ANJOS, Denize Monteiro dos.
Résumé:
Natural resources are exploited by man and the impacts of these disorderly actions
are perceptible in ecosystems. In general, the vegetation present in the river basins
is exposed to the various types of anthropic action. The effects are found in the
reduction of water abstraction, causing the impoverishment of the flora and fauna
biodiversity, productivity and scenic beauty, especially in the semi-arid region of
Northeast Brazil, where water is a determining factor. Despite the existence of the
Forest Code and its importance, the riparian forests of water basins and micro-basins
are increasingly being exploited in violation of the Forest Code. Geographic
Information Systems (SIG) and Remote Sensing (SR) techniques are important for
the management of natural resources, since they can assist in the planning,
monitoring and mapping of land use and land cover. In the semi-arid region of
northeastern Brazil, geotechnologies can be used to detect the landscapes and
facilitate the implementation of appropriate management techniques. The objective of
this work was to characterize the soil use and cover of the Rio da Cruz water basin,
to study the floristic composition of the arboreal and herbaceous components and to
verify the degree of occupation of the banks of two stretches of Rio da Cruz (PB).
The soil use and cover of the microbasin were classified using satellite images of the
years 2001, 2009 and 2017, in the rainy and dry periods. The floristic composition of
the arboreal and herbaceous strata of each year was determined by plot marking and
walking techniques, respectively. The classification of the images of the watershed of
the Rio da Cruz resulted in seven classes: Arboreal Caatinga, Arboreal Shrub
Caatinga, Anthropized Caatinga, Pastures and Agriculture, Rock Outcrops, Bodies of
Water and Buildings. A reduction of the Arboreal Caatinga and increase in the other
classes of Caatinga and in the Pastures and Agriculture when comparing the years
and periods of 2001 and 2017 was observed. The applied techniques are relevant for
classification of the use and soil cover of the semi-arid region in conditions of
precipitation regular, but in years of higher precipitation the tree vegetation is
overestimated and may make it difficult to identify the targets, especially in the rainy
season. It was verified the existence of few arboreal individuals and wide use of the
Rio da Cruz margins for agroforestry activities, indicating the need to enforce the
Forest Code and the adoption of mitigating measures to mitigate the impacts caused
by anthropic action.
