Abstract
Although habitat fragmentation is one of the greatest threats to biodiversity worldwide, virtually no attention has been paid to the quantification of error in fragmentation statistics. Landscape pattern indices (LPIs), such as mean patch size and number of patches, are routinely used to quantify fragmentation and are often calculated using remote-sensing imagery that has been classified into different land-cover classes. No classified map is ever completely correct, so we asked if different maps with similar misclassification rates could result in widely different errors in pattern indices. We simulated landscapes with varying proportions of habitat and clumpiness (autocorrelation) and then simulated classification errors on the same maps. We simulated higher misclassification at patch edges (as is often observed), and then used a smoothing algorithm routinely used on images to correct salt-and-pepper classification error. We determined how well classification errors (and smoothing) corresponded to errors seen in four pattern indices. Maps with low misclassification rates often yielded errors in LPIs of much larger magnitude and substantial variability. Although smoothing usually improved classification error, it sometimes increased LPI error and reversed the direction of error in LPIs introduced by misclassification. Our results show that classification error is not always a good predictor of errors in LPIs, and some types of image postprocessing (for example, smoothing) might result in the underestimation of habitat fragmentation. Furthermore, our results suggest that there is potential for large errors in nearly every landscape pattern analysis ever published, because virtually none quantify the errors in LPIs themselves.
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References
Andrén H, Angelstam P (1988) Elevated predation rates as an edge effects in habitat islands: experimental evidence. Ecology 69:544–47
Benitez-Malvido J, Martinez-Ramos M (2003 )Impact of forest fragmentation on understory plant species richness in Amazonia. Conserv Biol 17:389–400
Brown DG, Duh J, Drzyzga SA (2000) Estimating error in an analysis of forest fragmentation change using North American landscape characterization (NALC) data. Remote Sens of Environ 71:106–17
Brittingham MC, Temple SA (1983) Have cowbirds caused forest songbirds to decline? Bioscience 33:31–35
Cardille JA, Turner MG (2001) Understanding landscape metrics I. In: Gergel SE, Turner MG (eds) Learning landscape ecology: a practical guide to concepts and techniques. Springer, Berlin Heidelberg New York, pp 85–100
Congalton RG, Green K (1999) Assessing the accuracy of remotely sensed data: principles and practices. Lewis, Boca Raton (FL)
Cordeiro NJ, Howe HF (2003) Forest fragmentation severs mutualism between seed dispersers and an endemic African tree. Proc Natl Acad Sci USA 100:14052–56
Edwards G, Lowell KE (1996) Modeling uncertainty in photointerpreted boundaries. Photogram Eng Remote Sens 62:377–91
Fahrig L (2003) Effects of habitat fragmentation on biodiversity. Annu Rev Ecol Evol Syst 34:487–515
Ferraz G, and others. 2003 Rates of species loss from Amazonian forest fragments. Proc Natl Acad Sci USA 100:14069–73
Foody G (2002) Status of land cover classification accuracy assessment. Remote Sens Environ 80:185–201
Fortin MJ, Boots B, Csillag F, Remmel TK (2003) On the role of spatial stochastic models in understanding landscape indices in ecology. Oikos 102:203–12
Gardner RH (1999) RULE: map generation and spatial analysis program. In: Klopatek JM, Gardner RH (eds) Landscape ecological analysis: issues and applications. Springer, Berlin Heidelberg New York, pp. 280–303
Gardner RH, O’Neill RV (1991) The use of neutral models for landscape analysis. In: Turner MG, Gardner RH (eds) Quantitative methods in landscape ecology: the analysis and interpretation of landscape heterogeneity. Springer, Berlin Heidelberg New York, pp. 289–307
Gardner RH, Milne BT, O’Neill RV, Turner MG (1987) Neutral models for the analysis of broad-scale landscape patterns. Ecosystems 1:19–28
Gergel SE (2002) Cumulative impact of levees and dams on the duration of temporary floodplain ponds: a terrain model approach for assessing multiple disturbances at broad scales. Ecol Appl 12(6):1740–54
Griffiths GH, Lee J, Eversham BC (2000) Landscape pattern and species richness; regional scale analysis from remote sensing. Int J Remote Sens 21:2685–704
Hagen A (2003) Fuzzy set approach to assessing similarity of categorical maps. Int J Geogr Inf Sci 17:235–49
Hammond TO, Verbyla DL (1996) Optimistic bias in classification accuracy assessment. Int J Remote Sens 17:1261–66
