Assessment of native species and ungulate grazing in the Southwest: Terrestrial wildlife

Abstract

______________________________________Range managers in the Southwestern States are increasingly being required to develop management strategies that take into consideration the conservation of wildlife populations. However, information on many aspects of the fundamental biology and impacts of grazing on individual species is still lacking in the scientific and government literature. This report documents a project designed to assemble this information for terrestrial wildlife in Arizona and New Mexico that have the potential to be negatively impacted by grazing or range management practices. To achieve this, a two-stage panel process was developed that employed a variety of wildlife experts to create a list of potentially vulnerable species and to develop an informational database. Panelists first reviewed and assessed all terrestrial vertebrates in the region to develop an initial list. In the second stage, the panelists refined the list, reviewed published information drafted into individual species accounts, and then augmented these accounts with information from their own experience and observations. The resulting database contains accounts for 305 species and subspecies of amphibians, reptiles, birds and mammals, including a computer database that allows managers to search and query the species accounts based on geographic distribution as well as shared ecological and life history characteristics.

Terrestrial species viability assessments for national forests in northeastern Washington

“…In three separate studies, this species was absent from heavily grazed or browsed areas but was found on nearby ungrazed or lightly grazed comparison plots (Berger et al 2001, Medin and Clary 1991, Mosconi and Hutto 1982). The negative impact was considered to be a result of alteration of important vegetation structure and composition, as well as negative impacts on water quality or water regimes that affect vegetation (Zwartjes et al 2005).…”

“…Livestock grazing may contribute to reduced fire frequency in ponderosa pine forests by reducing the amount of grass that facilitated the spreading of low-intensity fires (Zwartjes et al 2005). The depletion of competing grasses and lack of fire encouraged the growth of shrubs and dense stands of young conifers (Chambers andHolthausen 2000, Touchan et al 1996).…”

“…Dense ponderosa pine forests that resulted from reduced frequency of low-intensity fires are at a greater risk of stand-replacing fires (Chambers andHolthausen 2000, Touchan et al 1996). A great reduction in grass biomass owing to grazing is likely to negatively affect the prey base for western bluebirds (Zwartjes et al 2005). In addition, Bull et al (2001), found western bluebirds to be more abundant at ponds that were protected from livestock grazing than those not protected.…”

Cordilleran Flycatcher (Empidonax occidentalis)

“…They increased with snag density, and were most abundant in stands with >3 snags per acre. They were also most abundant in stands with >20% of snags in decay class 2 (Zwartjes et al 2005). Cordilleran Flycatchers prefer cool, well-structured forests with a dense understory (Zwartjes et al 2005) Cordilleran Flycatchers are present in New Mexico from May to September (Parmeter et al 2002).…”