Skip to main content
Advanced Search

Filters: Tags: dispersal (X)

37 results (14ms)   

Filters
Contacts (Less)
View Results as: JSON ATOM CSV
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...
Bryophytes disperse by small unicellular spores between 7 ?m und usually less than 100 ?m. A large percentage of species is sterile and propagates vegetatively either by special brood bodies or fragments of whole plants. It is shown that there is no difference in the effectiveness between generative and vegetative propagation. Size and weight of the diaspores suggest that both must easily be dispersed and the species must therefore have wide ranges. This does, however, not result in ubiquitous occurrence. This is only true for part of the species. Many, even sterile species show wide transcontinental ranges. On the other hand, there are many examples of limited to very limited distribution in spite of a rich production...
The present distribution of the Mexican vole (Microtus mexicanus) is not entirely the product of post-Pleistocene forest fragmentation and extinction; recent dispersal also is indicated. Literature records further suggest that this phenomenon may reflect a general pattern of northward range expansion in many southwestern mammal species. Published in Western North American Naturalist, volume 52, issue 3, in 1992.
thumbnail
These bat location estimates have been reported by Bogan and others (In press) and come in the form of a GIS shape file. Three species of nectar-feeding phyllostomid bats migrate north from Mexico into deserts of the United States (U.S.) each spring and summer to feed on blooms of columnar cacti and century plants (Agave spp). However, the habitat needs of these important desert pollinators are poorly understood. We followed the nighttime movements of two species of long-nosed bats (Leptonycteris yerbabuenae and L. nivalis) in an area of late-summer sympatry at the northern edges of their migratory ranges. We radiotracked bats in extreme southwestern New Mexico during 22 nights over two summers and acquired location...
thumbnail
The Randomized Shortest Path (RSP) raster delineates potential dispersal paths for male-mediated gene flow between grizzly bear (Ursus arctos) populations in the Greater Yellowstone Ecosystem (GYE) and the Northern Continental Divide Ecosystem (NCDE). A RSP algorithm was used to estimate the average number of net passages for all grid cells at a spatial resolution of 300 m in the study region which spans parts of Montana, Idaho, and Wyoming. RSP rasters identify potential movement paths for 3 levels of random deviation determined by the parameter Θ (i.e., Θ = 0.01, 0.001, and 0.0001) for bears moving from an origin to a destination node. Lower values of Θ result in greater exploration and more random deviation around...
thumbnail
Montane Conifer Connectivity of areas of high elevation and high human footprint in the North Pacific Landscape Conservation Cooperative study area. This application provides Montane Conifer Connectivity for 2000 and 2080 (A1B).The three primary geospatial layers used in this analysis were a digital elevation model (DEM), a vegetation layer, and a human footprint layer. Due to the geographic extent of the North Pacific Landscape Conservation Cooperative, digital elevation models from different sources had to be used to create one seamless DEM. The digital elevation models were obtained from the Shuttle Radar Topography Mission (SRTM), the United States Geologic Survey, and the Government of the Yukon Territory....
thumbnail
Overview Land and resource managers in the North Pacific Landscape Conservation Cooperative (NPLCC) currently lack conservation planning tools that can directly feed into the planning, design, delivery, and monitoring of ecosystems across all levels of biodiversity from genes to ecosystems. The North Pacific Forest Landscape Corridor and Connectivity Project utilized a landscape connectivity simulator (UNICOR) and a genetic simulation program (CDPOP) to model the functional (dispersal and genetic) connectivity in the North Pacific Landscape. The outputs from these programs indicated areas with high potential for landscape and genetic isolation and low probability of dispersal and colonization. In addition, this...
The rate of future climate change is likely to exceed the migration rates of most plant species. The replacement of dominant species by locally rare species may require decades, and extinctions may occur when plant species cannot migrate fast enough to escape the consequences of climate change. Such lags may impair ecosystem services, such as carbon sequestration and clean water production. Thus, to assess global change, simulation of plant migration and local vegetation change by dynamic global vegetation models (DGVMs) is critical, yet fraught with challenges. Global vegetation models cannot simulate all species, necessitating their aggregation into plant functional types (PFTs). Yet most PFTs encompass the full...
thumbnail
This dataset describes the diameter, shape, settling velocity, and specific gravity of eggs from 9 female pallid sturgeon and 14 female shovelnose sturgeon as determined in laboratory studies. Pallid sturgeon and shovelnose sturgeon are believed to broadcast demersal eggs in the current, near the river bed over coarse substrate. It is hypothesized that eggs settle immediately following fertilization, but field conditions preclude direct observation. The dispersal of sturgeon eggs is affected by physical properties of the eggs and hydraulic conditions at the spawning location.
