Natural systems and greenspaces 81considerable confidence in analysis and planning (Karr 2002). To understand
their development, the underlying evidence and variability, other ecological
principles, and fuller definitions of terms, see basic ecology texts such as by
Barbouret al.(1987), Krebs (1994), Smith (1996), Morin(1999), Ricklefs and Miller
(2000), Townsendet al.(2000), and Odum and Barrett(2005). To further sense
thescientific questions, methods, analyses, results, discussion, and excitement
of ecological discovery, peruse recent issues of journals such asEcology, Ecosystem
Ecology, Biological Conservation,Conservation Biology, Journal of Animal Ecology, Journal
of Applied Ecology,Journal of Ecology, Landscape Ecology, Limnology and Oceanography,
Oecologia, Oikos,and scattered articles inNatureandScience.
Tohelp understand why this particular set of natural systems principles is
important, visualize the following distinctive characteristics of urban regions.
Hardly any other place on Earth has these attributes. Furthermore, virtually all
theecological principles were developed from research mainly done elsewhere,
so this chapter also emphasizes the applicability of ecological principles to these
unusual urban places.
Distinctive characteristics of urban regionsinclude: (1) packed people, increasing
in density toward the center of the region; (2) extensive impermeable surface
also increasing toward the center; (3) large aggregations of rectangular residen-
tial lots; (4) major transportation routes, sometimes with strip development,
radiating from the central portion, and at times jammed with commuters;
(5) central heat-island effect; (6) agricultural and/or wooded land relatively con-
tinuous in the outer portion, fragmented in the middle, and nearly absent in
the central portion; (7) many busy irregular fine-scale road networks; (8) exten-
sive areas with a diversity of prominent non-native species; (9) highly diverse air
pollution in the central and downwind portion; (10) groundwater levels lowered
and polluted in large areas; (11) extensive surfacewater pollution, commonly a
mix of agricultural runoff, stormwater runoff, human wastewater effluent, and
industrial waste; (12) stream systems widely disrupted; and (13) wetlands exten-
sively eliminated. Other distinctive characteristics of urban regions of course
could be added, but these illustrate the kinds of issues that ecological princi-
ples will be called on to address for society.
Before turning to ecosystem and population principles, a range of exception-
ally important ecological principles at broader scales are briefly mentioned. Most
important are thelandscape and regional ecologyprinciples (Forman 1995 ,Burel
and Baudry1999,Farina2005,Perlman and Milder2005,Turner 2005, Odum
and Barrett2005). These were briefly introduced in Chapter1 and will be pro-
gressively described and widely used throughout this book on urban regions.
Continental ecology and global ecologyprinciples include a heterogeneous array
related to paleoecology, biogeography, biomes/major vegetation types, winds and