Transcript pptx

Nicholas J. Gotelli
Community Ecologist, Writer, Programmer, Musician
BIOL 7083 Symposium
Warwick Allen
“I don’t do my work in order to persuade people to
conserve pitcher plants. As far as my work goes, I am
ultimately a hedonist. The real reason I do my work is
that I love it, and it’s intellectually satisfying to me.
Everything else follows secondarily.”
Pitcher plant communities
• Ph.D. – Florida State University. 1982 – 1985
(advisor: Dan Simberloff)
• M.S. – Florida State University. 1980 – 1982
(advisor: Lawrence Abele)
• B.A. – University of California, Berkley. 1976 – 1980
• 2000 - present. Full Professor, Department of Biology,
University of Vermont
• 2008 - 2010. Adjunct Professor, Xishuangbanna Tropical
Botanical Garden, Chinese Academy of Sciences
• 1995 - 2000. Associate Professor, Department of Biology,
University of Vermont
• 1992 - 1994. Assistant Professor, Department of Biology,
University of Vermont
• 1988 - 1992. Assistant Professor, Department of Zoology,
University of Oklahoma
• 1987 - 1988. Post-doctoral Associate, Department of Biology,
Colorado State University
• 1985 - 1987. Lecturer, Department of Organismic and
Evolutionary Biology, Harvard University
Teaching Interests
• Theoretical, Community, Population, and
Experimental Ecology
• Ecological Modeling
• Biostatistics
• Biogeography
• Invertebrate Zoology
Research Interests
Community structure
Altered nutrient regimes
Extinction risk
Invasive species
Ecological statistics
Null models
Software development
Food Webs
“So the other direction that food web analysis
has gone – that to me is much more satisfying –
is to deliberately simplify and collapse all that
complexity; to deliberately distort nature and
pigeonhole it into a couple of key little trophic
groups of predators or consumers or parasitoids
and work out the critical linkages there”
Purple pitcher plant
(Sarracenia purpurea)
Ideal study system:
• Perfect for small scale
• Complete and selfcontained
• Relatively simple
(five trophic levels)
Food Webs
Insight into important
ecological topics:
• Top-down vs bottom-up
• Trophic cascades
• Community assembly rules
• Extinction risk
Food Webs
A Series of Sarracenia Experiments
• Sprayed nitrogen and phosphorous on pitcher plant
bogs to examine how this alters morphology (relative
keel size and relative tube diameter)
• Measured changes in photosynthesis, flowering, and
population growth rates
• Examined effects of prey additions, pitcher volume
alterations, and removal of top trophic level consumers
• Patterns in biodiversity also investigated
• Increased anthropogenic
nitrogen from “acid rain”
changed leaf type from
pitcher to phyllode leaves
Ellison & Gotelli, 2002a
• Photosynthesis and ability to
flower increased, but population
growth rate decreased
• Increased nitrogen leads to
higher extinction risk
Ellison & Gotelli, 2002b
• Interestingly, increased nutrient input from prey had no
effect on morphology, growth rate or photosynthesis,
but changed levels of elements in plant tissue
• Inquiline communities nitrogen input is relatively low
in comparison to that from the atmosphere
• May provide a reliable biological indicator of
atmospheric nitrogen deposition and saturation in
Wakefield et al., 2005
• Just begun publishing his work at the community level
• Reverse latitudinal trend in species richness (highest in
northern sites), perhaps mediated by top-down
• Local (within population)
variation in food web
structure is higher than
continental variation
• Development of speciesspecific proteomic
indicators to determine
ecosystem health
Buckley et al., 2003; Buckley et al., 2010; Gotelli et al., 2011
• Changes in food web structure is
predicted best by trophic
structure models as opposed to
keystone species or habitat
• Important to look at a wide range
of trophic interactions in order to
properly understand what is
occurring in a system
• Consequences for predicting
effects of climate change, habitat
destruction, and invasive species
Gotelli & Ellison, 2006
A Primer of Ecology
• Read by many students and
recommended in many ecology
• An excellent introduction to
• Particular focus on
Ecological Statistics
• Published in collaboration with
Aaron Ellison
• Part 1: Probability & statistical
• Part 2: Experimental design
• Part 3: Common ecological
Quantifying Biodiversity:
Procedures and Pitfalls in the Measurement And
Comparison Of Species Richness
• Co-authored by Robert Colwell
• 1,519 citations
• Rarefaction or asymptote estimation allows for
meaningful comparisons of species richness
• Led to development of EstimateS software
• New paper (March 2012) provides an update:
“Models and estimators linking individual-based and
sample-based rarefaction, extrapolation and
comparison of assemblages”
Null Models
• “We always have to ask ‘patterns
compared to what?’ In the
absence of an experimental data
set (and most data sets in ecology
are not based on experiments),
we have to have some base level
against which we compare
• Free download online!
