Office: CB4017
Lab: CB3019
| Introduction | Course Objectives |
| Evaluation | Report Format |
| Report Due Date | Report Style |
| Final Term Report | Oral Reports |
| Term Project | Tentative Timetable |
This course is designed for the senior undergraduate student
who wants to understand processes, structure, function, pattern, and scale in
ecological communities. Course instruction will include a mixture of lectures, general
discussions, and investigative assignments. The lectures will emphasize
conceptual, empirical, and experimental approaches to the study of ecological
communities. All students will be required to present an oral review of a
recent research paper in community ecology, and to participate actively in the
class term project.
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Course Objectives:
1. To familiarize students with ecological and evolutionary principles applicable to community
ecology.
2. To introduce students to the relevant and recent literature on a variety
of patterns and processes in ecological communities.
3. To inspire students to question and discuss current concepts and
controversies in community ecology.
4. To assist students in developing the skills, discipline, and study habits
necessary for self-instruction in this and other areas of ecology.
5. To help provide students with the theoretical and empirical background
necessary to solve ecological problems, and to help develop the skills
necessary to effectively communicate those solutions.
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Evaluation:
Two in-class tests - 25% each, assignments, participation, oral
and written review of a scientific paper, and interim reports - 30%, final term
report 20%. There may be one or more in-class quizzes that do not
contribute to the course grade.
Please note: The final term report is a term project and not a final examination. Students will be ineligible to write a special examination as outlined in general regulation VII in the Lakehead University Calendar.
Performance will be evaluated regularly. The evaluation will be based on the
student's grasp of important issues, logical reasoning, non-trivial criticisms
of the material, and the ability to solve ecological problems. Students are
encouraged to actively share their ideas and their questions. The class project
will take place outdoors, and additional excursions may be scheduled if they
are logistically feasible.
Written or oral reports may be assigned at intervals during the course.
Evaluation of these reports will be based on the student's ability to
synthesize a field of enquiry, to apply that synthesis to a particular problem,
or to develop significant new insights into ecological or evolutionary issues.
The reports should not, in general, be restatements of review papers. Rather
they will require the student to apply what is known (and what's not known) to
an unresolved question in ecology. Evaluation will be devoted equally to
clarity of presentation, rigour of treatment, and suitability of the report to
the assignment.
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Report Due Date:
All regular reports will be due two weeks after the
assignment date. Late submission will be penalized at the rate of 10 % per calendar
day unless prior permission is received. The due date for the final report is
12:30 31 March 2005. Reports
submitted after 31 March 2005 will not be accepted for grading.
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Report Style:
Be concise. Use the active voice. Organize your thoughts
before you begin writing. Omit needless or redundant words. Express your
thoughts as clearly as possible even if it means re-writing the report.
Use quotations only when you cannot express the thoughts yourself.
Never borrow a phrase without quotations. Never repeat observations,
interpretations, or ideas without proper citation. Never cite a reference
that you have not read.
Criticize shortfalls and suggest improvements only if they are likely to interest, and be of value, to your readers.
Evaluate the paper carefully and include only relevant material. Use visual
aids in your presentation (e.g., overheads) whenever appropriate.
If you plan on
computer projection (e.g., MS PowerPoint Presentation), please arrange to have
a laptop computer and data projector available in the classroom for your
presentation. Concentrate on communicating the central ideas and themes
of the research or theory to your peers. Criticize only the contribution, not its authors.
Rehearse your presentation to make
sure "it works". Prepare to lead a discussion on the topic by making
a list of important or unresolved questions you would like to see addressed.
Can you articulate your perspective of the issues? Can you design a definitive
study to test the theory? What additional theoretical innovations are necessary
to facilitate empirical tests?
Each student will also be required to write a
short critique of the research paper that they have reviewed for the class. The
critique should include both positive and negative aspects. The report should
concentrate on how the approach used in the reviewed paper can or cannot
contribute to future progress in understanding ecological communities. Students
should familiarize themselves with recent "notes and comments" in The
American Naturalist, or the "forum" section in Oikos for appropriate
examples of constructive critiques. Students should also be certain to review
and reference the appropriate ecological literature. The maximum length of
the written review will be four typed
pages (double-spaced, 2.5 cm margins, minimum height of lower-case letters 2
mm).
