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The Northwest Forest Plan is a large-scale ecosystem management plan that establishes a system of federal reserves interspersed with matrix forestlands where timber and other commodity production are given priority. Generally, management on reserved lands attempts to protect species associated with older forests. Whereas management in matrix lands emphasizes timber production, it maintains some protections for species associated with older forests. We conducted surveys at randomly selected points within the range of the Scott Bar Salamander (Plethodon asupak) and the southern portion of the range of the Siskiyou Mountains Salamander (P. stormi). We conducted surveys on both reserved and matrix lands to assess the relative role that these allocations play in the long-term persistence of Plethodon salamanders in this region. At low elevations (<1219 m), the proportion of sample points with captures of Plethodon spp. was significantly higher in matrix lands than on reserved lands. However, the number of Plethodon spp. captured at matrix and reserved land points was similar. Matrix land mitigations may be essential to provide protection for salamanders with small ranges and limited dispersal abilities. Oregon Ensatina (Ensatina eschscholtzii), the 2nd most commonly encountered amphibian, was more evenly distributed across the landscape than Plethodon spp. and was not associated with either reserved nor matrix lands.
Parental investment declines with increasing age of offspring, producing a conflict between parent and offspring over amount of parental investment. The degree of parent-offspring conflict may be associated with the gender of the offspring, mating system such as polygyny, and variation in reproductive success among individuals. We examined the dynamics of maternal investment through time by observing nursing behavior in Roosevelt Elk (Cervus elaphus roosevelti). Suckling rate (P =0.031) and suckling time per bout (P =0.014) by calves decreased with calf age, and male suckling rate (P =0.047) and suckling time per bout (P =0.008) were greater than those for females. Maternal initiation of nursing was greater in the early nursing period (P =0.009), and almost all suckling bouts were terminated by the mother. Our results were similar to those of studies on other polygynous ungulate species which exhibit differences in maternal investment in offspring based on gender.
Harbor Seals (Phoca vitulina) are the most abundant and widespread seal species in Washington State. Most seal haul-out sites are unavailable at high tide, hence abundance estimates are conducted at low tide when it is commonly accepted that most seals are hauled-out. On sites unaffected by tides, however, it is less clear whether tide level has an effect on seal abundance. We counted hauled-out Harbor Seals from sunrise to sunset on floating water-breakers at Semiahmoo Marina, Washington, to examine the effect of tides on haul-out behavior. Because haul-out behavior is affected by several factors, we conducted mixed-factor analyses that included tide level, tidal current, time of season, and time of day as fixed factors, and several meteorological variables as random factors. The number of hauled-out Harbor Seals was significantly associated with tide level, time of season, and time of day. Results suggest that seal counts in Semiahmoo Marina should be made late in the pupping season and early in the afternoon at moderately positive tide levels to achieve the highest counts. They also indicate that tide was associated with seal numbers unrelated to site availability because seal numbers were positively related to tide height, a finding opposite to studies at tidal haul-out sites.
American Dippers (Cinclus mexicanus) in winter often foraged in habitats not used for nesting, including deltas of coastal creeks, and occasionally ponds, tiny streams, and ditches. The birds migrated altitudinally, at least 12 crossed a saltwater channel, and some apparently made wider, regional movements (5 to 50% of banded birds, with annual variation). In 2 relatively severe winters, we resighted fewer banded birds (<40% versus >65%) and annual survival was lower (<40% versus >50%), compared to 2 relatively mild winters. Birds foraging in the intertidal zone on deltas preyed on amphipods (low fat content) and fish, but this habitat was unavailable at high tide.
Silvicultural practices such as thinning are performed both for commodity production and to help achieve fuel reduction and biodiversity goals. Although there are several studies that have examined effects of clearcut harvest techniques on forest songbirds, few have examined the effects of thinning. We studied the response of songbirds to different silvicultural approaches to forest management. We experimentally manipulated three 80 to 110 y-old Douglas-fir stands to evaluate influences of commercial thinning and clearcut harvest silvicultural systems on populations of diurnal breeding birds in southwestern Oregon. We conducted 10 to 12 bird point count surveys in each stand between 1992 and 1994 (prior to treatment), and point count surveys of birds 6 times each year from 1998 through 1999 (subsequent to treatment). We found that relative abundance and species richness were highest in the uncut control plots, slightly lower in the thinned plots, and lowest in the clearcut plots. A species-by-species analysis of those species with sufficient data showed marked negative short-term impacts of clearcutting on 12 of 16 species, potentially moderate negative impacts of thinning on 9 of 16 species, as well as positive impacts of thinning on at least 3 species.
We tried using morphometrics to determine sex for a population of Common Ravens (Corvus corax) in northwestern Wyoming. We attempted to correlate 13 external measurements to sex using discriminant function analyses. Sex was verified with a DNA test that identified females with 2 PCR-amplified gene copies (1 each from the W and Z chromosomes) and males with 1 gene copy (only Z chromosome). We created a predictive model of sex of ravens for easy field use. We found that by using 2 separate discriminant functions with footpad length and body mass measurements simultaneously, we were able to correctly classify 97% of female samples, 91% of male samples, and had an unknown category that included 15% of samples.
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