INTEGRATING HUMAN AND ECOLOGICAL SYSTEMS USING MULTI-LEVEL NETWORKS

Transcription

1 INTEGRATING HUMAN AND ECOLOGICAL SYSTEMS USING MULTI-LEVEL NETWORKS 1 Jeffrey C. Johnson, University Term Professor Department of Anthropology University of Florida

2 2 CONNECTING THE ANTHROPOSPHERE, BIOSPHERE, AND HYDROSPHERE

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5 LINK BETWEEN ENVIRONMENTAL CHANGE AND HUMAN BEHAVIOR Environmental Change (Trophic cascade in ecological network) 5 Ecosystem Response (Reduced Biodiversity/simplified ecological network) Disruption of Human Productive Networks Human Behavioral Response (Economic alternatives/internal/external Migration Networks)

6 CONCEPTUAL AND MODELING CONTRIBUTION 6 [A] To include explicit coupling between environmental changes and human systems. [C] To produce models that are mechanistic and process-based, while accounting for uncertainties. This enhances the reliability and predictive power of the models, furnishes us with insights into the nature of tipping points that trigger human migration. [H] To include the capacity to generate scenarios of environmental changes and assess their likelihood.

7 ECOSYSTEM FEEDBACKS 7

8 ECOSYSTEM BASED MODELING 8

9 Blame Human System Extractive behavior Extractive/Productive Behavioral Networks Human System Resilience/Adaptive Capacity Human Community Structure Incentives & well-being Nutrient output Behaviors Institutions Etc. Natural System Focus Dominant conceptualization Community structure Trophic structure Habitat Water quality, Etc. proposed These interactions account for the total socio-ecological system Important to understand interactions both within and between ecosystem elements. But what about the elements of each system? 9

10 Behavioral structures EXAMPLES OF HUMAN SYSTEM (BEHAVIORAL) Behavioral incentives and dependencies Behavioral system robustness Behavioral system adaptability Terrestrial Based Behaviors (Nutrient Influx) Link between human behavioral networks and ecological networks 10

11 11 CONVENTIONAL VIEW Human activities impact ecosystems (direct impacts) A slightly updated view is concerned with both direct and indirect effects (e.g., trophic cascades) But still it is humans that impact ecosystems both directly and indirectly

12 LESS ATTENTION HAS BEEN FOCUSED ON Ecosystem elements that impact human systems 12 Human system robustness, flexibility and adaptability

13 13 IN A SUMMARY OF A SYMPOSIUM ON ECOSYSTEM BASED MANAGEMENT GISLASON ET AL. (2000) DESCRIBE SIX CONSERVATION OBJECTIVES IN TERMS Ecosystem diversity Species diversity Genetic variability within species Directly impacted species Ecologically dependent species Trophic level balance OF THE MAINTENANCE OF:

14 14 THERE IS NO MENTION OF THE HUMAN PORTION OF THE SYSTEM THAT MIGHT HAVE ANALOG HUMAN CONSERVATION OBJECTIVES: For Example: Fisher diversity (productive diversity) Fishing constituency diversity Ecologically dependent communities Social and economic balance Directly impacted groups Indirectly impacted groups Human system diversity

15 15 WHAT DO WE MEAN BY HUMAN BEHAVIORAL STRUCTURES? In fisheries, it is the structural relationship between different types of species and gear combinations vis-à-vis the people that use them In network analysis, 2-mode relations expressed as 1-mode relations These systems have important structural characteristics And the structural system can be directly linked to elements of the natural system This can easily be to other productive activities (e.g. farming)

16 IMPORTANT STRUCTURAL CHARACTERISTICS OF BEHAVIORAL NETWORKS Nodes are species-gear combinations and fishers Network density (food web connectance in ecological speak) Graph centralization (extent to which a single node [behavior] dominates the system) Network fragmentation characteristics (based on keystone removal) 16

