Treesearch

Anatone is a natural, non-manipulated bluebunch wheatgrass population accession originating from Asotin County in Southeastern Washington. It is a long-lived perennial bunchgrass better adapted to low elevation, semi-arid sites with long, hot growing seasons than other bluebunch wheatgrass accessions or available releases. Its seedling vigor and establishment also exceed those of other accessions and released cultivars. Anatone's ready germination, rapid development, ability to compete with exotic annuals, and drought tolerance make it an excellent choice for restoration of cheatgrass...

We used a comparative mensurative landscape-level experiment to quantify the relative importance of mature forest area and fragmentation and differences among watersheds in influencing avian community diversity in the Oregon Coast Range, USA. Our study design included three large hydrological basins, two levels of fragmentation, and six levels of mature forest area. We recorded 82 species of birds in a total of 1046 plots in 30 landscapes. Our four response variables were species richness, species density, species evenness, and total bird density. We used a combination of factorial ANOVA...

We examined attributes of pinon pine (Pinus edulis) associated with the probability of infestation by pinon ips (Ips confusus) in an outbreak in the Coconino National Forest, Arizona. We used data collected from 87 plots, 59 infested and 28 uninfested, and a logistic regression approach to estimate the probability ofinfestation based on plotand tree-level attributes. Pinon pine stand density index was a good predictor of the likelihood of infestation by pinon ips at the plot level, and a cross-validation analysis confirmed that the model correctly classified 82% ofthe cases. Diameter at...

Juniperus osteosperma-Pinus monophylla or P. edulis (P-J) woodlands are the most widespread plant community in Zion National Park (ZNP), southwestern Utah. These woodlands dominate nearly half of the park's land area. Our study of this vegetational complex is based on a sample consisting of 115 macroplots (each 0.01 ha in area) objectively distributed across the entire area of ZNP. We recognize 3 subtypes within the P-J complex: juniperus osteosperma (Utah juniper) alone, juniper with P. monophylla (single-leaf pinyon), and juniper with P. edulis (two-leaf pinyon). The 2 pinyon pines...

Nepalomyia Hollis and Neurigonella Robinson are synonymized. The genus Nepalomyia is more fully characterized and the Nearctic species are revised. Nepalomyia nigricornis (Van Duzee) and N. sombrea (Harmston & Knowlton) are reassigned and redescribed. Two new species, N. dilaticosta Runyon & Hurley and N. hesperia Runyon & Hurley, are described. New combinations are created for the following non-Nearctic species: Nepalomyia bidentata (Yang & Saigusa), N. brevifurcata (Yang & Saigusa), N. crassata (Yang & Saigusa), N. daliensis (Yang & Saigusa), N. daweishana (Yang & Saigusa), N. dentata...

The endangered Southwestern Willow Flycatcher (Empidonax traillii extimus) breeds at numerous sites throughout its range that vary greatly in floristics, vegetation structure, and the extent of human alteration of the habitat. Here we present information on nesting habitat characteristics of Willow Flycatchers in the largest extant population of the subspecies along the upper Gila River in New Mexico. We compared 19 habitat variables between nest sites and sites not included in flycatcher territories. A logistic regression model identified three variables as significant predictors of...

As part of a study to determine effects of removing fire fuels on riparian bird species, over 400 nests of 10 species were found and monitored during the pre-treatment period, 2000-2002. In this presentation, we report on the relationships between species-specific relative abundance, nesting success, and habitat measures such as stem density, canopy cover, and fuel loads of exotic and native trees.

Organic matter retention is an integral ecosystem process affecting C and nutrient dynamics and biota in streams. Influences of discharge (Q), reach-scale channel form, and riparian vegetation on coarse particulate organic matter (CPOM) retention were analyzed in 2 headwater streams in northeastern Oregon. Ginkgo biloba leaves were released in coniferous forest reaches and downstream floodplain meadow reaches during spring high flow and summer baseflow. Transitional reaches were also analyzed during summer baseflow. Paper strips, simulating sedge blade retention, were released in meadow...

Despite the numerous values of riparian areas and the recognition of fire as a critical natural disturbance, few studies have investigated the behavior, properties, and influence of natural fire in riparian areas of the western USA. Riparian areas frequently differ from adjacent uplands in vegetative composition and structure, geomorphology, hydrology, microclimate, and fuel characteristics. These features may contribute to different fire environments, fire regimes, and fire properties (frequency, severity, behavior, and extent) in riparian areas relative to uplands. In certain forested...

Sweet resin bush (Euryops subcarnosus DC ssp. vulgaris B. Nord; or, Euryops multifidis (L. f.) DC.), a South African shrub introduced to Arizona in the 1930s, was discovered on the Santa Rita Experimental Range (SRER) in 1998. Due to the threat of spread of this invasive plant and its potential to cause adverse environmental and economic effects, and because it posed a threat to the Federally listed endangered Pima pineapple cactus (Coryphantha sheerii Muehlenph. L.D. Benson var. robustispina L.D. Benson), we initiated a project in early 1999 with the overall goal of eradicating about 154...