scholarly journals Winter range drift in the George River Caribou Herd: a response to summer forage limitation?

Rangifer ◽  
2003 ◽  
Vol 23 (5) ◽  
pp. 113 ◽  
Author(s):  
Isabelle Schmelzer ◽  
Robert Otto

Space use by the George River caribou herd (GRCH) changes in correspondence with migration patterns. The traditional range of this herd encompasses an area of approximately 900 000 km2. Range use is seasonal and includes travel to traditional calving grounds. Winter range use however, is more variable. The GRCH has grown rapidly from 5000 animals in 1954 to approximately 775 000 in 1993. Beginning in the mid 1980s, the calving and summer range habitats of the GRCH have deteriorated, resulting in a decline in physical condition and subsequent poor calf survival and low pregnancy rates. We assessed the importance of the winter range as a food source compensating for poor summer range quality through an evaluation of winter range drift and use intensity. We hypothesized that if winter ranges provide a compensatory source of forage, then George River caribou should avoid sites heavily used during the previous winter at a population level. Winter ranges for the GRCH were calculated using 4300 caribou locations obtained 1986-2000. We found that in spite of a doubling in net range area, the size of annual winter ranges did not increase, indicating the occurrence of range drift. Further, George River caribou exhibited avoidance of wintering areas at several spatial scales. Avoidance occurred across a use threshold, where the degree of use (or density) during the previous winter determined the level of avoidance during the subsequent winter. As the spatial scale decreased, the degree of avoidance increased. Caribou significantly avoided areas used the previous winter at spatial scales below and including 245 km2 (corresponding to a 75% use distribution). Results suggest winter foraging allows caribou suspend the effects of density-dependent summer forage limitation on herd productivity. As such, analysis of GRCH population trends should be considered in light of both summer and winter range resources.

Rangifer ◽  
2003 ◽  
Vol 23 (5) ◽  
pp. 267 ◽  
Author(s):  
Frank L. Miller ◽  
Samuel J. Barry

Spatial and temporal use of seasonal, and collectively, annual ranges by four female Peary caribou (Rangifer taran-dus pearyi) was investigated using satellite telemetry. Knowledge of how caribou use space allows a better understanding of their demands on those ranges and enhances evaluation of associated environmental stressors. The study took place during an environmentally favorable caribou-year with high reproduction and calf survival and low (none detected) 1+ yr-old mortality, 1 August 1993 to 31 July 1994, Bathurst Island, south-central Queen Elizabeth Islands, Canadian High Arctic. All four females exhibited a pattern of single-island seasonal, and collectively, annual range use. Estimates of the maximum area encompassed by each individual during the course of the annual-cycle varied from 1735 to 2844 km2 (mean±SE = 2284±250 km2). Although, there was 46% spatial overlap among individual ranges, temporal isolation resulted in the four individuals maintaining seasonal ranges distinctly separate from each other. This collective area encompassed 4970 km2 and equaled about 31% and 18% of Bathurst Island and the Bathurst Island complex, respectively. Individual wintering areas formed a relatively small portion of each individual's annual range (mean±SE=71±17 km2): 24 km2, 158 days of occupation, <1% of the annual area; 70 km2, 187 days, 4%; 95 km2, 200 days, 4%; and 94 km2, 172 days, 6%. Seasonal movements were greatest during pre-rut and pre-calving.


Rangifer ◽  
1996 ◽  
Vol 16 (4) ◽  
pp. 193 ◽  
Author(s):  
J.D. Jacobs ◽  
A.R. Maarouf ◽  
E.A. Perkins

Records from permanent meteorological stations in and around the range of the George River Caribou Herd have been analyzed for the 1950-1991 period in order to identify climatic factors potentially influencing the numbers, condition, and distribution of caribou. Winter conditions identified include a significant temperature decrease over the period and some years of extreme snowfall. Spatial variations in snow cover may be responsible for shifts in winter range. Indications are that summer climate has not varied significantly, but spring and summer conditions may not have been particularly favourable for plant productivity in the summer range of females and calves. Climatological observations more representative of the summer range are needed for a better understanding of ecological relationships there.


