Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

NATIONAL SCIENCE FOUNDATION

Titre : Spatial Scaling and the Effects of Patch Mosaic Structure in Semiarid Ecosystems

Organismes NSF : Division Of Environmental Biology (DEB)

Durée : August 1, 1988 — July 31, 1993

Description
Ecosystems consist of mosaics of landscape elements or patches, and this patchiness is evident at many spatial scales. This research will answer two general questions : (1) Are landscape patterns repetitive over different spatial scales ?, and (2) How does the patch structure of a landscape mosaic affect ecosystem dynamics and functions ? The first question will be addressed by determining the patterns of distribution of patches (vegetation and disturbed areas as well as distributions of arthropod populations) at nested spatial scales ranging from <1 m2 to >10 km2 in semiarid ecosystems. By determining the degree of repetitiveness of mosaic patterns over ranges of scales in both Euclidean and fractal dimensions, one can assess the domains in which ecological patterns and processes operate independently of scale. These domains set the limits within which results from studies at any particular scale can be extrapolated to other scales. Establishing these limits is of critical importance to any attempts to derive generalizations about ecological patterns or processes in landscape mosaics or to compare the results of investigations of different ecological systems. To address the second question, the movement patterns of biotic vectors (ants and beetles) will be studied at fine to intermediate scales to determine how they relate to the patch- mosaic structure of the landscapes. By experimentally altering the patch structure of local environments or the movement patterns of animals, the roles that these organisms may play in the redistribution of materials or energy among patches in these ecosystems will be estimated. To the extent that the investigations indicate repetitiveness of patterns over a range of spatial scales, the studies conducted at fine scales may serve as a "microcosm" representing larger-scale landscape mosaics. Thus, although micro and macro-scale systems may differ biologically, they may share statistical similarities in patterns, allowing the development of procedures for experimentally investigating the movement of materials among elements in a landscape by focusing on fine-scale analogs of macro-landscapes. Research of this nature may be of fundamental importance in promoting the better management of the natural resources of arid lands. Additionally, there could be heretofore unrecognized benefits that would derive from the use of new mathematical approaches to the analysis of ecological data.

Partenaire (s) : John Wiens jaws lamar.colostate.edu (Principal Investigator)

Financement : $319,681.00

Présentation (National Science Foundation)