scholarly journals Caribou of the Central Arctic Region of Alaska in relation to adjacent caribou herds

Rangifer ◽  
1986 ◽  
Vol 6 (2) ◽  
pp. 65
Author(s):  
D. R. Carruthers ◽  
R. D. Jakimchuk
Keyword(s):  
Rangifer Tarandus ◽  
Arctic Region ◽  
Early Spring ◽  
Summer Period ◽  
Western Arctic ◽  
Unusual Increase

There was an unusual increase in numbers of caribou (Rangifer tarandus granti) in the Central Arctic region of Alaska from 1981 to 1985. In fall and winter numbers were up to five times greater than at the onset of calving in June. Numbers appeared to double during the month of June each year, then remain relatively stable over the summer period with a further increase in the fall. Ingress of caribou from outside the region in fall was observed in all years and egress in the early spring is postulated. We conclude that a small resident herd inhabits the region year round with numbers increasing through ingress of caribou from the Western Arctic herd possibly beginning as early as June. Increases or decreases in the size of adjacent herds probably will affect the numbers of caribou occupying the Central Arctic region.

scholarly journals Aerial survey and telemetry data analysis of a peripheral caribou calving area in northwestern Alaska

Rangifer ◽  
2019 ◽  
Vol 39 (1) ◽  
pp. 43-58
Author(s):  
Alexander K. Prichard ◽  
Ryan L. Klimstra ◽  
Brian T. Person ◽  
Lincoln S. Parrett
Keyword(s):  
Industrial Development ◽  
Rangifer Tarandus ◽  
Aerial Survey ◽  
The Arctic ◽  
Primary Data ◽  
Data Sets ◽  
Telemetry Data ◽  
Western Arctic ◽  
Data Source

With industrial development expanding in the Arctic, there is increasing interest in quantifying the impacts of development projects on barren ground caribou (Rangifer tarandus granti). The primary data source to assess caribou distribution and predict impacts in remote areas of Alaska has shifted in recent decades from aerial survey data to telemetry data, but these techniques have different strengths and weaknesses. The ranges of two caribou herds, the Western Arctic Herd and the Teshekpuk Herd, overlap in northwest Alaska between Wainwright and Atqasuk, Alaska. Based on long-term telemetry data sets, this region was thought to be outside of the core calving ranges of both herds. Calving has long been reported to occur in this general area, but early reports assumed caribou were from the Western Arctic Herd and only one systematic aerial survey of caribou density and distribution during calving has been conducted in this area in recent decades. Following interest in industrial development in this area, we conducted aerial strip-transect surveys during early to mid-June 2013–2015 to directly assess the density and distribution of caribou in the area and we used existing telemetry data to compare our results to the seasonal distribution of both herds. Total caribou densities varied between 0.36 and 1.06 caribou/km² among years, and calf densities varied 0.04 and 0.25 calves/km² among years. Contrary to assumptions by early researchers in the area, telemetry data indicated that caribou in this area during early to mid-June were from the Teshekpuk Herd. The use of telemetry data alone underestimated the importance of this area for calving, but the combination of aerial surveys and telemetry data provided complementary information on caribou use of this area showing the importance of collecting the appropriate types of data for assessing potential impacts of development on caribou.

The effect of nitrogen fertilizer on the seasonal production of an irrigated ryegrass-clover pasture at Badgery's Creek

1965 ◽  
Vol 5 (19) ◽  
pp. 417 ◽  
Author(s):  
FC Crofts
Keyword(s):  
Nitrogen Fertilizer ◽  
Crude Protein ◽  
Dry Matter ◽  
Early Spring ◽  
Late Spring ◽  
Summer Period ◽  
Fertilizer Nitrogen ◽  
Clover Pasture

Nitrogen fertilizer applied as sulphate of ammonia at 23 to 92 pounds of nitrogen an acre in early spring made forage available for grazing six weeks earlier and returned 19 to 22 pounds of additional dry matter (with 14 to 19 per cent crude protein) for each pound of fertilizer nitrogen applied. However, the responses to nitrogen fertilizer became progressively less over the late spring and summer period and the responses in the autumn, when additional forage is urgently needed for winter reserves, were relatively small.

scholarly journals Composition of late summer diet by semi-domesticated reindeer in different grazing conditions in northernmost Finland

Rangifer ◽  
2015 ◽  
Vol 35 (1) ◽  
pp. 39-52 ◽  
Author(s):  
Pauline Bezard ◽  
Sophie Brilland ◽  
Jouko Kumpula
Keyword(s):  
Diet Composition ◽  
Rangifer Tarandus ◽  
Coniferous Forest ◽  
Late Summer ◽  
Early Spring ◽  
Food Plants ◽  
Sample Site ◽  
Rotation System ◽  
Plant Groups ◽  
Microhistological Analysis

