Scale and patches

Scale is represented as both grain and extent. Extent refers to the area being investigated. Grain is the size of individual units of observation (McGarigal and Marks, 1994).

Patch size depends on the phenomenon being investigated so scale is a function of 'the level of spatial resolution at which the landscape is perceived or considered' (Forman and Godron, 1986)

Heterogeneity is implicit in the landscape, which means that as the scale of analysis is altered - different levels of heterogeneity found in the landscape can be observed. As the scale of observation becomes finer, more detail becomes apparent so what is detected in the landscape are patches within patches. This means that the pattern detected in the landscape is a function of the scale of analysis.

The scale and dynamics of human land use can vary considerably from natural processes. Increased human activity in the landscape can result in the rescaling of landscape pattern in both space and time. Human land use not only rescales patch dynamics but also changes the shape of patch boundaries, introduces novel patches and homogenises landscape pattern (Urban et al., 1987).

Human induced pattern varies more temporally than 'natural' patterns because it is determined by not only natural constraints in the landscape but also cultural and economic constraints and personal whims (Urban et al., 1987).

Reading 1.2 by Urban, O'Neill and Shugart to help you understand spatial patterns

Reading 1.3 "Scale sensitive ecological properties" by Bissonette is a helpful article.