Spatial analysis for patterns 141or data, a conservative approach of only pinpointing the clearest major results
wastaken. With this approach, errors discovered or new data added are unlikely
tohave a significant effect on the results highlighted, though of course cau-
tion in interpretation is always warranted. Many minor results, and even major
results not pinpointed, are evident in the figures and color maps, and are likely
tobe discovered and highlighted in the future.
Aspatial-analysis technique usinglandscape metricsbears mention (Fortin1999,
Klopatek and Gardner1999,Leitaoet al.2006), though it was not used here. Land-
scape metrics are measures (and equations) that quantifyspatial attributesof a
large area, such as connectivity, patch density, total interior habitat, boundary
length or density, and association of types of objects. The beauty of these is
that important ecological characteristics are known to correlate with spatial
attributes. Theseecological characteristicsat the landscape scale include interior
species, large-home-range species, aquifers, wildfire hazard, wildlife movement
routes, animal dispersal, species-rich sites, stream-network flows, fish migra-
tion, and so forth. Thus a particular quantitative level for a spatial attribute
is an indicator or surrogate for conditions of an ecological characteristic on the
land.
The idea of spatial attributes and ecological characteristics will be used peri-
odically in this book. Landscape metrics do not replace direct, detailed mea-
surements of ecological characteristics at the landscape scale that may be time
consuming, or experiments that may be impossible. Rather, because of the pre-
viously documented relationship between spatial attributes and ecological char-
acteristics, the landscape metrics may represent a useful handle to ecological
understanding and planning of landscapes.
In landscape ecology thelandscapeis a kilometers-wide area over which local
land uses and ecosystems are repeated in similar form (Forman1995). For opera-
tional convenience in analyzing urban regions, thelandscapeconcept is narrowed
slightly and refers to a compact (<2:1 length-to-width ratio) area of >100 km^2
with repeated internal heterogeneity, such as a cropland landscape or a wooded
landscape.
The first section below, ‘‘nature in urban regions,” will emphasize natural
vegetation areas and connectivity for species movement. The second section,
‘‘ F ood in urban regions” will focus on cropland areas, including regional diversity
and stability. The third section, ‘‘Water in urban regions” will highlight water
bodies and areas that affect them. These are explored outside the metropolitan
area, that is, in the surrounding urban-region ring.
Thirty-seven major patterns and results emerged from spatially analyzing the
38 urban regions. These are presented in the nature-in-urban-regions section as