Treesearch

Grazing is a major ecosystem disturbance in arid regions that are increasingly threatened by climate change. Understanding the long-term impacts of grazing on rangeland vegetation dynamics in a complex terrain in mountainous regions is important for quantifying dry land ecosystem services for integrated watershed management and climate change adaptation. However, data on the detailed long-termspatial distribution of grazing activities are rare,which prevents trend detection and environmental impact assessments of grazing. This study quantified the impacts of grazing on vegetation dynamics...

Background: The main objective of this study was to examine the climatic sensitivity of the radial growth response of 13 eastern white pine (Pinus strobus L.) provenances planted at seven test sites throughout the northern part of the species' native distribution in eastern North America. Methods: The test sites (i.e., Wabeno, Wisconsin, USA; Manistique, Michigan, USA; Pine River, Michigan, USA; Newaygo, Michigan, USA; Turkey Point, Ontario, Canada; Ganaraska, Ontario, Canada; and Orono, Maine, USA) examined in this study were part of a range-wide white pine provenance trial established in...

Purpose of Review Increased availability of current forest resource information provides an opportunity to evaluate the continued concerns about forest sustainability in North America. The purpose of this study is to assess and discuss the current state and trends of North American forest resources, sustainable forest management, and their implications for forest sustainability. Recent Findings Recent information indicates that forest sustainability in North America is not under threat. Forest area, inventory, and carbon stocks have been increasing while wood harvest has been declining....

Amazonian bird species often have patchy spatial distributions, and previous work has attributed this pattern to habitat specialization and dispersal limitation; however, we know comparatively little about the origins and maintenance of the isolated populations that constitute a patchy distribution. In this study, we ask whether patchy populations are interconnected by dispersal. We formulated 2 alternative hypotheses: (1) patchy populations are relicts of ancient connectivity or dispersal; and (2) patchy populations are centers of local abundance embedded in a matrix of contemporary...

Recent studies have highlighted the need for im- proved characterizations of aerodynamic conductance and temperature ( g A and T 0 ) in thermal remote-sensing-based surface energy balance (SEB) models to reduce uncertain- ties in regional-scale evapotranspiration (ET) mapping. By integrating radiometric surface temperature ( T R ) into the Penman–Monteith (PM) equation and finding analytical so- lutions of g A and T 0 , this need was recently addressed by the Surface Temperature Initiated Closure (STIC) model. However, previous implementations of STIC were confined to the ecosystem-scale...

We studied blue-stain fungi (Ophiostomataceae: Ophiostomatales) of mountain pine beetle in declining epidemic populations affecting three pine species in Colorado. Using morphological and molecular characterizations, we determined the presence of the mutualist L. longiclavatum in the southern Rocky Mountains of Colorado, where it was as common as the warm temperature adapted O. montium within the insect’s specialized maxillary mycangium. The species was more prevalent than its “sibling species” G. clavigera which is the the common mycangial mutualist documented in USA populations. Findings...

The mite and fungal biota associated with the mountain pine beetle (MPB) (Dendroctonus ponderosae Hopk.) may not be stable throughout an irruptive event. In congeneric beetles, variations in the frequency of their associated organisms affect population trends and similar effects may occur in MPB.We studied fungi and mite trends in a declining irruptive MPB population as it attacked three different pine hosts in the Colorado Front Range. During the study, we found two new associates including one biologically relevant mite and one beneficial blue-stain fungus. Fungi hyperphoretic on mites...

The La Sal daisy, Erigeron mancus, is endemic to treeline ecotone and alpine meadow habitats of the La Sal Mountains in Utah, an insular, laccolithic mountain range on the Colorado Plateau in southeastern Utah. From 2009 to 2011 we established elevational transects through upper spruce-fir forest, treeline ecotone, and alpine meadow habitats on Laurel Ridge in the Middle Mountain group of the La Sal Mountains to measure (1) periodic changes in E. mancus population density, (2) changes in the elevation of the E. mancus population centroid, (3) changes in patch size occupied by E. mancus,...

Environmental DNA (eDNA) sampling - the detection of genetic material in the environment to infer species presence - has rapidly grown as a tool for sampling aquatic animal communities. A potentially powerful feature of environmental sampling is that all taxa within the habitat shed DNA and so may be detectable, creating opportunity for whole‐community assessments. However, animal DNA in the environment tends to be comparatively rare, making it necessary to enrich for genetic targets from focal taxa prior to sequencing. Current metabarcoding approaches for enrichment rely on bulk amplificat...

An integrated approach to understanding ecosystem service values in Wyoming and Montana, USA is presented. The assessment encompasses a major river basin, and includes a synthesis of existing data and research related to the natural system and separate data collection efforts regarding the social and economic importance of ecosystem services. A holistic look at the social-ecological system provides nuanced information about ecosystem service values and tradeoffs for the purpose of public land decision-making.The initial ecological assessment concluded that water resources were particularly...