A study of habitat fragmentation in Southeastern Brazil using remote sensing and geographic information systems (GIS)

https://doi.org/10.1016/S0378-1127(97)00072-8Get rights and content

Abstract

The purpose of this work was to study fragmentation of forest formations (mesophytic forest, riparian woodland and savannah vegetation (cerrado)) in a 15,774-ha study area located in the Municipal District of Botucatu in Southeastern Brazil (São Paulo State). A land use and land cover map was made from a color composition of a Landsat-5 thematic mapper (TM) image. The edge effect caused by habitat fragmentation was assessed by overlaying, on a geographic information system (GIS), the land use and land cover data with the spectral ratio. The degree of habitat fragmentation was analyzed by deriving: 1. mean patch area and perimeter; 2. patch number and density; 3. perimeter-area ratio, fractal dimension (D), and shape diversity index (SI); and 4. distance between patches and dispersion index (R). In addition, the folowing relationships were modeled: 1. distribution of natural vegetation patch sizes; 2. perimeter-area relationship and the number and area of natural vegetation patches; 3. edge effect caused by habitat fragmentation. The values of R indicated that savannah patches (R = 0.86) were aggregated while patches of natural vegetation as a whole (R = 1.02) were randomly dispersed in the landscape. There was a high frequency of small patches in the landscape whereas large patches were rare. In the perimeter-area relationship, there was no sign of scale distinction in the patch shapes. In the patch number-landscape area relationship, D, though apparently scale-dependent, tends to be constant as area increases. This phenomenon was correlated with the tendency to reach a constant density as the working scale was increased. On the edge effect analysis, the edge-center distance was properly estimated by a model in which the edge-center distance was considered a function of the total patch area and the SI.

References (23)

  • J.R. Krummel et al.

    Landscape patterns in a disturbed environment

    Oikos

    (1987)
  • Cited by (73)

    • Biodiversity conservation in the sacred groves of north-west Ethiopia: diversity and community structure of woody species

      2020, Global Ecology and Conservation
      Citation Excerpt :

      Edge effects such as changes in microclimate are stronger in smaller and irregular-shaped patches, resulting in habitat degradation and increased loss of core habitat (Laurance et al., 1997; Fahrig 2017). Particularly in tropical forests, such changes are likely to negatively affect large and old trees in favor of pioneer trees (Haddad et al., 2015), ultimately impacting forest regeneration due to a lack of seeds, which are predominantly produced by large, mature trees (Jorge and Garcia 1997). Besides patch-level characteristics, the ecological integrity of forest fragments also depends on land use and land cover changes in the matrix (i.e. at the landscape level).

    • Land-cover changes and an uncertain future: Will the Brazilian Atlantic Forest lose the chance to become a hopespot?

      2021, The Atlantic Forest: History, Biodiversity, Threats and Opportunities of the Mega-diverse Forest
    View all citing articles on Scopus
    View full text