Document Type

Report

Publication Date

9-2007

Abstract

Vegetation type, extent, continuity, and structure are some of the most important factors that determine wildlife diversity and distribution. Other contributing factors that shape wildlife communities include disturbance, competition, climate, and water availability. Because vegetation communities in the southwestern U.S. gradate sharply along zones of soil moisture, wildlife are often restricted to specific vegetation types. Along the Las Vegas Wash (Wash), Nevada, more than 250 wildlife species have been documented to occur in distinct wetland, riparian, and upland vegetation types. Recent studies have investigated the diversity and distribution of amphibians, birds, fishes, mammals, and reptiles (Shanahan 2005, 2005a, Van Dooremolen 2005, O'Farrell and Shanahan 2006, Larkin 2006). Moreover, focused surveys for the endangered southwestern willow flycatcher (Empidonax traillii extimus) and Yuma clapper rail (Rallus longirostris yumanensis) have been conducted since as early as 1998 (SWCA 1998, 1999, 2000, 2001, 2002, 2003, 2005, 2006; McKernan and Braden 2001, 2002). Field surveys have concluded that wildlife habitats are improving. Habitat analyses are integral components of the biological surveys that are conducted in the Wash. Because survey locations are finite, however, vegetation descriptions are often spatially limited. Vegetative communities described from a landscape perspective are helpful to understand the landscape structure and its effects on the distribution and abundance of organisms.

The Las Vegas Wash Coordination Committee, a multi-stakeholder collaborative planning group, has been facilitating biological resource inventories and ecological improvements along the Wash for the past several years. Besides the wildlife studies previously described, on the ground activities have included constructing multiple erosion control structures and stream bank protection facilities. Moreover, extensive revegetation projects have been completed to further protect the channel bed and banks from eroding as well as to improve wildlife habitat values. These activities are directed by a planning document that was completed in 2000, the Las Vegas Wash Comprehensive Adaptive Management Plan (CAMP). Among the action items that were listed in the CAMP was a recommendation to prepare a long-term wildlife management plan for the Wash, which is currently underway (Shanahan et al. 2007). In order for wildlife management planning to be successful, however, the availability and extent of wildlife habitats must be considered. Often, wildlife management is effectively accomplished by focusing management recommendations towards habitats.

The goal for this study is to identify and delineate land cover types along the Wash with specific attention given to vegetated cover types (i.e., vegetation communities). Vegetation communities are described by using standardized vegetation classifications (Association for Biodiversity Information 2001), Geographic Information System (GIS) technologies, and appropriate ecological methodologies (e.g., Barbour et al. 1999, Mueller-Dombois and Ellenberg 1974). This study provides a critical catalog of vegetative communities along the Wash using a repeatable standardized nomenclature. This study was conducted to facilitate wildlife management planning along the Wash (Shanahan et al. 2007), however, ecosystem restoration initiatives (Kloeppel et al. 2006, Bickmore 2003) were intended to benefit from these data as well. Specifically important land cover classifications, such as wetlands, are also presented to help plan for and meet long-term management goals along the Wash.

Keywords

Biotic communities--Classification; Desert plants; Ephemeral streams; Floodplain plants; Nevada--Las Vegas Wash; Vegetation classification

Disciplines

Biology | Desert Ecology | Environmental Indicators and Impact Assessment | Environmental Monitoring | Natural Resources and Conservation | Sustainability | Terrestrial and Aquatic Ecology | Water Resource Management

Language

English

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