The document describes a model for exploring viable ecological survival strategies for humans. It involves an individual-based model that simulates complex ecological systems with emergent food webs and species interactions. The model introduces human agents with various social structures and observes their impact on biodiversity over time. Preliminary results show humans typically becoming top predators that reduce diversity initially but sometimes find balanced strategies at higher migration or food input levels that preserve more species long-term. The goal is to better understand how we must structure societies to survive while minimizing environmental degradation.

1. 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 Edmonds
Centre for Policy Modelling
Manchester Metropolitan University

2. 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!”

3. 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
Simple
System-dynamics
ModelComplex
Individual-based
Model
Simple
System-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)

4. 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

5. 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

6. 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

7. 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)

8. 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.

9. 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)

10. 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

11. 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

12. 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

13. 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

14. 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)

15. 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

16. 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

17. 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

18. 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

19. 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)

20. 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

21. 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