Treesearch

1. Despite broad recognition that water is a major limiting factor in arid ecosystems, we lack an empirical understanding of how this resource is shared and distributed among neighbouring plants. Intraspecific variability can further contribute to this variation via divergent life-history traits, including root architecture. We investigated these questions in the shrub Artemisia tridentata and hypothesized that the ability to access and utilize surface water varies among subspecies and cytotypes. 2. We used an isotope tracer to quantify below-ground zone of influence in A. tridentata, and...

Bayesian population models can be exceedingly slow due, in part, to the choice to simulate discrete latent states. Here, we discuss an alternative approach to discrete latent states, marginalization, that forms the basis of maximum likelihood population models and is much faster. Our manuscript has two goals: (1) to introduce readers unfamiliar with marginalization to the concept and provide worked examples and (2) to address topics associated with marginalization that have not been previously synthesized and are relevant to both Bayesian and maximum likelihood models. We begin by explainin...

There is an urgent need to understand ecological responses of avian species to the rapidly expanding human footprint of conventional and renewable energy development in sagebrush and prairie ecosystems. The ferruginous hawk (Buteo regalis) and golden eagle (Aquila chrysaetos) are two sympatric raptors of conservation concern that occupy and flourish in the most intact sagebrush steppe region remaining in North America. To understand these species’ use of habitat relative to energy development, we built resource selection functions using a spatially representative sample of occupied nesting...

Roads can result in negative effects on wildlife including habitat loss, behavioral avoidance, reduced survival, reproduction and gene flow. These road effects are especially pronounced for large mammals given their large home-range requirements and low reproductive rates. To counteract these negative effects, road mitigation measures, such as underpasses and overpasses, are promoted; however, future landscape changes are rarely considered when selecting mitigation locations. We used GPS telemetry data on female American black bears Ursus americanus to examine their response to roads in...

A broader understanding of how landscape resistance influences climate change vulnerability for many species is needed, as is an understanding of how barriers to dispersal may impact vulnerability. Freshwater biodiversity is at particular risk, but previous studies have focused on popular cold-water fishes (e.g., salmon, trout, and char) with relatively large body sizes and mobility. Those fishes may be able to track habitat change more adeptly than less mobile species. Smaller, less mobile fishes are rarely represented in studies demonstrating effects of climate change, but depending on...

Pacific salmon spawning and rearing habitats result from dynamic interactions among geomorphic processes, natural disturbances, and hydro‐climatological factors acting across a range of spatial and temporal scales. We used a 21‐year record of redd locations in a wilderness river network in central Idaho, USA, to examine which covariates best predict Chinook salmon (Oncorhynchus tshawytscha) spawning occurrence and how shifts under a changing climate might affect habitat availability. We quantified geomorphic characteristics (substrate size, channel slope, valley confinement), climatic...

We examined the effects of two recent, high-severity disturbances on seed dispersal and conifer seedling establishment in a subalpine spruce-fir forest in the San Juan Mountains, Colorado. Our study area had undergone high forest mortality from a spruce beetle (Dendroctonus rufipennis) outbreak beginning ca. 2004, and a portion of the study area was additionally burned by the West Fork Complex wildfire in 2013. The aim of this study was to determine how seedling re-establishment patterns vary with seed availability, temperature, overstory composition, and understory cover across a topograph...

The mountain pine beetle (MPB) (Dendroctonus ponderosae) is a bark beetle that attacks and kills ponderosa pine (Pinus ponderosa), among other pine species throughout the western conifer forests of the United States and Canada, particularly in dense stands comprising large trees. There is information on the stand conditions that the insect prefers. However, there is a paucity of information on how small-scale variation in stand conditions influences the distribution of tree mortality within a stand. I examined the small-scale distribution of ponderosa pine basal area pre- and post a...

Recent studies demonstrate that by focusing on traits linked to fundamental plant life-history trade-offs, ecologists can begin to predict plant community structure at global scales. Yet, consumers can strongly affect plant communities, and means for linking consumer effects to key plant traits and community assembly processes are lacking. We conducted a global literature review and meta-analysis to evaluate whether seed size, a trait representing fundamental life-history trade-offs in plant offspring investment, could predict post-dispersal seed predator effects on seed removal and plant...

Biological soil crusts (biocrusts) are crucial components of dryland ecosystems, but they are slow to recover following disturbance. Herein, we evaluated several methods for restoring lichen-moss biocrusts that included factorial applications of moss fragments in a water-slurry (1) with and without lichen fragments (to restore biocrust taxonomic structure), (2) with and without clay (to facilitate establishment), and (3) with and without jute ground cloth (to facilitate establishment). Three and four years after inoculation, moss and lichen cover was up to five and eight times higher on...