Treesearch

Temperature, intensity, spread, and dimensions of fires burning in tropical savanna and slashed tropical forest in central Brazil were measured for the first time by remote sensing with an infrared imaging spectrometer that was designed to accommodate the high radiances of wildland fires. Furthermore, the first in situ airborne measurements of sensible heat and carbon fluxes in fire plumes were combined with remote measurements of flame properties to provide consistent remote-sensing-based estimators of these fluxes. These estimators provide a means to determine rates of fuel consumption...

We studied the resting habitat ecology of fishers (Martes pennanti) in 2 disjunct populations in California, USA: the northwestern coastal mountains (hereafter, Coastal) and the southern Sierra Nevada (hereafter, Sierra). We described resting structures and compared features surrounding resting structures (the resting site) with those at randomly selected sites that also were centered on a large structure. We developed Resource Selection Functions (RSFs) using logistic regression to model selection of resting sites within home ranges, and we evaluated alternative models using an information...

The fisher (Martes pennanti) is a forest mustelid that historically occurred in California from the mixed conifer forests of the north coast, east to the southern Cascades, and south throughout the Sierra Nevada. Today fishers in California occur only in 2 disjunct populations in the northwestern mountains and the southern Sierra Nevada. We studied the ecology of fishers in both populations (the north coast [Coastal] and southern Sierra Nevada [Sierra]) to characterize the size and composition of their home ranges, and to compare features between locations. Twenty-one (9 Coastal, 12...

The American marten (Martes americana) was historically distributed within coastal and high elevation fir fore sts of the Klamath Siskiyou Bioregion (KSB) and was represented by three recognized subspecies (M. a. caurina, M. a. sierrae, and M. a. humboldtensis). The fisher (Martes pennanti pacifica) was historically distributed throughout interior and near-coast forests of the KSB. Over the last 8 years we have conducted systematic surveys, using baited track plate stations, at 497 locations within the KSB, resulting in >35,000 days of survey effort. Survey results demonstrate that martens...

American martens (Martes americana) and fishers (M. pennanti) occur together in mixed-conifer forests of the southern Sierra Nevada. We studied their diets in the area of sympatry by examining their feces and comparing diet diversity and overlap. Diets of both species were more diverse than previously reported in North America. Although the diet of fishers appeared to include more remains of birds, lizards, hypogeous fungi, and insects than that of martens, the rank contribution of prey items to the diets did not differ and the Pianka index of dietary overlap was high. The great diversity...

Reliable estimates of trends in population size are critical to effective management of landbirds. We propose a standard for considering that landbird populations are adequately monitored: 80% power to detect a 50% decline occurring within 20 years, using a 2-tailed test and a significance level of 0.10, and incorporating effects of potential bias. Our standard also requires that at least two-thirds of the target region be covered by the monitoring program. We recommend that the standard be achieved for species’ entire ranges or for any area one-third the size of the temperate portions of...

We present a probability-based model for estimating fire risk. Risk is defined using three probabilities: the probability of fire occurrence; the conditional probability of a large fire given ignition; and the unconditional probability of a large fire. The model is based on grouped data at the 1 km²-day cell level. We fit a spatially and temporally explicit non-parametric logistic regression to the grouped data. The probability framework is particularly useful for assessing the utility of explanatory variables, such as fire weather and danger indices for predicting fire risk. The model may...

We describe the use of bivariate stochastic differential equations (SDE) for modeling movements of 216 radiocollared female Rocky Mountain elk at the Starkey Experimental Forest and Range in northeastern Oregon. Spatially and temporally explicit vector fields were estimated using approximating difference equations and nonparametric regression techniques. Estimated vector fields of movement were mapped onto the project area at selected times of the day to examine spatial patterns of movement in relation to topography. Using the concept of a potential function, we were able to study the...

We used two metrics, occupancy and relative abundance, to study forest stand characteristics believed to be important to a threatened seabird that nests in old-growth forests, the Marbled Murrelet (Brachyramphus marmoratus). Occupancy refers to murrelet presence or absence based on observed bird behaviors, while relative abundance refers to categories of low, medium, and high numbers of bird observations per survey in a forest stand. Within the murrelet?s nesting range in California and southern Oregon, we measured habitat and climatic variables in all old-growth stands surveyed for...

An essential element in the conservation of rare species is the ranking of some aspects of habitat quality. We developed a method to rank the importance of individual habitat patches to Marbled Murrelets (Brachyramphus marmoratus) in 26 old-growth forest stands in northern California, using estimates of stand occupaqcy as an index of nesting activity. We used survey data collected in the stands from 1992 to 1997. The analysis was based on an adjustment that incorporates uncertainty of detection into a binomial model. Maximum likelihood estimators were used for the proportion P of the...