7923

• UCREFRP Catalog Number: 7923
• Author: Carter, J. G. and V. A. Lamarra.
• Title: An Ecosystem Approach To Environmental Management, Chapter 17.
• USFW Year: n.d.
• USFW - Doc Type: 261-287
• Copyright Material: YES

With these goals in mind, it is necessary to use a
conceptual view of the ecosystem which can identify the
dominant static and dynamic variables (structure,
function, and rate process) which can depict ecosystem
"health" and identify departures from normality. These
departures can then be used in contingency planning as the
trigger for management decision making guided by a logic
flow model.

CONCEPTUAL VIEW OF THE AQUATIC ECOSYSTEM

The ecosystem view recognizes that the biological
components of the system exist within, interact with and
are constrained by the physical environment (Figure 2).

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Figure 2. Conceptual view of ecosystems
relative to external influences.

In addition, this view recognizes that the activities of
man may have a large influence on these ecosystem
components changing inputs and outputs across system
boundaries and the structure and functioning of the
biological components within individual ecosystems (Figure
3).

The primary producers (plants and algae) use solar
energy and input materials to generate carbohydrates which
are used for growth and reproduction (increase in biomass,
or primary production). Production then has two basic

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