Environmental Engineering Reference
In-Depth Information
of land abandonment has become a subject of major concern in many
countries because it results in the loss of biodiversity. It is also thought
that land managers may conserve biodiversity because it supports the
productivity and resilience of the ecosystems they manage and there is
now a signii cant literature on the functional and ecosystem service values
associated with biodiversity (Ellis and Fisher, 1987; Daily, 1997; Barbier,
2000; Daily et al., 2000).
However, the intensity and mode of disturbance clearly play an impor-
tant part in the management of ecosystems. Heavily disturbed agricultural
and forest ecosystems in many parts of the world are threatened by human
intervention that has resulted in a loss of biodiversity and resilience.
Clearly it is important to distinguish between managed landscapes that
undergo disturbance in which biodiversity appears to be thriving and
those in which it is threatened. In this chapter we explore the relationship
between human-induced disturbance and biodiversity. We also consider
the relationship between disturbance regimes and the properties of a
managed ecosystem - its productivity, resilience and stability.
All too frequently the application of 'good science' is not in itself
sui cient to guarantee desirable environmental outcomes with respect
to biodiversity conservation. This also requires an understanding of
socioeconomic and policy considerations: how markets allocate scarce
resources, how they inl uence decisions taken by land managers and why
they frequently fail to protect biodiversity and other non-market values.
To a degree, most land managers are af ected by the market. Thus, the
chapter also explores the economic linkages between markets and natural
resources, and the possibilities of exploiting the powerful creative forces
of the market in a manner that conserves biodiversity whilst also provid-
ing useful marketable goods and services. Finally the chapter concludes
with some policy recommendations on making markets account for the
benei ts of biodiversity conservation in managed landscapes. We begin by
distinguishing between genetic and functional diversity.
Genetic and functional diversity in managed landscapes
Several dei nitions have been proposed to capture the multifaceted nature
of biodiversity (ecosystems, species and genes). This is acknowledged in
the dei nition developed in the Convention on Biodiversity as follows:
'“Biological diversity” means the variability among living organisms from
all sources, including inter alia, terrestrial, marine and other aquatic eco-
systems and the ecological complexes of which they are part; this includes
diversity within species, between species and among ecosystems' (UNEP,
1995. p. 8).
1
A distinction is made in the literature between genetic diversity and