17 17 SUCH THINGS INFORM Robustness Resilience Potential Adaptability Links to Trophic Network

18 Graph of 2-mode behavioral network 18

19 Graph of fisher network vis-à-vis species/gear combinations 19

20 Fishing Behavioral Network (Pamlico Sound) 20

21 21 Multi-level Networks in Socio-ecological Systems [A] TO INCLUDE EXPLICIT COUPLING BETWEEN ENVIRONMENTAL CHANGES AND HUMAN SYSTEMS. [D] TO DEVELOP ANALYSES THAT ARE SEAMLESSLY LINKED ACROSS SCALES: FROM THE LOCAL TO GLOBAL SCALES AS WELL AS FOR SHORT (REFUGEE FLOWS) AND LONG (PERMANENT MIGRATION) TIME SCALES.

22 Supply Web Conceptual Multilevel 22 Socio-ecological Network Human Behavioral Network Ecological Network

23 EXAMPLES 23

24 SUPPLY WEB FOR PAMLICO SOUND 24

25 25 The linking of the human behavioral network to the trophic network with nodes in the trophic network arranged on the basis of trophic role similarity

26 26 Human Behavior Mapped to Supply Web Integrating Food Webs, Human Behavioral Networks and Supply Webs

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28 FISHERIES AND FOOD WEBS: PREDICTING AND SIMULATING DIRECT AND INDIRECT NETWORK EFFECTS 28 we will model the migration process as movements of people within a multilayer network of populations, with each location having its own coupled dynamics between environmental and social components and each pair of sending and receiving locations connected by multiple types of linkages

29 29 OUTLINE I. Coastal fisheries in NC: model ecosystem flows and ecological impacts, link with social network models II. III. IV. ECOPATH model development in Core Sound methods and results Model fishermen behavioral networks; what fisheries are linked by use of common gear and target species? Social, economic and ecosystem-wide impacts of alternative management policies examine robustness of fisheries using network models V. Estimate/Simulate Policy Impacts-Gill net ban - happening in NC now VI. Climate Change what if we lose seagrass?

30 30 ECOPATH is a network analysis program that integrates fishery and ecosystem data Carbon content of all species is modeled in a node (species) and arrow (flows) context Need to know for each species or group: Standing stock biomass (in gc/m 2 ) Consumption proportion (diet matrix, i eats j ) Consumption/biomass (Q/B) Production/biomass (P/B) Unassimilated carbon (waste) Diet composition Fishery harvests Production = catches + predation mortality + biomass accumulation + net migration + other mortality Outputs: Effective trophic levels, fishery impacts, ECOSIM - simulation models based on ECOPATH Human Behavioral Networks ECOPATH UCINET/ERGM software for social network analysis Allows network statistical analysis (network density, regular equivalence models, fragmentation, key player node removal)

31 CATCHES BY GEAR FROM NC DMF DATA 31 Gill nets Haul Seines Pound nets Crab pots Shrimp trawls Skimmer trawls

32 Trophic Position AREAS CLOSED TO TRAWLING 32 Other rays/skates Sea turtles Smooth dogfish Bay scallop Tunicates Brittlestars Jellyfish Bycatch Crabs_other Pink shrimp Conchs/whelks Atl brief squid Atl spadefish Red drum Shrimps_other Cownose rays Gastropods_pred Spanish mackerel Atl silverside Black drum Bottlenose dolphins Striped mullet Pompano Sheepshead Atl menhaden Cormorants Harvestfish/Butterfish Pigfish Bluefish Amphipod/isopod/cumacean Southern kingfish White shrimp Spotted seatrout Brown shrimp Ctenophores Pinfish Gulls Terns Gastropods_depfd Flounders (Paralichthids) Anchovies Shorebirds/waders Atl croaker Weakfish Sea cucumbers Blue crabs Brown pelicans Polychaetes_pred Polychaetes_suspfd Bivalves_suspfd Polychaetes_depfd Drift algae Bryozoans Zooplankton Spot Hard clam Seagrass Macroalgae_benthic Crab Pots Haul Seines Gill Nets Atl sharpnose shark Pound Nets Bacteria_aquatic Meiofauna Microalgae_benthic Detritus Bacteria_benthic Phytoplankton

