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Human activities have caused the decline of numerous species and ecosystems. To promote ecosystem resilience, recent management efforts aim to maintain ecosystem patterns and processes within their historical range of variability. There has been substantial concern that quaking aspen, the most widely distributed tree in North America and the most important deciduous tree in the subalpine forests of the Rocky Mountains, has declined significantly in the western landscape during the 20th century. This reported decline has been attributed to conifer encroachment associated with fire exclusion, as well as other causes. To assess long-term changes in the extent of quaking aspen in a 175000-ha study area in western Colorado,...
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Historical disturbance regimes are often considered a critical element in maintaining native plant communities. However, the response of plant communities to disturbance may be fundamentally altered as a consequence of invasive plants, climate change, or prior disturbances. The appropriateness of historical disturbance patterns under modern conditions and the interactions among disturbances are issues that ecologists must address to protect and restore native plant communities. We evaluated the response of Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh plant communities to their historical disturbance regime compared to other disturbance regimes. The historical disturbance regime of these...
Desert grasslands, which are very sensitive to external drivers like climate change, are areas affected by rapid land degradation processes. In many regions of the world the common form of land degradation involves the rapid encroachment of woody plants into desert grasslands. This process, thought to be irreversible and sustained by biophysical feedbacks of global desertification, results in the heterogeneous distribution of vegetation and soil resources. Most of these shrub-grass transition systems at the desert margins are prone to disturbances such as fires, which affect the interactions between ecological, hydrological, and land surface processes. Here we investigate the effect of prescribed fires on the landscape...
The global mean surface temperature increased 0.85°C during the period 1880 – 2012. Some climate models predict an additional warming of up 2 to 4 ◦ C over the next 100 years for the primary breeding grounds for North American ducks. Such an increase has been predicted to reduce mid - continent breeding duck populations by >70%. Managing continental duck populations in the face of climate change requires understanding how waterfowl have responded to historical spatio - temporal climatic variation. However, such responses to climate may be obscured by how ducks respond to variation in land cover. We estimated effects of climate on settlement patterns of breeding ducks in the Prairie - Parkland Region (PPR), boreal...
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Grasslands comprise a small part of the Chihuahuan Desert but are vital to the biological diversity of the ecoregion. Characteristic grasses of the Chihuahuan Desert are tobosa (Pleuraphis mutica) and black grama (Bouteloua eriopoda) but other common species include alakali sacaton (Sporobolus airoides), big alkali sacaton (S. wrightii), mesa dropseed (S. flexuosus), blue grama (B. gracilis), sideoats grama (B. curtipendula ), hairy grama (B. hirsuta), slender grama (B. filiformis), chino grama (B. brevista), spruce top grama (B. chondrosioides), bush muhly (Muhlenbergia porteri), several three awns (Aristida spp.), and fluff grass (Dasyochloa pulchela) (Johnson 1974, Dinerstein et al. 2000). Many of the sites discussed...
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This file represents the final version of an assessment of the extent, condition, and distribution of grassland types in Arizona as indicated by expert interviews and field verification. Coverage includes the state of Arizona, Southwestern portions of the state of New Mexico, and the Northern portion of Sonora, Mexico.
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Final Report - Executive Summary: This final project report is prepared to summarize the research project titled “Assessing evapotranspiration rate changes for proposed restoration of the forested uplands of the Desert Landscape Conservation Cooperatives (LCC)” for the Desert LCC of the Bureau of Reclamation as a requirement for closing out the project. This report includes the scope of work, summary of research project, results, and conclusions.Among all of the components of the terrestrial water cycle, evapotranspiration (ET) consumes the largest amount of water. Accurate estimation of ET is very important to understand the influence of ET to the hydrologic response of recharge and runoff processes in the water...
Categories: Data, Publication; Types: Citation, Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: 2012, ATMOSPHERE, ATMOSPHERE, ATMOSPHERIC WATER VAPOR, ATMOSPHERIC WATER VAPOR, All tags...
Abstract (from http://www.bioone.org/doi/abs/10.3417/2017006): The Earth system is undergoing rapid, profound anthropogenic change. The primary axes of change include not only the climate system, but also the spread of invasive species, altered biogeochemical and hydrological cycles, modified disturbance regimes, and land degradation and conversion. These factors are influencing the distribution of species and the structure and function of ecosystems worldwide, interacting with climatic stressors that may preclude the persistence of many current species distributions and communities. Ecological disturbances such as wildfires and insect outbreaks can interact with climate variability to precipitate abrupt change...
Abstract (from SpringerOpen): Wildfires in the Pacific Northwest (Washington, Oregon, Idaho, and western Montana, USA) have been immense in recent years, capturing the attention of resource managers, fire scientists, and the general public. This paper synthesizes understanding of the potential effects of changing climate and fire regimes on Pacific Northwest forests, including effects on disturbance and stress interactions, forest structure and composition, and post-fire ecological processes. We frame this information in a risk assessment context, and conclude with management implications and future research needs. Large and severe fires in the Pacific Northwest are associated with warm and dry conditions, and such...
Abstract (from http://onlinelibrary.wiley.com/doi/10.1002/gdj3.47/abstract): Two datasets of soil temperature observations collected at Norman, Oklahoma, USA, were analysed to study horizontal and vertical variability in their observations. The first dataset comprised 15-min resolution soil temperature observations from 20 September 2011 to 18 November 2013 in seven plots across a 10-m transect. In each plot, sensors were located at depths of 5, 10, and 30 cm. All seven plots observed fairly consistent maximum soil temperature observations during the spring, fall, and winter months. Starting in late May, the observed spread in soil temperatures across the 10-m transect increased significantly until August when the...
