Changes in Herbaceous and Suffrutescent Perennials in Grazed and Ungrazed Desertified Grassland in Southeastern Arizona, 1958-1978
Chew RM. 1982. Changes in Herbaceous and Suffrutescent Perennials in Grazed and Ungrazed Desertified Grassland in Southeastern Arizona, 1958-1978. The American Midland Naturalist. 108(1):159-169
Cover of plants was measured in creosote bush (Larrea tridentata) and tarbush (Flourensia cernua) vegetations with a newly established cattle exclosure in 1958, and again in 1976-1977. Within the exclosure and in contiguous grazed areas. Protection from cattle grazing for 18-19 years did not alter the direction of vegetation change. Unpalatable species, particularly snakeweed (Gutierrezia sarothrae) and fluff grass (Tridens pulchellus), increased significantly within and without the exclosure from less than 1% cover in 1958 to as much as 20% in 1977. There was significant, but limited, increase of palatable perennial grasses within the exclosure, particularly in shallow washes. These grasses also increased within the exclosure, particularly in shallow washes. These grasses also increased in grazed creosote bush vegetation, particularly bush muhly (Muhlenbergia porteri), but decreased in grazed tarbush vegetation. There is evidence that there was less moisture stress in the shallow soil over caliche in the creosote bush vegetation than in the deep soil of tarbush. There was high mortality of fluff grass after a prolonged freeze in Dec. 1978. Such infrequent events confound the interpretation of data on long-term vegetational changes.
- Type
- Journal Article
- Authors
- Chew, Robert
- Units
- CHIR , CORO , SAGU , SODN
- Keywords
- Arizona, Botany (economic), Ecology (Community Ecology), Ecology (Plant), Grazing