Introduction – humans, nature and human nature - Ecological Applications: Toward a Sustainable World - page 33

Toward a sustainable future
An activity is 'sustainable' if it can be continued into the future. If we want to eat
tuna in future, we cannot continue to harvest them faster than the population can
replace those that are lost. Nor can farmers continue to use fertilizers indiscrimi-
nately if people want to retain the ecosystem services provided by rivers, lakes and
oceans that are impacted by the agricultural excess. The recognition of the impor-
tance of sustainability as a unifying idea came of age in the early 1990s. Since then
the focus has shifted from a purely ecological perspective to one that incorporates
the economic and social conditions that infl uence sustainability. Thus, sustainability
has ecological, economic and sociopolitical dimensions.
The ecological dimension
From the ecological point of view, sustainability topics can be organized according
to the underlying structure of ecology theory. At the lowest level is the ecology of
individuals - niche requirements, life-history traits and dispersal/migratory behav-
ior. Knowledge at this level is crucial when reintroducing species that have gone
locally extinct, restoring natural grassland and forest, or predicting the arrival of
damaging invaders. Next comes the population level - all individuals of a single
species in a particular place. Population theory is central to the management of
endangered species, pests and harvests. Then there is community (species composi-
tion) and ecosystem (energy and nutrient fl ux) ecology. Theory at this level helps
managers devise plans to restore natural communities, counteract invasions, increase
the range of harvestable products and make agroecosystems sustainable. Finally, at
the largest scales, landscape ecology is crucial when designing networks of nature
reserves, and global climate change has implications for just about everything else.
The economic dimension
There is an economic side to every resource management argument. Sometimes the
costs and benefi ts are relatively straightforward to compute. But imaginative
approaches are needed to determine the value of a species or an ecosystem service
(e.g. travel cost paid by people to access a natural area provides a minimum value of
this recreational service). Viewed from the broadest perspective of all, the total value
of the world's ecosystem services has been roughly estimated at $38 trillion - more
than the gross domestic product of all nations combined. The 'new economics'
provides persuasive reasons for taking great care of biodiversity.
The sociopolitical dimension
Environmental issues almost always have a sociopolitical angle too. Sociologists can
help managers reconcile the desires of all interested parties. And political scientists
help determine whether sustainable management should be fostered by penalties or
inducements, or be set in law or encouraged by education. At the local level, when
people are well connected in groups and networks, and when their knowledge is
sought and incorporated during environmental management planning, they are
more likely to retain a care-taking role in the long term. If an environmental problem
occurs at too large a scale for local solutions, the sociopolitical machinations need
to occur globally. Estimates of future greenhouse gas emissions and the resulting
changes to global temperature vary according to sociopolitical factors - our predic-
tions need to be based on models that take these things into account.