Identifying the Scale Thresholds for Field-Data Extrapolation via Spatial Analysis of Landscape Gradients |
| |
Authors: | Chi-Ru Chang Pei-Fen Lee Mei-Ling Bai Tzer-Ton Lin |
| |
Institution: | (1) Department of Landscape Architecture, Chinese Culture University, 55 Hwa-kang Road, Yangmingshan, Shilin 111, Taipei, Taiwan;(2) Institute of Ecology and Evolutionary Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei, 106, Taiwan;(3) Department of Zoology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei, 106, Taiwan;(4) Fushan Experimental Forest, Taiwan Forest Research Institute, P.O. Box 132, Ilan, Taiwan |
| |
Abstract: | Despite recent advances in resolving the scale issue, it remains problematic that so many ecological field studies are still
conducted only at small scales because of the constraints imposed by limited resources. To maximize the use of these data,
it would be helpful if the researchers could provide guidelines for the appropriate range and scale for the extrapolation
of the data and identify the new information that would be needed to extend the scope of their extrapolation. In this paper,
we present a method that can be used to detect scale thresholds for the extrapolation of field data through spatial analyses
of the physical landscape, using the Fushan Forest, Taiwan, as an example. First, the relationship between the vegetation
and the physical landscape was inferred from sample-plot data; this information was in turn used to extrapolate the data over
the whole forest area. We then compared the environmental variables in the sample plots versus those in the whole forest area
via principal component analysis, landscape classification, and spatial autocorrelation analysis. Analyses of the entire Fushan
Forest area showed that there are at least three major spatial scales at which physical gradients are expressed: elevation
at the scale of the full forest extent (more than 3,000 m), topographic position at 550 m, and aspect at 250 m. Analyses of
the sample plots showed that the plots captured only two of these gradients—topographic position and aspect, but not elevation.
Therefore, information from the current field data can only be extrapolated to within 550 m from the sample plots; further
information derived from cross-elevation samples is needed to extrapolate beyond that range. |
| |
Keywords: | landscape analysis spatial autocorrelation gradient analysis subtropical rain forest principal components analysis landscape classification |
本文献已被 SpringerLink 等数据库收录! |
|