Using a variety of sampling techniques and observations we describe aspects of the reproductive ecology and early life-history of Bear Lake sculpin, Cottus extensus, a species endemic to Bear Lake, Utah-Idaho. Adult sculpin spawned in shallow water (0.5-6.0 m depths) in cavities beneath large cobbles and boulders. During 1993, egg mass densities were highest (> 4.0 m(2)) at 1.0-2.0 m depths. Electivity indices verified substrate selection and also indicated an avoidance of sand- and gravel-embedded materials. During years of low water elevation, suitable spawning substrates were restricted to one Or two limited areas of the lake and comprised < 0.004% of the total benthic area. Disturbance from turbulence, as would...
Translocations of greater sage-grouse (Centrocercus urophasianus) have been attempted in 7 states and one Canadian province with very little success. To recover a small remnant population and test the efficacy of sage-grouse translocations, we captured and transported 137 adult female sage-grouse from 2 source populations to a release site in Strawberry Valley, Utah, USA, during March-April 2003-2005. The resident population of sage-grouse in Strawberry Valey was approximately 150 breeding birds prior to the release. We radiomarked each female and documented survival, movements, reproductive effort, flocking with resident grouse, and lek attendance. We used Program MARK to calculate annual survival of translocated...
Abstract (from http://rspb.royalsocietypublishing.org/content/282/1799/20142454): Hybridization between native and non-native species has serious biological consequences, but our understanding of how dispersal and selection interact to influence invasive hybridization is limited. Here, we document the spread of genetic introgression between a native ( Oncorhynchus clarkii) and invasive ( Oncorhynchus mykiss) trout, and identify the mechanisms influencing genetic admixture. In two populations inhabiting contrasting environments, non-native admixture increased rapidly from 1984 to 2007 and was driven by surprisingly consistent processes. Individual admixture was related to two phenotypic traits associated with fitness:...
thumbnail
For several decades, grizzly bear (Ursus arctos) populations in the Greater Yellowstone Ecosystem (GYE) and the Northern Continental Divide Ecosystem (NCDE) have increased in numbers and range extent. Whereas the NCDE population is contiguous with grizzly bear populations in the Canadian Rocky Mountains, genetic evidence suggests the GYE population remains isolated. Recent analyses indicate the effective population size of GYE grizzly bears has increased and is approaching levels needed for long-term viability. With only ~110 km distance separating current estimates of occupied range for these populations, the potential for immigration into the GYE from an NCDE migrant, or vice versa, is likely greater now than...
thumbnail
Linkage Mapper uses GIS maps of core habitat areas and resistances to identify and map linkages between core areas. Each cell in a resistance map is attributed with a value reflecting the energetic cost, difficulty, or mortality risk of moving across that cell. Resistance values are typically determined by cell characteristics, such as land cover or housing density, combined with species-specific landscape resistance models. As animals move away from specific core areas, cost-weighted distance analyses produce maps of total movement resistance accumulated.The tool identifies adjacent (neighboring) core areas and create maps of least-cost corridors between them. It then mosaics the individual corridors to create...
thumbnail
Symphyotrichum expansum (Puepp ex Spreng.) Nesom is reported new to Utah from the Escalante River drainage. A major range extension is reported for Aralia racemosa L. in the Escalante drainage, and additional populations are reported of the rare species Imperata brevifolia Vasey in Utah, including the 1st record for the Grand Staircase--Escalante National Monument. Heterotheca grandiflora Nutt. is reported new to north central Arizona. New locations and notes on an additional 22 rare species in Glen Canyon National Recreation Area are listed. Published in Western North American Naturalist, volume 65, issue 1, on pages 103 - 111, in 2005.
thumbnail
The data are included in 8 separate text files: 1) "Sample_coordinates.txt". The file contains sample identifiers along with geographic coordinates associated with each sample. Coordinates are specified as UTM Zone 10 values (WGS84). 2) "Sample_genotypes.txt". The file contains a sample identifier along with microsatellite genotypes associated with each sample. 3) "uniform_conductances.asc". An ASCII text-based representation of a map containing idealized habitat for Northern Spotted Owls. 4) "1870_conductance.asc". An ASCII text-based representation of a map containing idealized habitat for Northern Spotted Owls in the 1870's. 5) "1940_conductance.asc". An ASCII text-based representation of a map containing idealized...
