scholarly journals The Temporal Dynamics of Carbon Dioxide under Snow in a High Elevation Rocky Mountain Subalpine Forest and Meadow

2005 ◽  
Vol 37 (4) ◽  
pp. 527-538 ◽  
Author(s):  
R. C. Musselman ◽  
W. J. Massman ◽  
J. M. Frank ◽  
J. L. Korfmacher
Keyword(s):  
Carbon Dioxide ◽  
Temporal Dynamics ◽  
Rocky Mountain ◽  
High Elevation ◽  
Subalpine Forest

A fire history from tree rings in a high-elevation forest of Rocky Mountain National Park

2004 ◽  
Vol 34 (6) ◽  
pp. 1259-1273 ◽  
Author(s):  
Arne Buechling ◽  
William L Baker
Keyword(s):  
20Th Century ◽  
National Park ◽  
Rocky Mountain ◽  
High Elevation ◽  
Rocky Mountain National Park ◽  
Subalpine Forest ◽  
Summer Drought ◽  
High Severity ◽  
Surface Fires ◽  
Crown Fires

Historical fire patterns in a subalpine forest of Rocky Mountain National Park were quantified from an analysis of forest stand ages and fire-scarred trees. A comparatively detailed sample of 3461 tree cores and 212 fire scars was collected from a 9200-ha study area north of Estes Park, Colorado. A total of 41 fire events were identified in the record. Annually precise fire dates, beginning in 1533, include 22 high-severity crown fires, 7 low-severity surface fires, and 8 mixed-severity events with both surface and crown fire components. Fire rotation was estimated for both surface fires (7587 years) and crown fires (346 years). Fire rotation did not appear to vary with fuel characteristics associated with topographical differences in the study area. Fires larger than 300 ha were few, but they determined a large proportion of the area burned since 1700 and were significantly correlated with a reconstructed index of summer drought. Low fire activity in the 20th century was associated with decreased severity and frequency of drought episodes. Long fire rotations preclude definitive conclusions regarding the effects of fire suppression in the 20th century, but relationships between high-severity fires, fuels, and drought suggest that climatic variability remains the primary influence on fire cycles in high-elevation ecosystems of the southern Rocky Mountains.

Interactions of sapsuckers and Cytospora canker can facilitate decline of riparian willows

Botany ◽  
2014 ◽  
Vol 92 (7) ◽  
pp. 485-493 ◽  
Author(s):  
Kristen M. Kaczynski ◽  
David J. Cooper ◽  
William R. Jacobi
Keyword(s):  
Large Scale ◽  
Temporal Dynamics ◽  
Rocky Mountain ◽  
Aerial Photo ◽  
Stream Flows ◽  
The Past ◽  
Cytospora Chrysosperma ◽  
Willow Bark ◽  
Moose Population ◽  
Cytospora Canker

Drought has caused large-scale plant mortality in ecosystems around the globe. Most diebacks have affected upland forest species. In the past two decades, a large-scale decline of riparian willows (Salix L.) has occurred in Rocky Mountain National Park, Colorado. We examined whether climatic or biotic factors drive and maintain the willow community decline. We compared annual growth and dieback of willows inside and outside of 14-year-old ungulate exclosures and measured groundwater depth and predawn xylem pressures of stems as indicators of drought stress. We also performed an aerial photo analysis to determine the temporal dynamics of the decline. Aerial photo analysis indicated willow decline occurred between 2001 and 2005 and was best explained by an increase in moose population and a decrease in peak stream flows. A new mechanism for willow stem dieback was identified, initiated by red-naped sapsucker wounding willow bark. Wounds became infected with fungus that girdled the stem. DNA analyses confirmed Valsa sordida (Cytospora chrysosperma) as the lethal fungus. Captured sapsuckers had V. sordida spores on feet and beaks identifying them as one possible vector of spread. Predawn xylem pressure potentials remained high through the growing season on all study willows regardless of depth to ground water. Our results indicate that additional mechanisms may be involved in tall willow decline.

scholarly journals Nested Recharge Systems in Mountain Block Hydrology: High-Elevation Snowpack Generates Low-Elevation Overwinter Baseflow in a Rocky Mountain River

