Treesearch

Armillaria possesses several intriguing characteristics that have inspired wide interest in understanding phylogenetic relationships within and among species of this genus. Nuclear ribosomal DNA sequence–based analyses of Armillaria provide only limited information for phylogenetic studies among widely divergent taxa. More recent studies have shown that translation elongation factor 1-α (tef1) sequences are highly informative for phylogenetic analysis of Armillaria species within diverse global regions. This study used Neighbor-net and coalescence-based Bayesian analyses to examine...

For environmental problems such as climate change, uncertainty about future conditions makes it difficult to know what the goal of mitigation efforts should be, and inequality among the affected parties makes it hard for them to know how much they each should do toward reaching the goal. We examine the effects of scientific uncertainty and wealth inequality in experiments where subjects decide how much to contribute toward reducing a common threat. We also explore how the framing of uncertainty affects collective action. Our results suggest that uncertainty lowers contributions, but...

The concepts of animal units, animal unit months, and animal unit equivalents have long been used as standards for range management planning, estimating stocking rates, reporting actual use, assessing grazing fees, ranch appraisal, and other purposes. Increasing size of cattle on rangelands has led some to suggest that the definition of animal units and animal unit months requires revision. Range managers need to understand these concepts and arbitrarily changing them would lead to confusion. The Rangeland Assessment and Monitoring Committee reviewed this issue and concluded that the...

Water is a critical resource in dry forest and rangeland environments of western North America, largely determining the distribution of plant and animal species across a broad range of elevations and ecosystems. Water is also essential for human endeavors, directly affecting where and how human communities and local economies have developed. The Blue Mountains of northeast Oregon and southeast Washington are an important source of water for forest ecosystems and human uses. Surrounding communities rely on water from national forest lands in the Blue Mountains for drinking water, industrial...

In the Blue Mountains, climate change is likely to have significant, long-term implications for freshwater resources, including riparian areas, wetlands (box 7.1), and groundwater-dependent ecosystems (GDEs, box 7.2). Climate change is expected to cause a transition from snow to rain, resulting in diminished snowpack and shifts in streamflow to earlier in the season (Leibowitz et al. 2014, Luce et al. 2012; see chapter 3). Additional effects include changes in extreme high- and low-flow events; alteration of groundwater recharge rates; changes in the fate and transport of nutrients;...

Fire is returning to many conifer-dominated forests where species composition and structure have been altered by fire exclusion. Ecological effects of these fires are influenced strongly by the degree of forest change during the fire-free period. Response of fire-adapted species assemblages to extended fire-free intervals is highly variable, even in communities with similar historical fire regimes. This variability in plant community response to fire exclusion is not well understood; however, ecological mechanisms such as individual species’ adaptations to disturbance or competition and...

Determining how changes in abiotic conditions influence community interactions is a fundamental challenge in ecology. Meeting this challenge is increasingly imperative in the Anthropocene where climate change and exotic species introductions alter abiotic context and biotic composition to reshuffle natural systems.

The dominant influences on climatic patterns in the Pacific Northwest are the Pacific Ocean and the Cascade Range. The diurnal temperature range is higher east of the Cascade crest, further inland from the Pacific Ocean. More precipitation falls west of the Cascade Mountains crest, and a strong rain shadow greatly reduces precipitation east of the crest. The southern portion of the Blue Mountains, including the Strawberry subrange, is in the rain shadow of the Cascade Mountains and is predominantly influenced by Great Basin climatic patterns, resulting in warmer and drier conditions. In...

Dispersal can strongly influence the demographic and evolutionary trajectory of populations. For many species, little is known about dispersal, despite its importance to conservation. The Greater Sage-Grouse (Centrocercus urophasianus) is a species of conservation concern that ranges across 11 western U.S. states and 2 Canadian provinces. To investigate dispersal patterns among spring breeding congregations, we examined a 21-locus microsatellite DNA dataset of 3,244 Greater Sage-Grouse sampled from 763 leks throughout Idaho, Montana, North Dakota, and South Dakota, USA, across 7 yr. We...

This newsletter is designed to keep managers and other users up-to-date with recently completed and ongoing research by RMRS scientists, as well as to highlight breaking news related to invasive species issues. The newsletter is produced by the RMRS Invasive Species Working Group (ISWG), a core group of scientists who volunteer to disseminate RMRS invasive species science to managers and the public through this newsletter, the website, and periodic white papers. All of our products, including past issues of the newsletter and lists of publications, can be found online at: https://www.fs.fed...