Author(s):  
A. D. Chalfoun

Abstract Purpose of Review Anthropogenic activities can lead to the loss, fragmentation, and alteration of wildlife habitats. I reviewed the recent literature (2014–2019) focused on the responses of avian, mammalian, and herpetofaunal species to oil and natural gas development, a widespread and still-expanding land use worldwide. My primary goals were to identify any generalities in species’ responses to development and summarize remaining gaps in knowledge. To do so, I evaluated the directionality of a wide variety of responses in relation to taxon, location, development type, development metric, habitat type, and spatiotemporal aspects. Recent Findings Studies (n = 70) were restricted to the USA and Canada, and taxonomically biased towards birds and mammals. Longer studies, but not those incorporating multiple spatial scales, were more likely to detect significant responses. Negative responses of all types were present in relatively low frequencies across all taxa, locations, development types, and development metrics but were context-dependent. The directionality of responses by the same species often varied across studies or development metrics. Summary The state of knowledge about wildlife responses to oil and natural gas development has developed considerably, though many biases and gaps remain. Studies outside of North America and that focus on herpetofauna are lacking. Tests of mechanistic hypotheses for effects, long-term studies, assessment of response thresholds, and experimental designs that isolate the effects of different stimuli associated with development, remain critical. Moreover, tests of the efficacy of habitat mitigation efforts have been rare. Finally, investigations of the demographic effects of development across the full annual cycle were absent for non-game species and are critical for the estimation of population-level effects.


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.


Rangifer ◽  
2008 ◽  
Vol 28 (1) ◽  
pp. 33
Author(s):  
Robert Serrouya ◽  
Bruce N. McLellan ◽  
Clayton D. Apps ◽  
Heiko U. Wittmer

Mountain caribou are an endangered ecotype of woodland caribou (Rangifer tarandus caribou) that live in highprecipitation, mountainous ecosystems of southeastern British Columbia and northern Idaho. The distribution and abundance of these caribou have declined dramatically from historical figures. Results from many studies have indicated that mountain caribou rely on old conifer forests for several life-history requirements including an abundance of their primary winter food, arboreal lichen, and a scarcity of other ungulates and their predators. These old forests often have high timber value, and understanding mountain caribou ecology at a variety of spatial scales is thus required to develop effective conservation strategies. Here we summarize results of studies conducted at three different spatial scales ranging from broad limiting factors at the population level to studies describing the selection of feeding sites within seasonal home ranges of individuals. The goal of this multi-scale review is to provide a more complete picture of caribou ecology and to determine possible shifts in limiting factors across scales. Our review produced two important results. First, mountain caribou select old forests and old trees at all spatial scales, signifying their importance for foraging opportunities as well as conditions required to avoid alternate ungulates and their predators. Second, relationships differ across scales. For example, landscapes dominated by roads and edges negatively affect caribou survival, but appear to attract caribou during certain times of the year. This juxtaposition of fine-scale behaviour with broad-scale vulnerability to predation could only be identified through integrated multi-scale analyses of resource selection. Consequently we suggest that effective management strategies for endangered species require an integrative approach across multiple spatial scales to avoid a focus that may be too narrow to maintain viable populations. Abstract in Norwegian / Sammendrag:Skala-avhengig økologi og truet fjellvillrein i Britisk ColumbiaFjellvillreinen i de nedbørsrike fjellområdene i sørøstre Britisk Columbia og nordlige Idaho som er en truet økotype av skogsreinen (Rangifer tarandus caribou), har blitt kraftig redusert både i utbredelse og antall. Mange studier har vist at denne økotypen er avhengig av vinterføden hengelav i gammel barskog hvor det også er få andre klovdyr og dermed få predatorer. Slik skog er også viktige hogstområder, og å forstå økologien til fjellvillreinen i forskjellige skaleringer er derfor nødvendig for å utvikle forvaltningsstrategier som kan berge og ta vare på denne reinen. Artikkelen gir en oversikt over slike arbeider: fra studier av begrensende faktorer på populasjonsnivå til studier av sesongmessige beiteplasser på individnivå. Hensikten er å få frem et mer helhetlig perspektiv på fjellvillreinen og finne hvordan de begrensende faktorene varierer etter skaleringen som er benyttet i studiet. Oversikten vår frembragte to viktige resultater; 1) Uansett skalering så velger dyrene gammel skog og gamle trær. 2) Dyrenes bruk av et område kan variere med benyttet skalering, for eksempel vil landskap utbygd med veier og hogstflater være ufordelaktig for overlevelsen, men synes likevel å kunne tiltrekke fjellvillreinen til visse tider av året. Forholdet mellom atferd ut fra fin-skalering og stor-skalering sårbarhet hva gjelder predasjon, ville kun blitt avdekket ved flere-skaleringsanalyse av hvordan ressursene benyttes. Ut fra dette foreslår vi at forvaltningsstrategier for truete bestander som eksempelvis fjellvillreinen, må baseres på tilnærminger ut fra ulike skaleringer for å hindre at et for snevert perspektiv kan begrense muligheten for vedvarende levedyktighet.


The Condor ◽  
2010 ◽  
Vol 112 (4) ◽  
pp. 731-743 ◽  
Author(s):  
Matthew Johnson ◽  
Peter Clarkson ◽  
Michael I. Goldstein ◽  
Susan M. Haig ◽  
Richard B. Lanctot ◽  
...  

The Condor ◽  
2007 ◽  
Vol 109 (2) ◽  
pp. 268-275 ◽  
Author(s):  
Carola Sanpera ◽  
Xavier Ruiz ◽  
Rocío Moreno ◽  
Lluís Jover ◽  
Susan Waldron

Abstract To better understand migratory connectivity between breeding and nonbreeding populations, we analyzed mercury (Hg) and stable isotope signatures of nitrogen (δ15N), carbon (δ13C), and sulfur (δ34S) in Audouin's Gulls (Larus audouinii) breeding in two different colonies, the Ebro Delta (northeastern Spain) and the Chafarinas Islands (southwestern Mediterranean). Although abundant information is available on the biology and trophic ecology of this gull's breeding populations, little is known about migration patterns, distribution in winter, or conditions faced during the nonbreeding period. Analyses were carried out on first primary feathers, grown during the summer while gulls are on the breeding grounds, and mantle feathers, grown during the winter. Different isotopic signatures (δ15N, δ13C, and δ34S) in summer (primary) feathers from each area agree with the observed differences in diet between the two colonies. In winter (mantle) feathers, isotopic signatures did not differ, consistent with a common wintering ground and common diet, although the lack of isotopic basemaps in marine systems precludes assignment to a geographical area of reference. Future research is needed to relate isotopic signatures and Hg values in mantle feathers to trophic ecology in wintering areas. Results for Hg indicate that the excretory role played by primary feathers precludes their use as indicators of trophic ecology.


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.


The Condor ◽  
2000 ◽  
Vol 102 (1) ◽  
pp. 127-136 ◽  
Author(s):  
Juan C. Alonso ◽  
Manuel B. Morales ◽  
Javier A. Alonso

AbstractWe examined the seasonal movements of wing-tagged and radio-marked adult female Great Bustards Otis tarda in a population in northwestern Spain. Four different movement patterns were found: females that migrated between breeding and wintering areas (20%), females that only left their year-round home range area to mate (32%), females that migrated from a wintering-mating area to a nesting-summering area (16%), and females that stayed all year round within a relatively small home range area (32%). All females displayed fidelity to their nesting and wintering areas, and most also showed fidelity to their leks. Migration patterns were not affected either in timing or distance by breeding success. The maximum distance between natal and dispersal locations during their first year of life was significantly higher in migratory females than in sedentary ones. These patterns explained the seasonal variations in population numbers observed in the study area. Surveys showed that the number of females increased from 600–700 breeding birds, with 1,000–1,100 birds present from October to March.


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