330 Big pictures
Human activities in the past century have caused the extinction rate to sky-
rocket. Although the effects of species extinction, so far, have been minor on
society, the seeds of pervasive societal problems are likely being sown, and the
ethics of knowingly wiping away species is appalling. Continuing the current
rate of biodiversity loss promises a convulsion equivalent to the replacement of
dinosaurs by mammals around the globe 65 million years ago. Habitat removal
has enormously favoredHomo sapiensand about 40 domesticated species, plus
range expansions of numerous ‘‘non-native” species (McNeill2000).
Urban regions are generally not the centers of species extinction, though
urbanization in about 30 ecoregions, mostly coastal and large-island areas
with concentrations of endemic vertebrates, may be quite significant (Robert
McDonald, personal communication). Rather, urban regions are centers of peo-
ple, their activities, and their impacts that spread widely outward across the
land. Market forces and politics may degrade distant areas, yet public support,
votes, and funding in cities may also protect nature and species in distant areas.
Rare species probably exist in all urban regions and their protection is valu-
able (Beatley1994). However, this has to be placed in a priority context of time
and space. In the face of concentrated people, activities, and impacts, plus ongo-
ing outward urbanization, the chance of ‘‘permanent” or long-term protection
of rare species in an urban region is low. Still, even short-term protection may
suffice if a rare species then spreads to more suitable areas beyond the region.
Endemic species which are known only in an urban region (such as Capetown,
South Africa and Perth, Australia) warrant special protection effort. Neverthe-
less, with funding and protection efforts always limited, conservation priorities
should normally be in areas outside urban regions, where long-term protection
against species extinction is more likely to succeed.
The emerald network extending across an urban region, as well as across a
state or province or geographic region, was highlighted in the preceding section
(also see Chapters2 and 10 )asawaytocounteract the effects of climate change.
Theselarge natural areas,that can sustain large-home-range vertebrates and min-
imal viable populations of interior species (Chapter4), are the keystones. Emer-
alds in an urban region also have the largest interior-to-border ratios, which
greatly facilitates management and protection against habitat degradation by
concentrated people and their activities.
Yetevenemeralds can be degraded. Costa Rica has a widely known set of seven
large conservation-park areas. One day the Minister of Natural Resources and
Energy commented that the quality of these national parks is only as good as the
nation’s economy (Rene Castro Salazar, personal communication). If the economy
turns sour and families run out of food and jobs, people look to these areas as
safety nets. ‘‘Parques nationales” (national parks, which belong to the people) are