subalpine rangeland as a rara avis ecosystem is very important because ofecological features. consistency and resistance of this ecosystem is so frangible and itsnatural equilibrium is instable due to the effects of biotic and abiotic factors. the landslideas one of negative consequences in upland area is seen in masoleh watershed (north ofiran). this study has investigated the roles of biotic ...

Winter climate change has great potential to affect the functioning of terrestrial ecosystems. In particular, increased soil frost associated with reduced insulating snow cover may impact nitrogen (N) dynamics in cold ecosystems, but little is known about variability these effects among aggregates. A manipulation experiment was conducted investigate absence on N cycling within aggregates a spru...

Algae are generally a high-quality diet source because they provide essential compounds to aquatic consumers. In forested stream ecosystems, the availability of algae is low compared terrestrial organic matter, which may constrain dietary transfer However, there could be other overlooked resource pools that consumers in river ecosystems. We conducted field study along subalpine continuum Austri...

Tree recruitment is a spatially structured process that may undergo change over time because of variation in postdispersal processes. We examined seed pilferage, seed germination, and seedling survival in whitebark pine to determine whether 1) microsite type alters the initial spatial pattern of seed caches, 2) higher abiotic stress (i.e. higher elevations) exacerbates spatial distribution chan...

Understanding seasonal changes in soil microbial quotient (qMB, i.e., the MBC-to-SOC ratio) along altitudinal gradients and their dominant drivers is essential for determining effects of environmental on organic carbon pool. A 3-year situ core incubation experiment was thus conducted a dry valley shrub, valley-mountain ecotone forest, subalpine coniferous an alpine meadow across 2,431-m gradien...

How does recent climate warming and climate variability alter fitness, phenotypic selection and evolution in natural populations? We combine biophysical, demographic and evolutionary models with recent climate data to address this question for the subalpine and alpine butterfly, Colias meadii, in the southern Rocky Mountains. We focus on predicting patterns of selection and evolution for a key ...

As humans increasingly dominate the nitrogen cycle, deposition of reactive (Nr) will continue to have adverse consequences for ecosystems. In Rocky Mountains, Nr remains elevated and has become dominated by ammonium, despite efforts reduce emissions. Currently, spatial models do not fully account urban agricultural emissions, sources that contribute observed high rates ammonium in adjacent To a...

The snowshoe hare (Lepus americanus) is a habitat specialist with a broad geographic range associated with boreal and subalpine forests in North America (Hall 1981, Hodges 1999a,b). It reaches southern range limits in the Southern Rocky Mountains in northern New Mexico, USA. Here, scant and mostly anecdotal evidence suggests that it is restricted to high-elevation, subalpine conifer forests dom...

Widespread tree mortality caused by outbreaks of native bark beetles (Circulionidae: Scolytinae) in recent decades has raised concern among scientists and forest managers about whether beetle outbreaks fuel more ecologically severe forest fires and impair postfire resilience. To investigate this question, we collected extensive field data following multiple fires that burned subalpine forests i...

Relationships between the flammability properties of a given plant and its chances of survival after a fire still remain unknown. We hypothesize that the bark flammability of a tree reduces the potential for tree survival following surface fires, and that if tree resistance to fire is provided by a thick insulating bark, the latter must be few flammable. We test, on subalpine tree species, the ...