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2249
Author(s):  
Éowyn M. S. Campbell ◽  
M. Cathryn Ryan
Keyword(s):  
Rocky Mountain ◽  
High Elevation ◽  
Third Order ◽  
Relative Temperature ◽  
Local Flow ◽  
Fracture Systems ◽  
Lower Elevation ◽  
Flow Systems ◽  
Longitudinal Sampling

The majority of each year′s overwinter baseflow (i.e., winter streamflow) in a third-order eastern slopes tributary is generated from annual melting of high-elevation snowpack which is transmitted through carbonate and siliciclastic aquifers. The Little Elbow River and its tributaries drain a bedrock system formed by repeated thrust faults that express as the same siliciclastic and carbonate aquifers in repeating outcrops. Longitudinal sampling over an 18 km reach was conducted at the beginning of the overwinter baseflow season to assess streamflow provenance. Baseflow contributions from each of the two primary aquifer types were apportioned using sulfate, δ34SSO4, and silica concentrations, while δ18OH2O composition was used to evaluate relative temperature and/or elevation of the original precipitation. Baseflow in the upper reaches of the Little Elbow was generated from lower-elevation and/or warmer precipitation primarily stored in siliciclastic units. Counterintuitively, baseflow generated in the lower-elevation reaches originated from higher-elevation and/or colder precipitation stored in carbonate units. These findings illustrate the role of nested flow systems in mountain block recharge: higher-elevation snowmelt infiltrates through fracture systems in the cliff-forming—often higher-elevation—carbonates, moving to the lower-elevation valley through intermediate flow systems, while winter baseflow in local flow systems in the siliciclastic valleys reflects more influence from warmer precipitation. The relatively fast climatic warming of higher elevations may alter snowmelt timing, leaving winter water supply vulnerable to climatic change.

scholarly journals Two New Late Pleistocene Avifaunas From New Mexico

The Condor ◽  
2006 ◽  
Vol 108 (3) ◽  
pp. 721-730 ◽  
Author(s):  
Rebecka L. Brasso ◽  
Steven D. Emslie
Keyword(s):  
New Mexico ◽  
Great Basin ◽  
Late Pleistocene ◽  
New Records ◽  
Rocky Mountain ◽  
Subalpine Forest ◽  
Radiocarbon Dates ◽  
Aegolius Funereus ◽  
Boreal Owl ◽  
Gymnogyps Californianus

Abstract We report two new late Pleistocene avifaunas from New Mexico, recovered from Sandia Cave during archaeological excavations by F. Hibben in the 1930s and the nearby Marmot Cave excavated in 2000. The fossil assemblage from Sandia Cave consists of at least 30 taxa, including seven extralimital and two extinct species, Coragyps occidentalis (extinct vulture) and Ectopistes migratorius (Passenger Pigeon). The avifauna from Marmot Cave is limited to eight taxa shared with Sandia Cave. Two new records of Gymnogyps californianus (California Condor) are reported from these sites, as well as new records of Lagopus sp. (ptarmigan), Aegolius funereus (Boreal Owl), and Micrathene whitneyi (Elf Owl) from New Mexico. Two new radiocarbon dates on fossil G. californianus from Sandia and Marmot cave are reported at 10 795 ± 50 and 25 090 ± 220 14C years before present (B.P.), respectively. These collections provide further evidence for mixed avian communities in New Mexico during the late Pleistocene and are similar to other cave avifaunas of comparable age from the Great Basin and Rocky Mountain regions. The birds from Sandia Cave that are shared with other fossil avifaunas include species currently found in arctic tundra, boreal, and steppe habitats, as well as open, xeric communities. This collection provides additional evidence for widespread steppe-tundra, shrub, and subalpine forest environments at lower elevations of western North America during the late Pleistocene.

Postglacial vegetation dynamics at high elevation from Fairy Lake in the northern Greater Yellowstone Ecosystem, Montana, USA

2019 ◽  
Vol 92 (2) ◽  
pp. 365-380 ◽  
Author(s):  
James V. Benes ◽  
Virginia Iglesias ◽  
Cathy Whitlock
Keyword(s):  
Fire History ◽  
Late Glacial ◽  
High Elevation ◽  
Subalpine Forest ◽  
Greater Yellowstone Ecosystem ◽  
Southwestern Montana ◽  
History Of ◽  
Greater Yellowstone ◽  
High Elevations ◽  
Early Late

