Treesearch

In species management and conservation, surrogate species or groups of species can be used as proxies for broader sets of species when the number of species of concern is too great to allow each to be considered individually. However, these surrogate approaches are not applicable to all situations. In this article we discuss how the nature of the ecological system, the objectves and scale of management, and the level of available knowledge influence the decision about using a surrogate approach. We use species-area relations to define a "surrogate zone" in which the approach may be most...

Effectively managing habitat for threatened populations of Canada lynx (Lynx canadensis) requires knowledge of habitat conditions that provide for the ecological needs of lynx. We snow-tracked lynx to identify habitat conditions associated with hunting behavior and predation during winters of 2002-2003 and 2003-2004 in the northern Cascade Range in Washington state, USA. We recorded number and success of predation attempts, prey species killed, and trail sinuosity on 149 km of lynx trails. Lynx killed snowshoe hares (Lepus americanus), red squirrels (Tamiasciurus hudsonicus), and cricetids...

Use of mechanical thinning and prescribed fire to reduce fuels in dry forest ecosystems has become increasingly common in western North America. Nevertheless, few studies have quantified effects of fuels reduction treatments on wildlife. We evaluated effects of fuels reduction on quantity and quality of forage available to elk (Cervus elaphus) in northeastern Oregon. From 2001 to 2003, 26 stands of true fir (Abies spp.) and Douglas-fir (Pseudotsuga menziesi [Mirbel] Franco) were thinned and burned, whereas 27 similar stands were left untreated to serve as experimental controls. We estimated...

The purpose of this work is to understand the nature of growth-climate relationships for Douglas-fir (Pseudotsuga menziesii) across the climatic dimensions of its niche. We used a combination of biophysically informed sampling (to identify sample sites) and dendroclimatology (to identify growth-climate relationships) along a climate gradient in Northwestern United States mountain ecosystems from the western Olympic Peninsula, Washington, to the eastern Rocky Mountain Front, Montana. We used a multiscale sampling strategy that accounted for continentality, physiography, and topography as...

Lynx (Lynx canadensis) occur in the northern counties of Washington state, USA; however, current distribution and status of lynx in Washington are poorly understood. During winters 2002-2004 we snow-tracked lynx for 155 km within a 211-km2 area in northern Washington, to develop a model of lynx-habitat relationships that we could use to assess their potential distribution and status in the state. We recorded movements and behaviors of lynx with a global positioning system and overlaid digitized lynx trails on various habitat layers using a geographic information system. Based on univariate...

We present a decision-support application that evaluates danger of severe wildland fire and prioritizes subwatersheds for vegetation and fuels treatment. We demonstrate the use of the system with an example from the Rocky Mountain region in Utah; a planning area of 4.8 million ha encompassing 575 subwatersheds. In a logic model, we evaluate fire danger as a function of three primary topics: fire hazard, fire behavior, and ignition risk. Each primary topic has secondary topics under which data are evaluated. The logic model shows the state of each evaluated watershed with respect to fire...

To understand the biogeography of truffle-like fungi, DNA sequences were analysed from representative taxa of Hysterangiales. Multigene phylogenies and the results of ancestral area reconstructions are consistent with the hypothesis of an Australian, or eastern Gondwanan, origin of Hysterangiales with subsequent range expansions to the Northern Hemisphere. However, neither Northern Hemisphere nor Southern Hemisphere taxa formed a monophyletic group, which is in conflict with a strictly vicariant scenario. Therefore, the occurrence and importance of long-distance dispersal could not be...

We investigated the effect of western hemlock dwarf mistletoe (Arceuthobium tsugense (Rosend.) G.N. Jones ssp. tsugense) on the 13-year basal area growth of large (>45.7 cm diameter at breast height) western hemlock (Tsuga heterophylla (Raf.) Sarg.) trees in an old-growth forest in southwestern Washington state. We controlled for spatial effects on tree growth by using twenty-seven 0.4-ha plots that had uninfected, lightly, moderately, and severely infected classes of trees present on each plot. Basal area growth was analyzed using analysis of covariance of a randomized block design that...

The high altitude spruce-fir (Abies fraseri (Pursh) Poiret.-Picea rubens Sarg.) forests of the southern Appalachian Mountains, USA, experience frequent cloud immersion. Recent studies indicate that cloud bases may have risen over the past 30 years, resulting in less frequent forest cloud immersion, and that further increases in cloud base height are likely in the event of continued climate warming. To assess the impact of this trend on the regeneration of high altitude spruce-fir forests and the migration of plant communities, in particular the encroachment of spruce-fir forests and...

Pocket gophers have the potential to alter the dynamics of grasslands by creating mounds that bury existing vegetation and locally reset succession. Gopher mounds may provide safe sites for less competitive species, potentially increasing both species diversity and vegetation heterogeneity (spatial variation in species composition). We compared species composition, diversity, and heterogeneity among gopher mounds of different ages in three montane meadows in the Cascade Range of Oregon. Cover of graminoids and forbs increased with mound age, as did species richness. Contrary to many...