university at buffalo engineering for ecosystem restoration summer workshop series 25 june 2010...
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University at BuffaloEngineering for Ecosystem Restoration
Summer Workshop Series25 June 2010
David BlerschDept. of Civil, Structural and Environmental Engineering
University at Buffalo
Ecological Systems Modeling:Lecture 2: Systems and Ecosystems
Systems and EcosystemsWhat is a system?
A system is a group of parts which are connected and work together. Systems with living and nonliving parts are called ecosystems (short for ecological system) (Odum, Odum, and Brown, 1997)
What is an ecosystem?
Some definitions of “ecosystem”Classic: A dynamic set of living organisms (plants, animals and
microorganisms) all interacting among themselves and with the environment in which they live (soil, climate, water, and light).
A biotic and functional system or unit which is able to sustain life and includes all biological and non-biological variables in that unit (Jorgensen and Bendoriccio 2001).
A community of species interacting to process energy and nutrients through a complex of foodwebs (Adey and Loveland (2007)).
A network of biotic (species populations) and abiotic (nutrients, soil, water, etc.) components found at a particular location that function together as a whole through primary production, community respiration, and biogeochemical cycling (Kangas (2004)).
An organized system of land, water, mineral cycles, living organisms, and their programmatic behavioral control mechanisms. (Odum 1994).
Properties of EcosystemsAn ecosystem…Is the fundamental unit of ecology (?)…Is the “exquisite potential of the universe.” (Adey and Loveland
2007)Is conservative of matter and energyPerforms energy capture and transformationPerforms mineral retention and cyclingHas rate regulation and controlOrganizes towards production and respiration balance
Thermodynamic LawsFirst Law of Thermodynamics (Law of Conservation) The total energy of any system and its surroundings is
conserved (i.e., Energy is neither created nor destroyed, it changes from one form to another).
Second Law of Thermodynamics (Entropy Law)The entropy change of any system and its surroundings,
considered together, resulting from any real process, is positive and approaches a limiting value of zero for any process that approaches irreversibility (i.e., for any real process, some energy is lost as waste heat).
Energetic basis for ecosystems
Waste Heat
Less total energy at each level
Grazers
Plants
Sun
Carnivores
Hierarchy: Food Chains and Pyramid Charts
Embodied energy at each level
1000
100
10
1
Rudimentary Systems Diagrams
Odum 1956
“Electrical” Analog
“Pulmonary” analog
Using a Systems LanguageWhy a systems language?To convert non-quantitative verbal models to… more
quantitative, more accurate, more predictive, more consistent, and less confusing network diagrams.
Understanding systems…Understanding environment and society as a system means
thinking about parts, processes, and connections. To help understand systems, it is helpful to draw pictures of
networks that show components and relationships.
Energy Circuit Diagrams
From Odum (1994)
System Frame: A rectangular box drawn to represent the boundaries of the system selected.
ENERGY SYSTEMS SYMBOLS
Pathway Line: a flow of energy, often with a flow of materials.
SOURCE: outside source of energy; a forcing function..
STORAGE: a compartment of energy storage within the system storing quantity as the balance of inflows and outflows
Pathway Line: a flow of energy, often with a flow of materials.
SOURCE: outside source of energy; a forcing function..
STORAGE: a compartment of energy storage within the system storing quantity as the balance of inflows and outflows
Pathway Line: a flow of energy, often with a flow of materials.
SOURCE: outside source of energy; a forcing function..
STORAGE: a compartment of energy storage within the system storing quantity as the balance of inflows and outflows
INTERACTION: process which combines different types of energy flows or material flows to produce an outflow in proportion to a function of the inflows.
PRODUCER: unit that collects and trnasforms low-quality energy under control interactions of higher quality flows.
CONSUMER: unit that transforms energy quality, stores it, and feeds it back autocatalytically to improve inflow
.
Multiplier or Work Gate
A
B
AxB
HEAT SINK: A pathway for dissipated energy necessary forany real process.
Autocatalytic unit
A stored quantity is used in a feedbackloop to interact as a multiplier with theinput energy source of that quantity.
Maximum Power Principle: Systems prevail that develop designs that maximize the flow of useful energy (Lotka, 1922)
“Self-organization selects network connections that feed back transformed energy to increase inflow of resources or use them more efficiently.” (Odum and Odum 2001)
INTERACTION: process which combines different types of energy flows or material flows to produce an outflow in proportion to a function of the inflows.
