Monodominância de aroeira: fitossociologia, relações pedológicas e distribuição espacial em Tumiritinga-MG

• Autor(a) principal: Oliveira, Felipe Pinho de
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5472
• topic: Myracrodruon urundeuva; Comunidades vegetais; Plantas; Solos; Myracrodruon urundeuva; Plant communities; Plants; Soils; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::CIENCIA DO SOLO

The framework of advanced environmental degradation in the central region of the Rio Doce in the state of Minas Gerais by is attributed several authors to the practice of extensive cattle raising added to interactions with the soil, climate, geomorphology and also anthropic interactions. As an aggravating factor of the degradation in the region, some researchers begin to draw attention to the expansion of mono-dominated fragments by the aroeira forest species (Myracrodruon urundeuva Fr. All.). Parallel to this scenario, M. urundeuva appears in the official list of species of flora threatened with extinction in the category "Vulnerable" from 1992 until the present day. On the other hand the Regulatory Ordinance number 85 of September 26, 1991 of IBAMA allows the exploitation of the species in secondary forests through a forest management plan. It is felt that the lack of knowledge about the mono-dominated fragments by aroeira entails the insecurity of the law operators regarding the authorization for intervention in these environments; this is aimed at the recovery of degraded areas and the sustainable management of these fragments. In the search to clarify questions about the areas under mono-dominance of aroeira, this work aimed to characterize the major floristic composition, the horizontal structure and the parametric structure of forest stands under the mono-dominance of Myracrodruon urundeuva in Tumiritinga-MG; evaluate the existence of correlation between chemical and physical attributes of the soil and the expansion of settlements mono-dominated by the aroeira; evaluate the performance of the maximum likelihood classifier and the classifier of artificial neural networks to map the areas occupied by fragments of aroeira in mono-dominance in the city of Tumiritinga-MG; and evaluate the potential use of remote sensing data on board the Landsat TM-5 and RapidEye satellites for the mapping of the areas mono-dominated by aroeira. For this the city of Tumiritinga was widely covered by registering with a GPS navigation device and photo the forms of land use prevalent throughout the studied region. Sixteen inventory plots of forest were distributed throughout the city representing the diversity of environments where the Aroeirais manifest. In the plots inventory xi circles, the total height and botanical identification of all individuals with CAP> 15.7 cm were recorded. From the collected data it was made an analysis of horizontal structure, parametric structure and floristic of the fragments mono-dominated by aroeira in the city of Tumiritinga using the Mata Nativa 2.0 software. In eleven of the sixteen parts of inventory, three undisturbed samples composed of soil were collected and three simple disturbed samples of soil were collected randomly. For each plot it was selected an adjacent pasture from where three simple undisturbed soil samples were collected and three deformed soil samples composed of soil, totaling 33 samples of soil under "Aroeirais" and 33 samples of soil under pasture. The soil samples were submitted to the following chemical analysis: pH in H2O; levels of Ca2+, Mg2+, K+, Al3+, exchangeable Na+, available P, H + Al, SB, t, T, V, m; MOS and ISNa, and the following physical tests: texture, Dp, Ds, Pt, Pmic, Pmac, Ko and water retention at field capacity (-10 kPa) at the permanent wilting point (- 1500 kPa) and in tensions equivalent to -300 kPa and -500 kPa. In order to evaluate the hypothesis of equality between the averages of chemical and physical parameters obtained in mono-dominance of aroeira and grazing systems, it was applied the t test for independent samples, at 5% of significance. For classification of the RapidEye image two methods of supervised classification were evaluated: the classification by the maximum likelihood algorithm and the classification by Artificial Neural Networks. We tested 19 combinations involving bands, principal components and the normalized difference of vegetation index (NDVI). The network training was carried out by trial and error. For the classification of the Landsat image, the maximum likelihood algorithm was used and tests were made with 10 combinations involving bands, principal components and NDVI. The assessment of the thematic maps that were produced was performed using the Kappa and conditional Kappa coefficients for the class of aroeira soil use. The horizontal structure and the floristic analysis of forest fragments inventoried in the city of Tumiritinga-MG prove the monodominant occurrence of M. urundeuva in the study region. The monodominance of aroeira is characterized by low diversity of species and dominance reflected in 96% of individuals that were sampled, 96% of the baseline measure and 96% of the total amount of stored wood. The chemical parameters K+, Ca2+, Mg2+, SB, T and t differed significantly between the grazing systems and aroeira monodominance, the values of all parameters in the aroeira monodominance system were superior. The physical parameters Dp, Pmic, Pt and silt content differed significantly between the grazing systems and aroeira monodominance; the values of Dp, Pmic and Ptot higher in soils under aroeira monodominance and silt content were superior in the upper pasture. The best results were found for the classification of the RapidEye image was obtained by the maximum likelihood algorithm that showed a kappa coefficient equal to 80 and 90 for conditional Kappa. For the Landsat image the Kappa and conditional Kappa coefficients for the aroeira class were respectively 80 and 76. Through the thematic maps produced it was observed that 22% of the city of Tumiritinga, 10,758 ha, is under the occupation of the aroeira in monodominance. Given the size that the settlements monodominated by aroeira occupy in the landscape, the implications of the aroeira monodominance imposes on the biodiversity in soil conservation, and in the sustainability in the local agroecosystem, it is necessary to pursue further studies in order to clarify the edaphic and ecological mechanisms involved in the maintenance and expansion of areas monodominated by aroeira. The knowledge of the conditioning processes of this system may help the development of plans for sustainable forest management; in which the combination the timber and not timber production will be able to increase the productivity and the income of farmers.