Environmental Engineering Reference
In-Depth Information
example, the Yellowstone National Park in the United States employed
a 'natural burn' policy of management that culminated in catastrophic
forest i res.
As described above, human-induced perturbation on managed eco-
systems is a critical factor in maintaining biodiversity. However, the
application of best scientii c practice by land managers may not in itself
be sui cient to achieve biodiversity conservation goals. This is because
markets may fail to account for the value of biodiversity to society. It is
essential therefore that land managers are aware of the limitations and
opportunities of the market. The next section explores the economic link-
ages between markets and biodiversity.
Biodiversity in managed landscapes: economic issues
As reviewed above, biological resources in many of the world's low-
intensity managed habitats represent a signii cant contribution to economic
activity. However, many traditional low-intensity managed habitats are
threatened by development - a change in land use management due to the
prospect of increased private returns. According to the economic theory
of general equilibrium, the search for opportunities for increased private
returns can ensure that resources are allocated to the highest-value use
available, so that economic ei ciency is achieved. This result depends on
a number of conditions. If these conditions are fully met, land use change
motivated by private proi t need not be a cause for concern. However,
managed landscapes, in common with most environmental goods, have
characteristics that ensure that the necessary conditions will never be fully
met in practice. In general terms, this failure implies that any resulting
allocation of resources is likely to be economically inei cient, meaning
that it would be possible to reallocate resources in such a way as to make
at least one member of society 'better of '.
Some mention of the distinction between economic ei ciency and equity
is worthwhile at this point. Economists place great emphasis on economic
ei ciency but this will not necessarily result in a fair outcome. For a society
to be sustainable, its welfare should not be declining over time (WCED,
1987; Pezzey, 1989). In theory there are potentially a number of ei cient
time paths that are sustainable. However, ei ciency does not necessarily
guarantee sustainability between, say, current and future generations,
in terms of the distribution of natural resources such as biodiversity
(Common and Perrings, 1992; Perman et al., 2003).
In the case of managed landscapes, the danger is that land use change
guided by market signals alone may lead not to benei cial development
but to loss of valuable and possibly irreplaceable resources. The neces-
sary conditions that must hold in order for market-led development to
