Mark Bertness:
Facilitating Community Ecology
Presented by: Laura Brown
BIOL 7083
Background
• Born July 13, 1949 WA
• B.S. University of Puget
Sound
(psychology/chemistry)
• M.S. Western
Washington University
(Biology)
• Ph.D University of
Maryland (evolutionary
ecology) Geerat Vermeij
Tree
Brian Silliman
John Bruno
Jonathan M. Levine
ME!
Research Overview
• Consumer control of salt marshes
• Human impacts on coastal ecosystems
• Role of foundation species and positive
interactions in community organization
• Climate change impacts on coastal ecosystems
• Historical states of impacted ecosystems
Cross section of a southern New England salt marsh illustrating the major vegetation zones
and general results of this paper.
Increasing Competition
©2002 by National Academy of Sciences
Increasing Physical Constraints
Bertness M D et al., 2002
Spartina alterniflora Zone
Spartina alterniflora Zone
Spartina alterniflora Zone
Spartina alterniflora Zone
Spartina alterniflora Zone
Treatment
Number of Stems
Biomass (g)
With Fiddlers
23.1±2.4
20.6±2.5
Without Fiddlers
13.3±1.4
15.7±1.8
• Roots and rhizomes provide
structural support
• Increases above ground biomass
• Soil drainage
• Soil oxidation reduction potential
• In situ decomposition of belowground plant debris
• Facilitative Mutualism!
Bertness 1985
Spartina patens Zone
Spartina patens Zone
Lower bound is set by environmental stress
Bertness 1991
Spartina patens Zone
Bertness 1991
Juncus gerardii Zone
Wrack!
Salicornia and Distichlis
Juncus Zone
• Initial colonizers
• Shade substrate
• Alleviate salt stress
Bertness and Shumway 1993
Bertness 1992
Rocky Intertidal
Bertness 1989
Community Structure
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Time
Spatial heterogeneity
Competition
Predation
Climatic stability
Productivity
• Predation Hypothesis
– Dominant predators
keep species diversity
high by reducing
monopolizers
• Competition hypothesis
– Highly diverse
communities arise in
environments that are
stable and result from
competition managed
niches
Menge and Sutherland 1976
Menge and Sutherland 1987
Community Structure
Menge and Sutherland 1987
Positive interactions in communities
Bertness and Callaway 1994
“Current concepts of the role of interspecific
interactions in communities have been shaped
by a profusion of experimental studies of
interspecific competition over the past few
decades. Evidence for the importance of
positive interactions- facilitations- in
community organization and dynamics has
accrued to the point where it warrants formal
inclusion into community ecology theory, as it
has been in evolutionary biology.”
The greater influence between
competition and positive interactions?
Bertness and Callaway 1994
Facilitation
Study Type
Benthics
%
MEPS
%
Facilitation
3.4
2.2
Predation
15.1
10.6
Propagule
Supply
12.3
6.1
Disturbance
6.8
4.2
Competition
2.7
1.2
Shaded = Facilitation
Open = Competition
Brooker et al., 2008
Facilitation
• Niche Concept
• S. alterniflora zone stabilization
Bruno, Stachowicz and Bertness 2003
Facilitation
• Niche Concept
• S. alterniflora zone
stabilization
• Environmental Stress
• Desert shrubs reduce soil
temp, but outcompete for
shade
Bruno, Stachowicz and Bertness 2003
Facilitation
• Niche Concept
• S. alterniflora zone
stabilization
• Environmental Stress
• Desert shrubs reduce soil
temp, but outcompete for
shade
• Invasibility with higher richness
Bruno, Stachowicz and Bertness 2003
Facilitation
• Niche Concept
• S. alterniflora zone stabilization
• Environmental Stress
• Desert shrubs reduce soil temp, but
outcompete for shade
• Invasibility with higher richness
• Keystone species
• Intermediate Disturbance Hypothesis
• Keystone species and species within those
species
Bruno, Stachowicz and Bertness 2003
Facilitation
Community Structure
Menge and Sutherland 1987
Facilitation
Intraspecific
Interspecific
Bruno, Stachowicz and Bertness 2003
Conclusion
Competition
Predation
Facilitation
Mark Bertness
Citations
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Bertness, M.D. 1985. Fiddler crab regulation of Spartina alterniflora production on a New England salt marsh.
Ecology 66:1042-1055.
Bertness, M.D. 1989. Intraspecific competition and facilitation in a northern acorn barnacle population. Ecology
70:257-268.
Bertness, M.D. 1991. Zonation of Spartina patens and Spartina alterniflora in a New England salt marsh. Ecology
72:138-148.
Bertness, M.D. 1992. Ecology of New England salt marsh. American Scientist 80:260-268.
Bertness, M.D., P.J. Ewanchuk and B.R. Silliman. 2002. Anthropogenic modification of New England salt marsh
landscapes. 99:13985-1398.
Bertness, M.D. and R. Callaway. 1994. Positive interactions in communities. Tree 9:191-193.
Bertness, M.D. and S.W. Shumway. 1993. Competition and facilitation in marsh plants. The American Naturalist
142:718-724.
Brooker, R.W. F.T. Maestre, R.M. Callaway, C.L.Lortie, L.A. Cavieres, G. Kunstler, P. Liancurt, K. Tielborger, J.M.J.
Travis, F. Anthelme, C. Armas, L. Coll, E. Corcket, S. Delzon, E. Forey, Z. Kikvidze, J. olofsson, F. Pugnaire, C.L. Quiroz,
P. Saccone, K. Schiffers, M. Seifan, B. Touzard, and R. Michalet. 2008. Journal of Ecology 96:18-34.
Bruno, J.F., J.J. Stachowicz, and M.D. Bertness. 2003. Inclusion of facilitation into ecological theory. Trends in
Ecology and Evolution 18:119-125
Menge, B.A. and J.P. Sutherland. 1976. Species diversity gradients: synthesis of the roles of predation,
competition, and temporal heterogeneity. The American Naturalist 110:351-369.
Menge, B.A. and J.P. Sutherland. 1987. Community regulation: variation in disturbance, competition, and
predation in relation to environmental stress and recruitment. The American Naturalist 130:730-757.