scholarly journals Assessing the Impacts of Summer Range on Bathurst Caribou’s Productivity and Abundance since 1985

2014 ◽  
Vol 05 (04) ◽  
pp. 130-145 ◽  
Author(s):  
Wenjun Chen ◽  
Lori White ◽  
Jan Z. Adamczewski ◽  
Bruno Croft ◽  
Kerri Garner ◽  
...  
Keyword(s):  
2008 ◽  
Vol 8 (16) ◽  
pp. 4855-4864 ◽  
Author(s):  
C. S. Boxe ◽  
A. Saiz-Lopez

Abstract. We utilize a multiphase model, CON-AIR (Condensed Phase to Air Transfer Model), to show that the photochemistry of nitrate (NO3−) in and on ice and snow surfaces, specifically the quasi-liquid layer (QLL), can account for NOx volume fluxes, concentrations, and [NO]/[NO2] (γ=[NO]/[NO2]) measured just above the Arctic and coastal Antarctic snowpack. Maximum gas phase NOx volume fluxes, concentrations and γ simulated for spring and summer range from 5.0×104 to 6.4×105 molecules cm−3 s−1, 5.7×108 to 4.8×109 molecules cm−3, and ~0.8 to 2.2, respectively, which are comparable to gas phase NOx volume fluxes, concentrations and γ measured in the field. The model incorporates the appropriate actinic solar spectrum, thereby properly weighting the different rates of photolysis of NO3− and NO2−. This is important since the immediate precursor for NO, for example, NO2−, absorbs at wavelengths longer than nitrate itself. Finally, one-dimensional model simulations indicate that both gas phase boundary layer NO and NO2 exhibit a negative concentration gradient as a function of height although [NO]/[NO2] are approximately constant. This gradient is primarily attributed to gas phase reactions of NOx with halogens oxides (i.e. as BrO and IO), HOx, and hydrocarbons, such as CH3O2.


2017 ◽  
Vol 130 (4) ◽  
pp. 320 ◽  
Author(s):  
Rick Rosatte

During 2000 and 2001, Elk (Cervus canadensis) were restored to the Bancroft, Ontario area. The objective of this study was to determine the home range and movements of six social units of Elk, 5–12 years after restoration, in an area of about 2500 km2 near Bancroft. Home range and movements were calculated from 40 221 Global Positioning System locations acquired from 56 collared Elk (16 bulls and 40 cows) between 2006 and 2013. Annual home ranges were found to be significantly greater (mean 110.3 km2, standard error [SE] 11.2) for Elk in areas where winter feeding by humans did not occur compared with those (mean 51.0 km2, SE 9.0) where winter feeding was prevalent. Elk in winter feeding areas had smaller ranges in winter than other seasons. On a seasonal basis, home range size was larger for Elk in areas where winter feeding did not occur; mean winter home range for Elk in non-feeding areas was 73.4 km2 (SE34.0) compared with 8.3 km2 (SE 2.6) for Elk in areas where winter feeding occurred. The 20 Elk that were monitored for multiple years exhibited home range fidelity among years. The entire range of all radio-collared Elk within the social groups studied covered 1716.4 km2 during 2006–2013. Average daily movements of Elk in the study arearanged from 1.0 to 2.1 km/day with greatest movements occurring during spring and summer. However, some Elk were capable of moving an average of 5–7km in a 12-h interval. Movements (about 5 km) to winter range occurred during October to December each year. Cows moved to calving areas in May with mean movements of Elk to spring/summer range about 6 km. Cow/calf groups moved to fall ranges by early September with mean movements of about 4 km. During the rut, mean bull movements of 16.0 km to cow groups over 1–5 days occurred in early September. Hunting of Elk during the fall of 2011 and 2012 did not appear to significantly affect the movements and dispersion of Elk in the study area.


Author(s):  
Mark Boyce ◽  
Evelyn Merrill ◽  
Ronald Marrs

Summer range is not thought to be limiting to elk because abundant, high quality forage is available whereas a shortage of forage usually exists on elk winter ranges. Nevertheless, summer nutrition and fat reserves acquired on summer ranges influence growth, survival and reproduction of ungulates (Klein 1965, Verme 1963, 1965, Julander et al. 1961). The enormous area of summer range for the Northern Yellowstone elk herd renders detailed field surveys impractical. This study was initiated to evaluate the feasibility of using LANDSAT satellite imagery to (1) characterize vegetation communities on summer range from LANDSAT multispectral scanner (MSS) data and digitized vegetation maps of Yellowstone National Park, (2) predict plant production within grassland types and (3) correlate elk population characteristics with fluctuations in plant production and weather.


