Biodiversity across a Rural Land‐Use Gradient

Abstract

Private lands in the American West are undergoing a land‐use conversion from agriculture to exurban development, although little is known about the ecological consequences of this change. Some nongovernmental organizations are working with ranchers to keep their lands out of development and in ranching, ostensibly because they believe biodiversity is better protected on ranches than on exurban developments. However, there are several assumptions underlying this approach that have not been tested. To better inform conservation efforts, we compared avian, mesopredator, and plant communities across the gradient of intensifying human uses from nature reserves to cattle ranches to exurban developments. We conducted surveys at randomly selected points on each type of land use in one Colorado watershed between May and August of 2000 and 2001. Seven bird species, characterized as human commensals or tree nesters, reached higher densities ( all p < 0.02 ) on exurban developments than on either ranches or reserves. Six bird species, characterized as ground and shrub nesters, reached greater densities ( all p < 0.015 ) on ranches, reserves, or both of these types of land use than on exurban developments. Domestic dogs ( Canis familiaris ) and house cats ( Felis catus ) were encountered almost exclusively on exurban developments, whereas coyotes ( Canis latrans ) were detected more frequently ( p = 0.047 ) on ranchlands than exurban developments. Ranches had plant communities with higher native species richness and lower non‐native species richness and cover than did the other types of land use ( all p < 0.10 ). Our results support the notion that ranches are important for protecting biodiversity and suggest that future conservation efforts may require less reliance on reserves and a greater focus on private lands.

Broad-Scale Assessment of Rangeland Health, Grand Staircase–Escalante National Monument, USA

“…Furthermore, higher human footprint classes dominate most of the private and BOR lands whereas the human footprint least affects NPS and DOD lands. On private land holdings throughout the West, particularly Colorado, Utah, New Mexico, and Montana, largeacreage ranches are being broken up into smaller ranchettes which increases human densities and brings along associated infrastructure, exotic plants, domestic predators and a subsequent change in biodiversity (Maestas et al 2003, Odell et al 2003. This shift in land use could potentially increase the influence of the human footprint within and near these areas of development.…”

Influence of Grazing Intensity on Swamp Plant Communities in the Tropical Montane Wetland Ecosystems, Nilgiris, Southern India

“…However, excessive grazing can result in the ecological disturbance of vulnerable grassland and wetland ecosystems leading to biodiversity loss and biological invasions (Milchunas and Lauenroth, 1993;Perevolotsky and Seligman, 1998;Marty, 2005;Dahwa et al, 2013). Thus the response of local and regional biodiversity to grazing may be positive or negative depending upon its intensity and frequency and the species specific responses of the constituent vegetative and herbivore taxa (Freilich et al, 2003;Maestas et al, 2003). For instance, in the absence of large herbivores that historically grazed most grassland, livestock can serve as their functional equivalents assisting in the maintenance of localized biodiversity (Maestas et al, 2003;Marty, 2005).…”

“…Thus the response of local and regional biodiversity to grazing may be positive or negative depending upon its intensity and frequency and the species specific responses of the constituent vegetative and herbivore taxa (Freilich et al, 2003;Maestas et al, 2003). For instance, in the absence of large herbivores that historically grazed most grassland, livestock can serve as their functional equivalents assisting in the maintenance of localized biodiversity (Maestas et al, 2003;Marty, 2005).…”

Input–output modeling, outdoor recreation, and the economic impacts of weeds

“…Much of this exurban expansion has come via the conversion of working ranches to smaller holdings that serve as residential properties, creating a landscape that typically is fragmented (Mitchell et al 2002) and may be more likely to be dominated by nonnative invasive species (Epanchin-Niell et al 2010). The negative ecological implications of these changes have received considerable attention (Hansen et al 2002;Maestas et al 2003) as have the effects on working ranches (Rowe et al 2001;Brunson and Huntsinger 2008). These landscapes have been a primary focus of wildfire mitigation and fuel hazard reduction activities, at least in terms of government policy.…”