99th ESA annual meeting talk about my masters work with Splachnaceae mosses coexisting in peatlands in Newfoundland, Canada. Individual-based modelling was used to look at key factors influencing coexistence
Examining Coexistence between Splachnaceae Mosses with Individual-Based Modelling
1. Studying Coexistence Between Mosses
With Individual Based Modelling
Presented by Chris Hammill
For The ESA Annual Meeting 2014
2. Road Map
● Where I Work
● My Study Organisms
● About the Model
- Space
- Agents
- Interactions
● Analysis
● Results
● Take Home Messages
3.
4.
5.
6. Splachnaceae
➢ Globally Distributed
➢ 50% are Coproentomophilous
➢ Coprophily:
Habitat specialists for dung or carrion
➢ Entomophily (Myophily):
A specialized dispersal strategy using flies as spore
dispersal vectors
8. Splachnum Mosses
In Newfoundland Peatlands
➢
Two Species:
Splachnum ampullaceum and S. pensylvanicum
➢
Found on moose dung
➢
Grow in pure and mixed populations
➢
Share many fly vectors
➢
Differ in attraction cues
➢
Seem to inhabit the same niche
9. ➢
Two Species:
Splachnum ampullaceum and S. pensylvanicum
➢
Found on moose dung
➢
Grow in pure and mixed populations
➢
Share many fly vectors
➢
Differ in attraction cues
➢
Seem to inhabit the same niche
Splachnum Mosses
In Newfoundland Peatlands
So: How do they coexist?
26. Competition
➢
Each new year, former dung piles become immature moss
populations
➢
Starting conditions for competition are determined by spore
allotment from dispersal
➢
Moss protonemata compete for space according to
Discrete Lotka-Volterra dynamics
32. • Transfer is proportional to moss attractiveness
• Transfer only effective when dung is more attractive than moss
• Transfer is proportional to the attractiveness difference between
moss and dung
Influence of Attractiveness
34. Model Construction
● Model Written in Java
● Simulations run for 1000 year
● Year end peatland snap-shots
● 3 – 30 Mb per simulation
● Post processing and summarization done in R
37. Analysis
● Ran simulations at predetermined parameter
combinations
● Summarized each simulation
● Determined the average ratio of
The two species
● Create a Random Forest of Regression Trees.
● Examine Variable Importance Measures
46. Take Home Messages
● Staggered phenologies are sufficient to offset
huge competitive differences
● Achieving near optimal attractiveness is
important for reducing odds of extinction
47. Acknowledgements
Drs. Paul Marino, Suzanne Dufour, Amy
Hurford, Shawn Leroux, Lourdes Pena-Castillo,
and Tom Chapman
Andrew Chaulk, Greg Dickson, Jenna Paul,
Olga Trela
And ESA for giving me this
opportunity to share my work