Ecological Costs of Livestock Grazing in Western North America

Abstract

Livestock grazing is the most widespread land manageraent pracPice in western North America Seventy percent of the western United States is grazea~ including wilderhess area~ tvlldlife refuge& national forest~ and even some national park~ The ecological costs of this nearly ubiqui. tous form of land use can be drarr~pi~ Examples of such costs include loss of biodiversity; lowering of population densities for a wide variety of taxa~ disruption of ecosystem funcPion~ including nutrient cycling and succession,, change in community organization; and change in the physical characteristics of both terrestrial and aquatic habitat~ Because livestock congregate in riparian ecosysten~ which are among the biologically richest habitats in arid and semiarid region~ the ecological costs of grazing are magnified in these site~ Range science has traditionally been laden with economic assumppions favoring resource use Conservation biologists are encouraged to contribute to the ongoing social and scientific dialogue on grazing issuex Costus ecol6gicos del pastoreo de ganado en el oeste de Estados Unidos Resumen: El pastoreo de ganado es la prdcpica de manejo de la tierra mds ampliamente upilizada en el oeste de Norte Am~xt E1 setenta por ctento del oeste de Estados Untdos se upiliza para pustoreo, incluyendo dreas silvestreg refugios de vida silvestre, bosques nacionales e inclusive algunos parques nacionale& El costo ecol6gico de esta forma ubicua de uso de ia Pierra puede set dramdpico. Ejemplos de este costo incluyen pdrdida de ia biodiversidad; decrecimiento de las densidades de poblaci6n para una amplia variedad de taxone~, alteraciones en ias funciones del ecosistem, incluyendo ciclos de nutrientes y sucesiones; cambios en ia organizaci6n de la comunidad y cambios en las caracteris. Picas flsicas de hdhitas terrestres y acudpico~ Dado que el ganado se congrega en ecosistemas ribere~og los cuales estdn entre los hdbitas biol6gicamente mds ricos dentro de ias regiones dridas y semi.dridag los costos ecol6gicos del pastoreo se magnifican en estos siPio& Tradicionalment~ la ciencia de Pastizale~ ha estado cargada de suposiciones, eco-n6micas que favorecen el uso del recurso. Se alienta a los bi61ogos conservacionistus a contribuir al didlogo social y ctenttflco en los problemas del pastoreo.

Vegetation Description, Rare Plant Inventory, and Vegetation Monitoring for Craig Mountain, Idaho.

“…Water quality, hydrologic regimes, ungulate winter range, recreational opportunities, and rare plant populations have been adversely affected by the direct and indirect consequences of livestock grazing. Livestock grazing can result in many ecological changes, including, 1) alteration of ecosystem structure -such as abetting the loss of stable vegetation cover and a general decline in habitat conditions, aiding the spread of weeds, changing vegetation stratification, contributing to soil erosion r and siltation of streams, decreasing the quality and quantity of water, and in woodlands, removal of highly flammable fuels, which helps to reduce the incidence of ground fires that previously controlled dense tree seedling establishment; 2) disruption of ecosystem functions -such as ecological succession and nitrogen and other nutrient cycling; 3) alteration of composition -such as decreases in species richness, and decreases in the density of individual species (Hall 1977;Fleischner 1994;Oliver et al 1994). …”

“…Domestic livestock grazing may also lead to 1) competition with native herbivores for forage; 2) impacts on predator control efforts; 3) transmission of disease to native animals; and 4) increased fencing, a common livestock management tool that can create obstacles for some native wildlife (Fleischner 1994, and references cited within).…”

“…Livestock can affect several components of riparian systems, including the vegetation, soils, stream charmel morphology and bank stability, and water quantity and quality (Fleischner 1994, and references cited within). Most traditional grazing systems have been developed for grassland, not riparian plant species.…”

Wildfire Assessment Using FARSITE Fire Modeling: A Case Study in the Chihuahua Desert of Mexico

“…These open niches have allowed for the introduction of some highly invasive grasses including the African love-grasses (Eragrostis sp.). Additionally, these high intensity fires have exacerbated effects on soil quality and erosion (Ansley, 2011;Esque et al, 2010;Fleischner, 1994).…”

“…After fire, there is little to no vegetation left to hold the soil from wind and water erosion. The result is typical in all ecosystems after fire, but it is highly detrimental to desert ecosystems as erosion is already viewed as a large threat to desert ecosystems (Fleischner, 1994). Furthermore, many studies have found that fireinduced soils have decreased hydraulic conductivity (K) after burns (Doerr et al, 2000;Ravi et al, 2006;Ravi et al, 2009).…”