Analyzing Vegetation–Soil–Topography Relationships of Landscapes: A Multiscale Geosystem Approach and Its Application

Abstract

Most landscape-ecological models deal with either between-component relationships at a single hierarchical level or with hierarchy of a single geocomponent, often ignoring variety of types of between-component relationships and density of linkages in space. We developed the multiscale geosystem approach to clarify the relations between landscape attributes, governing ecological processes, and relevant scale levels of processes description. We treat landscape as a multipattern geosystem that is composed by superposition of spatial relationships formed at several scale levels and reflecting various contemporary ecological processes as well as legacy of former processes and geographical phenomena. We propose the procedure that allows comparison of a series of hypotheses about the appropriate spatial extent of the higher-order system, i.e., the extent to which the focal system responds to constraint. Constraints from the higher-order system are interpreted as an emergent effect evolving as a result of interactions between neighboring spatial units. The properties of a landscape unit are treated as a product of both intra-level interactions between geocomponents and inter-level relations with a set of surrounding units. The proposed statistical procedure is aimed at splitting spatial variance of geocomponents’ (soils and vegetation) properties to effects of inter-level and intra-level interactions. Non-metric multidimensional scaling was applied to reduce dimensionality of raw field data collected in Republic of Udmurtia (mixed-forests zone) and to range ecological factors affecting vegetation and soil properties. Response surface regression models were applied to relate properties of soils and vegetation to each other and to a set of relief morphometric properties measured from digital elevation model in a range of square neighborhoods. Comparison of quality of equations built for various neighborhoods allowed establishing the size of holistic higher-order geosystems that impose frame conditions on properties of the focus-level units. We revealed contemporary and former-time processes that shaped patterns of vegetation and soil cover and their characteristic space scale. The proposed approach is scale-invariant and can be applied to study of relations between the focus-level units and the higher-order units at any map resolution.