Changes in herbaceous plant density and canopy cover of creo sotebush (Larrea tridentata Sesse & Moc. ex DC) and associated shrubs following brush control treatments were measured in Sonoran and Chihuahuan Desert communities. Treatments were app lied in 2 successive years at the Santa Rita Experimental range, Arizona, and 3 locations in Chihuahua, Mexico. Across all loca tions and years 1.5 kg/ha tebuthiuron {JV-{5-(l,l-dimethylethyi)l,3,4-thiadiazol-2-yl>AyV'-dimethyIurea}>1.0 kg/ha tebuthiuron = disking = disking with furrowing >2-way railing >0.5 kg/ha tebuthiuron > land imprinting in reducing canopy cover of creo sotebush and associated shrubs. At the Santa Rita Experimental Range annual precipitation was above long-term mean in 1982, 1983,1984,and 1985;and grassdensity increased on all treated and untreated plots. Annual precipitation was below long-term mean during 1986 and 1987 and grass density decreased on both treated and untreated plots but did not decrease to pre-treatment densities. Forb densities were less than 3 plants/m2 throughout the study, except in 1987when Russian thistle {Salsola iberica Sennen & Pau) increased on all plots. At the Chihuahuan locations, grassdensities usually increased during the first year of the study, but very low precipitation throughout the study caused subsequent reductions in grass and forb densities. In dry years brush control treatments did not increase herbaceous plant density.

Abstract:This study is about four cacti species in the state of Chihuahua, (Coryphantha macromeris, Mammillaria lasiacantha, Echinocereus dasyacanthus and Ferocactus wislizenii). Geographic distribution was inferred with MaxEnt. Projection was estimated under three scenarios simulated from IPCC (A2, B1 and A1B) and four periods (2000, 2020, 2050 and 2080) with 19 climatic variables. MaxEnt projects a species decrease in 2020 under scenario A2, increasing in the following years. In 2080 all species, except E. dasyacanthus, will occupy a larger area than their current one. Scenario B1 projected for 2050 a decrease for all species, and in 2080 all species except E. dasyacanthus will increase their area. With A1B, C. macromeris decreases 27% from 2020 to 2050. E. dasyacanthus increases from 2020 to 2050 and decreases 73% from 2020 to 2080. M. lasiacantha decreases 13% from 2020 to 2080 and F. wislizenii will increase 13% from 2020 to 2080. Some species will remain stable on their areas despite climate changes, and other species may be affected under the conditions of the A1B scenario. It is important to continue with studies which give a broader perspective about the consequences of climate change, thus enabling decision-making about resource management.

Patterns of end-of-season standing crop were evaluated during a 4-year period on an oak-bunchgrass range site under shortduration grazing in northern Mexico. Patterns weredetermined as a function of reduction of tinding crop biomass of grease8 witbin strata (300 m e8cb) from 8 central watering point. Signifhnt differences in endslae8son standing crop (KO.05) were found among the strata. Four-year average standing crop biomass was 383 kg/br witbin 300 m from the central watering point; wherea% standing crop biomass was 53% 691,855, and 805 kg/ha within strata 300-600,600-900,~1,200, and 1,200-1,500 m from the centnl watering point, respectively.

Seeding exotic grasses remains a common practice to increase forage production for cattle in northern Mexico. Even while interest in wildlife conservation and management has been increasing since the late 1990s because of the economic value of wildlife for sport hunting, cattle production still represents an important part of the ranch income. Our objective was to review the available information on exotic grasses and its effect on native rangelands and wildlife. To obtain the information included in this article, we reviewed the published information and personal information and observations. Ranchers need to balance and make commitments to optimize cattle and wildlife economic output. In general, the negative perception of biologists, ranchers, and the general public toward exotic grasses is less pronounced than in the United States even when the ecological benefits of maintaining healthy native rangelands is well‐understood. Differences in primary productivity and domestic animal production between exotic and native grasses are well‐documented; however, information on impacts of exotic grasses on wildlife is extremely limited. The preservation of native rangelands is important; however, exotic grasses will continue to be seeded in northern Mexico as long as cattle production remains an important economic activity. Exotic grasses in many cases will be impossible to eradicate; therefore, management will be necessary to ensure optimization of habitat for livestock and wildlife species. In this context many research questions need to be answered to optimize domestic livestock production and maintain healthy wildlife populations. Governments, non‐governmental organizations, and other entities interested in conservation should combine efforts and develop incentive programs for ranchers to preserve native rangelands in Mexico and to avoid seeding exotic grasses. © 2013 The Wildlife Society.