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Male boreal toads (Bufo boreas) are thought to return to the breeding site every year but, if absent in a particular year, will be more likely to return the following year. Using Pollock's robust design we estimated temporary emigration (the probability a male toad is absent from a breeding site in a given year) at three locations in Colorado, USA: two in Rocky Mountain National Park and one in Chaffee County. We present data that suggest that not all male toads return to the breeding site every year. Our analyses indicate that temporary emigration varies by site and time (for example, from 1992 to 1998, the probability of temporary emigration ranged from 10% to 29% and from 3% to 95% at Lost Lake and Kettle Tarn,...
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,...
Twelve northern desert shrub communities having the same macroclimate but differing habitats were studies. Arranged in order of decreasing production of live stems plus current growth, the communities were: (1) Sarcobatus vermiculatus (9,172 kg/ha), (2) Grayia spinosa (7,412 kg/ha), (3) Artemisia tridentata (5,474 kg/ha), (4) Chrysothamnus nauseosus (4,836 kg/ha), (5) Atriplex confertifolia (3,194 kg/ha), (6) Eurotia lanata (2,026 kg/ha), (7) Hilaria jamesii-Atriplex confertifolia (1,995 kg/ha), (8) Atriplex corrugata (1,949 kg/ha), (9) Chrysothamnus greenii filifolius (1,866 kg/ha), (10) Atriplex nuttallii (1,309 kg/ha), (11) Elymus salinus (865 kg/ha), and (12) Tetradymia spinosa (564 kg/ha). The communities were...
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This study examines the establishment patterns of exotic and ruderal species along trail corridors in grassland areas of the Colorado Front Range. The effects of trail presence, trail age, and trail traffic levels on exotic and ruderal species establishment are explored to ascertain the potential impacts of trails on surrounding vegetation. Established trails exhibited a greater presence of exotic and ruderal species along the immediate trailside, showing that disturbed trailsides tend to encourage the growth of these species over time. Furthermore, the established trails exhibited significantly less native, nonruderal, and overall species richness at the trailside. These trailside patterns did not show a significant...
Areas occupied by white-tailed prairie dogs (WTPD; Cynomys leucurus) and Gunnison's prairie dogs (GPD; C. gunnisoni) are not well-known in Colorado (USA) and elsewhere. Suitable methodology for monitoring changes in populations of WTPD and GPD over broad areas also has not been well established. We evaluated occupancy modeling methodology to establish baseline occupancy rates for WTPD and GPD in Colorado. We estimated that WTPD occupied 24.1% (SE = 12.8) of 47,710 0.25-km2 plots and GPD occupied 7.5% (SE = 1.3) of 158,225 0.25-km2 plots in Colorado during 2004 and 2005. Areas reported as colonies in the Colorado Division of Wildlife's database were not good predictors of WTPD and GPD occupancy. Occupancy rates were...
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Forests of the southern Rocky Mountains are punctuated by persistent meadows called parks that are dominated by grasses and forbs. In an attempt to elucidate the maintenance of subalpine parks in the Gunnison Basin, Colorado, soil texture and tree morphology differences along 60-m transects spanning the forest-park ecotone were studied in 6 representative parks. Seedling survivorship, percent seed germination, and soil moisture available to plants were also studied along one of the transects in Willow Park. Soil analyses revealed 40% more silt and significantly less sand and clay in all 6 parks (P < 0.001), which supports the traditional hypotheses that edaphic factors are involved in restricting establishment of...
We quantified annual sediment deposition, bank erosion, and sediment budgets in nine riverine wetlands that represented a watershed continuum for 1 year in the unregulated Yampa River drainage basin in Colorado. One site was studied for 2 years to compare responses to peak flow variability. Annual mean sediment deposition ranged from 0.01 kg/m(2) along a first-order subalpine stream to 21.8 kg/m(2) at a sixth-order alluvial forest. Annual mean riverbank erosion ranged from 3 kg/m-of-bank at the first-order site to 1000 kg/m at the 6(th)-order site. Total sediment budgets were nearly balanced at six sites, while net export from bank erosion occurred at three sites. Both total sediment deposition (R(2) = 0.86, p <...
