A talk presented at TERI University, laying out a conceptual framework for discussions of distributional areas and ecological niches.

1. The BAM Diagram: A Useful Heuristic
A. Townsend Peterson
University of Kansas

3. Charles Elton – niche as role
in communities
G. Evelyn Hutchinson –
multidimensional ecological niches,
bionomic versus scenopoetic variables

7. GEOGRAPHY – THE DISTRIBUTION

8. The Area of Distribution
G Physiological
requirements
(Abiotic)
A
Favorable biotic
environment
(Biotic)
B
Accessible to
dispersal
(Movements)
M

9. The A and B Circles
• Physiological
requirements
• Non-reactive variables.
Uncoupled
• Roughly independent of
the interactions
• Low “resolution”
• Biotic requirements and
impacts. Resource
consumption,
interactions,
competitors,
predators...
• Variables interactive,
dynamically coupled
• High resolution
A B

10. A Useful and Forgotten Distinction of
Hutchinson (1978)
• Scenopoetic variables. Non-
interacting, slowly changing
from a species point of view.
Define conditions
• Bionomic variables. Coupled,
fast changing. Define
regulation
• Hutchinson´s useful
distinction was quickly
forgotten and then
reinvented by Austin, Begon,
Jackson & Overpeck,
Meszena and others.

11. M = Barriers

12. Abiotic niche
Biotic interactionsAccessibility
Classic BAM Configuration

13. Abiotic niche
Biotic interactionsAccessibility
Biotic interactions
Accessibility
Abiotic nicheHow Hutchinson
Saw the World

14. Hutchinson
needs to get
out and
travel a bit!

16. Abiotic niche
Biotic interactionsAccessibility
Abiotic niche
Biotic interactions
Accessibility
Wallace’s World

17. Demonstration of M Effects
• Clear demonstration of the importance of
dispersal limitation on species’ distributions
• Invasive species – originally confined to a
native distributional area
• Some transport (often human-mediated)
expands M
• Distribution expands accordingly

18. Abiotic niche
Biotic interactionsAccessibility
Area presenting
appropriate
combinations of
abiotic and
biotic conditions
(= potential
distribution)
Actual geographic distribution
(abiotic and biotic conditions fulfilled,
accessible to dispersers)

20. Aedes albopictus
• Known as the “Asian Tiger
Mosquito”
• Invader; fastest spreading
mosquito in the world
• Aggressive daytime biter
and pest
• Known to transmit
Dengue, La Crosse, St.
Louis, Eastern Equine,
Ross River, Rift Valley, and
West Nile Viruses

21. Aedes albopictus
Present predicted distribution, native range in Asia

22. Aedes albopictus:
USA invasion
Projected Asian niche into USA present to create
invasion risk-map. How well did GARP perform...

23. Aedes albopictus:
USA invasion

24. Aedes albopictus:
world risk-map

26. Abiotic niche
Biotic interactionsAccessibility
BAM and Eltonian Noise
Abiotic niche
Biotic
interactions
Accessibility

28. ENVIRONMENT

29. Five Goals of Niche Modeling?
1. ESTIMATE THE FUNDAMENTAL NICHE
2. ESTIMATE THE FUNDAMENTAL NICHE
3. ESTIMATE THE FUNDAMENTAL NICHE
4. ESTIMATE THE FUNDAMENTAL NICHE
5. ESTIMATE THE FUNDAMENTAL NICHE

30. How Would the Fundamental Niche Look?
• In any one dimension, expected to be
unimodal
• In multiple dimensions, expected to be convex
• So, simple models are probably better
• Need to take sampling and incomplete
representation into account carefully

31. http://d1vn86fw4xmcz1.cloudfront.net/content/royptb/
367/1596/1665/F1.large.jpg

34. The Area of Distribution
G Physiological
requirements
(Abiotic)
A
Favorable biotic
environment
(Biotic)
B
Accessible to
dispersal
(Movements)
M

36. Fundamental
niche
Existing
fundamental
niche
Realized
ecological
niche

38. Can EVOLVE Will change
with any
range
difference

39. ?
?

41. SUMMARY

46. Assess levels of spatial
autocorrelation in
environmental data,
adjust input point data
accordingly
Estimate ecological
niche (various
algorithms)
Evaluation reality of
model transfer results,
when possible
Transfer to other
situations—time and
space
Project niche
model to
geographic
space
Model calibration,
adjusting parameters to
maximize quality
Collate primary
biodiversity data
documenting
occurrences
Process environmental
layers to be maximally
relevant to distributional
ecology of species in
question
Collate GIS database of
relevant environmental
data layers
Assess BAM scenario for
species in question; avoid
M-limited situations
Saupe et al. 2012. Variation in niche and distribution model performance: The need
for a priori assessment of key causal factors. Ecological Modelling, 237–238, 11-22.
Estimate M as
area of analysis
in study
Barve et al. 2011. The crucial role of the
accessible area in ecological niche modeling and
species distribution modeling. Ecological
Modelling, 222, 1810-1819.
Assess extrapolation
(MESS and MOP)
KU Ecological Niche Modeling Group. 2013.
Constraints on interpretation of ecological niche
models by limited environmental ranges on
calibration areas. In preparation.
Model evaluation
Peterson et al. 2008. Rethinking receiver operating
characteristic analysis applications in ecological niche
modelling. Ecological Modelling, 213, 63-72.
Model thresholding
Peterson et al. 2007. Transferability and
model evaluation in ecological niche
modeling: A comparison of GARP and
Maxent. Ecography, 30, 550-560.
Assess spatial precision of
occurrence data, adjust
inclusion of data (obs and
env) accordingly
General Methodological Summary:
Peterson et al. (2011) Ecological Niches
and Geographic Distributions, Princeton
University Press, Princeton.
Refine
estimate of
current
distribution via
land use, etc.
Reduce dimensionality
Compare present and
future to assess
effects of change

47. town@ku.edu