Components of Healthy
Ecosystems/Ecosystem
Management
Wally Covington
Ecosystem Studies
► Ecosystem
studies
 based on general
systems principles
 focus on the movement
of energy, nutrients,
water, organisms, etc.
 through landscape units
called ecosystems
An ecosystem:
What is it?
► Size?
 Can be as large or small
as needed to fit the
purpose of study
►A
single leaf
► A forested stand
► A watershed
► Hierarchical units
Definitions:
►
Watershed: topographically
defined unit of land, all precip.
flows out of a single stream
►
Stand: any area of forest
vegetation whose site
conditions, past history, and
current species composition are
sufficiently uniform to be
managed as a unit
 A watershed can have many
stands
Ecosystem Study Examples –
Hubbard Brook
► Ecosystem-level
study
of a forested
watershed
► Hubbard Brook Valley;
Durham, NH
► Six small watersheds
with similar geology,
soils, and vegetation
Ecosystem Study Examples –
Hubbard Brook
►
Watershed: topographically
defined unit of land, all precip.
flows out of a single stream
►
Monitor:
 precipitation in (rain gauges)
 streamflow out (weir)
 nutrients in:
► Plants,
soil, and those lost
in water
Ecosystem Study Examples –
Hubbard Brook
►
1. Study paired watershedecosystem before a
disturbance
►
2. Then disturb the system
►
3. Compare inputs and
outputs before and after
(In this case, forest harvesting
practices such as a clear-cut =
treatement)
(or use “paired watersheds” –
one disturbed, other not)
►
4. Differences in water,
nutrients, etc. – due to the
treatment
Organic Budgets/Nitrogen Cycle
►
►
►
►
Very different in deciduous
vs. coniferous forests
Decomposition – (therefore,
release of nitrogen in ionic form) is
often faster in deciduous
forests
Coniferous trees need less
nitrogen/decomposition is
often slower
Fire can be important in
mobilizing nitrogen
Computer Models:
Central to Ecosystem Management
► Need
computer
models:
 Complexity of forest
ecosystems
 Complexity of
management decisions
What is a model?
►
Model = an abstract
►
representation of a system or
process
Formulated in many different
►
Physical models
ways
–
reduced
size; model airplanes or model
buildings
 Better visualize
 Better understand the forces
►
Abstract models
-
use
symbols and equations:
 Verbal, graphical, and
mathematical models
Ecosystem Management
►
The ecosystem approach:
 healthy ecosystems and sustainable economies
 a method for sustaining or restoring natural systems and their functions
and values
 goal driven, and it is based on a collaboratively developed vision of desired
future conditions that integrates ecological, economic, and social factors.
 applied within a geographic framework defined primarily by ecological
boundaries.
►
The goal of the ecosystem approach: restore and sustain the health,
productivity, and biological diversity of ecosystems and the overall
quality of life through natural resource management that is fully
integrated with social and economic needs.