Treesearch

Lack of roost habitat (trees >40 cm diameter breast height [dbh] and >18 m2/ha basal area) can limit populations of Merriam’s turkeys (Meleagris gallopavo merriami). The Black Hills region has relatively large populations of Merriam’s turkeys, yet trees >40 cm dbh are uncommon. Consequently, I studied roosting habitat of this subspecies in a hierarchical manner to quantify roost habitat requirements in an area of apparent limited suitable roost habitat. Little or no selection for roosts occurred among macrohabitats. Basal area at roost sites averaged 19 - 25 m2/ha. Winter and summer...

Habitat selection patterns of Merriam’s Turkeys were compared in hierarchical analyses of three levels of habitat stratification. Habitat descriptions in first-level analyses were based on dominant species of vegetation. Habitat descriptions in second-level analyses were based on dominant species of vegetation and overstory canopy cover. Habitat descriptions in third-level analyses were based on dominant species of vegetation, overstory canopy cover, and structural stages (dbh categories). First-level analyses showed turkeys selected for ponderosa pine and selected against meadow habitats....

Service-life tests indicate that ponderosa pine fenceposts treated with preservatives performed well after field exposure of 30 years. Treating plants in the Black Hills area used commercial methods to treat the posts with creosote, pentachlorophenol, and waterborne arsenicals. Test sites were in the northern Great Plains-one in the semiarid western portion near Scenic, South Dakota, the other in the more humid eastern portion near Brookings. The annual service cost of the untreated posts ranged from $1.06 to $1.18 per post depending upon test plot location. The lowest annual cost of the...

One of the most critical, and difficult, steps in the Limits of Acceptable Change (LAC) process is the selection of indicators. To help with this step, this paper (I) briefly reviews some desirable characteristics of indicators and (2) lists indicators that have been proposed or adopted in LAC plans. From a comparison of this list of indicators and desirable characteristics of indicators we briefly evaluate progress to-date and identify three major problems in selecting LAC indicators. Indicators from dispersed backcountry and wild and scenic rivers, as well as from designated wilderness,...

Provides information on fire as an ecological factor in forest habitat types, and in pinyon-juniper woodland and oak-maple brushland communities occurring in Utah. Identifies Fire Groups based on fire's role in forest succession. Describes forest fuels and suggests considerations for fire management.

We report the first measurements of friction angles for a naturally formed gravel streambed. For a given test grain size placed on a bed surface, friction angles varied from 10º to over 100º; friction angle distributions can be expressed as a function of test grain size, median bed grain size, and bed sorting parameter. Friction angles decrease with increasing grain size relative to the median bed grain size, and are a systematic function of sorting, with lower friction angles associated with poorer sorting. The probability distributions of critical shear stress for different grain sizes...

Of 32 species of abundant breeding birds, populations of 10 species differed significantly between small cutting units and adjacent uncut forest. Foliage foragers and tree gleaners were less abundant in cutting units, while flycatching species and ground foragers were more common there. Of nesting guilds, conifer tree nesters were least abundant in cutting units, and ground nesters were more common there. Results suggest that bird management should consider diverse community-level habitat needs and that if maintenance of tree-dependent species is important, broadleaf trees and snags of all...

Birds were sampled monthly for two years in Rocky Mountain juniper Uuniperus scopulorum) woodlands and in adjacent grasslands. Total numbers and species richness were consistently higher in every season in juniper stands than on grasslands. Rocky Mountain juniper stands provide food and thermal cover in the winter; migratory corridors in the fall and spring; and feeding, nesting, and perching sites in the summer.

Ecology focuses on tangible organisms; ecological complexity results from the myriad of patterns with which the many different types of organisms interact in their environments. Yet ecology is by no means devoid of abstraction. To produce general principles out of the mass of complicated natural histories, ecology is replete with concepts, such as competition, evolution, and succession, and abstruse structures, such as communities and ecosystems.

A small population of Prairie Falcons (Falco mexicanus) (mean = 6 pairs/year) nesting in northcentral Wyoming quit nesting in response to a severe spring snowstorm in 1984. Temperatures during the April storm were similar to years when the falcons reproduced successfully, but the monthly snowfall was 89.2 cm as compared to the 30-yr monthly average of 29.92 cm (90% CI = 21.44 -38.40 cm). Analysis of prey abundance suggested that significantly fewer prey-sized birds were present on the study area in 1984 than in 1985, possibly as a result of the storm. The nesting failure may have been in...