AbstractThe postglacial vegetation and fire history of the Greater Yellowstone Ecosystem is known from low and middle elevations, but little is known about high elevations. Paleoecologic data from Fairy Lake in the Bridger Range, southwestern Montana, provide a new high-elevation record that spans the last 15,000 yr. The records suggest a period of tundra-steppe vegetation prior to ca. 13,700 cal yr BP was followed by open Picea forest at ca. 11,200 cal yr BP. Pinus-Pseudotsuga parkland was present after ca. 9200 cal yr BP, when conditions were warmer/drier than present. It was replaced by mixed-conifer parkland at ca. 5000 cal yr BP. Present-day subalpine forest established at ca. 2800 cal yr BP. Increased avalanche or mass-wasting activity during the early late-glacial period, the Younger Dryas chronozone, and Neoglaciation suggest cool, wet periods. Sites at different elevations in the region show (1) synchronous vegetation responses to late-glacial warming; (2) widespread xerothermic forests and frequent fires in the early-to-middle Holocene; and (3) a trend to forest closure during late-Holocene cooling. Conditions in the Bridger Range were, however, wetter than other areas during the early Holocene. Across the Northern Rockies, postglacial warming progressed from west to east, reflecting range-specific responses to insolation-driven changes in climate.

The contribution of beneath-snow soil respiration to total ecosystem respiration in a high-elevation, subalpine forest

2006 ◽  
Vol 20 (3) ◽  
pp. n/a-n/a ◽  
Author(s):  
Russell K. Monson ◽  
Sean P. Burns ◽  
Mark W. Williams ◽  
Anthony C. Delany ◽  
Michael Weintraub ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Ecosystem Respiration ◽  
High Elevation ◽  
Subalpine Forest ◽  
Total Ecosystem Respiration

Disturbance Regime and Disturbance Interactions in a Rocky Mountain Subalpine Forest

1994 ◽  
Vol 82 (1) ◽  
pp. 125 ◽  
Author(s):  
Thomas T. Veblen ◽  
Keith S. Hadley ◽  
Elizabeth M. Nel ◽  
Thomas Kitzberger ◽  
Marion Reid ◽  
...  
Keyword(s):  
Rocky Mountain ◽  
Subalpine Forest ◽  
Disturbance Regime ◽  
Disturbance Interactions

scholarly journals Soil, plant, and transport influences on methane in a subalpine forest under high ultraviolet irradiance

2009 ◽  
Vol 6 (7) ◽  
pp. 1311-1324 ◽  
Author(s):  
D. R. Bowling ◽  
J. B. Miller ◽  
M. E. Rhodes ◽  
S. P. Burns ◽  
R. K. Monson ◽  
...  
Keyword(s):  
High Elevation ◽  
Subalpine Forest ◽  
Atmospheric Methane ◽  
Vegetation Canopy ◽  
Conifer Forest ◽  
Uv Irradiance ◽  
Plant Foliage ◽  
Net Uptake ◽  
Scalar Similarity ◽  
Ultraviolet Irradiance

Abstract. Recent studies have demonstrated direct methane emission from plant foliage under aerobic conditions, particularly under high ultraviolet (UV) irradiance. We examined the potential importance of this phenomenon in a high-elevation conifer forest using micrometeorological techniques. Vertical profiles of methane and carbon dioxide in forest air were monitored every 2 h for 6 weeks in summer 2007. Day to day variability in above-canopy CH4 was high, with observed values in the range 1790 to 1910 nmol mol−1. High CH4 was correlated with high carbon monoxide and related to wind direction, consistent with pollutant transport from an urban area by a well-studied mountain-plain wind system. Soils were moderately dry during the study. Vertical gradients of CH4 were small but detectable day and night, both near the ground and within the vegetation canopy. Gradients near the ground were consistent with the forest soil being a net CH4 sink. Using scalar similarity with CO2, the magnitude of the summer soil CH4 sink was estimated at ~1.7 mg CH4 m−2 h−1, which is similar to other temperate forest upland soils. The high-elevation forest was naturally exposed to high UV irradiance under clear sky conditions, with observed peak UVB irradiance >2 W m−2. Gradients and means of CO2 within the canopy under daytime conditions showed net uptake of CO2 due to photosynthetic drawdown as expected. No evidence was found for a significant foliar CH4 source in the vegetation canopy, even under high UV conditions. While the possibility of a weak foliar source cannot be excluded given the observed soil sink, overall this subalpine forest was a net sink for atmospheric methane during the growing season.

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