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? 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 watershed- ecosystem before a disturbance ► 2. Then disturb the system (In this case, forest harvesting practices such as a clear-cut = treatement) ► 3. Compare inputs and outputs before and after (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 ways ► Physical models – 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.