Components of Healthy Components of Healthy Ecosystems/Ecosystem Ecosystems/Ecosystem

ManagementManagement

Wally CovingtonWally Covington

Ecosystem StudiesEcosystem Studies

► Ecosystem studiesEcosystem studies based on general based on general

systems principlessystems principles focus on the focus on the

movement of energy, movement of energy, nutrients, water, nutrients, water, organisms, etc. organisms, etc.

through landscape through landscape units called units called ecosystemsecosystems

An ecosystem:An ecosystem:What is it?What is it?

► Size?Size? Can be as large or Can be as large or

small as needed to small as needed to fit the purpose of fit the purpose of study study

► A single leafA single leaf► A forested standA forested stand► A watershedA watershed► Hierarchical unitsHierarchical units

Definitions:Definitions:

► Watershed:Watershed: topographically defined unit topographically defined unit of land, all precip. flows out of land, all precip. flows out of a single streamof a single stream

► Stand: Stand: any area of forest any area of forest vegetation whose site vegetation whose site conditions, past history, and conditions, past history, and current species composition current species composition are sufficiently uniform to are sufficiently uniform to be managed as a unitbe managed as a unit

A watershed can have A watershed can have many standsmany stands

Ecosystem Study Examples – Ecosystem Study Examples – Hubbard BrookHubbard Brook

► Ecosystem-level Ecosystem-level study of a forested study of a forested watershedwatershed

► Hubbard Brook Hubbard Brook Valley; Durham, NHValley; Durham, NH

► Six small Six small watersheds with watersheds with similar geology, similar geology, soils, and soils, and vegetationvegetation

Ecosystem Study Examples –Ecosystem Study Examples – Hubbard BrookHubbard Brook

► Watershed: Watershed: topographically defined unit topographically defined unit of land, all precip. flows out of land, all precip. flows out of a single streamof a single stream

► Monitor: Monitor: precipitation in precipitation in (rain (rain

gauges)gauges)

streamflow out streamflow out (weir)(weir)

nutrients in:nutrients in:► Plants, soil, and those Plants, soil, and those

lost in waterlost in water

Ecosystem Study Examples – Ecosystem Study Examples – Hubbard BrookHubbard Brook

► 1. Study paired 1. Study paired watershed-ecosystem watershed-ecosystem before a disturbancebefore a disturbance

► 2. Then disturb the 2. Then disturb the systemsystem (In this case, forest (In this case, forest harvesting practices such as a harvesting practices such as a clear-cut = treatement)clear-cut = treatement)

► 3. Compare inputs and 3. Compare inputs and outputs before and outputs before and afterafter (or use “paired (or use “paired watersheds” – one disturbed, watersheds” – one disturbed, other not)other not)

► 4. Differences in water, 4. Differences in water, nutrients, etc. – due to nutrients, etc. – due to the treatmentthe treatment

Organic Budgets/Nitrogen CycleOrganic Budgets/Nitrogen Cycle

► Very different in Very different in deciduous vs. coniferous deciduous vs. coniferous forestsforests

► Decomposition – Decomposition – (therefore, (therefore,

release of nitrogen in ionic form)release of nitrogen in ionic form) is often faster in is often faster in deciduous forestsdeciduous forests

► Coniferous trees need Coniferous trees need less less nitrogen/decomposition is nitrogen/decomposition is often sloweroften slower

► Fire can be important in Fire can be important in mobilizing nitrogenmobilizing nitrogen

Computer Models:Computer Models:Central to Ecosystem ManagementCentral to Ecosystem Management

► Need computer Need computer models:models: Complexity of forest Complexity of forest

ecosystemsecosystems Complexity of Complexity of

management management decisionsdecisions

What is a model?What is a model?

► Model Model = = an abstract an abstract representation of a system representation of a system or processor process

► Formulated in many Formulated in many differentdifferent ways ways

► Physical modelsPhysical models – – reduced size; model reduced size; model airplanes or model buildingsairplanes or model buildings Better visualizeBetter visualize Better understand the Better understand the

forcesforces► Abstract modelsAbstract models - - use use

symbols and equations:symbols and equations: Verbal, graphical, and Verbal, graphical, and

mathematical modelsmathematical models

Ecosystem ManagementEcosystem Management

► The ecosystem approach: The ecosystem approach: healthy ecosystems and sustainable economieshealthy ecosystems and sustainable economies a method for sustaining or restoring natural systems and their a method for sustaining or restoring natural systems and their

functions and values functions and values goal driven, and it is based on a collaboratively developed vision goal driven, and it is based on a collaboratively developed vision

of desired future conditions that integrates ecological, economic, of desired future conditions that integrates ecological, economic, and social factors. and social factors.

applied within a geographic framework defined primarily by applied within a geographic framework defined primarily by ecological boundaries. ecological boundaries.

► The The goalgoal of the ecosystem approach: restore and sustain the of the ecosystem approach: restore and sustain the health, productivity, and biological diversity of ecosystems and health, productivity, and biological diversity of ecosystems and the overall quality of life through natural resource management the overall quality of life through natural resource management that is fully integrated with social and economic needs.that is fully integrated with social and economic needs.