Treesearch

This Special Section includes 8 peer-reviewed papers on the wolverine (Gulo gulo) in southern North America. These papers provide new information on current and historical distribution, habitat relations at multiple spatial scales, and interactions with humans. In aggregate, these papers substantially increase our knowledge of wolverine ecology and population dynamics in North America, in many cases replacing previous speculations and informed judgments with empirical information. North American wolverines occur primarily in tundra, taiga, and subalpine environments. These environments...

We tested the hypotheses that white pine blister rust (Cronartium ribicola J.C. Fisch.) damage in whitebark pine (Pinus albicaulis Engelm.) stands leads to reduced (1) seed cone density, (2) predispersal seed survival, and (3) likelihood of Clark's Nutcracker (Nucifraga columbiana (Wilson, 1811)) seed dispersal. We gathered data from two sets of paired forest sites in the Bitterroot Mountains of eastern Idaho and western Montana that were similar in topography, canopy structure, tree species composition, and successional stage, but differed in rust infection level, crown kill, and tree...

Dividing regions into manageable landscape units presents special problems in landscape ecology and land management. Ideally, a landscape should be large enough to capture a broad range of vegetation, environmental and disturbance dynamics, but small enough to be useful for focused management objectives. The purpose of this study was to determine the optimal landscape size to summarize ecological processes for two large land areas in the southwestern United States. We used a vegetation and disturbance dynamics model, LANDSUMv4, to simulate a set of nine scenarios involving systematically...

Inspection of cavity nests and nest boxes is often required during studies of cavity-nesting birds, and fiberscopes and pole-mounted video cameras are sometimes used for such inspection. However, the cost of these systems may be prohibitive for some potential users. We describe a user-built, wireless cavity viewer that can be used to access cavities as high as 15 m and with entrance diameters as small as 2.5 cm. System components include a wireless camera, boom with near-infrared lighting system, hand-held television, and telescoping pole. The unit can be assembled in about one day with...

Although understanding habitat relationships remains fundamental to guiding wildlife management, these basic prerequisites remain vague and largely unstudied for the wolverine. Currently, a study of wolverine ecology conducted in Montana, USA, in the 1970s is the sole source of information on habitat requirements of wolverines in the conterminous United States. The Montana study and studies conducted in Canada and Alaska report varying degrees of seasonal differences in wolverine habitat use. This article provides an empirical assessment of seasonal wolverine habitat use by 15 wolverines...

Wildland fire is a significant disturbance in many ecosystems worldwide and the interaction of fire with climate and vegetation over long time spans has major effects on vegetation dynamics, ecosystem carbon budgets, and patterns of biodiversity. Landscape-Fire-Succession Models (LFSMs) that simulate the linked processes of fire and vegetation development in a spatial domain are one of the few tools that can be used to explore the interaction of fire, weather and vegetation over century-long time scales. There is a diverse set of approaches to predicting fire regimes and vegetation...

The genus Leymus includes about 30 long-lived perennial Triticeae grasses distributed throughout cold and/or semiarid regions of Americas, Europe, and Asia. Leymus cinereus and L. triticoides display divergent growth habit adaptations to different microenvironments in western North America. L. cinereus, a tall caespitose bunch grass, is commonly found near mountain and foothill waterways. L. triticoides, a relatively short rhizomatous grass, is restricted along stream banks or saline wetlands. Subterranean tiller and rhizome buds appear similar but display different responses to gravity...

In 2000, a collaborative range-monitoring program, "Reading the Range," was established with the University of Arizona Cooperative Extension in Gila County, the Gila County Cattle Growers, and the Tonto National Forest with the assistance of the US Department of Agriculture Renewable Resources Extension Act grant program. Funding for Reading the Range has continued with the assistance of the Gila County Board of Supervisors, the Natural Resources Conservation Service (NRCS), and the Tonto Natural Resources Conservation District. This monitoring program uses standardized monitoring technique...

Determining mechanisms responsible for weed resistance and invasion success are two issues that have potential in aiding successful land management decisions. The first experiment evaluates the competitive effects of an invasive annual grass downy brome (Bromus tectorum L.), an invasive biennial forb dyer's woad (Isatis tinctoria L.), and a reclamation shrub prostrate kochia (Kochia prostrata [L.] Schrad.) on nitrate acquisition, shoot and root growth, leaf carbon: nitrogen ratio, and leaf N of a perennial grass crested wheatgrass (Agropyron cristatum [L.] Gaertner x A. desertorum [Fisch....

Conservation of the wolverine (Gulo gulo) at the southern extent of its North American range requires reliable understandings of past and present distribution patterns and broad-scale habitat relations. We compiled 820 verifiable and documented records of wolverine occurrence (specimens, DNA detections, photos, and accounts of wolverines being killed or captured) in the contiguous United States from museums, the literature, and institutional archives. We spatially referenced 729 records with areal precision [less than/equal to] 1 township (93.2 km2) and temporal precision [less than/equal...