Keyspatial attributes 123(a) Rare featuresin the urban region were marked: topographic (e.g., volcano
[Portland], high point next to the sea where migrating birds congregate
[Barcelona]); geologic (limestone area [Barcelona], island [Bangkok]); veg-
etational (mangrove swamp [Kagoshima], palm oasis [Rahimyar Khan]);
water-body (lake [Nairobi], freshwater wetland [Ottawa]); and human-
created (reservoir [Beijing], large long-established military base rich in
biodiversity [San Diego] [Goodman1996,Leslieet al.1996]).
(b) Large areas of natural vegetation,differentiated by type where possible (e.g.,
marsh, forest), were marked.
(c) Isolated areasof potentially viable natural vegetation were marked (palm
oasis [Rahimyar Khan], salt flat [Tehran]). These are likely to support
many uncommon species and to be key sources of species for populating
surrounding areas.
(d) The nearest lobesof natural vegetation projecting toward a metropolitan
area (Rome, Bucharest) were marked. These are key sources of species
that colonize parks and other greenspaces across the metro area, as well
as nearby access points to nature for recreationists from the city.
(e) Strategically located sites for regional connectivity,i.e., species movement and
waterflow,were marked. These include gaps or narrows connecting
large natural areas and a row of natural ‘‘stepping stones” (Ulaanbaatar,
Nantes).Even using these diverse approaches for pinpointing major biodiversity areas,
themaps are incomplete, often woefully so. Nevertheless, because of the many
other major benefits provided for society, as listed above, these sites are among
the mostimportantanywhere in the urban region.
In addition to the 26 widespread site types above, 16 others were infrequent
in the urban regions, but were deemed important and mapped:
(1) Ice and snow (atop high mountains; Santiago, Ulaanbaatar, Portland,
Erzurum, Sapporo, Tehran).
(2) Lava bed (Mexico City, Kagoshima, Portland).
(3) Canal (Beijing, Cairo, Bangkok, Berlin, Moscow).
(4) Fortypercent of distance to a neighboring larger city (Ottawa, Philadel-
phia, San Diego, Rahimyar Khan; this recognizes that a larger nearby
city probably has a larger urban region).
(5) Barrier across river (Seoul, London).
(6) Greenbelt (London, Ottawa, Seoul).
(7) Urban-growth boundary (Portland).