 This study aims to investigate the diet composition of semi-domesticated reindeer (Rangifer tarandus tarandus) in late summer in different kinds of grazing conditions in northernmost Finland. The composition of diet by reindeer was determined on the grounds of microhistological analysis of feces samples collected in early August in different seasonal grazing areas (winter or summer/year-round grazing areas) in three reindeer management districts. Although the proportion of different plant groups varied between the studied districts, the quantified group of ground lichens (which also contained small amounts of mushrooms) was the most abundant, varying from 33.0 to 46.4% in the analyzed samples. In general, there were significant differences in the proportions of lichen between districts, but not between grazing areas. The proportion of lichen in samples increased significantly when the amount of lichen pasture around a sample site increased. The proportion of dwarf shrubs and leaves in samples varied from 24.9 to 37.9% and differed significantly between districts, but not between grazing areas. In the same way, the proportion of graminoids varied between 20.9 and 36.2% and differed significantly between districts and also between grazing areas. Higher amounts of graminoids in feces were observed in summer/year-round grazing areas than in winter grazing areas. Finally, the proportion of bryophytes varied between 2.9 and 6.5% and was significantly different between districts, but not between grazing areas. An increase in old and mature coniferous forest around a sample site significantly increased the amounts of bryophytes in samples. The results indicate that reindeer adapt their summer diet composition according to the availability of food plants. The results also show that when reindeer are allowed to select their summer ranges freely, reindeer tend to use lichen pastures intensively also during summer, which causes a considerable reduction in lichens due to grazing and trampling. Therefore, a proper seasonal pasture rotation system to protect lichen pastures from grazing and trampling, from early spring to late autumn, is an essential part of sustainable pasture use in reindeer herding.

scholarly journals Recent vegetation phenology variability and wild reindeer migration in Hardangervidda plateau (Norway)

2018 ◽  
Vol 1 ◽  
pp. 1-7
Author(s):  
Romain Courault ◽  
Alexiane Franclet ◽  
Kévin Bourrand ◽  
Clélia Bilodeau ◽  
Sonia Saïd ◽  
...  
Keyword(s):  
Rangifer Tarandus ◽  
Cultural Landscapes ◽  
Global Climate ◽  
Early Spring ◽  
Home Ranges ◽  
Mountain Range ◽  
Arctic Ecosystems ◽  
Isolated Populations ◽  
Ecological Habitat ◽  
Wild Reindeer

More than others, arctic ecosystems are affected by consequences of global climate changes. The herbivorous plays numerous roles both in Scandinavian natural and cultural landscapes (Forbes et al., 2007). Wild reindeer (<i>Rangifer tarandus</i> L.) herds in Hardangervidda plateau (Norway) constitute one of the isolated populations along Fennoscandia mountain range. The study aims to understand temporal and spatial variability of intra- and inter-annual home ranges extent and geophysical properties. We then characterize phenological variability with Corine Land Cover ecological habitat assessment and bi-monthly NDVI index (MODIS 13Q1, 250&amp;thinsp;m). Thirdly, we test relationships between reindeer’s estimated densities and geophysical factors. All along the study, a Python toolbox (“GRiD”) has been mounted and refined to fit with biogeographical expectancies. The toolbox let user’s choice of inputs and facilitate then the gathering of raster datasets with given spatial extent of clipping and resolution. The grid generation and cells extraction gives one tabular output, allowing then to easily compute complex geostatistical analysis with regular spreadsheets. Results are based on reindeer’s home ranges, associated extent (MODIS tile) and spatial resolution (250&amp;thinsp;m). Spatial mismatch of 0.6&amp;thinsp;% has been found between ecological habitat when comparing raw (100&amp;thinsp;m<sup>2</sup>) and new dataset (250&amp;thinsp;m<sup>2</sup>). Inter-annual home ranges analysis describes differences between inter-seasonal migrations (early spring, end of the summer) and calving or capitalizing times. For intra-annual home ranges, significant correlations have been found between reindeer’s estimated densities and both altitudes and phenology. GRiD performance and biogeographical results suggests 1) to enhance geometric accuracy 2) better examine links between estimated densities and NDVI.

Evaluation of the regional mineral potential (non-hydrocarbon) of the western Arctic region

1978 ◽  
Author(s):  
O R Eckstrand ◽  
G A Gross ◽  
R V Kirkham ◽  
G B Leech ◽  
C R Mcleod ◽  
...  
Keyword(s):  
Arctic Region ◽  
Mineral Potential ◽  
Western Arctic

scholarly journals Pronounced Fidelity and Selection for Average Conditions of Calving Area Suggestive of Spatial Memory in a Highly Migratory Ungulate

2020 ◽  
Vol 8 ◽  
Author(s):  
Matthew D. Cameron ◽  
Kyle Joly ◽  
Greg A. Breed ◽  
Christa P. H. Mulder ◽  
Knut Kielland
Keyword(s):  
Spatial Memory ◽  
Resource Selection ◽  
Rangifer Tarandus ◽  
Human Impacts ◽  
Environmental Stochasticity ◽  
Life History Stage ◽  
High Quality ◽  
Western Arctic ◽  
Underlying Mechanisms ◽  
Study Species

