Ecosystem Theory for Environmental Management

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1 Ecosystem Theory for Environmental Management Brian D. Fath Biology Department, Towson University Towson, MD 21252, USA

2 Ecosystem Theory for Environmental Management Outline 1) Open systems: input-output models Ecological and Human systems 2) Network Analysis: understanding connectivity and indirect effects 3) Ecosystem Growth and Development

3 A New Ecology: Systems Perspective 1) Ecosystems have Openness 2) Ecosystems have Connectivity 3) Ecosystems have Directionality 4) Ecosystems have Emergent Hierarchies 5) Ecosystems have Complex Dynamics a) Growth and Development b) Disturbance and Decayc Coming to bookstores May 2007!!

4 Open systems connect to their environment through both inputs and outputs Environment Source System Sink Input-State-Output

5 Open Systems build and maintain order and organization by taking in high quality energy, using it, and passing degraded energy outside of the system. High quality Energy Input System (human or natural) Low quality Energy output (waste heat)

6 Ecological and human systems are open Input System Output Sustainability is dependent on the energymatter flows that support it AND having a sink for the waste.

7 Simplified Ecosystem

8 Simplified Human System

9 Economy as a closed system A perpetual motion machine

10 Economy as an open system Environment energy raw materials waste heat material waste

11 Input Sustainability Challenges Limited Supply? Input? System Output

12 Energy Estimation Using Peak Production (M.K. Hubbert) Production starts at zero; Production then rises to a peak; After peak, production declines until resource is depleted. Production peaks Production starts Production declines Time

15 North Sea Oil and Gas Production

16 Global Oil and Gas Production

17 Historical view of Fossil Fuel use Where are we on the curve? Fossil Fuel Age Fossil Fuel Use? 10,000 BC 1AD 2000AD 5000AD Time

18 Output Sustainability Challenges Limited Sink? Input Output? System

19 Environmental Impacts of Fossil Fuel Use Limited Sink for output Photochemical smog Acid mine drainage Oil spills Climate Change

20 Sustainability Challenges System Dynamics? Input System? Output

21 Input Environment Ecosystem? Output Ecosystems have evolved and developed within these input-output environmental constraints. Thermodynamically, what patterns of organization arise in ecosystems?

22 Ecosystem Growth and Development 0. Boundary Growth: Low-entropy energy enters the system. I. Structural Growth: Increase in biomass - number and size of components in the ecosystem increase. II. Network Growth: Growth in system connectivity gives more pathways & matter and energy cycling. III. Information Growth: Qualitative growth in system behavior from exploitative patterns to more energetically efficient ones.

23 Ecosystem Development Trends (Odum 1969) Ecosystem Attribute Developmental Mature Stage Stage Community energetics Gross production/community respiration (P/R ratio) <1> ~1 Biomass supported/unit energy flow (B/E ratio) low high Food chains linear weblike Nutrients Mineral cycles open closed Nutrient exchange rate rapid slow Overall homeostasis Internal symbiosis undeveloped developed Nutrient conservation poor good Entropy high low Information low high

24 Ecological Goal Functions In ecological models, goal functions are assumed to measure given properties or tendencies of ecosystems, emerging as a result of selforganization processes in their development (Marques 1998).

25 Ecological Goal Functions 1 Minimize specific entropy production (Prigogine 1947). Decrease in the respiration to biomass ratio. 2 Maximize energy throughflow (Odum 1983). Increase in the internal energy flow. 3 Maximize exergy degradation (Kay 1984). As the amount of exergy captured increases, so does the amount dissipated. 4 Maximize exergy storage (Jørgensen & Mejer 1977). Exergy storage (biomass) and information increase due to shift to more complex species composition. 5 Maximize retention time (Cheslak & Lamarra 1981). Biological components develop mechanisms to increase time lags to maintain the energy stores longer.