Hess G (1994) Pattern and error in landscape ecology: a commentary. Landscape Ecol 9:35
Hess GR, Bay JM (1997) Generating confidence intervals for composition-based landscape indexes. Landsc Ecol 12:309–20
Imbernon J, Branthomme A (2001) Characterization of landscape patterns of deforestation in tropical rain forests. Int J Remote Sens 22:1753–65
Laurance W, and others. 2000. Conservation – Rainforest fragmentation kills big trees. Nature 404:836
McGarigal K, Cushman SA, Neel MC, Ene E. 2002. FRAGSTATS: spatial pattern analysis program for categorical maps. Computer software program produced at the University of Massachusetts, Amherst. [Online] URL: www.umass.edu/landeco/research/fragstats/fragstats.html
Peralta P, Mather P (2000) An analysis of deforestation patterns in the extractive reserves of Acre, Amazonia from satellite imagery: a landscape ecological approach. Int Journal Remote Sen 21:2555–70
Plourde L, Congalton RG (2003) Sampling method and placement: how do they affect the accuracy of remotely sensed maps? Photogram Eng Remote Sens 69:289–98
Pontius G, Huffaker D, Denman K (2004. Useful techniques of validation for spatially explicit land-change model. Ecol Modell 179:445–61
Remmel TK, Csillag F, Mitchell SW, Boots B. 2002. Empirical distributions of landscape pattern indices as functions of classified image composition and spatial structure. Proceedings of Symposium on Geospatial Theory, Processing, and Applications, Ottawa, Canada, 9–12 July 2002
Saunders DA, Hobbs RJ, Margules CR (1991) Biological consequences of ecosystem fragmentation — a review. Conserv Biol 5(1):18–32
Saura S, Martinez-Millan J (2001) Sensitivity of landscape pattern metrics to map spatial extent. Photogram Eng Remote Sens 67:1027–36
Shao G, Liu D, Zhao G (2001) Relationships of image classification accuracy and variation of landscape statistics. Can Journal of Remote Sens 27:33–43
Skole D, Tucker C (1993) Tropical deforestation and habitat fragmentation in the Amazon: satellite data from 1978 to 1988. Science 260:1905–10
Stehman SV (2001) Statistical rigor and practical utility in thematic map accuracy assessment. Photogram Eng Remote Sens 67:727–34
Stehman SV, Wickham JD, Smith JH, Yang L (2003) Thematic accuracy of the 1992 National land-cover data for the eastern United States: statistical methodology and regional results. Remote Sens Environ 86:500–16
Terborgh J, and others. (2001) Ecological meltdown in predator-free forest fragments. Science 294:1923–26
Turner MG, Gardner RH, O’Neill RV (2001) Landscape ecology in theory and practice: pattern and process. Springer, Berlin Heidelberg New York
Turner MG, O’Neill RV, Gardner RH, Milne BT (1989) Effects of changing spatial scale on the analysis of landscape pattern. Lands Ecol 3:153–62
Villard M-A, Trzcinski MK, Merriam G (1999) Fragmentation effects on forest birds: relative influence of woodland cover and configuration on landscape occupancy. Conserv Biol 13:774–83
Wickham JD, O’Neill RV, Riitters KH, Wade TG, Jones KB (1997) Sensitivity of selected landscape pattern metrics to land-cover misclassification in land-cover composition. Photogram Eng Remote Sens 63:397–402
[WISCLAND] Wisconsin Initiative for Statewide Cooperation on Landscape Analysis and Data. 1993. User’s guide to WISCLAND land cover data. Wisconsin Department of Natural Resources, Madison, USA
With KA, King AW (1997) The use and misuse of neutral landscape models in ecology. Oikos 79:219–29
Acknowledgements
W.T.L. was supported by NSF grants IRI-9204129, IRI-9626584, ITR-0085836, ONR grant N00014-95-1-0557, AFOSR grant F49620-98-1-0375, the NASA Terrestrial Ecology Program, and EPA STAR fellowship U 915196-01-1. Part of this work was conducted while W.T.L. and S.E.G. were postdoctoral associates at the National Center for Ecological Analysis and Synthesis, a center funded by NSF (grant DEB-0072909), the University of California, and the Santa Barbara campus. We thank D. Brown, J. Cardille, Y. Carmel, M.J. Fortin, G. Hess, M. Kinnaird, C. McCain, J. Parrish, K. Phrodite, V. Radeloff, and D. Vazquez for valuable comments on this paper. We also thank an anonymous reviewer of an earlier version of this paper for comments on normalization methods.
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Langford, W.T., Gergel, S.E., Dietterich, T.G. et al. Map Misclassification Can Cause Large Errors in Landscape Pattern Indices: Examples from Habitat Fragmentation. Ecosystems 9, 474–488 (2006). https://doi.org/10.1007/s10021-005-0119-1
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DOI: https://doi.org/10.1007/s10021-005-0119-1