Landscape vegetation modelling with vital attributes and fuzzy systems theory
Ecological Modelling. Special issue: Fuzzy modelling in ecology
Landscape vegetation modelling is a simulation modelling approach to the analysis of landscape dynamics. The model developed here is a spatially-explicit ecologically-mechanistic simulator based on previous work in vital attributes theory and fuzzy systems theory. The model employs multiple individual forest stands with spatially-linked processes of seed distribution and disturbance propagation. Two synthetic landscapes were constructed consisting of four distinct environments with 400 polygons arranged in a hex grid mapped onto a torus. The two landscapes differ in inherent environmental heterogeneity, with one landscape consisting of smooth gradation in the four environments (gradient landscape) and the other with randomized environments (random landscape). The two landscapes are subjected to five different fire regimes. The effects of fire regime, environmental heterogeneity, and the interaction of environmental heterogeneity and fire regime are presented with regard to landscape characteristics of fragmentation, patch diversity, and gamma diversity. Environmental heterogeneity and fire regime form a complex relationship of non-monotonic response and interaction effects. Landscape fragmentation and diversity are found to have a modal or sinusoidal relationship to fire return interval, and the positions of the minima and maxima differ between the random and gradient landscapes. Landscape gamma diversity shows relatively less effect of fire return interval, although longer fire return intervals generally produce higher gamma diversity through the development of higher alpha diversity in mesic fire-sensitive stands. An interaction exists between landscape heterogeneity and fire return interval where some fire return intervals accentuate and some attenuate the differences between the gradient and random landscapes. Interaction effects of environmental heterogeneity and fire return interval on gamma diversity are small.
Roberts, D.W. and Li, Bai Lian, "Landscape vegetation modelling with vital attributes and fuzzy systems theory" (1996). Aspen Bibliography. Paper 1670.