A warming climate, fire exclusion, and land cover changes are altering the conditions that produced historical fire regimes and facilitating increased recent wildfire activity in the northwestern United States. Understanding the impacts of changing fire regimes on forest recruitment and succession, species distributions, carbon cycling, and ecosystem services is critical, but challenging across broad spatial scales. One important and understudied aspect of fire regimes is the unburned area within fire perimeters; these areas can function as fire refugia across the landscape during and after wildfire by providing habitat and seed sources. With increasing fire activity, there is speculation that fire intensity and...
Wildfire refugia are forest patches that are minimally-impacted by fire and provide critical habitats for fire-sensitive species and seed sources for post-fire forest regeneration. Wildfire refugia are relatively understudied, particularly concerning the impacts of subsequent fires on existing refugia. We opportunistically re-visited 122 sites classified in 1994 for a prior fire refugia study, which were burned by two wildfires in 2012 in the Cascade mountains of central Washington, USA. We evaluated the fire effects for historically persistent fire refugia and compared them to the surrounding non-refugial forest matrix. Of 122 total refugial (43 plots) and non-refugial (79 plots) sites sampled following the 2012...
Abstract (from http://link.springer.com/article/10.1007%2Fs10980-015-0160-1): Content Changing aspen distribution in response to climate change and fire is a major focus of biodiversity conservation, yet little is known about the potential response of aspen to these two driving forces along topoclimatic gradients. Objective This study is set to evaluate how aspen distribution might shift in response to different climate-fire scenarios in a semi-arid montane landscape, and quantify the influence of fire regime along topoclimatic gradients. Methods We used a novel integration of a forest landscape succession and disturbance model (LANDIS-II) with a fine-scale climatic water deficit approach to simulate dynamics of...
Public Summary: The area burned by wildfires is expected to increase in many watersheds of the world over the next century as a function of climate change. Increased sedimentation due to soil erosion in burned watersheds can negatively impact downstream aquatic ecosystems and the quality and supply of water. At least 65% of the water supply in the western USA originates in watersheds covered by trees, shrubs, and/or grasses that are prone to wildfire16. Understanding how changing fire frequency, extent, and location will affect watersheds, reservoirs, and the ecosystem services they supply to communities is therefore of great societal importance. A primary threat to socio-ecological systems in this region from...
Abstract (from http://www.publish.csiro.au/WF/WF16165): Interannual variability in burn severity is assessed across forested ecoregions of the western United States to understand how it is influenced by variations in area burned and climate during 1984–2014. Strong correlations (|r| > 0.6) between annual area burned and climate metrics were found across many of the studied regions. The burn severity of individual fires and fire seasons was weakly, but significantly (P < 0.05), correlated with burned area across many regions. Interannual variability in fuel dryness evaluated with fuel aridity metrics demonstrated weak-to-moderate (|r| >0.4) relationships with regional burn severity, congruent with but weaker than...
Ceratoides lanata (Rydb.) J.T. Howell, common winterfat, is valued for its nutrient content and palatability to livestock; however, the subspecies Ceratoides lanata var. subspinosa (Rydb.) J.T. Howell, (‘subspinosa’) is considered unpalatable. Curiously, observations of ‘subspinosa’ revealed several populations in central New Mexico that were heavily grazed. Volatile terpene profiles are associated with differences in palatability in many plant species. To determine whether differences in volatile profiles between ‘subspinosa’ populations would correlate with apparent differences in palatability, plants from 13 populations of ‘subspinosa’ were collected. Volatile analysis of shoot samples identified 33 compounds....
Hanging garden plant communities form at seeps on cliffs. A given community may include common riparian species, disjunct populations, and species endemic to hanging gardens. What structures hanging harden communities, and how they respond to disturbance are poorly understood. In 1989, fireworks ignited a hanging garden in Knowles Cañon, destroying aboveground vegetation. Permanent plots were established in July 1993 to monitor changes in vegetation and soil biota. Revegetation of the garden has been limited to grasses, forbs, and ferns where water was present at the soil surface, and shrubs and trees sprouting from surviving rootstocks. Water drips from the overhanging cliff in the central area, where plant cover...
Hanging garden plant communities form at seeps on cliffs. A given community may include common riparian species, disjunct populations, and species endemic to hanging gardens. What structures hanging harden communities, and how they respond to disturbance are poorly understood. In 1989, fireworks ignited a hanging garden in Knowles Cañon, destroying aboveground vegetation. Permanent plots were established in July 1993 to monitor changes in vegetation and soil biota. Revegetation of the garden has been limited to grasses, forbs, and ferns where water was present at the soil surface, and shrubs and trees sprouting from surviving rootstocks. Water drips from the overhanging cliff in the central area, where plant cover...
map background search result map search result map Interaction of historical and nonhistorical disturbances maintains native plant communities The Knowles Cañon Hanging Garden, Glen Canyon National Recreation Area, Five Years after Burning: Vegetation and Soil Biota Patterns Extent and Condition of Grasslands in Arizona, Northern Mexico, and Southwestern New Mexico Status and Distribution of Chihuahuan Desert Grasslands in the United States and Mexico Report and Publications: Assessing Evapotranspiration Rate Changes for Proposed Restoration of the Forested Uplands of the DLCC Interaction of historical and nonhistorical disturbances maintains native plant communities Report and Publications: Assessing Evapotranspiration Rate Changes for Proposed Restoration of the Forested Uplands of the DLCC Extent and Condition of Grasslands in Arizona, Northern Mexico, and Southwestern New Mexico Status and Distribution of Chihuahuan Desert Grasslands in the United States and Mexico