A major goal of landscape ecology is to understand the formation, dynamics, and maintenance of spatial heterogeneity. Spatial heterogeneity is the most fundamental characteristic of all landscapes, and scale multiplicity is inherent in spatial heterogeneity. Thus, multiscale analysis is imperative for understanding the structure, function and dynamics of landscapes. Although a number of methods have been used for multiscale analysis in landscape ecology since the 1980s, the effectiveness of many of them, including some commonly used ones, is not clear or questionable. In this paper, we discuss two approaches to multiscale analysis of landscape heterogeneity: the direct and indirect approaches. We will focus on scale variance and semivariance methods in the first approach and 17 landscape metrics in the second. The results show that scale variance is potentially a powerful method to detect and describe multiple-scale structures of landscapes, while semivariance analysis may often fail to do so especially if landscape variability is dominant at broad scales over fine scales. Landscape metrics respond to changing grain size rather differently, and these changes are reflective of the modifiable areal unit problem as well as multiple-scale structures in landscape pattern. Interestingly, some metrics (e.g., the number of patches, patch density, total edge, edge density, mean patch size, patch size coefficient of variation) exhibit consistent, predictable patterns over a wide range of grain sizes, whereas others (e.g., patch diversity, contagion, landscape fractal dimension) have nonlinear response curves. The two approaches to multiple-scale analysis are complementary, and their pros and cons still need to be further investigated systematically.

As a means of studying inter— and intrazonal invasion in black sagebrush (Artemisia nova A. Nels) communities six maturity classes were established for pinyon (Pinus monophylla Torr. and Frem.) and juniper (Juniperus osteosperma (Torr.) Little) in east—central Nevada. Pinyon and juniper invade and increase in black sagebrush communities until the understory, except for a few hardy plants, is eliminated. Juniper invades first and tends to be eventually replaced by pinyon. Accelerated invasion by both species started about 1921 and is closely related to overgrazing, fire suppression, and climatic change.

ada Rena Paul has had over 30 years as student and professor working in the general area of Range Ecology and Management. He has initiated numerous studies concerned with range ecology, vegetation-soil relationships, range condition and trend, big game habitat management, brush encroachment, ecology of the pinyonjuniper woodland, mine waste reclamation, and remote sensing with emphasis on arid lands. Other qualifications include: commercial instrument rated pilot with over 3,000 hours, currently Associate Editor, JoumolofRanae Management, Certified Range. _ Management Consultant. Remote sensing applications PAUL T. TUELLER technology for rangeland management Tbe future of rangeland resmwces development and management in dependent upon increased scientific capability. Remote sensing technology can contribute information for a variety of rangeland resource management applications. In future we can expect to see an increased number of profnsion~l range managers with expertise in remote sensing. This training will include, in addition to principles of aerial photo interpretation, digttnl image analysis technology, increased use of geographic information systems, airborne video remote sensing, and the use of newly develop ing high resolution systems. The data will be obtained from both aircraft and spacecraft. Appltcations will include inventory, evaluation, and monitoring of rangeland resources and the incorporntion of remote senstng data to support and improve the decision processes on the use, development, and management of nngelnnd lesOurce area*.

No abstract

No abstract