by spotted owls typically rolex submariner

Wysłany: Sob 15:04, 19 Mar 2011

Areas used by spotted owls typically have greater than 40% canopy cover and often have more than 70% canopy cover [7][21][23][41][62].[link widoczny dla zalogowanych] Despite variation in tree height and DBH, canopy cover varied little, ranging from 88% to 95% on small nest plots in grand fir forests of eastern Washington. Areas containing 90% of telemetry locations typically had greater than 40% canopy cover in this region [62]. Review of several studies found that northern spotted owl nesting and roosting sites in the California Klamath and Coast regions had more than 80% cover. Canopy cover within 82 feet (25 m) of California spotted owl nest sites in foothill riparian and oak woodlands in the southern Sierra Nevada averaged 86% [21]; and in white fir-mixed-conifer forests in northeastern California,[link widoczny dla zalogowanych], canopy cover was typically greater than 80% in a similar-sized area around nest sites [41]. Cover of vegetation above 7 feet (2.1 m) is typically more than 70% at California spotted owl nest sites, although canopy cover as low as 30% to 40% has been observed at higher elevations. Although a review notes the occurrence of Mexican spotted owls in sparsely vegetated habitats [4], other reviews state that they typically occupy stands with more than 40% [23] or 60% canopy cover.[link widoczny dla zalogowanych] In ponderosa pine-Gambel oak forests of Arizona, canopy cover was typically greater than 40% with only 2 roost stands having canopy cover from 25% to 40%. In addition, 75% of roost stands had more than 60% canopy cover [29].
Spotted owls may select areas with high canopy cover [12][26][53][59][61][63]. In coniferous forests in Oregon and Washington, canopy cover in small plots near northern spotted owl nests was significantly (P<0.095) greater than at random plots within spotted owl home ranges. However, when data were not pooled across study areas, only nest sites in the Olympic and Cascade regions had significantly (P<0.004) greater canopy cover than random plots [12]. Six California spotted owls in coniferous habitats of the Tahoe National Forest used stands with more than 40% canopy cover significantly more, and stands with less than 40% canopy cover significantly less than expected based on availability (P<0.005).[link widoczny dla zalogowanych] In addition, California spotted owl home ranges contained significantly (P<0.02) more forest with more than 70% canopy cover than expected [59]. California spotted owls in coniferous forests in the Sierra Nevada consistently selected areas with high canopy cover [60].