Treesearch

Developing a method of agricultural field reclamation to native grasses in the Lower San Pedro Watershed could prove to be a valuable tool for educational and practical purposes. Agricultural field reclamation utilizing native grass crop production will address water table depletion, soil degradation and the economic viability of the communities within the watershed. The focus of this study was to analyze the conversion of agricultural fields to native grass crops of three representative sites. Study sites include; a farm with fields that were seeded and allowed to grow for a period of...

The black-tailed prairie dog (Cynomys ludovicianus) was once widely distributed throughout the western United States; however, anthropogenic influences have reduced the species’ numbers to 2 percent of historical populations. Black-tailed prairie dogs are described as a keystone species in the grassland ecosystem, and provide many unique services, including burrows for other species (e.g. burrowing owls [Athene cunicularia] and rattlesnakes [Crotalus spp.]), nutrient rich soil that, in turn, provides rich vegetation for grazers, and food for many carnivores and birds of prey. Several...

Cattle have grazed continuously over the past three centuries in the Sky Island region and most work has focused on how these grazers have affected riparian and grassland habitats. I examined the effects of grazing on a fuller spectrum of desert habitats that occur in the close proximity to the San Bernardino Valley of Mexico and the United States. Plots in each of five habitats were placed in two adjoining areas: where grazing had not occurred for 25+ years and where grazing had only ceased 4+ years before this study. Vegetation responded quickly to removal of cattle in mesic environments...

Effects of low severity prescribed burning treatments and a wildfire on soil erosion and deposition in the oak savannas in the Southwestern Borderlands are reported. Measurements in the spring and fall, respectively, characterize soil movements following winter rains and high-intensity summer rainstorms. Annual values are also presented. Relationships between soil erosion and deposition and precipitation amounts, physiographic characteristics, and vegetation were analyzed to determine possible cause-and-effect implications. The information should be useful in developing strategies for...

Between February and July, 2011, over 360,000 acres burned across the Coronado National Forest during one of the most active fire seasons in recorded history. Burned Area Emergency Response (BAER) Teams evaluated post-fire watershed conditions and prescribed treatments based on threats to known values at risk. Hillslope stabilization treatments were prescribed and implemented for areas of high soil burn severity on both the Horseshoe 2 and Monument Fires. These treatments consisted of seeding on the Horseshoe 2 Fire and application of agricultural straw mulch and seed on the Monument Fire....

Management of the Madrean oak woodlands and the less dense and ecologically different oak savannas must be based on sound ecological information. However, relatively little is known about the Madrean oak ecosystems in spite of the fact that they cover about 80,000 km2 in the southwestern United States and northern Mexico. Emory oak (Quercus emoryi), the dominant tree in most stands, is usually associated with other oak and juniper species. Trees are utilized for firewood, fence posts, and construction materials and oak acorns are gathered as food by local inhabitants. The woodlands and...

Private and public land managers are attempting to reintroduce fire into the ecosystems of the Peloncillo Mountains to reduce the density of woody species, increase the herbaceous plant cover, and improve the area’s ecological diversity. The Cascabel Watershed Study, which includes 12 small gauged watersheds, was started in 2000 to evaluate the impacts of cool-season (November-April) and warmseason (May-October) prescribed fires on biological and physical components of the oak (Quercus spp.) savannas that are common to the Southwestern Borderlands Region. The Whitmire Wildfire in May 2008...

Due to a century of fire suppression practices, the Madrean Archipelago regions in Arizona have accumulated excessive fuel loads that increase wildfire sizes, intensities, and frequencies. Wildfire induced structural changes in forest ecosystems can either benefit or adversely impact wildlife species. Therefore, it is imperative to understand how wildlife species react to such ecosystem changes after wildfires in both the short-term and long-term time periods. We examined scientific literature to determine wildlife distribution, abundance, elevational migration, and behavioral changes...

Aquatic environments in the Madrean Sky Islands (MSI) consist of a matrix of perennial and intermittent stream segments, seasonal ponds, and human-built cattle trough habitats that support a diverse suite of aquatic macroinvertebrates. Although environmental conditions and aquatic communities are generally distinct in lotic and lentic habitats, MSI streams are characterized by isolated perennial pools for much of the year, and thus seasonally occur as lentic environments. In this study, we compared habitat characteristics and Coleoptera and Hemiptera assemblages of stream pools with those...

Western mosquitofish Gambusia affinis has major impacts on Gila topminnow Poeciliopsis occidentalis. Thirteen years have passed since information on negative impacts has been published. I will list and discuss additional examples where mosquitofish have impacted topminnow. In addition, it appears that long-term drought has a synergistic and negative effect on this relationship. Since the last publications detailing the loss of Gila topminnow populations to mosquitofish, two natural topminnow populations have been lost in the Santa Cruz River basin: Redrock Canyon and Sharp Spring. Drought...