Landscape features such as mountains, rivers, and ecological gradients may strongly affect patterns of dispersal and gene flow among populations and thereby shape population dynamics and evolutionary trajectories. The landscape may have a particularly strong effect on patterns of dispersal and gene flow in amphibians because amphibians are thought to have poor dispersal abilities. We examined genetic variation at six microsatellite loci in Columbia spotted frogs (Rana luteiventris) from 28 breeding ponds in western Montana and Idaho, USA, in order to investigate the effects of landscape structure on patterns of gene flow. We were particularly interested in addressing three questions: (i) do ridges act as barriers...
thumbnail
I examined dispersal and social organization of Gunnison's prairie dogs (Cynomys gunnisoni) for 7 years at Petrified Forest National Park, Arizona. Within colonies, individuals lived in harem-polygynous family groups called clans. The number of clans at the study site each year ranged from 21 to 23, with a mean of 22.3. Clan size (the number of adults living in the same territory) ranged from I to 19, with a mean of 5.30. Clans contained 1.06 +/- 0.39 (SD) breeding males,, 3.01 +/- 2.08 breeding females, and 1.23 +/- 1.65 nonbreeding yearling males. Some clams contained two breeding males, and others contained no resident breeding male. The area of clan territories ranged from 0.16 ha to 1.82 ha, with a mean of...
thumbnail
Conclusions: At small spatial scales, where extirpation risks are high, landscape fragmentation will likely have long-term negative consequences on the genetic variation of individual assemblages of coastal cutthroat trout. Thresholds/Learnings: Synopsis: This study aimed to determine if coastal cutthroat trout were genetically structured within streams and to assess the effects of habitat fragmentation on coastal cutthroat trout genetic variation. Habitat fragmented by roads and other human disturbances acted as dispersal barriers, which strongly influenced coastal cutthroat trout genetic structure, diversity, and differentiation. At range-wide spatial scales, fragmentation potentially contributes to coastal cutthroat...
Dams create barriers to fish migration and dispersal in drainage basins, and the removal of dams is often viewed as a means of increasing habitat availability and restoring migratory routes of several fish species. However, these barriers can also isolate and protect native taxa from aggressive downstream invaders.We examined fish community composition two years prior to and two years after the removal of a pair of low-head dams from Boulder Creek,Wisconsin, U.S.A. in 2003 to determine if removal of these potential barriers affected the resident population of native brook trout (Salvelinus fontinalis). Despite the presence of other taxa in the downstream reaches, and in other similar streams adjacent to the Boulder...
map background search result map search result map Philopatry, Dispersal, and Social Organization of Gunnison's Prairie Dogs Notes on significant collections and additions to the flora of Glen Canyon National Recreation Area, Utah and Arizona, between 1992 and 2004 linkage-mapper North Pacific Forest Landscape Corridor and Connectivity Project: Assessing Landscape and Species Vulnerability - Spatial Data Influences of barriers to movement on within-watershed genetic variation of coastal cutthroat trout North Pacific Forest Landscape Corridor and Connectivity Project: Assessing Landscape and Species Vulnerability - Final Report Potential movement paths for male grizzly bear (Ursus arctos) dispersal between the Northern Continental Divide and Greater Yellowstone Ecosystems, 2000-2015 Randomized shortest paths for Grizzly Bear dispersal between the GYE and NCDE Radio telemetry data on nighttime movements of two species of migratory nectar-feeding bats (Leptonycteris) in Hidalgo County, New Mexico, late-summer 2004 and 2005 Microsatellite markers, habitat quality, and sample location data for Northern Spotted Owls (Strix occidentalis caurina) Physical characteristics of pallid sturgeon and shovelnose sturgeon eggs Physical characteristics of pallid sturgeon and shovelnose sturgeon eggs Influences of barriers to movement on within-watershed genetic variation of coastal cutthroat trout Philopatry, Dispersal, and Social Organization of Gunnison's Prairie Dogs Notes on significant collections and additions to the flora of Glen Canyon National Recreation Area, Utah and Arizona, between 1992 and 2004 Radio telemetry data on nighttime movements of two species of migratory nectar-feeding bats (Leptonycteris) in Hidalgo County, New Mexico, late-summer 2004 and 2005 North Pacific Forest Landscape Corridor and Connectivity Project: Assessing Landscape and Species Vulnerability - Spatial Data North Pacific Forest Landscape Corridor and Connectivity Project: Assessing Landscape and Species Vulnerability - Final Report Microsatellite markers, habitat quality, and sample location data for Northern Spotted Owls (Strix occidentalis caurina) linkage-mapper Potential movement paths for male grizzly bear (Ursus arctos) dispersal between the Northern Continental Divide and Greater Yellowstone Ecosystems, 2000-2015 Randomized shortest paths for Grizzly Bear dispersal between the GYE and NCDE