An effective "review" will begin with a short paragraph outlining the central issue
addresed by the paper. This paragraph will demonstrate that the reviewer knows how the
research issue fits into "the big question". The second paragraph will specify how
the contribution contributes to the broader theme. Subsequent paragraphs will detail the
positive and negative aspects of the contribution.
Dates Topic
4 January Introduction - Community
as a Unit of Study
6 January – Structure of Winter Bird Communities
11 January Species
Interactions - Competition
13 January Describing Ecological Communities
28 January Species
Interactions - Introduction to Predator-Prey Dynamics
20 January Intra- and Inter-specific
Competition
25 January Species
Interactions - More on Predation
27 January Predator-Prey Interactions
1 February Species Interactions - Mutualism
3 February Simulating Ecological Communities
8 February Species
Interactions - Host-Parasite and Plant-Herbivore Dynamics
10 February Student Reports
14-18 February Study Week - No Class
22 February TEST 1 - 25% OF GRADE
24 February Class Project
1 March Resource
Consumption Theory
3 March Niche Theory
and Habitat Selection
8 March Coexistence and
Isoleg Theory
10 March Student Reports
15 March Large-Scale Patterns
17 March Student Reports
22 March Alternative Processes
24 March TEST 2 - 25% OF GRADE
29 March Neutral Models and Species Assembly
31 March Student Reports
31 March FINAL
REPORT DUE – 20% OF GRADE
Lectures: 08:30-10:20 Tuesday Room AT 2003 (occasionally Thursday 10:30-12:20, AT 3002)
Laboratories: 10:30-12:20 Thursday AT 3002
Return to Douglas
Morris' Home Page
What is an Ecological Community?
Pattern, Process, Function, and Scale
Something to think about:
Imagine an example of what you consider to be an ecological community. Which
attributes would need to be summarized in order to describe the community? How
might you begin to understand how processes within and between species
influence those attributes?
Required Reading:
Morin, P. J. 1999: Chapter 1.
Further Reading:
Rosenzweig, M. L. 1995. Species diversity in space and time. Cambridge
University Press.
Southwood, T. R. E. 1987. The concept and nature of the community. In, J. H.
R. Gee and P. S. Giller (eds.), Organization of communities: past and present.
Blackwell Scientific Publications, pp. 3-27.
Interactions within Guilds
Competition Coefficients
Volterra-Gause Model
Graphical Volterra-Gause Theory
Tests and Curvilinearities
Exploitation and Interference
Does Competition Structure Communities?
Something to do:
Contemplate the effects of different curvilinear zero growth isoclines on
the stability of competitive interactions. Discuss your interpretations with a
fellow student.
Required Reading:
Morin, P. J. 1999: Chapter 2, pages 29-40; Chapter 3.
Classical Reading:
MacArthur, R. H. 1958. Population ecology of some warblers of northeastern
coniferous forests. Ecology 39: 599-619.
Further Reading:
Amarasekare, P. 2003. Competitive coexistence in spatially structured environments:
a synthesis. Ecology Letters 6: 1109-1122.
Hanski, I. 1995. Effects of landscape pattern on competitive interactions. InHansson, L., L. Fahrig, and G. Merriam, eds. Mosaic landscapes and ecological processes. Chapman and Hall, New York. pp. 203-224.
Do Predators Control Prey Numbers?
General Models
Lotka-Volterra Theory
Donor-Control Dynamics
Predator-Prey Isoclines
Effect of Time Lags
Rotated Isloclines
Rosenzweig-MacArthur Theory
Stable Limit Cycles
Something to think about:
Choose an example of a predator-prey interaction. What specific
characteristics of the interaction may act to reduce variability in population
numbers? How could you manipulate one or both species to test your ideas?
Required Reading:
Morin, P. J. 1999: Chapter 5.
Classical Reading:
Huffaker, C. B. 1958. Experimental studies on predation: Dispersion factors
and predator-prey oscillations. Hilgardia 27: 343-383.
Further Reading:
Gilg, O., I. Hanski, and B. Sittler. 2003. Cyclic dynamics in a simple vertebrate predator-prey community. Science 302:866-868.
