122 Thirty-eight urban regions
(22) Recreation/tourist area for one-day trip (based mainly on parks, natural
areas, cultural features, etc. from published maps and travel guides, plus
consultations with knowledgeable persons).
(23) Mountain range (approximate ridgeline marked).
(24) Political/administrative boundary (boundary of another major political/
administrative unit, e.g., nation [San Diego/Tijuana example], state or
province [Philadelphia], or county [Edmonton], is marked when some-
what perpendicular to a radius of the region to help determine the
region’s boundary).
(25) Sixty percent of distance to a smaller, but >250 000 population, city
(recognizing that the outside city has its own urban region).
(26) Seventy percent of distance to <250 000 population city outside region
(recognizing that the outside city has its own urban region, and that it is
asmaller city than in the preceding case; 70 % [and/or 60 %] occasionally
appears twice in about the same direction on an image because of two
cities in that direction).The last six site types (numbers 21--26) were particularly important in determin-
ing the boundaries of urban regions, as highlighted in the preceding section.
Biodiversity areas (number 15 above) have a special importance in urban
regions because of the high concentration of people and their manifold effects.
These sites usually have importance far beyond maintaining rare species and
natural communities. Many biodiversity areas maintain water resources, pro-
vide diverse recreation, protect cultural heritage resources, provide high visual
quality, minimize soil erosion and stream sedimentation, provide wood prod-
ucts, and accomplish other key objectives of society.
Since rigorous data on biodiversity areas in urban regions are rarely avail-
able or easily obtainable, a protocol for identifying these was developed. In a
fewcases (e.g., Edmonton, Chicago, London) ecologists and other experts have
identified many of the most important biodiversity areas, which provides a good
basis for mapping. In many urban regions published maps, travel guides, and
other literature identified biodiversity areas in the form of parks, natural areas,
wildlife conservation areas, and the like, which were mapped. Then for some
urban regions, knowledgeable consultants were able to pinpoint a few key bio-
diversity areas.
However, in addition the aerial images and other maps were further examined
through the lens of landscape ecology (Forman1995,Farina2005,Groomet al.
2006)toidentify and mark probable key biodiversity areas. This highlighted five
important types of biodiversity areas: