SPATIO-TEMPORAL ANALYSIS OF LANDSCAPE PATTERNS IN THE CATOLÉ WATERSHED, NORTHERN MINAS GERAIS1

Selma Alves Abrahão,Marco Antonio Zanella,Rodrigo Nogueira Martins,Danilo Pereira Ribeiro,Ana Paula Ferreira Colares

doi:10.1590/1806-90882018000400007

Abstract

ABSTRACT The aim of this study was to quantify the spatio-temporal changes in land use/ cover (LULC), as well as analyze landscape patterns over a 20-year period (1995 - 2015) in the Catolé watershed, northern Minas Gerais State, using landscape metrics. The LULC maps were obtained using Landsat 5 and 8 data (Processing level 1) through supervised classification using the maximum likelihood classifier. Seven thematic classes were identified: dense vegetation, sparse vegetation, riparian vegetation, cropland, planted forest, bare soil, and water. From the LULC maps, classes related to the natural landscape (dense, sparse, and riparian vegetation) were grouped into forest patches, which was then ordered by size: very small (< 5 ha); small (5 - 10 ha); medium (10 - 100 ha); large (100 ha); and a general class (no distinction of patch size). Then, metrics of area, size and density, edge, shape, proximity and core area were calculated. The dense vegetation portion of the study area decreased considerably within a given time, while the portion of cropland and bare soil increased. Overall, in the Catolé river basin, the total area of natural vegetation decreased by 3,273 hectares (4.62%). Landscape metrics analysis exhibited a reduction in the number of very small patches, although the study area was still considered as fragmented. Moreover, a maximum edge distance of 50 m is suggested for conducting studies involving core area metrics in the Catolé watershed, as values above this distance would eliminate the very small patches.

Highlights

Progressive changes in natural environments have led to habitat loss and landscape fragmentation worldwide (Cardille and Foley, 2003; Vieira et al, 2003)
In the Catolé river basin, the total area of natural vegetation decreased by 3,273 hectares (4.62%)
Landscape metrics analysis exhibited a reduction in the number of very small patches, the study area was still considered as fragmented

Summary

Introduction

Progressive changes in natural environments have led to habitat loss and landscape fragmentation worldwide (Cardille and Foley, 2003; Vieira et al, 2003). Human activities have modified the environment to the extent that most common landscape patterns exhibit mosaics of human settlements, agricultural land, and scattered fragments of natural ecosystems (Midha and Mathur, 2010) Owing to all these interferences, conservation areas are becoming increasingly surrounded by intensively modified environments, and, in the longterm, appear to be condemned to function as isolated natural ecosystems. A reduction in natural vegetation cover has resulted in imbalances of the physical and biotic aspects of environments, which is a serious issue for the survival of numerous species in many ecosystems It jeopardizes the maintenance of the dynamic balance of landscapes and can lead to a decrease in gene flow, reproductive isolation of species, and, a loss in genetic diversity (Neves et al, 2014; Dantas et al, 2017). Increasing human interference is changing the structural and functional patterns of landscapes worldwide and has significantly impacted biodiversity (Sinha and Charma, 2006)

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