. Die kanadische Feld - naturforscher. 1971 Stelfox: Bighorn Schafe in Kanada 1800-1970 113. Abbildung 6. Die kahle winter Bereich entlang des Athabasca Tal, Jasper National Park. Dies ergibt sich aus mehreren Jahren der Übernutzung von mehr Schafe als der Bereich unterstützen kann. Photo Credit: A. Loewen, Jasper Park Warden Service. Krankheit sehr wahrscheinlich war die Ursache für die Epidemie, die sich zur gleichen Zeit in Waterton. Verschlechtertem Angebot Bedingungen und armen Nutri- zweifellos die Tiere gegen die Krankheit prädisponiert (Abbildungen 6 und 7). Hirsch wurden von Wärtern auf 1.700 geschätzt 1947 (Ban-Feld 1947). Die e

• Bildanbieter: Book Worm / Alamy Stock Foto
• Bild-ID: RG2R2X
• Dateigröße: 7,2 MB (929,5 KB Komprimierter Download)
• Freigaben (Releases): Model - nein | Eigentum - nein
• Format: 2099 x 1191 px | 35,5 x 20,2 cm | 14 x 7,9 inches | 150dpi

Weitere Informationen

Dieses Bild ist ein gemeinfreies Bild. Dies bedeutet, dass entweder das Urheberrecht dafür abgelaufen ist oder der Inhaber des Bildes auf sein Urheberrecht verzichtet hat. Alamy berechnet Ihnen eine Gebühr für den Zugriff auf die hochauflösende Kopie des Bildes.

Dieses Bild kann kleinere Mängel aufweisen, da es sich um ein historisches Bild oder ein Reportagebild handel

. The Canadian field-naturalist. 1971 Stelfox: Bighorn Sheep in Canada 1800-1970 113. Figure 6. A denuded winter range along the Athabasca Valley, Jasper National Park. This results from several years of overuse by more sheep than the range can support. Photo Credit: A. Loewen, Jasper Park Warden Service. disease was very likely the cause of the epidemic which occurred at the same time in Waterton. Deteriorated range conditions and poor nutri- tion undoubtedly predisposed the animals to the disease (Figures 6 and 7). Mule deer were estimated by wardens at 1, 700 in 1947 (Ban- field 1947). The elk population in Waterton was light before 1937 as they apparently did not migrate from the Belly River valley until 1932. Elk within the park in 1945 were estimated at not more than 500 (Banfield 1947). Thus, approximately 1, 000 bighorns, 1, 500 mule deer and elk and 2, 211 livestock, (almost 5, 000 ungulates) were foraging within this 204- square-mile park in 1936. Heavy snows in that year contracted the winter range to about 50 square miles, so the density must have ap- proached 100 ungulates per square mile. Buechner (1960) reported that on bighorn sheep ranges which had been stocked with domestic cattle, sheep and horses, the bighorns disappeared because they were unable to survive on deteriorated ranges. In addition, he believed that domestic stock probably introduced dis- eases harmful to bighorns. Studies during the Banff die-off revealed chronic actinomycosis and "verminous" broncho-pneumonia caused by lungworm (Cowan 1943). Poor range conditions resulting from over- stocking of bighorns and elk in the parks during the late 1930's and early 1940's were described by Clarke (1941), Green (1949), and Cowan (1950). In 1943, when the elk population in Banff was estimated at 3, 500 to 4, 000, Green (1949: 33) stated, "The elk pressure on all ranges, especially those of limited extent, has. Please note that these images are extracted from scanned page images that ma

Stockbilder mithilfe von Tags suchen

• bookcentury1900
• bookcolle