A distinguishing characteristic of many migratory animals is their annual return to distinct calving (birthing) areas in the spring, yet the navigational mechanisms employed during migration that result in this pattern are poorly understood. Effective conservation of these species requires reliable delineation of such areas, quantifying the factors that influence their selection, and understanding the underlying mechanisms resulting in use of calving areas. We used barren-ground caribou (Rangifer tarandus granti) as a study species and identified calving sites of the Western Arctic Herd in Alaska using GPS collar data from 2010–2017. We assessed variability in calving areas by comparing spatial delineations across all combinations of years. To understand calving area selection at a landscape scale, we performed a resource selection analysis comparing calving sites to available locations across the herd’s range and incorporated time-varying, remotely sensed metrics of vegetation quality and quantity. We found that whereas calving areas varied from year to year, this annual variation was centered on an area of recurring attraction consistent with previous studies covering the last six decades. Calving sites were characterized by high-quality forage at the average time of calving, but not peak calving that year, and by a narrow range of distinct physiographic factors. Each year, calving sites were located on areas of above-average conditions based on our predictive model. Our findings indicate that the pattern of spring migration for pregnant females was to migrate to areas that consistently provide high-quality forage when averaged across years, and then upon arriving at this calving ground, refine selection using their perception of annually varying conditions that are driven by environmental stochasticity. We suggest that the well-documented and widespread pattern of fidelity to calving grounds by caribou is supportive of a navigational mechanism based on spatial memory at a broad scale to optimize foraging and energy acquisition at a critical life-history stage. The extent to which migrants depend on memory to reach their spring destinations has implications for the adaptability of populations to changing climate and human impacts.

scholarly journals FEATURES OF BEHAVIOR OF ORDINARY SPRAT (BY RESULTS OF HYDROACOUSTIC RESEARCHES)

2018 ◽  
pp. 65-73
Author(s):  
Igor Borisovich Balchenkov ◽  
Tatiana Vasilievna Pomogaeva
Keyword(s):  
Caspian Sea ◽  
Water Area ◽  
Early Spring ◽  
Middle Part ◽  
Summer Period ◽  
The Caspian Sea ◽  
Research Ship ◽  
Study Results ◽  
Seasonal Aspect ◽  
Made In

Caspian sprats are reserve target species. The study of species identification of Caspian sprats was carried out on board a research ship “Researcher of the Caspian Sea” using EK-60 hydroacoustic complex having stationary antennas with a split beam of 38 and 120 kHz. The behavior and distribution of ordinary sprats in the western part of the Caspian Sea (Middle part of the Caspian Sea off the coast of Dagestan) was investigated. Echo recordings of hydroacoustic surveys made in 2011-2017 covering the water area with depths from 20 to 300 meters were considered. A database with hydroacoustic research files was created, containing the parameters of the surveys and the graphic display of the echograms. Taking into account the negative reaction of ordinary sprat to light, both day and night recordings were considered. Characteristic echoes of ordinary sprat are described in the seasonal aspect. These studies, describing the nature of the behavior of ordinary sprats, are important for the organization of fishing in the western part of the Caspian Sea. It has been stated that density of sprat shoals during spring-summer period is not high, fishing by bottom trawl is efficient only at the end of August. The most promising sprat accumulations can be found in early spring (March) and in October and November, when sprat is caught in the industrial scale. The study results describing special behavior of ordinary sprats can be used in organizing sprat fishing in the Western part of the Caspian Sea.

scholarly journals Diets of Overwintering Caribou, Rangifer tarandus, Track Decadal Changes in Arctic Tundra Vegetation

2007 ◽  
Vol 121 (4) ◽  
pp. 379 ◽  
Author(s):  
Kyle Joly ◽  
M. Jeanie Cole ◽  
Randi R. Jandt
Keyword(s):  
Population Dynamics ◽  
Global Warming ◽  
Rangifer Tarandus ◽  
Arctic Ecosystems ◽  
Fecal Analysis ◽  
Tundra Vegetation ◽  
Western Arctic ◽  
Winter Diets ◽  
Long Term Studies

We compared winter diets of Western Arctic Herd Caribou (Rangifer tarandus) from 1995/1996 and 2005 using microhistological fecal analysis on samples collected at paired permanent vegetation transects. Changes in the diets of Caribou followed the same trends as vegetative changes documented in long-term studies in northwestern Alaska. Lichens were significantly less prevalent on the landscape and in the winter diets of Caribou between 1995/1996 and 2005, while graminoids (grasses and sedges) were significantly more prevalent. Dramatic changes are forecasted for Arctic ecosystems under global warming scenarios which may continue the trend of declining lichens in northwestern Alaska and in the diet of Western Arctic Herd Caribou. The question of whether or not the altered diet will affect the population dynamics of this herd remains unresolved.

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