Hudson, P. J., and O. N. Bjornstad. 2003. Vole stranglers and lemming cycles. Science 302: 797-798.
Ostfeld, R. S., and R. D. Holt. 2004. Are predators good for your health? Evaluting
evidence for top-down regulation of zoonotic disease reservoirs. Frontiers in Ecology and the
Environment 1: 13-20.
Functional Responses
Numerical Responses
Ricklef's Equilibrium Model
Prudent Predators and Harvesting
Relationship to Food Webs
The Meanings of Stability
Persistence
Resistance
Resilience
Variability
Something to think about:
Contemplate the influence of fur-trapping or game fishing on the structure
of ecological communities. What are the implications to the ecological stability
of the constituent communities?
Required Reading:
Beisner, B. E., D. T. Haydon, and K. Cuddington. 2003. Alternative stable states in ecology. Frontiers in Ecology and the Environment 1: 376-382.
Morin, P. J. 1999: Chapter 4.
Further Reading:
Brown, J. S., and B. P. Kotler. 2004. Hazardous duty pay and the foraging cost of predation. Ecology Letters 7: 999-1014.
Pimm, S. L. 1991. The balance of nature? University of Chicago Press.
Two Pathways to Mutualism
Population Models
Stability Analyses
Stability Revisited
Cheaters
Direct Effects
Indirect Effects
Something to do:
With a classmate, discuss the importance of mutualistic interactions to
ecological communities. How many conditions can you imagine where it is
possible for interspecific competitors to be mutualists? Discuss the conditions
under which a specific predator-prey interaction could function as a
mutualistic interaction between species.
Required Reading:
Morin, P. J. 1999: Chapter 7.
Further Reading:
Addicott, J. F. 1986. On the population consequences of mutualism. In, J. Diamond and T. J. Case (eds.), Community ecology. Harper and Row, New York.
Addicott,. J. F. 1996. Cheaters in yucca/moth mutualism. Nature 380: 114-115.
Bertness, M. D., and R. Callaway. 1994. Positive interactions in communities. Trends in Ecology and Evoluation 9: 191-193.
Bronstein, J. L. 1994. Our current understanding of mutualism. Quarterly Review of Biology 69: 31-51.
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.
Dickman, C. R. 1992. Commensal and mutualistic interactions among terrestrial vertebrates. Trends in Ecology and Evolution 7: 194-197.
Kareiva, P. M., and M. D. Bertness (eds). 1997. Positive interactions in communities. Ecology 78: 1945-2024.
Pellmyr, O., and C. J. Huth. 1994. Evolutionary stability of mutualism between yuccas and yucca moths. Nature 372: 257-260.
Pellmyr, O., J. Leebens-Mack, and C. J. Huth. 1996. Non-mutualistic yucca
moths and their evolutionary consequences. Nature 380: 155-156.
Population Models
Consequences for Community Ecology
Plant-Herbivore Coexistence
Stability Analyses
Review of Species Interactions
Question of the week:
Discuss why it is necessary to include both "horizontal" and
"vertical" interactions in any realistic model of ecological
communities. Which sets of interactions are likely to be more important in the
structure of the overall community? Defend your answer.
Required Reading:
Morris, D. W. 2000. Science and the conservation of biodiversity. Canadian Journal of Zoology 78: 2059-2060.
Ostfeld, R., & Keesing, F.
2000. The function of
biodiversity in the ecology of vector-borne zoonotic diseases. Canadian Journal of Zoology 78:
2061-2078.
Further Reading:
Hassell, M. P., and R. M. May. 1989. The population biology of host-parasite
and host-parasitoid associations. In, R. M. May and S. A. Levin (eds.),
Perspectives in ecological theory. Princeton University Press, 319-347.
Basic Models
Perfectly Substituable Resources
One Species per Resource?
Divergence or Convergence?
More Realistic Models
Essential Resources
Something to talk about:
Debate the conditions that allow numerous species to exist at a single
trophic level within an ecological community. Is the number of competing
species likely to depend upon their location in the food web?
Required Reading: Morin, P. J. 1999.
Chapter 2, pages 40-53.