A new species of poplar is recognized based on abundant specimens from the early Middle Eocene Parachute Creek Member of the Green River Formation in eastern Utah and western Colorado and compared with two other contemporary species. A rare twig bearing both leaves and fruits serves as a Rosetta stone, linking the vegetative and reproductive structures that formerly were only known from dispersed organs. Fruit and foliage characters distinguish Populus tidwellii sp. n. from Populus cinnamomoides (Lesquereux) MacGinitie (typified on specimens from Green River Station, WY), to which the isolated leaves had formerly been attributed. In addition, new data from fruits and foliage confirm that there were two distinct...
Wildlife managers in northwestern Colorado have had difficulty accurately estimating numbers of subadult male elk (Cervus elaphus) by sampling winter population densities and sex ratios. We investigated emigration and survival of telemetered 2-year-old male elk in a trophy hunting area in a northwestern Colorado Game Management Unit (GMU) to evaluate management strategies. We hypothesized that skewed numbers of males resulted from high subadult mortality or dispersal of subadult males. We used telemetered elk and Kaplan-Meier staggered entry methods to estimate emigration probability of 0.56 and 0.33 in 1995 and 1996, respectively. Maximum distances moved by emigrants from their capture point averaged 87 km (median...
Sixteen species of Haliplidae belonging to three genera are recorded from Colorado: *Brychius hornii Crotch, Peltodytes callosus (LeConte), P. edentulus (LeConte), *P. litoralis Matheson, *Haliplus apicalis C.G. Thomson, *H. canadensis Wallis, H. cribrarius LeConte, H. deceptus Matheson, *H. distinctus Wallis, H. fulvus Fabricius, H. immaculicollis Harris, H. leechi Wallis, H. longulus LeConte, *H. stagninus Leech, *H. tortilipenis Brigham and Sanderson, and H. triopsis Say. Seven of these species (*) represent new state records, and H. distinctus is reported from the United States for the first time. Haliplids found in Colorado generally fit one of the following distributional patterns for North America: Western,...
In the northern Colorado Front Range, fire suppression during the 20th century is believed to have created a high hazard of catastrophic fire in ponderosa pine (Pinus ponderosa) forests. Since the early 1990s, resource managers have increased the use of prescribed fires to re-create fire regimes and forest structures similar to those of the pre-Euro-American settlement period in order both to reduce fire hazard and to improve forest health. To improve understanding of historical fire regimes, we conducted a study of fire history along an elevational gradient from \sim1830 to 2800 m in ponderosa pine forests in the northern Front Range. Fire-scar dates were determined from 525 partial cross sections from living and...
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Stream fragmentation alters the structure of aquatic communities on a global scale, generally through loss of native species. Among riverscapes in the Great Plains of North America, stream fragmentation and hydrologic alteration (flow regulation and dewatering) are implicated in the decline of native fish diversity. This study documents the spatio–temporal distribution of fish reproductive guilds in the fragmented Arkansas and Ninnescah rivers of south-central Kansas using retrospective analyses involving 63 years of fish community data. Pelagic-spawning fishes declined throughout the study area during 1950–2013, including Arkansas River shiner (Notropis girardi) last reported in 1983, plains minnow (Hybognathus...
Categories: Data, Publication; Types: Citation, Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: CATFISHES/MINNOWS, Colorado, Colorado, FISH, Federal resource managers, All tags...
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We used the United States National Grid to develop a sampling grid for monitoring programs in the Great Plains Landscape Conservation Cooperative, delineated by Bird Conservation Regions 18 and 19. Landscape Conservation Cooperatives are science based partnerships with the goal to inform and guide conservation at regional landscape levels. Developing a standardized sampling grid for a LCC is a new endeavor and is designed to reduce program costs, avoid repetition in sampling, and increase efficiency in monitoring programs. This is possible because the grid’s nationwide coverage, uniform starting point, and scalability allow researchers to expand their monitoring programs from a small, local level to a regional or...
We estimated survival rates of greater sage-grouse (Centrocercus urophasianus) in North Park, Colorado, USA, from band-recovery data of 6,021 birds banded during spring, 1973-1990, with recoveries through 1993. Average annual adult female survival ((S) over bar = 0.59, SE = 0.011) was greater than average adult male survival ((S) over bar = 0.37, SE = 0.007), and average subadult (<1 yr old at time of banding) female survival ((S) over bar = 0.77, SE = 0.030) was greater than average subadult male survival ((S) over bar = 0.63, SE = 0.034). Four weather covariates (spring and winter precipitation and temperature) did not contribute to predicting annual survival. Published in Journal of Wildlife Management, volume...
