Caatinga herbaceous stratum dynamics under grazing intensities by goats in a semi-arid region of brazilian Northeast.
A native grassland Caatinga has been submitted to three grazing intensitics (GI) by goats (1981-84) to vcrify the etfcct of these GI on vegctation degradation. Treatments varied from I doell ha to I doe/3 ha, including Exclusion (without grazing) by oecupying seven arcas which ranged from ISto 45 ha. Rainlall was 484.8. 364.4. 552.8, and 605.3 mm in October/80-Septemberl 81, 1981-82, 1982-83 and 1983-84, respectively. The cffcct 01' GI on the frequency of herb species and on the density 01' woody seedling (height < 0.5 m) has been evaluatcd by using I m' (2 x 0.5 m) quadrats in cach year of rcscarch. Neither the hcrb species frequency nor the woody seedling density was influenced by GI. Frequencies of31 herb species wcrc cvaluatcd by considering the effect of prccipitation: these were divided into three groups. Group I (17 species) and group 2 (12 speeies) were inílucnccd by precipitation and have had their highest trcqucncics in 1984 and 1983. respectively. Selaginella convoluta and i lerissantia crispa. which cornpriscd thc third group, wcrc not intluenced by precipitation. Rainíall has also inlluenced the dcnsity of woody seedlings (P < 0.05), with the 1984 density (3.005) being superior to 1983 and 1982 densities (2.055 and 1.895 plantsl m", respectively). Considering the year of 1981, the mcan density in this period was 2.40 I plants/m', excluding seedlings ofthe tree Tabebuia spongiosa, to which 18.9 plants/m" in 1983 was excluded frorn analysis. In conclusion. high GI by goats during three years was not suffieient to cause Caatinga hcrbaceous stratum dcgradation. Precipitation was the most importam Iact or.
| Main Authors: | , , , |
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| Other Authors: | |
| Format: | Artigo de periódico biblioteca |
| Language: | English eng |
| Published: |
2004-09-11
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| Subjects: | Intensidade de pastejo, Estrato herbário, Nordeste, Região semi-árida, Caatinga, Caprino, |
| Online Access: | http://www.alice.cnptia.embrapa.br/alice/handle/doc/154338 |
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