Further Reading:
Morris, D. W., and T. W. Knight. 1996. Can consumer-resource dynamics
explain patterns of guild assembly? The American Naturalist 147: 558-575.
Smith, V. H., and R. D. Holt. 1996. Resource competition and within-host
disease dynamics. Trends in Ecology and Evolution 11: 386-389.
Fundamental and Realized Niches
Maguire's Niche
Evolution of the Fundamental Niche
Niche Dimensionality
Character Displacement and Niche Shifts
Limiting Similarity
Distinct or Shared Preferences?
Density-dependent Habitat Selection
Isodar Theory
Something to think about:
Contemplate the role that ecological niches play in evolution. Is it be
possible for the fundamental niche to change through evolutionary time?
Required Reading:
Morin, P. J. 1999. Chapter 2,
pages 53-66; Chapter 10.
Further Reading:
Holt, R. D., and M. S. Gaines. 1992. Analysis of adaptations in
heterogeneous landscapes: implications for the evolution of fundamental niches.
Evolutionary Ecology 6: 433-447.
Morris, D. W. 1988. Habitat-dependent population regulation and community
structure. Evolutionary Ecology 2: 253-269.
Morris, D. W. 1994. Habitat matching: alternatives and implications to populations and communities. Evolutionary Ecology 8: 387-406.
Morris, D. W. 2003. Toward an ecological synthesis: a case for habitat selection. Oecologia 136: 1-13.
Classical Reading:
Grinnell, J. 1917. The niche-relationships of the California thrasher. The
Auk 34: 427-433.
Many Species on Few Resources
The Paradox of Enrichment
The Trade-off Principle
Qualitative Versus Quantitative Resources
Distinct Preference Organization
Shared Preference Organization
Centrifugal Organization
Implications to Coexistence and Competition for Resources
Something to do:
Select a guild of similar species with which you are reasonably familiar.
Evaluate their morphological and physiological differences in terms of
trade-offs in ecological efficiency. Do they confirm the trade-off principle?
Required Reading:
Rosenzweig, M. L. 1989. Habitat selection, community organization, and small
mammal studies. In, D. W. Morris et al. (eds.), Patterns in the structure of
mammalian communities. Texas Tech University Press, pp. 5-21.
Further Reading:
Rosenzweig, M. L. 1987. Community organization from the point of view of
habitat selectors. In, J. H. R. Gee and P. S. Giller. Organization of
communities: past and present. Blackwell Scientific Publications, pp. 469-490.
Morris, D. W. 1999. Has the ghost of competition passed? Evolutionary Ecology Research 1: 3-20.
Morris, D. W., D. L. Davidson, and C. J.
Krebs. 2000. Measuring the ghost of competition:
insights from density-dependent habitat selection on the coexistence and
dynamics of lemmings. Evolutionary
Ecology Research. 2: 41-67.
Rosenzweig, M. L. 1991. Habitat selection and population interactions: the
search for mechanism. American Naturalist 137: S5-S28.
Diversity Filters
Local Versus Regional Diversity
Two Competitors in Two Identical Patches
Predator-Prey Dynamics in Space
Diffusive Instability
Predator-Prey Dynamics in Experimental Microcosms
Introduction to Metapopulations
Colonization/Competition Trade-offs and Coexistence
Something to think about:
How would you modify Marcel Holyoak's design to evaluate the role
of colonization versus competitive ability on the coexistence of competing
ciliate species in a patchy landscape? What key factors should you manipulate
to gain the greatest insights into competitive coexistence?
Required Reading:
Morin, P. J. 1999. Chapter 11.
Further Reading:
Brown, J. H. 1995. Macroecology. University of Chicago Press.
Gotelli, N. J., and W. G. Kelley. 1993. A general model of metapopulation
dynamics. Oikos 68: 36-44.
Holyoak, M. 2000. Habitat patch arrangement and metapopulation persistence of predators and prey. American Naturalist 156:378-389.
Leibold, M. A., M. Holyoak, N. Mouquet, P. Amarasekare, J. M. Chase, M. F. Hoopes, R. D. Holt, J. B. Shurin, R. Law, D. Tilman, M. Loreau, and A. Gonzalez. 2004. The metacommunity concept: a framework for multi-scale community ecology. Ecology Letters 7: 601-613.
