Landscapes Forest and Global Change - ESA - Escola Superior ...

M.B. Horta et al. 2010. Landscape Structure of a Conservation Area and its Surroundings in Minas Gerais State, Brazil
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(1.559,20ha), followed by the grasslands (515,08ha) and pasture (31,76ha). When comparing
the number of patches one can see that the majority belonged to the grasslands comprising 35
pieces, followed by 8 pasture and 6 forest pieces. The mean patch area was higher for forest
class (258,36ha) that presented a continuous and large patch inside the conservation area of
1.529,20ha. Patch density was 1,66 for grasslands, 0,38 for pasture and 0,28 for forest.
Table 1: Landscape metrics used for the landscape structure characterization inside and outside the
conservation area*
Acronym
Metric Name (units)
Area Metrics
TA
Total Area (hectares)
CA
Total Class Area (hectares)
PD
Patch density (no./100 ha)
NP
Number of patches
AREA MN
Mean Patch Area (hectares)
AREA
Patch Size (patch size selected minimum and maximum)
Shape Metrics
SHAPE MN
Mean shape index
Core Metrics
TCA Total Core Area (ha) – specified edge depth (20 m)
CAI
Core Area Index (percent)
Isolation/Proximity Metrics
ENN MN
Mean euclidean nearest neighbor distance distribution (meters)
Contagion/Interspersion Metrics
IJI
Interspersion and Juxtaposition Index (percent)
* Full description of landscape metrics equations is provided in Mac Garigal and Marks (1995)
The mean shape index varied from 1,68 (grasslands) to 2,02 (forest). The core area index was
higher for forests. The mean distance among patches was lower for the grasslands (109,82m),
followed by pastures (164,83m) and forests (224,93m). The pastures showed high interspersion
and juxtaposition index (95,41%). This index was 63,82% for grasslands and 49,38% for the
forest class.
The results for the surrounding area are presented in Table 2. The total surrounding landscape
comprises an area of 52.674,92ha. The pastures cover the largest area (28.561,80ha), followed
by forest (16.833,28 ha) and grasslands (31,76ha). Two small urban areas are located inside the
surrounding area occupying 35,56ha. The forest cover presented the highest number of patches
(334), followed by pastures (224) and grasslands (102). The mean patch area was higher for
pastures (119,00ha). For the grasslands and forest covers the value of this variable was
respectively 71,02ha and 50,39ha. Patch density was 0,63 for forest, 0,45 for pasture and 0,19
for forest.
Mean shape index in the surrounding area varied from 1,69 (forest) to 2,10 (grasslands). Core
area index was similar for forest (86,58%) and grasslands (85,91%). Mean distance among
patches was lower for urban area (72,11m), followed by pasture (139,73m), forest (191,37m)
and grasslands (312,11m). The highest interspersion juxtaposition index was found for
grasslands (63,82%).
Considering the whole landscape area, the forest to be preserved inside the conservation area
represents 8,43% and the grasslands 6,63%. The 6 forest and 35 grasslands patches were
equivalent to 1,76% and 25,54% of the total patches. The largest forest patch inside the
conservation area (> 1.000ha) represented 0,29% and the largest grasslands one (> 100 ha)
5,83%. Regarding isolation, 50,00% of forest patches and 57,14% of grasslands presented
distances lower than 100m.
Forest Landscapes and Global Change-New Frontiers in Management, Conservation and Restoration. Proceedings of the IUFRO Landscape Ecology
Working Group International Conference, September 21-27, 2010, Bragança, Portugal. J.C. Azevedo, M. Feliciano, J. Castro & M.A. Pinto (eds.)
2010, Instituto Politécnico de Bragança, Bragança, Portugal.