26 Network analysis Representation of ecological systems as interacting components. Used to identify and quantify direct and indirect effects in the system. f 31 =10 x 3 =2 x 1 =50 f 13 =1 f 32 =1 f 21 =10 x 2 = F = x = T = [ ] [ ]

27 Network Environ Analysis Flow Analysis (g ij = f ij /T j ) identifies flow intensities along indirect pathways Path Analysis - enumerates pathways in a network Storage Analysis (c ij = f ij /x j ) identifies storage intensities along indirect pathways Utility Analysis (d ij = (f ij f ji )/T i ) identifies utility intensities along indirect pathways

28 Propagation of network indirect effects Flow: N = I + G + G 2 + G 3 + G 4 + Storage: Q = I + P + P 2 + P 3 + P 4 + Utility: U = I + D + D 2 + D 3 + D 4 + integral = initial + direct + input indirect Flow: N = (I G) 1 Storage: Q = (I P) 1 Utility: U = (I D) 1

29 Network model representing different growth & development stages z 1 =5 y 1 =1.5 y 2 =1.1 x 1 =6 f 14 =1 f 21 =4.5 x 2 =4.5 f 32 =3.4 x 4 =2.5 f 43 =2.5 x 3 =3.4 z 1 =10 y 1 =3 y 2 =2.2 x 1 =12 f 14 =2 f 21 =9 x 2 =9 f 32 =6.8 x 4 =5 f 43 =5 x 3 =6.8 a) y 4 =1.5 y 3 =0.9 b) y 4 =3 y 3 =0.9 A= z 1 =10 x 1 =14.2 y 1 =3.6 f 21 =10.6 x 2 =10.6 y 2 =2.6 z 1 =10 x 1 =16.7 y 1 =2.1 f 21 =14.6 x 2 =14.6 y 2 =3.6 A= f 13 =3 f 14 =1.2 f 32 =8 f x 4 =3 43 =3 x 3 =8 f 13 =4.8 f 14 =1.9 f 32 =11 f x 4 = =4.8 x 3 =11 c) y 4 =1.8 y 3 =2 d) y 4 =2.9 y 3 =1.4

30 Network model results Figure Specific entropy (output/biomass) Energy throughflow Exergy storage Exergy degradation Retention time 7a b c d

31 Conclusions System moves to more conservative strategies storage, throughflow, cycling, and retention time increase Growth Form Boundary Growth (0) Structural Growth (I) Network Growth (II) Information Growth (III) Condition Biomass Throughflow Biomass Maintenance Network Cycling Information Growth Stage Initial input Early-tomiddle succession Middle-tolate succession Climax Thermodynamic Orientor Specific entropy Energy throughflow Exergy degradation Exergy storage Retention time Specific entropy Energy throughflow Exergy degradation Exergy storage Retention time Specific entropy Energy Throughflow Exergy degradation Exergy storage Retention time Specific entropy Energy Throughflow Exergy degradation Exergy storage Retention time

32 Policy Recommendations based on lessons learned from ecosystems: 1. Mimic ecosystem dynamics Transition from exploitative growth to conservative development phase Increase network, efficiency, cycling, retention 4. Live within input and output limits Build structure based on sustainable inputs Don t exceed assimilative capacity of environment 3. Rescale human activity within context of global biosphere

33 What we have: 1) Ecosystem Theory (tentative) 2) Methodologies (e.g., network analysis) to quantify indirectness and complexity 3) Case Studies of Stakeholder participation What we don t have: 1) Easy data requirements 2) Institutional structures for holistic investigation 3) Magic Bullet

34 What we need: 2) Link between ecosystem properties and ecosystem indicators ( spider diagrams?) 2) Better communication between scientists and managers 3) Management applications of ecosystem theory 4) Funding, Time, and Students 5) Paradigm shift to systems thinking

35 Thank you for your attention

Quo vadis ecosystem? Insights from ecological modelling and systems ecology

Brian D. Fath Quo vadis ecosystem? Insights from ecological modelling and systems ecology Professor, Biology Dept., Towson University, USA Research scholar, International Institute for Applied Systems