Paula Couto *
* Grupo de Análise de Sistemas Ambientais (GASA) - Universidade Nova de Lisboa
Title: Factorial Analysis applied to landscape metrics defined in FRAGSTATS
Abstract:
A programme for spatial analysis based on a grid of pixels (FRAGSTATS 3.0) was used and the results of the analysis of 50 maps of land occupation using this programme were presented. 33 metrics of the landscape's structure were used and the properties of the metrics for various landscapes (maps of land occupation in Continental Portugal) were investigated. The metrics of the landscape's structure describe the size and form of the landscapes, the abundance of each type of spot and the spatial distribution of similar or different spots. To overcome the ambiguity of individual metrics and behavioural peculiarities, a varied factorial approach was adopted to describe and compare landscape structures. An analysis of main components for the 33 metrics and 50 landscapes was carried out. The first five factors explain 91.2% of the variation. These factors can be interpreted as an average of compaction of the spot, image texture (distribution of the pixels and proximity), landscape area, number of classes, area-perimeter relation (fractional measures).
Keywords: Landscape structure, Factorial approach, Fragstats
]]>Resumo:
Um programa de análise espacial baseado numa grelha de pixeis (FRAGSTATS 3.0) foi usado e os resultados da análise de 50 mapas de ocupação do solo usando esse programa são apresentados. Foram usadas 33 métricas da estrutura da paisagem e investigadas as propriedades das métricas para diversas paisagens (mapas de ocupação de solo de Portugal Continental). As métricas da estrutura da paisagem descrevem o tamanho e forma das paisagens, a abundância de cada tipo de mancha e a distribuição espacial de manchas similares ou dissimilares. Para ultrapassar a ambiguidade de métricas individuais e peculiaridades do seu comportamento, foi adoptada uma aproximação factorial multivariada para descrever e comparar estruturas da paisagem. Foi executada uma análise de componentes principais para as 33 métricas e 50 paisagens. Os primeiros cinco factores explicam 91.2% da variação. Estes factores podem ser interpretados como média da compactação da mancha, textura da imagem (distribuição dos pixeis e adjacência), área da paisagem, número de classes, relação área - perímetro (medidas fractais).
Texto completo apenas disponível em PDF.
Full text only available in PDF format.
Bibliografia
Baskent EZ, Jordan GA, 1995, Characterizing spatial structure of forest landscapes. Can J For Res 25:1830-1849. [ Links ]
Forman, R.T.T. e M. Godron, 1981, Patches and structural components for a landscape ecology. BioScience 31: 733-740. [ Links ]
Forman, R.T.T. e M. Godron, 1986, Landscape Ecology. John Wiley and Sons, New York, 619 pp [ Links ]
Gustafson EJ, Parker GR., 1992. Relationship between landcover proportion and indices of landscape spatial pattern. Landscape Ecology 7:101-110. [ Links ]
Gustafson, E.J., 1998. Quantifying landscape spatial pattern: What is the state of the art. Ecosystems: 143-156. [ Links ]
Kendall, 1980, Multivariate analysis. Second Edition, Charles Griffin &Company Limited. [ Links ]
LaGro, J., Jr., 1991, Assessing patch shape in landscapes mosaics. Photogrammetric Engineering and Remote Sensing 57, 285-293. [ Links ]
Li, H. and Reynolds, J.F., 1993. A new contagion index to quantify spatial patterns of landscapes. Landscape Ecology 8: 155-162. [ Links ]
McGarigal K, McComb WC. 1995. FRAGSTATS: spatial pattern analysis program for quantifying landscape structure. Portland (OR): USDA Forest Service, Pacific Northwest Research station; General Technical Report PNW-GTR-351. [ Links ]
Morrison, D.F., 1990, Multivariate Statistical Methods. Third Edition, McGraw-Hill Inc., New york NY. [ Links ]
O'Neill, R.V., Krummel, J.R., Gardner, R.H., Sugihara, G., Jackson, B., DeAngelis, D.L., Milne, B.T., Turner, M.G., Zygmunt, B., Christensen, S.W., Dale, V.H. and R.L. Graham, 1988. Indices of landscape pattern. Landscape Ecology 1: 153-162. [ Links ]
Pickover CA., 1990, Computers, pattern, chaos and beauty: graphics from an unseen world. New York: St Martin's. [ Links ]
Pielou EC., 1975, Ecological diversity. New York: Wiley-Interscience [ Links ]
Riitters KH, O'Neill RV, Hunsaker CT, Wickham JD, Yankee DH, Timmons SP, Jones KB e Jackson BL, 1995, A factor analysis of landscape pattern and structure metrics. Landscape Ecology, 11, 197-202 [ Links ]
Rogers, C., 1993, Describing landscapes: indices of structure. M.S. Thesis, Simon Fraser University, Burnaby, British Columbia, 170 pp. [ Links ]
Romme WH., 1982, Fire and landscape diversity in Sub-Alpine forests of Yellowstone National Park. Ecol. Monogr, 52, 199-221. [ Links ]
Shannon, C.E., e Weaver, W., 1949, The mathematical theory of communication (Urbano University of Illinois Press). [ Links ]
Simpson E.H., 1949, Measurement of diversity. Nature, 163, 688. [ Links ]
Turner, M.G. and Gardner, R.H. (editors), 1991. Quantitative Methods in Landscape Ecology. Springer-Verlag, New York NY. [ Links ]
Turner, M.G., 1990, Spatial and temporal analysis of landscape patterns. Landscape Ecology, 4, 21-30. [ Links ]
Turner, M.G., Costanza, R. and Sklar, F.H., 1989(a). Methods to evaluate the performance of spatial simulation models. Ecological Modeling 48:1-18. [ Links ]
Turner, M.G., R.V. O'Neill, R.H.Gordon, e B.T.Milne, 1989(b), Effects of changing spatial scale on the analysis of landscape pattern. Landscape Ecology, 3, 153-162. [ Links ]
Whitcomb, R.F., J.F.Lynch, M.K.Klimkiewwicz, C.S. Robbins, B.L. Whitcomb, and D.Bystrak, 1981, Effects of forest fragmentation on avifauna of the eastern deciduous forest. Forest island dynamics in man-dominated landscapes. Springer-Verlag, New York. [ Links ]
Wiens, J.A., 1989, Spatial scaling in ecology. Functional Ecol., 3, 385-397. [ Links ]
]]>