• A strong proponent for the use of null models in
ecology for examining community level processes
• Has published numerous papers on the subject as
well as his book
• What is a null model?
• A model built around randomizations of known or
imagined ecological data but with the absence of a
particular ecological mechanism
• Often used to compare results against a model which
includes the mechanism (i.e. is a pattern
deterministic or stochastic?)
• Gotelli provides a highly-cited review of the main
uses of null models in ecology:
1. Biodiversity measures (rarefaction)
2. Species co-occurrence patterns (detection of
species interactions)
3. Macroecology (identify constraining boundaries
in bivariate scatterplots)
Gotelli, 2001
Application of null models:
Meta-analysis examining Jared
Diamond’s assembly rules
model (1975)
Less co-occurrence of species
than expected by chance
Non-random structure greater
for homeotherms than
Demonstrates the power of
using null models in
community ecology
Gotelli & McCabe, 2003
Null Models/Ecosim
• EcoSim: null models software for ecology
• Developed in collaboration with Gary Entsminger
• Creates null models to look at:
- Co-occurrence patterns
- Niche overlap
- Species diversity
- Macroecological patterns
• EcoSimR currently being built
Other Software
• BioGeoSim: Biogeography software for ecologists
• Developed with Gary Entsminger, Carsten Rahbek,
and Gary Graves
• Used to analyze observed species ranges against
stochastic/null models and environmental variables
Easy Wind
The Littlest Birds
Gypsy Affair
Jawless Fishes
Kesey Bear Band
Touch of Grey
Many others…
• ESA meetings – The Hot
BIOL 7083
Buckley, H. L., Miller, T. E., Ellison, A. M. & Gotelli, N. J. (2010) Local- to continental-scale
variation in the richness and composition of an aquatic food web. Global Ecology and
Biogeography, 19, 711-723.
Buckley, H. L., Miller, T. E., Ellison, A. M. & Gotelli, N. J. (2003) Reverse latitudinal trends in
species richness of pitcher-plant food webs. Ecology Letters, 6, 825-829.
Colwell, R. K., Chao, A., Gotelli, N. J., Lin, S-Y., Mao, C. X., Chazdon, R. L. & Longino, J. T. (2012)
Models and estimators linking individual-based and sample-based rarefaction, extrapolation and
comparison of assemblages. Journal of Plant Ecology, 5, 3-21.
Ellison, A. M. & Gotelli, N. J. (2002a) Nitrogen availability alters the expression of carnivory in
the northern pitcher plant, Sarracenia purpurea. PNAS, 99, 4409-4412.
Ellison, A. M. & Gotelli, N. J. (2002b) Nitrogen deposition and extinction risk in the northern
pitcher plant, Sarracenia pupurea. Ecology, 83, 2758-2765.
Gotelli, N. J. (2001) Research frontiers in null model analysis. Global Ecology and Biogeography,
10, 337-343.
Gotelli, N. J. (2008) A Primer of Ecology, Fourth Edition. Sinauer Associates Inc., Sunderland,
Massachusetts. 291p.
Gotelli, N. J. & Colwell, R. K. (2001) Quantifying biodiversity: procedures and pitfalls in the
measurement and comparison of species richness. Ecology Letters, 4, 379-391.
Gotelli, N. J. & Ellison, A. M. (2004) A Primer of Ecological Statistics. Sinauer Associates Inc.,
Sunderland, Massachusetts. 479p.
Gotelli, N. J. & Ellison, A. M. (2006) Food-web models predict species abundances in response to
habitat change. PLOS Biology, 4, 1869-1873.
Gotelli, N. J. & Graves, G. R. (1996) Null Models in Ecology. Smithsonian Institution Press,
Washington D. C. 368p.
Gotelli, N. J. & McCabe, D. J. (2002) Species co-occurrence: a meta-analysis of J. M. Diamond’s
assembly rules model. Ecology, 83, 2091-2096.
Gotelli, N. J., Smith, A. M., Ellison, A. M. & Ballif, B. A. (2011) Proteomic characterization of the
major arthropod associates of the carnivorous pitcher plant Sarracenia purpurea. Proteomics,
11, 2354-2358.
Wakefield, A. E., Gotelli, N. J., Wittman, S. E. & Ellison, A. M. (2005) Prey addition alters nutrient
stoichometry of the carnivorous plant Sarracenia purpurea. Ecology, 86, 1737-1743.
Gotelli Website -
ESA Interview -