PRODUCER: unit that collects and trnasforms low-quality energy under control interactions of higher quality flows.
CONSUMER: unit that transforms energy quality, stores it, and feeds it back autocatalytically to improve inflow
.
INTERACTION: process which combines different types of energy flows or material flows to produce an outflow in proportion to a function of the inflows.
PRODUCER: unit that collects and trnasforms low-quality energy under control interactions of higher quality flows.
CONSUMER: unit that transforms energy quality, stores it, and feeds it back autocatalytically to improve inflow
.
TRANSACTION: a unit that indicates the sale of goods or services (solid line) in exchange for payment of money (dashed line).
SWITCHING ACTION: symbol that indicates one or more switching functions where flows are interrupted or initiated.
BOX: miscellaneous symbol for whatever unit or function is labled.
Conventionssources arrangedaccording totheir quality
Components arranged withinboundary according to theirquality
Used Energy
Typical Energy Sources
Odum (1994)
Hierarchical arrangement of systemsI I I I I I I V
A
B
C
D
E
J
K
L
S
T
Z
Hierarchical Levels
Parallel Processes
EnergySource
Putting it together
Producer ConsumerEnergySource
Feedback
Simple Production-Consumption cycle
Systems Model: Aquatic system
Odum (1994)
A forest ecosystem….
Bio-mass
Plants
Bio-mass
Wildlife
Nutrients Nutrient Recycle
Used Energy
Forest Ecosystem
Sunlight
.
Bio-mass
Plants
Bio-mass
Wildlife
Nutrients Nutrient Recycle
Used Energy
Forest Ecosystem
Sunlight
More complexity. .
Bio-mass
Plants
Bio-mass
Wildlife
Nutrients
Positive Feedback
Nutrient Recycle
Used Energy
Forest Ecosystem
Sunlight
Goods &Services
Markets
Sales
Purchases
Cutting
X
Even more complexity…
Renewable Sources
NaturalEcosystems
AgricultureGreenSpace
Commerce& Industry
Infra-Structure
PeopleGov't
$
Waste
Fuel Goods Services
People
Support Region
City
.
Bio-mass
Plants
Bio-mass
Wildlife
Nutrients Nutrient Recycle
.
Bio-mass
Plants
Bio-mass
Wildlife
Nutrients Nutrient Recycle
Nested models…
Your turn…1st Annual Ecosystem Model Scavenger Hunt!
Procedures for Circuit Diagramming1. Draw the frame of attention that selects the boundary
2. Make a list of the important input pathways that cross the boundary
3. Make a list of the components believed to be important
4. Make a list of the processes believed to be important within the defined system.
5. Remember that matter is conserved.
6. Check to see that money flows form a closed loop within the frame and that money inflows across the boundary lead to money outflows.
7. Check all pathways to see that energy flows are appropriate.
8. If a complex diagram has resulted (> 25 symbols), redraw it to make it neat and save it as a useful inventory and summary of the input knowledge. Redraw the diagram with the same boundary definition, aggregating symbols and flows to obtain a model of the desired complexity (perhaps 3-10 symbols).
9. Conventions:
sources arrangedaccording totheir quality
Components arranged withinboundary according to theirquality
Used Energy
References
Abrams, P., B.A. Menge, G.G. Mittelbach, D. Spiller, and P. Yodzis. 1996. The role of indirect effects in food webs. Pp. 371-395. In: Food Webs: Integration of Patterns and Dynamics. G.A. Polis and K.O. Winemiller (eds.). Chapman & Hall, New York.
Adey, W.H., and K. Loveland. 2007. Dynamic Aquaria: Building and Restoring Living Ecosystems (3rd Edition). Academic Press, San Diego, California.
Gerardin, L. 1968. Bionics. McGraw-Hill, New York. Jorgensen, S.E., and G. Bendoricchio. 2001. Fundamentals of Ecological
Modelling (3rd Edition). Elsevier Science, New York.Kangas, P.C. 2004. Ecological Engineering: Principles and Practice. Lewis
Publishers, Boca Raton, Florida.Odum, H.T. 1994. Ecological and General Systems: An Introduction to Systems
Ecology. University Press of Colorado, Niwot, Colorado.Odum, H.T., and E.C. Odum. 2000. Modeling for All Scales: An Introduction to
System Simulation. Academic Press, San Diego, California.
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