33 Trophic Position OPEN TO TRAWLING 33 Pound Nets Cownose rays Smooth dogfish Other rays/skates Red drum Conchs/whelks Shorebirds/waders Atl brief squid Atl spadefish Terns Gulls Black drum Jellyfish Sheepshead Pompano Sea turtles Cormorants Spanish mackerel Bay scallop Brown pelicans Ctenophores Pink shrimp Bluefish Flounders (Paralichthids) Gastropods_pred Spotted seatrout Crabs_other Striped mullet Harvestfish/Butterfish Brittlestars Southern kingfish Gastropods_depfd Pigfish Atl croaker Atl silverside Shrimps_other Weakfish Pinfish Tunicates Atl menhaden Bivalves_suspfd Bycatch Anchovies Polychaetes_suspfd Polychaetes_pred Blue crabs Amphipod/isopod/cumacean Drift algae Spot Brown shrimp Haul Seines Skimmer Trawls Shrimp Trawls Gill Nets White shrimp Polychaetes_depfd Bryozoans Crab Pots Seagrass Bottlenose dolphins Sea cucumbers Atl sharpnose shark Bacteria_benthic Bacteria_aquatic Hard clam Zooplankton Macroalgae_benthic Meiofauna Microalgae_benthic Detritus Phytoplankton

34 34 Closed to Trawling

35 35 Open to Trawling

36 36 ASIDE: NODES IN THE FOOD WEB GRAPH WERE BASED ON TROPHIC ROLES Mathematical approach to determining the role of a node in a network The role of institutions in policy networks The role of a country in migration networks The role of a country in a trade network [F] To integrate representation of the roles played by social institutions.

37 CATCHES AND TROPHIC 37 LEVELS OF THE SIX FISHERIES PREDATORS BY GEAR TYPE ETL=2.6 8 ETL=3.62 ETL= 3.04 ETL=2.88 ETL = 2.79 ETL= 2.94

38 WHAT ABOUT THE FISHERS BEHAVIOR? 38

39 FISHERS TROPHIC NICHE CORRESPONDENCE ANALYSIS OF 39 LANDINGS

40 FISHERMAN BEHAVIORAL NETWORK 40 PARTICIPANTS USE SAME GEARS AND CATCH SAME SPECIES

41 ECOLOGICAL IMPACT - NODES SCALED BY BIOMASS OF LANDINGS IN FALL 41

42 VALUE (US $) OF LANDINGS IN FALL

43 WHICH NODES ARE KEY PLAYERS? 43

44 KEY PLAYER IN HUMAN BEHAVIORAL 44 NETWORKS Which node, if removed, has the greatest effect on fragmenting the network? Military Intelligence: Who is the key terrorist? Medicine: Which patient is the one spreading the disease? Intervene by removing or monitoring that node, it is a key player in the network. In our fisheries network, which species or gear type is the key player? Which will cause disruption of the network, making it difficult to switch gears. F= Fragmentation index S k = Component in network n = nodes in network Component is where each node can reach every other node by some path Borgatti, S.P., Everett, M.G. and Freeman, L.C Ucinet for Windows: Software for Social Network Analysis. Harvard, MA: Analytic Technologies.