We conducted a 2-year field experiment to determine whether archery and muzzleloading hunting seasons caused elk to move prematurely onto private land during late summer. The study site was divided into north and south areas, and each area received both an early- and late-opening treatment. Early-opening treatment was an archery season that opened 1 week earlier (23 Aug) than the historical opening, and late-opening treatment was an archery season that opened 2 weeks later (13 Sep), yielding a 21-day difference in opening dates. We relocated 80 radiocollared female elk, captured at random locations on summer ranges, approximately 2 times per week for a 3-month period surrounding early- and late-opening dates each...
The energy consumption and fossil CO2 emissions from the Canadian vegetable greenhouse industry were assessed using greenhouse statistics from 2002 to 2007. The fossil CO2 emissions were compared to the fossil CO2 emitted during transport of an equal weight of food by truck and by airplane from two horticultural production centers in the southern USA to four locations in Canada. The calculations in this paper for Canadian greenhouse energy use for heating were verified against farm energy use survey data collected from greenhouse operators in 1996. Allowing for extrapolations to 1996 from the 2002 to 2007 period, the survey data were underestimated by 12%. Since the survey data were not corrected for possible household...
We surveyed a discrete population of Mountain Plovers (Charadrius montanus) in South Park, Park County, Colorado, to determine the size and relative contribution of this geographically isolated area to the global population of plovers. First, we mapped potential plover habitat within South Park based on landform and vegetation descriptors. Second, we identified occupied habitat using observations from a systematic inventory of potential habitat from 1995-1999 and from a study of breeding biology from 2000-2002. Third, we estimated breeding densities within a framework designed specifically for distance sampling. We mapped 82750 ha of potential habitat. We recorded 2516 plover locations from which we estimated 29...
Distributional patterns and species diversity of benthic insects in an alpine stream in Gunnison County, Colorado, USA were investigated on several levels of spatial scale, from faunal replacement over 1,000 vertical m to microdistribution within the stony substratum. Ecotones including zonation in terrestrial vegetation and in trout distribution did not appear to affect faunal replacement. Competition among congeners accounted for 7-30% of the cases, while in the majority of species, faunal replacement appeared to be associated with gradual changes in the physical gradient. Trout zonation may affect total numbers of insects, however, as the trout-free headwaters had two to six times higher insect densities. Microdistribution...
The ability to apply a hydrologic model to large numbers of basins for forecasting purposes requires a quick and effective calibration strategy. This paper presents a step wise, multiple objective, automated procedure for hydrologic model calibration. This procedure includes the sequential calibration of a model's simulation of solar radiation (SR), potential evapotranspiration (PET), water balance, and daily runoff. The procedure uses the Shuffled Complex Evolution global search algorithm to calibrate the U.S. Geological Survey's Precipitation Runoff Modeling System in the Yampa River basin of Colorado. This process assures that intermediate states of the model (SR and PET on a monthly mean basis), as well as the...
Decomposition of grass leaf litter was studied on a shortgrass prairie using chemicals (HgCl2 and CuSO4) to prevent microbial activity (abiotic treatment), 53??m nylon mesh to exclude mesofauna (microbial treatment), and l?mm nylon mesh to allow the access of mesofauna. After 9 months, 15.2% of the blue grama grass litter was decomposed in the microbial treatment, and 29.4% was decomposed in the microbial plus mesofaunal treatment. After 7 months, 6.2% of the litter had disappeared from the abiotic treatment. There was a general decrease in C:N ratios with the microbial treatment lowest at the end of the experiment. Total available carbohydrates generally decreased with time. Certain mite families fluctuated with...
map background search result map search result map Impacts of recreation trails on exotic and ruderal species distribution in grassland areas along the Colorado Front Range. Persistence of subalpine forest--meadow ecotones in the Gunnison Basin, Colorado Publication: Fragmentation and drying ratchet down Great Plains stream fish diversity Final Report: Integrated monitoring within BCR’s: Creating a wildlife monitoring grid for the GPLCC Impacts of recreation trails on exotic and ruderal species distribution in grassland areas along the Colorado Front Range. Persistence of subalpine forest--meadow ecotones in the Gunnison Basin, Colorado Publication: Fragmentation and drying ratchet down Great Plains stream fish diversity Final Report: Integrated monitoring within BCR’s: Creating a wildlife monitoring grid for the GPLCC