Treesearch

Big sagebrush (Artemisia tridentata) is one of the most widespread and abundant plant species in the intermountain regions of western North America. This species occupies an extremely wide ecological niche ranging from the semi-arid basins to the subalpine. Within this large niche, three widespread subspecies are recognized. Montane ecoregions are occupied by subspecies vaseyana, while subspecies wyomingensis and tridentata occupy basin ecoregions. In cases of wide-ranging species with multiple subspecies, it can be more practical from the scientific and management perspective to assess...

Ecological research is increasingly concentrated at particular locations or sites. This trend reflects a variety of advantages of intensive, site-based research, but also raises important questions about the nature of such spatially delimited research: how well does site based research represent broader areas, and does it constrain scientific discovery? We provide an overview of these issues with a particular focus on one prominent intensive research site: the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA. Among the key features of intensive sites are: long-term, archived...

This research note compiles 43 years of research and monitoring data to produce the first comprehensive checklist of the dry forest avian community found within the Guánica Biosphere Reserve. We provide an overview of the reserve along with sighting locales, a list of 185 birds with their resident status and abundance, and a list of the available bird habitats. Photographs of habitats and some of the bird species are included.

The federal crop insurance program has been a major fixture of U.S. agricultural policy since the 1930s, and continues to grow in size and importance. Indeed, it now represents the most prominent farm policy instrument, accounting for more government spending than any other farm commodity program. The 2014 Farm Bill further expanded the crop insurance program and introduced a number of new county-level revenue insurance plans. In 2013, over $123 billion in crop value was insured under the program. Crop revenue insurance, first introduced in the 1990s, now accounts for nearly 70% of the...

Soil quality assessments are essential for determining impacts on belowground microbial community structure and function. We evaluated the suitability of active carbon (C), a rapid field test, as an indicator of soil biological quality in five paired forest stands (clear cut harvested 40 years prior and unharvested) growing on volcanic ash-cap soils in northern Idaho. Active C was compared with several traditional measures of soil microbial properties (microbial biomass, respiration, fungal hyphal biomass, bacterial number and biomass and PLFA community structure). Despite the significant...

Understanding the local context that shapes collective response to wildfire risk continues to be a challenge for scientists and policymakers. This study utilizes and expands on a conceptual approach for understanding adaptive capacity to wildfire in a comparison of 18 past case studies. The intent is to determine whether comparison of local social context and community characteristics across cases can identify community "archetypes" that approach wildfire planning and mitigation in consistently different ways. Identification of community archetypes serves as a potential strategy for...

Uncertainty in the estimation of hydrologic export of solutes has never been fully evaluated at the scale of a small-watershed ecosystem. We used data from the Gomadansan Experimental Forest, Japan, Hubbard Brook Experimental Forest, USA, and Coweeta Hydrologic Laboratory, USA, to evaluate many sources of uncertainty, including the precision and accuracy of measurements, selection of models, and spatial and temporal variation. Uncertainty in the analysis of stream chemistry samples was generally small but could be large in relative terms for solutes near detection limits, as is common for...

Milder winters have contributed to recent outbreaks of Dendroctonus ponderosae in Canada, but have not been evaluated as a factor permitting concurrent outbreaks across its large range (ca.1500 9 1500 km) in the western United States (US). We examined the trend in minimum air temperatures in D. ponderosae habitats across the western US and assessed whether warming winters explained the occurrence of outbreaks using physiological and population models.

In this issue of the GSD Update, we take a look back at selected studies of the Grassland, Shrubland and Desert Ecosystems Science Program (GSD) that depict its strengths and focus areas. Significant results of recent research and science delivery by GSD scientists are highlighted. We feature program research that lines up with the strategic research priorities of the USDA Forest Service (USDA-FS) and the Rocky Mountain Research Station (RMRS). In particular, we spotlight accomplishments in: research that supports ecosystem resiliency, and native and invasive species management; the role...

Recent research has shown that exposing seeds to smoke stimulates germination for a multitude of plant species, including several species in the genus Penstemon (Scrophulariaceae). I evaluated whether smoke, either alone or followed by 10 wk of stratification (moist prechilling), influenced germination for 10 Penstemon species native to the Interior West of North America. Seeds were collected from 3 to 9 wild populations per species, with each population serving as a replicate for that species in the experimental design. I found that percent germination increased in response to smoke for 3...