干旱区生态环境知识资源中心

Native vegetation of semiarid grasslands and desert ecosystems that comprise the Arbosufrutescent Desert scrub vegetation in north-central Sonora has been degraded by overgrazing, drought, farming, woodcutting, and a host of other activities over the past century. Several studies were conducted at "Rancho Grande" and at "Rancho El Carrizo," Sonora from 1992 to 1999 to evaluate the effect of several range improvement practices on wildlife habitat. Twenty-five-thousand seedlings of eight native shrubs and trees were transplanted on a site in north-central Sonora. Survival rates among species varied from 55 to 84 percent 1 year after transplanting and from 10 to 41 percent 3 years after planting. Reestablishment of native shrubs represents a promising technique that could restore native woody vegetation on degraded ecosystems that lack diversity. Habitat management by disking and shredding coupled with improvement in grazing management with short-duration grazing, have also resulted in improved native herbaceous conditions on thousands of acres of private ranches. These results are encouraging. The potential impact that re-establishment of native shrubs, control of undesirable brush species, and improvements in grazing management may have on wildlife occupying rangelands in north-central Sonora will be discussed.