BOTANICAL COMPOSITION CHANGES OF TWO RANGELANDS UNDER EXCLUSION AND GRAZING, IN ZACATECAS, MEXICO
Grazing is a factor that regulates structural vegetation changes in rangelands. The use of exclosures allows to record modifications occurrying in the rangelands. The objective of this study was to know changes in botanical composition occurred in exclosures and grazed rangelands located at La Esperanza, Villa Hidalgo, Zacatecas (22o 30? 10 N and 101o 39? 40 W, 2480 m elevation) and El Salto, Pinos, Zacatecas (22o 29? 50 N and 101o 30? 40 W, 2100 m elevation) for six years. Eight 20 m Canfield lines for each year 1985 to 1991 (except 1986) and inside or outside exclosures, were done. Degree of likeness in botanical composition between sites and conditions within site, was determined by Jaccard coefficient; a similarity matrix was developed and results were represented in dendrograms. A total of 83 species were recorded. Botanical composition between sites was different. In 1985, no differences between inside and outside of exclosure in each site were found but differences were evident in following years, mainly the amount of species. At La Esperanza there was 45, 80, 65, 90 and 70 % increase in number of species inside the exclosure, for years 1987 to 1991, in relation to 1985. At El Salto the increase occurred outside the exclosure, in a proportion of 35, 60, 40, 65 y 55 % for the same years, in relation to 1985.
| Main Authors: | , , |
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| Format: | Digital revista |
| Language: | spa |
| Published: |
Colegio de Postgraduados
1997
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| Online Access: | https://www.agrociencia-colpos.org/index.php/agrociencia/article/view/1495 |
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