45 NODES ARE REMOVED ACCORDING 45 TO FRAGMENTATION CRITERION

46 Relative biomass ECOSIM: SIMULATE GILL NET BAN 46 AT 5 YEARS Red drum Striped mullet Relative biomass Jellyfish Skates/rays 1.0 Brown shrimp 0.9 Loggerhead sea turtles Year

47 Relative biomass ECOSIM: 90% TRAWLING DECLINE Relative biomass 1.1 Jellyfish Skates/rays Red drum 1.0 Brown shrimp 0.9 Loggerhead sea turtles Striped mullet Year

48 Relative biomass NO GILL NET FISHERY, 48 FISHERS SWITCH TO SHRIMPING 1.2 Relative biomass 1.1 Red drum Striped mullet Skates/rays 1.0 Brown shrimp 0.9 Loggerhead sea turtles Jellyfish Year

49 ECONOMIC IMPACTS OF GILL 49 NET BAN Species Total ( ) Net Ban Loss Spotted Sea trout $ 134,844 $ 673 $ 134,171 Striped Mullet $ 221,387 $ 132 $ 221,255 Flounders $ 1,218,472 $ 647,881 $ 570,591 Red drum $ 55,373 $ 4,981 $ 50,392 Brown Shrimp $ 268,329 $ 268,329 $ 0 White Shrimp $ 283,479 $ 283,479 $ 0 Blue Crabs $ 330,130 $ 330,130 $ 0 Total $ 3,708,238 $ 2,242,090 $ 1,466,148

50 CLIMATE CHANGE IMPACTS REDUCTION IN SEAGRASS DUE TO INCREASED SALINITY, BARRIER ISLANDS COLLAPSE, SEA LEVEL RISE 50

51 RELATIONSHIP OF THIS SOCIO-ECOLOGICAL 51 ANALYSIS TO CURRENT PROJECT The fisherman social network is not robust, and will be disrupted by the net bans We predicted impacts to ecosystem and social system: Species targeted by gill nets will increase, including sea turtles Indirect food web effects may cause unexpected increases or declines Fisherman will lose income, market value ($1.4 million, a 38% decline) Fisherman may switch between gears (gill netting to trawling or pound netting) or leave the ecosystem (e.g., migrate) Tipping points Dynamic models of switching behavior can now be examined (i.e, fishermen will move into neighboring fisheries in the gear x species network, with a probability ~ $ value of landings, within economic, regulatory, and social constraints. Climate change will have ecosystem impacts, they can be modeled. Ecosystem based approaches to management are now possible.

52 THIS APPROACH HELPS IN MEETING THE FOLLOWING RESEARCH OBJECTIVES [A] To include explicit coupling between environmental changes and human systems. Helps in realistically modeling Multi-Level Networks across human and natural systems [B] To provide the capability to simulate spatial movements of humans. Help in simulating how policy shifts both directly and indirectly effect migration networks [C] To produce models that are mechanistic and process-based, while accounting for uncertainties. This enhances the reliability and predictive power of the models, furnishes us with insights into the nature of tipping points that trigger human migration. Help in predicting economic tipping points in migration [D] To develop analyses that are seamlessly linked across scales: from the local to global scales as well as for short (refugee flows) and long (permanent migration) time scales. Multi-level networks can also be linked across time and space [E] To provide the ability to capture decision making at different levels of aggregation in population. Policy networks can be incorporated into models as one additional level [F] To integrate representation of the roles played by social institutions. The roles of various institutions in policy networks can be determined using graph theoretic approaches (e.g., regular equivalence) [G] To provide for simplicity and parameter-parsimony. This will increase model applicability and likelihood of clear analytical relationships that would serve as building blocks to develop a general theory. A general theory based on multi-level networks [H] To include the capacity to generate scenarios of environmental changes and assess their likelihood. Simulating direct and indirect effects of environmental changes across levels and scales 52

53 IMPLICATIONS FOR CURRENT RESEARCH This socio-ecological framework allows for the integration of human and ecological systems at various levels and scales Ideas from the simulations allows for the estimation of direct and indirect impacts on elements of networks at different levels This will help inform the effects of environmental changes (or other changes) on human behavioral networks (e.g., migration behavior) and tipping points 53

54 QUESTIONS? 54