) were the only turtles found in the marsh after 767 trap days. Trachemys scripta stomachs (n = 50) contained mostly the nonnative plant Commelina diffusa and nonnative snails (Pomacea...

Background: Fuel reduction treatments have been widely implemented across the western US in recent decades for both fire protection and restoration. Although research has demonstrated that combined thinning and burning effectively reduces crown fire potential in the few years immediately following treatment, little research has identified effectiveness of thinning and burning treatments beyond a decade. Furthermore, it is unclear how posttreatment disturbances such as a bark beetle outbreak affect fuel treatment effectiveness. Results: We evaluated differences in surface and canopy fuel...

Studies of habitat selection and use by wildlife, especially large herbivores, are foundational for understanding their ecology and management, especially if predictors of use represent habitat requirements that can be related to demography or fitness. Many ungulate species serve societal needs as game animals or subsistence foods, and also can affect native vegetation and agricultural crops because of their large body size, diet choices, and widespread distributions. Understanding nutritional resources and habitat use of large herbivores like elk (Cervus canadensis) can benefit their...

This case study was developed as part of a larger, interdisciplinary research project to assess the social, hydrological, and ecological effects of beaver-related watershed restoration approaches in rangeland streams of the Western United States. It is one of five case studies being undertaken to investigate the social context of beaver-related restoration in western rangelands. The Scott River basin in northern California is the first place in the state where watershed restoration using beaver dam analogues (BDAs, instream post and vegetation-weave structures that mimic natural beaver...

National forest planning and management traditionally have involved addressing a broad spectrum of natural resource issues and ecological conditions to comply with forest management regulations and policies. In 2012, the U.S. Department of Agriculture Forest Service issued a new forest planning rule requiring that national forests and grasslands identify and evaluate information on the ecosystem services provided by plan areas from which people benefit as part of the plan assessment phase of plan revision. Specifically, planning teams are directed now to identify “key” ecosystem services...

Wildfire ecosystems are thought to be self-regulated through pattern–process interactions between ignition frequency and location, and patterns of burned and recovering vegetation. Yet, recent increases in the frequency of large wildfires call into question the application of self-organization theory to landscape resilience. Topography represents a stable bottom-up template upon which fire interacts as both a physical and an ecological process. However, it is unclear how topographic control changes geographically and across spatial scales. We analyzed fire perimeter and topography data...

A species’ population structure and history are critical pieces of information that can help guide the use of available native plant materials in restoration treatments and decide what new native plant materials should be developed to meet future restoration needs. In the western United States, Pseudoroegneria spicata (bluebunch wheatgrass; Poaceae) is an important component of grassland and shrubland plant communities and commonly used for restoration due to its drought resistance and competitiveness with exotic weeds. We used next‐generation sequencing data to investigate the processes...

The forested watersheds of the Pacific Northwest can sequester a significant amount of atmospheric carbon dioxide (CO2), making them valuable carbon sinks for offsetting the carbon emissions that are contributing to global changes in the climate. However, as trees are storing carbon, water is leaching it from the soil. Some of the carbon is captured by microbial communities living in the stream’s hyporheic zone, a region within the streambed, where it is turned back into CO2. Gas exchanges between water and air release this CO2 back into the atmosphere. These carbon fluxes previously have...

Riparian vegetation along streams provides a suite of ecosystem services in rangelands and thus is the target of restoration when degraded by over-grazing, erosion, incision, or other disturbances. Assessments of restoration effectiveness depend on defensible monitoring data, which can be both expensive and difficult to collect. We present a method and case study to evaluate the effectiveness of restoration of riparian vegetation using a web-based cloud-computing and visualization tool (ClimateEngine.org) to access and process remote sensing and climate data. Restoration efforts on an...

This report highlights significant research findings and accomplishments of the Pacific Northwest Research Station during fiscal year 2017.