Estrutura e diversidade de trechos de Cerrado sensu stricto às margens de rodovias no estado de Minas Gerais

Abstract

Roads are one of the main known degradation factors of the Cerrado because, despite their economic relevance, they cause cuts in extensive continuous masses of natural biota. According to the current legislation, roadside borders should be considered as permanent preservation areas. However, there are few studies that aim to evaluate the real conservationist potential of these protection areas. We sampled 40 plots of 50 x 10 m, arranged randomly at the edge of highways, and sampled all living tree individuals with circumference at 30 cm from the ground greater or equal to 15 cm. The phytosociological parameters of relative density, dominance and frequency, importance value, Pielou equability and the diversity indices of Shannon-Weaver and Simpson were calculated. The richness was estimated using Jackknife 2, Bootstrap and Mao Tao indices. We sampled 790 individuals belonging to 88 species and 35 families, with a high diversity index of 3.64 for Shannon-Weaver, 0.94 for Simpson, and 0.81 for equability. The most representative species were Dalbergia miscolobium , Piptocarpha rotundifolia , Machaerium acutifolium , Ouratea hexasperma and Stenocalyx dysentericus . The families with the highest number of species were Fabaceae (20 species), Myrtaceae (8 species) and Bignoniaceae (7 species). The estimated richness was 108 by the Bootstrap estimator and 159 by the Jacknife 2 estimator, demonstrating that the number of species at the roadsides tends to be greater than those found in some protected Cerrado areas. Based on our results, we can infer that the roadside borders are important to conservation, harboring a great amount of the Cerrado tree flora, which justifes their protection by law and recommends their maintenance, given the current intensive degradation of the Cerrado biome.