Treesearch

Climate classifications supply climate visualization with inference about general vegetation types. The Köppen classification system of thermal classes and an arid class is widely used, but options are available to strengthen climate change detection. For this study, I incorporated temperature and aridity information into all climate classes to isolate climate change, added a hypertropical class to better detect warming and drying in tropical zones, and developed a consistent ruleset of thermal classes with one temperature variable for streamlined application, yet maintained primary Köppen...

Present-day species distributions modeled with climate variables cannot provide potential future climate space for species that have contracted in range due to extirpations, regardless of abundant sample sizes within current ranges. My objective was to examine effects of range contractions on modeling of species to determine suitable space under climate change, exploring different approaches to modeling based on historical range maps. As examples of this issue, I estimated the current and future bioclimate envelopes of American bison (Bison bison) and elk (Cervus elaphus) from their...

Prescribed fall burning is commonly used worldwide on rangeland sites to enhance vegetation resources and restore disturbed ecosystems, but little is known about how it may alter microbial communities and insect activities. We used two site treatments (low- to moderate-burn severity plots and unburned control plots) at a high-elevation (2 100 m above sea level) shrub-steppe rangeland site. Four yr after the prescribed burn, captured insects primarily consisted of Coleoptera (beetles), Hymenoptera (ants, bees, and wasps), and Orthoptera (grasshoppers and crickets) species with similar or...

Great Basin bristlecone pine (Pinus longaeva D.K. Bailey) presence in the Stansbury Mountains of north-central Utah has been reported prior to the year 2020, but these reports lack adequate population characterization and the delineation of distinct stands of trees. In summer 2020, we identified and documented the presence of 5 separate stands of bristlecone pine in the Stansbury Mountains. These stands are removed from the nearest bristlecone populations in other mountain ranges by a distance of approximately 120 km; as such, they represent a unique outlier population of the species. We...

High-severity fires and short-interval reburns strongly influence forest structure and composition and may overwhelm forest ecosystem resilience and catalyze persistent shifts to non-forest conditions. Recent increases in annual area burned and severity in the western United States (US) highlight the need to better understand the long-term effects of high-severity fire, including interactions with subsequent fires. In the early 20th century, the northern US Rocky Mountains experienced several fire seasons with widespread, high-severity fires, under fire weather comparable with extreme...

Many tools that identify wildfire risks and hazards across the landscape assume that all houses and properties within a community have the same level of risk. However, there are often substantial differences across properties, such as building materials and distance to overgrown vegetation. Tools that don’t account for parcel-level risk cannot provide the details necessary for informing action on private property, such as maintaining defensible space, posting a visible address sign, or hardening a structure.To provide practitioners with a practical method for assessing how wildfire risk...

Fire regimes are a major agent of evolution in terrestrial animals. Changing fire regimes and the capacity for rapid evolution in wild animal populations suggests the potential for rapid, fire-driven adaptive animal evolution in the Pyrocene. Fire drives multiple modes of evolutionary change, including stabilizing, directional, disruptive, and fluctuating selection, and can strongly influence gene flow and genetic drift. Ongoing and future research in fire-driven animal evolution will benefit from further development of generalizable hypotheses, studies conducted in highly responsive taxa,...

Using genetic material from what may be the largest DNA database of its kind on cougars, researchers mapped the connectivity of these wild cat populations across Washington and into British Columbia, Canada. One of the big reveals from tracking how cougar genes flow across the state is: Cougars on the Olympic Peninsula - especially males - are not likely to mingle with other populations.

Dry conifer forests in the western US historically experienced frequent fire prior to European American colonization. Mean fire return interval ranged from about 5-35 years, with the majority of fires burning at low-to-moderate severity. The arrival of European Americans initiated notable reductions in fire frequency through the cessation of Indigenous burning, livestock grazing, and fire suppression. These activities effectively excluded fire from most dry conifer forests, thereby allowing live and dead fuels to accumulate. There are concerns that this fuel accumulation is causing...

During container nursery production of Purshia tridentata (antelope bitterbrush), we found that three fall fertilization applications successfully loaded plants with nitrogen (N) with little effect on plant biomass. Using 15N-labeled fertilizer to track N movements, we observed that N-loaded seedlings attained luxury consumption and ultimately translocated more N toward roots. In trees, such N-loading efforts have been reported to increase seedling survival and growth after outplanting by improving initial root growth. This leads to enhanced access to water and nutrients that increases...