man on earth – the challenge of discovering viable ecological survival strategies
DESCRIPTION
Many previous societies have killed themselves off and, in the process, devastated their environments. Perhaps the most famous of these is that of “Easter Island”. This suggests a grand challenge: that of helping discover what kinds of rationality and/or coordination mechanisms might allow humans and the greatest possible variety of other species to coexist. As their contribution towards this, the agent community could investigate these questions within simulations to suggest hypotheses as to how this could be done. The particular problem for our community is that of designing and releasing a society of plausible agents into a simulated ecology and assessing: (a) whether the agents survive and (b) if they do survive, what impact they have upon the diversity of other species in the simulation. No other community is currently in a position to explore this problem as a whole. The simulated ecology needs to implement a suitably dynamic, complex and reactive environment for the test to be meaningful. In such a simulation, agents (as any other entity) would have to eat other entities to survive, but if they destroy the species they depend upon they are likely to die off themselves. Up to now there has been a lack of simulations that combine a complex model of the ecology with a multi-agent model of society – there have been complex models of society but with simple ecological representations and complex ecological models but with little of human social complexity in them. In order for progress to be made with humanity’s challenge, we will have to move beyond simple ideas and solutions and embrace the complexity of the socio-ecological complex as a whole. A suitable dynamic ecological model and simple tests with agents are described to illustrate this challenge, as the first steps towards a meaningful test bed to under pin the implied research programme.TRANSCRIPT
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 1
Man on Earth – the challenge of discovering viable ecological survival strategies
Bruce EdmondsCentre for Policy Modelling
Manchester Metropolitan University
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 2
The Problem
• Many times, humans have devastated their local environment (e.g. Easter Island, Mayans)
• Other times, humans haven’t been able to survive due to non-adaption (e.g. Vikings in Greenland)
• We see only examples where some kind of balance has been achieved (but still at historical environmental cost) or cases where humans are surviving by currently degrading their environment
• We can see what happened/is happening but we do not know how to socially organise to ensure our own survival (e.g. comparative failure of climate change talks and efforts) given how individual humans are
• We don’t know how to collectively save ourselves!
“The Romans built much better than us – see how long their buildings have survived!”
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 3
The Double Complexity of Modelling Socio-Ecological Systems
Social Model
Ecological Model
Complex Individual-based Model
SimpleSystem-dynamics
Model
Complex Individual-based Model
SimpleSystem-dynamics
Model
Combined Complex Model
Socio-Ecological Model
“…The more serious shortcomings of existing modelling techniques, however, are of a structural nature: the failure to adequately capture nonlinear feedbacks within resource and environmental systems and between human societies and
these systems.” (Deffuant et al, 2012, p. 523)
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 4
The Wider Project
• The wider project is to understand how (given the nature of human beings) how structuring our society may affect our impact on the environment
• Thus understand how we might survive and preserve the greatest possible species diversity
• The combined socio-ecological system is highly dynamic and complex so that simple models (e.g. SD models, equilibrium models or ideas such as the “balance of nature”) are not adequate
• We need to test and understand what happens when complex social systems and complex and dynamic ecological models are combined
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 5
A Socio-Ecological Test Bed
• Here I present a dynamic, spatial, individual-based ecological model that displays some of the complexity, adaptability and fragility of observed ecological systems with emergent outcomes
• It evolves complex, local food webs, endogenous shocks from invasive species, is adaptive but unpredictable as to the eventual outcomes
• Into this agents representing humans can be “injected” with different societal structures/characteristics and the outcomes observed/analysed
• This may help us understand how we might have to structure out society, if we (as a species) are to survive and minimise our degradation of other species
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 6
The Model
• A wrapped 2D grid of well-mixed patches with:– energy (transient)– bit string of characteristics
• Organisms represented individually with its own characteristics, including:– bit string of characteristics– energy– position– stats recorders
A well-mixed patch
Each individual
represented separately
Slow random rate of migration
between patches
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 7
How Dominance is Decided
(Caldarelli, Higgs, and McKane 1998)
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 8
Model sequence each simulation tick
1. Input energy equally divided between patches.
2. Death. A life tax is subtracted, some die, age incremented
3. Initial seeding. until a viable is established, random new individual
4. Energy extraction from patch. energy divided among the individuals there with positive score when its bit-string is evaluated against patch
5. Predation. each individual is randomly paired with a number of others on the patch, if dominate them, get a % of their energy, other removed
6. Maximum Store. energy above a maximum level is discarded.
7. Birth. Those with energy > “reproduce-level” gives birth to a new entity with the same bit-string as itself, with a probability of mutation, Child has an energy of 1, taken from the parent.
