14
An Overview of Ecological Assessment Principles and Applications
phasis on how the concepts of system dynamics,
hierarchy theory, thresholds, and predictability apply to multiscale ecological assessments. The majority of this chapter is devoted to describing the
basic properties of an ecological assessment that
should be considered when such an assessment is
used to implement ecosystem management objectives. We present a brief overview of the relation
of purpose, issues, spatial scale, information needs,
and analysis methodologies to ecological assessments in this section. This chapter concludes with
a general discussion of the importance of information management to ecological assessments and
suggested linkages between assessments and adaptive management. Recommendations concerning
future research and management needs for ecological assessments are also provided.
1.2 Ecosystem Management and
Its Relation to Ecological
Assessments
1.2.1 Evolving Philosophies of
Ecosystem Management
Although interest in and support for ecosystem
management are relatively recent, many of its directives are deeply rooted in the work of resource
managers and ecologists early in this century. Concerns regarding the sustainability of our natural resources are expressed in the writings of Marsh, Pinchot, and Clements. Certainly, sustainability is a
core objective in so-called sustained yield management for forests, fisheries, and wildlife first promulgated in the United States over a century ago.
That sustainability should be the overarching goal
of land management was the central thesis of Aldo
Leopold's "Land Ethic" (Leopold, 1949).
During the first six decades of this century, natural resource managers defined sustainable management within the context of ecological paradigms, such as equilibrium population dynamics
and directional succession to stable climax communities. Even today, in the face of much contrary
data, many models for sustained yield of wood
fiber, wildlife, and fish stocks are based on the supposition that natural processes regulating competition, predation, and material cycling will produce
stable equilibrium populations and communities.
Furthermore, ecologists presumed that most of
these natural processes operated at relatively small
spatial and temporal scales and that the effects of
episodic disturbances and climatic fluctuations
could be discounted (Christensen, 1988).
This century began with a human population
slightly over I billion. Five decades later, our numbers had barely doubled, and we were just beginning to appreciate the pervasiveness of our activities and their impacts on our globe. During most of
this period, the markets for natural resources such
as wood and wildlife were largely local and regional. Our transportation and communication systems certainly had not achieved their current continental and global extent. Thus, it could be argued
that the need to include humans in resource management processes (as in protocols for ecosystem
management; see below) was not nearly so great
nor did it have the same meaning as today.
Ecological science during the second half of this
century has taught us that notions of directional
change and stable equilibria are, at best, nllive and,
at worst, wrong-headed. Ecosystems are being influenced by periodic and stochastic events operating at a variety of time scales, and the behavior of
critical elements at particular locations is heavily
influenced by the character of the surrounding landscape. Furthermore, we have discovered that seemingly sustainable activities occurring at individual
locations can accumulate across watersheds and
landscapes to produce unsustainable outcomes in
terms of resource production and collateral environmental impacts.
As we approach the new millennium, our numbers are nearing 6 billion. Humans now use or influence over 50% of Earth's primary production.
Even the most remote and wild regions of Earth are
now influenced by human activities. Perhaps more
important from a management perspective, global
communication is virtually instantaneous, and markets for most natural resources are truly global as
well. Including and involving humans in natural resource management is not only more compelling,
but also a far more complex and daunting challenge
than it was during the first half of this century.
During the past several decades, a number of legislative initiatives have attempted to deal with these
changing management challenges. For example,
the Multiple Use Sustained Yield Act of 1960 has
been the centerpiece of management in the USDA
Forest Service for nearly four decades. Like ecosystem management, the intent was to reconcile conflicting values and demands on public lands. However, some would argue that, instead, the effect was
that of institutionalizing such conflicts or that of
setting a higher priority on conflict resolution than
on sustainability (Fedkiw, 1999).
An Overview of Ecological Assessment Principles and Applications
phasis on how the concepts of system dynamics,
hierarchy theory, thresholds, and predictability apply to multiscale ecological assessments. The majority of this chapter is devoted to describing the
basic properties of an ecological assessment that
should be considered when such an assessment is
used to implement ecosystem management objectives. We present a brief overview of the relation
of purpose, issues, spatial scale, information needs,
and analysis methodologies to ecological assessments in this section. This chapter concludes with
a general discussion of the importance of information management to ecological assessments and
suggested linkages between assessments and adaptive management. Recommendations concerning
future research and management needs for ecological assessments are also provided.
1.2 Ecosystem Management and
Its Relation to Ecological
Assessments
1.2.1 Evolving Philosophies of
Ecosystem Management
Although interest in and support for ecosystem
management are relatively recent, many of its directives are deeply rooted in the work of resource
managers and ecologists early in this century. Concerns regarding the sustainability of our natural resources are expressed in the writings of Marsh, Pinchot, and Clements. Certainly, sustainability is a
core objective in so-called sustained yield management for forests, fisheries, and wildlife first promulgated in the United States over a century ago.
That sustainability should be the overarching goal
of land management was the central thesis of Aldo
Leopold's "Land Ethic" (Leopold, 1949).
During the first six decades of this century, natural resource managers defined sustainable management within the context of ecological paradigms, such as equilibrium population dynamics
and directional succession to stable climax communities. Even today, in the face of much contrary
data, many models for sustained yield of wood
fiber, wildlife, and fish stocks are based on the supposition that natural processes regulating competition, predation, and material cycling will produce
stable equilibrium populations and communities.
Furthermore, ecologists presumed that most of
these natural processes operated at relatively small
spatial and temporal scales and that the effects of
episodic disturbances and climatic fluctuations
could be discounted (Christensen, 1988).
This century began with a human population
slightly over I billion. Five decades later, our numbers had barely doubled, and we were just beginning to appreciate the pervasiveness of our activities and their impacts on our globe. During most of
this period, the markets for natural resources such
as wood and wildlife were largely local and regional. Our transportation and communication systems certainly had not achieved their current continental and global extent. Thus, it could be argued
that the need to include humans in resource management processes (as in protocols for ecosystem
management; see below) was not nearly so great
nor did it have the same meaning as today.
Ecological science during the second half of this
century has taught us that notions of directional
change and stable equilibria are, at best, nllive and,
at worst, wrong-headed. Ecosystems are being influenced by periodic and stochastic events operating at a variety of time scales, and the behavior of
critical elements at particular locations is heavily
influenced by the character of the surrounding landscape. Furthermore, we have discovered that seemingly sustainable activities occurring at individual
locations can accumulate across watersheds and
landscapes to produce unsustainable outcomes in
terms of resource production and collateral environmental impacts.
As we approach the new millennium, our numbers are nearing 6 billion. Humans now use or influence over 50% of Earth's primary production.
Even the most remote and wild regions of Earth are
now influenced by human activities. Perhaps more
important from a management perspective, global
communication is virtually instantaneous, and markets for most natural resources are truly global as
well. Including and involving humans in natural resource management is not only more compelling,
but also a far more complex and daunting challenge
than it was during the first half of this century.
During the past several decades, a number of legislative initiatives have attempted to deal with these
changing management challenges. For example,
the Multiple Use Sustained Yield Act of 1960 has
been the centerpiece of management in the USDA
Forest Service for nearly four decades. Like ecosystem management, the intent was to reconcile conflicting values and demands on public lands. However, some would argue that, instead, the effect was
that of institutionalizing such conflicts or that of
setting a higher priority on conflict resolution than
on sustainability (Fedkiw, 1999).