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Evidence from woodrat middens and tree rings at Dutch John Mountain (DJM) in northeastern Utah reveal spatiotemporal patterns of pinyon pine (Pinus edulis Engelm.) colonization and expansion in the past millennium. The DJM population, a northern outpost of pinyon, was established by long-distance dispersal (approximately 40 km). Growth of this isolate was markedly episodic and tracked multidecadal variability in precipitation. Initial colonization occurred by AD 1246, but expansion was forestalled by catastrophic drought (1250-1288), which we speculate produced extensive mortality of Utah Juniper (Juniperus osteosperma (Torr.) Little), the dominant tree at DJM for the previous approximately 8700 years. Pinyon then...
Evidence from woodrat middens and tree rings at Dutch John Mountain (DJM) in northeastern Utah reveal spatiotemporal patterns of pinyon pine (Pinus edulis Engelm.) colonization and expansion in the past millennium. The DJM population, a northern outpost of pinyon, was established by long-distance dispersal (approximately 40 km). Growth of this isolate was markedly episodic and tracked multidecadal variability in precipitation. Initial colonization occurred by AD 1246, but expansion was forestalled by catastrophic drought (1250-1288), which we speculate produced extensive mortality of Utah Juniper (Juniperus osteosperma (Torr.) Little), the dominant tree at DJM for the previous approximately 8700 years. Pinyon then...
Cheatgrass, a non-native annual grass, dominates millions of hectares in semiarid ecosystems of the Intermountain West (USA). Post-fire invasions can reduce native species diversity and alter ecological processes. To curb cheatgrass invasion, land managers often seed recently burned areas with perennial competitor species. We sampled vegetation within burned (19 years post-fire) and nearby unburned (representing pre-fire) pi onjuniper (Pinus edulisJuniperus osteosperma) woodland and sagebrush (Artemisia sp.) in western Colorado to analyze variables that might explain cheatgrass cover after fire. A multiple regression model suggests higher cheatgrass cover after fire with: (1) sagebrush v. pi onjuniper; (2) higher...
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Herbivore alteration of litter inputs may change litter decomposition rates and influence ecosystem nutrient cycling. In a semiarid woodland at Sunset Crater National Monument, Arizona, long-term insect herbivore removal experiments and the presence of herbivore resistant and susceptible pinyon pines (Pinus edulis) have allowed characterization of the population- and community-level effects of herbivory. Here we report how these same two herbivores, the mesophyll-feeding scale insect Matsucoccus acalyptus and the stem-boring moth Dioryctria albovittella alter litter quality, dynamics, and decomposition in this ecosystem. We measured aboveground litterfall, litter chemical composition, and first-year litter decomposition...
The Colorado River Basin has been, and continues to be, the focus of a wide diversity of research efforts to learn more about the effects of natural and human-induced disturbances on the processes and functioning of the basin's upland watersheds. These watersheds are situated at the headwaters of streams and rivers that supply much of the water to downstream users in the western United States. Responses of streamflow to vegetation manipulations have been, and are, one of the research foci in this water-deficient part of the country. The watershed-scale research, led by the U.S. Forest Service and its cooperators, has spanned nearly a century and included an array of vegetation types along a wide range of precipitation...
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These data are species distribution information assembled for assessing the impacts of land-use barriers, facilitative interactions with other species, and loss of long-distance animal dispersal on predicted species range patterns for four common species in pinyon-juniper woodlands in the western United States. The layers in the data release are initial distribution records of two kinds: point occurrence records and a raster layer for the general vegetation types where the species is a co-dominant, compiled from other sources. Both types of data are the baseline information in species distribution models for the associated publication.


    map background search result map search result map Insect Herbivory Increases Litter Quality and Decomposition: An Extension of the Acceleration Hypothesis Occurrence records and vegetation type data used for species distribution models in the western United States Insect Herbivory Increases Litter Quality and Decomposition: An Extension of the Acceleration Hypothesis Occurrence records and vegetation type data used for species distribution models in the western United States