Abstract

GUEVARA, Juan C.; ESTEVEZ, Oscar R.  and  STASI, Carlos R.. Vegetation response in a grazing intensity gradient in Mendoza, Argentina. Multequina [online]. 2006, vol.15, n.1, pp.27-36. ISSN 1852-7329.

The study evaluated changes in plant species and bare soil cover when vegetation was exposed to increased levels of cattle grazing intensity under a conservative stocking rate. Two homogeneous paddocks were selected to sample vegetation along transects originating from the watering point. Species and bare soil cover was recorded at increasing distances (from 0.3 to 3.8 km) from water, in two homogeneous paddocks, along four 50- m line-transects per paddock for each distance by the modified point-quadrat method. Cover data were amalgamated into six categories: bare soil (BS), forage grasses (FG), no forage grasses (NFG), forage shrubs (FS), no forage shrubs (NFS) and forage forbs (FF). The relationships among transects, based on cover, were analyzed through cluster analysis. As a complement, principal component analysis was performed. The distances 2.7, 3.2, and 3.5 km from water were characterized by high cover of FG, while BS, FS and NFS were associated with distances from 0.3 to 0.9 km. Distances of 2.1 and 2.4 km showed high cover of NFG, while FF was associated with distance of 3.8 km. We found that vegetation in the study site is particularly sensitive to the pressures of the current grazing regime with conservative stocking rate. Various approaches to minimize degradation around water facilities have been indicated.

Keywords : Cattle grazing; Conservative stocking rate; Plant cover; Bare soil.

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