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Future drought is projected to occur under warmer temperature conditions as climate change progresses, referred to here as global-change-type drought, yet quantitative assessments of the triggers and potential extent of drought-induced vegetation die-off remain pivotal uncertainties in assessing climate-change impacts. Of particular concern is regional-scale mortality of overstory trees, which rapidly alters ecosystem type, associated ecosystem properties, and land surface conditions for decades. Here, we quantify regional-scale vegetation die-off across southwestern North American woodlands in 2002-2003 in response to drought and associated bark beetle infestations. At an intensively studied site within the region,...
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Six large wildfires have burned in Mesa Verde National Park during the last 15 years, and extensive portions of burns were invaded by non-native plant species. The most threatening weed species include Carduus nutans, Cirsium arvense, and Bromus tectorum, and if untreated, they persist at least 13 years. We investigated patterns of weed distribution to identify plant communities most vulnerable to post-fire weed invasion and created a spatially explicit model to predict the most vulnerable sites. At the scale of the entire park, mature pi�on?juniper woodlands growing on two soil series were most vulnerable to post-fire weed invasion; mountain shrublands were the least vulnerable. At a finer scale, greater richness...
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Aspen exhibits a variety of ecological roles. In southern Colorado, the 1880 landscape mosaic contained a range of stand ages, of which half were >70 years old and half were younger. Pure aspen stands in southern Colorado are widespread and may result from previous short fire intervals that eliminated local conifer seed sources. Aspen regeneration in northern Yellowstone Park is controlled by ungulate browsing pressure and fire, so it has been limited since 1920. However, an episode of aspen seedling establishment occurred after the 1988 fires. We urgently need additional detailed, local case studies of aspen ecology to inform management decisions. Published in Sustaining Aspen in Western Landscapes: Symposium Proceedings,...
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Understanding the effect of variation in climate on large-fire occurrence across broad geographic areas is central to effective fire hazard assessment. The El Nin?o? Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) affect winter temperature and precipitation regimes in western North America through mid-latitude teleconnections. This study examines relationships of ENSO and the PDO to drought-induced fire occurrence in subalpine forests of three study areas across the Rocky Mountains: Jasper National Park (JNP, northern Rockies), Yellowstone National Park (YNP, central Rockies) and Rocky Mountain National Park (RMNP, southern Rockies) over the 1700?1975 period. Large-scale climatic anomalies...
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Fire severity, frequency, and extent are expected to change dramatically in coming decades in response to changing climatic conditions, superimposed on the adverse cumulative effects of various human-related disturbances on ecosystems during the past 100 years or more. To better gauge these expected changes, knowledge of climatic and human influences on past fire regimes is essential. We characterized the temporal and spatial properties of fire regimes in ponderosa pine forests of the southern San Juan Mountains of southwestern Colorado by collecting 175 fire-scarred tree samples from nine sites across a wide range of topographic settings. All tree rings and fire scars were dated using standard dendrochronological...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Colorado,
Ecological Society of America,
Ecology,
San Juan Mountains,
USA, All tags...
climate-fire interactions,
dendrochronology,
disturbances,
fire,
fire history,
human,
mixed conifer,
ponderosa pine,
regimes, Fewer tags
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