2019 ◽  
Vol 92 (5) ◽  
pp. 523-537 ◽  
Author(s):  
Kelly M Proffitt ◽  
Jesse DeVoe ◽  
Kristin Barker ◽  
Rebecca Durham ◽  
Teagan Hayes ◽  
...  

Abstract Forestry practices such as prescribed fire and wildfire management can modify the nutritional resources of ungulates across broad landscapes. To evaluate the influences of fire and forest management on ungulate nutrition, we measured and compared forage quality and abundance among a range of land cover types and fire histories within 3 elk ranges in Montana. We used historical fire data to assess fire-related variations in elk forage from 1900 to 2015. Fire affected summer forage more strongly than winter forage. Between 1900–1990 and 1990–2015, elk summer range burned by wildfire increased 242–1772 per cent, whereas the area on winter range burned by wildfire was low across all decades. Summer forage quality peaked in recently burned forests and decreased as time since burn increased. Summer forage abundance peaked in dry forests burned 6–15 years prior and mesic forests burned within 5 years. Forests recently burned by wildfire had higher summer forage quality and herbaceous abundance than those recently burned by prescribed fire. These results suggest that the nutritional carrying capacity for elk varies temporally with fire history and management practices. Our methods for characterizing nutritional resources provide a relatively straightforward approach for evaluating nutritional adequacy and tracking changes in forage associated with disturbances such as fire.


2001 ◽  
Vol 55 (3) ◽  
pp. 371-379 ◽  
Author(s):  
Arthur S. Dyke ◽  
James M. Savelle

AbstractThe fossil remains of 43 bowhead whales were mapped on the raised beaches of western Wollaston Peninsula, Victoria Island, Canadian Arctic, near the historic summer range limit of the Bering Sea stock in the Beaufort Sea. The elevations and radiocarbon ages of the remains demonstrate that the bowhead ranged commonly into the region following the submergence of Bering Strait at ca. 10,000 14C yr B.P. until ca. 8500 14C yr B.P. During the same interval, bowheads ranged widely from the Beaufort Sea to Baffin Bay. Subsequently, no whales reached Wollaston Peninsula until ca. 1500 14C yr B.P. Late Holocene populations evidently were small, or occupations were brief, in comparison to those of the early Holocene. Although the late Holocene recurrence may relate to the expansion of pioneering Thule whalers eastward from Alaska, there are few Thule sites and limited evidence of Thule whaling in the area surveyed to support this suggestion.


1977 ◽  
Vol 57 (1) ◽  
pp. 81-92 ◽  
Author(s):  
A. McLEAN ◽  
W. WILLMS

A 2-yr investigation of the herd distribution and diet selection of beef cattle on range was conducted near Kamloops, British Columbia. Two ranges were studied: one grazed in spring and fall, and the other in summer. Diet selection was determined by grazing two rumen-fistulated beef cattle, by clipping plots before and after grazing on the spring–fall range, and by conducting browse surveys on the summer range. Cattle distribution was determined on the spring–fall range. During the 2 yr, the diet composition averaged 93% grass, 2% forbs, 2% shrubs, and 3% trees. Grass was consumed more in the spring (95%) than in either summer or fall (93 and 92%, respectively). Interseasonal change in the consumption of the four plant types (grass, forbs, shrubs, trees) was greatest in the summer and fall. In the summer, consumption of forbs and trees increased, while consumption of grasses remained constant and consumption of shrubs decreased. In the fall, grass and shrub consumption increased, while forb and tree consumption decreased. Three open range habitats (south slope, knoll, flat field) and one treed habitat were defined for distribution studies. The south slope and flat field were utilized for feeding, while the knoll and treed habitats were used for both resting and feeding. The treed habitat was most important in providing shelter from adverse weather. Grazing intensity was generally less on the treed habitat than on the others.


The Condor ◽  
1970 ◽  
Vol 72 (4) ◽  
pp. 437-444 ◽  
Author(s):  
A. N. Lance
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document