. Effetti di pecore al pascolo su un rivierasche-stream ambiente . Figura 2.-lay-down recinzione che separa la pesantemente pascolato area dall'leggermente pascolato area. Nota la vasta e poco profonda in streaming in modo pesantemente pascolato restringimento area come si entra nell'area recintata. Dal tardo Ottocento e primi del novecento, il numero di pecore pascolano il polo Creek prati era a forma di fungo a essere- provocare la zona era sul Ketchum-Stanley pecore auto- modo. William Horton, District Ranger presso il Polo Creek Station, riportati in 1910 che 200.000 pecore erano utilizzando le pecore carraio ogni anno. Le bande di pecora che storicamente usato il polo

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. Effects of sheep grazing on a riparian-stream environment . Figure 2.—The lay-down fence separating the heavily grazed area from the lightly grazed area. Note the wide, shallow stream in the heavily grazed area narrowing as it enters the fenced area. By the late 1800's and early 1900's, sheep numbers grazing the Pole Creek meadows had mushroomed be- cause the area was on the Ketchum-Stanley sheep drive- way. William Horton, District Ranger at the Pole Creek Station, reported in 1910 that 200, 000 sheep were using the sheep driveway each year. The bands of sheep that historically used the Pole Creek meadows exerted more grazing pressure on the riparian-stream environment than was normally found under the most commonly used sheep grazing strategies. In 1910, a 30-acre (12.2-hectare) section of Pole Creek meadows was fenced and used as a Forest Service Guard Station (fig. 2 and 3). Thus, sheep were restricted from grazing the administrative site (Guard Station), but heavy grazing continued in the remainder of the meadow until the mid-1960's when sheep numbers began to decline. In 1910, Ranger Horton reported that inside the fenced ungrazed area, pine and fir seedlings had excellent survival, while outside the fenced site there was little or no survival. By 1934, the meadow adjacent to the fenced area received such heavy use that 150 acres (60.7 hectares) had to be reseeded. From 1959 to 1975, the meadow continued to receive heavy use for sheep forage and bedground. The USDA Forest Service took action in 1964 to close the sheep driveway from Ketchum to Stanley to spring travel. That action resulted in much less grazing pressure on the meadows. The fence around the guard station was not entirely effective in keeping out all sheep. In 1936, it had to be reconstructed to further exclude sheep grazing. From 1964 to 1974, 10 horses and mules were grazed in the fenced area for about 1 month each summer. Throughout recent years, however, grazing within the fenced area was l

Parole chiave associate all'immagine

• bookauthorunitedstatesforests
• bookcentury1900
• booksubjectsheep