8. Migration. randomly individuals move to one of 4 neighbours
9. Statistics. Various statistics are calculated.
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 9
a Mixed Ecology Development
• Here new species are continually developing and spread out in waves, but a mix of trophic levels are maintained (but this varies over time)
Typical Mixed Ecology the world state (left) Number of Species (centre) Log, 1 + Number of Individuals at each
trophic level (right)
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 10
Longer-Term Trends in Num. Species
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 11
Signatures of Outcomes: Neutral patches, random migration, plants only
• As predicted by Hubble’s “Neutral Theory”
• “skewed s-shaped” relative species abundance curve
• “Multinomial distribution” of log2 species distribution
• Except, species-area scatter chart might only reflect small scales
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 12
An Example of Adding Pretty Simple “Human” Agents
• The agents representing humans are “injected” (as a group) into the simulation once an ecology of other species has had time to evolve
• The state of the ecology is then evaluated some time later or over a period of time
• These agents are the same as other individual in most respects, including predation but “humans”:– can change their bit-string of skills by imitating others on the
same patch (who are doing better than them)– might have a higher “innovation” rate than mutation– might share excess food with others around– might have different migration rates etc.
• Could have many other learning, reasoning abilities
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 13
Some of The Dynamics In An Example Run
• The arrival of humans (when they don’t die out) has an immediate impact on the ecosystem, in terms of both population and species diversity
• Typically they become the top predator and wipe out other higher predators
• But also the diversity of human variety can “displace” species variety by inhabiting many niches
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 14
Human migr. rate vs. diversity (all with humans, other entities having 0.1 migration rate)
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 15
Extinction due to Consuming all Others
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 16
Waves of (Human) Predator-Prey Patterns
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 17
Effect of humans vs. food input to world
diversity of ecology, blue=with humans, red=without
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 18
Effect of humans vs. food input to world
proportion of ecology types, red=plant, blue=mixed, purple=single species, green=non-viable
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 19
Migration vs. food rate (all with humans)
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 20
Conclusions
• The ecological modelling community is bogged down in formal and equilibrium models that do now exhibit the complexity of co-evolution and adaption
• The MABS community is in a unique position to develop a body of knowledge of the properties of complex socio-ecological models
• And hence play a part in the debates as to how we can avoid socio-ecological collapse
• Standard test-beds, such as this one, where different social models are embedded could help compare what facilitates/hinders this
• Not “RoboCup” but a much more serious and important game of “SpeciesSurvival”
• Other standard test-beds are also needed
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 21
The End!
Bruce Edmonds:http://bruce.edmonds.name
Centre for Policy Modelling:http://cfpm.org
The basic model (without “humans”) is available at: http://openabm.org/model/4204
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 22
Non-Viable Ecology
Typical Non-Viable Ecology the world state (left) Number of Species (centre) Log, 1 + Number of Individuals at
each trophic level (right)
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 23
Dominant Species Ecology
Typical Dominant Species Ecology the world state (left) Number of Species (centre) Log, 1 + Number of
Individuals at each trophic level (right)
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 24
Rich Plant Ecology
Typical Rich Plant Ecology the world state (left) Number of Species (centre) Log, 1 + Number of Individuals at each
trophic level (right)
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 25
Neutral Patches, local migration, plants only
• unchanged “skewed s-shaped” relative species abundance curve
• “Multinomial distribution” of log2 species distribution but with more lower abundance species
• Pretty flat species-area scatter plot
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 26
Selective patches, random migration, plants only
• “Linear” drop in log 2 species abundance
• “Exponential” shaped relative species abundance graph
• Flatter species area scatter plot
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 27
Neutral Patches, random migration, predators
• Lots of new species plus flatter log 2 species distribution
• flat or curved species abundance distribution
• a variety of species-area curves
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 28
Other combinations
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 29
Effect of humans vs. environmental complexity
diversity of ecology, blue=with humans,
red=without
proportion of ecology types, red=plant, blue=mixed, purple=single species,
green=non-viable
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 30
Effect of humans vs. general migration rate
diversity of ecology, blue=with humans,
red=without
proportion of ecology types, red=plant, blue=mixed, purple=single species,
green=non-viable
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 31
Num. Species vs. Num. Variants (all with humans)
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 32
Innovation vs. migration rate (all with humans)
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 33
Starting from plant ecology (with humans)
Starting from a Plant Ecology the effects of innovation rate/mutation rate (left) and people migration rate/entity
migration rate (right) , red=plant, blue=mixed, purple=single species, green=non-viable
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 34
Starting from mixed ecology (with humans)
Starting from a Mixed Ecology the effects of innovation rate/mutation rate (left) and people migration rate/entity
migration rate (right) , red=plant, blue=mixed, purple=single species, green=non-viable
Man on Earth – the challenge of discovering viable ecological survival strategies, Bruce Edmonds, MABS, Paris, May 2014. slide 35
Starting from single species ecology (with humans)
Starting from a Single Species Ecology the effects of innovation rate/mutation rate (left) and people migration rate/entity migration rate (right) , red=plant, blue=mixed,
purple=single species, green=non-viable