Maurer, B. A. 1999. Untangling ecological complexity: the macroscopic perspective. University of Chicago Press.
Apparent Competition
Intraguild Predation
Competitive Mutualists
Predator Facilitation
General Principle of Coexistence
Mechanisms of Coexistence
Intermittent Competition
A test of Intermittent Competition
Interactions Among Processes
Generalized Predators
Specialized Predators
Parasitism and Disease
Something to think about:
Is it possible to design an experiment or field study to differentiate among
the many related factors that are expected to influence community organization?
What group of organisms would be most appropriate for study? Why?
Required Reading: Morin, P. J. 1999. Chapter 8.
Further Reading:
Arim, M., and P. A. Marquet. 2004. Intraguild predation: a widespread interaction related to species biology. Ecology Letters 7: 557-564.
Brown, J. S., Kotler, B. P., and W. A. Mitchell. 1997. Competition between
birds and mammals: a comparison of giving-up densities between crested larks
and gerbils. Evolutionary Ecology 11: 757-773.
Cody, M. L. 1989. Discussion: structure and assembly of communities. In, J.
Roughgarden, R. M. May, and S. A. Levin (eds.). Perspectives in ecological
theory. Princeton University Press, Princeton, pp. 227-241.
Kotler, B. P., Blaustein, L., and J. S. Brown. 1992. Predator facilitation:
the combined effects of snakes and owls on the foraging behavior of gerbils.
Ann. Zool. Fennici 29: 199-206.
Roughgarden, J. 1989. The structure and assembly of communities. In, J.
Roughgarden, R. M. May, and S. A. Levin (eds.). Perspectives in ecological
theory. Princeton University Press, Princeton, pp. 203-226.
Competitive Lotteries
Gap Theory
Neutral Models and Communities
Limits of Neutral Models
Incidence Functions
Species Assembly
Where to From Here?
Something to talk about:
Debate the likely consequences of forest fragmentation on the structure,
function, and scale of ecological communities. What does the future hold for
patterns of community organization in fragmented landscapes?
Required Reading:
Fox, B. J. 1989. Small-mammal community pattern in Australian heathland: a
taxonomically-based rule for species assembly. In, D. W.
Morris et al. (eds.), Patterns in the structure of mammalian communities. Texas
Tech University Press, pp. 91-103.
Further Reading:
Brown, J. H., Fox, B. J., and D. A. Kelt. 2000. Assembly rules: desert rodent communities are structured at scales from local to continental. American Naturalist 156: 314-321.
Chase, J. M. 2003. Community assembly: when should history matter? Oecologia 136: 489-498.
Fargione, J., C. S. Brown and D. Tilman. 2003. Community assembly and invasion: An experimental test of neutral versus niche processes. Proceedings of the National Academy of Sciences of the USA 100: 8916-1920.
Fox, B. J., and J. H. Brown. 1993. Assembly rules for functional groups in North American desert rodent communities. Oikos 67: 358-370.
Hubbell, S. P. 2001. The unified neutral theory of biodiversity and biogeography. Princeton University Press.
McGill, B. J. 2003. A test of the unified neutral theory. Nature 422: 881-885./
Nee, S., and G. Stone. 2003. The end of the beginning for neutral theory. Trends in Ecology and Evolution 18: 433-434.
Samuels, C. L., and J. A. Drake. 1997. Divergent perspectives on community convergence. Trends in Ecology and Evolution 12: 427-432.
Stone, L., Dayan, T., and D. Simberloff. 1996. Community-wide assembly patterns unmasked: the importance of species’ differing geographic ranges. American Naturalist 148: 997-1015.
Stone, L., Dayan, T., and D. Simberloff. 2000. On desert
rodents, favored states, and unresolved issues: scaling up and down regional
assemblages and local communities.
American Naturalist 156: 322-328.
Wiens, J. A. 1989. The ecology of bird communities I: Foundation and
Patterns. Cambridge University Press.
Wiens, J. A. 1989. The ecology of bird communities II: Processes and
Variations. Cambridge University Press.
Issues of Biodiversity
I have accumulated data on the relative abundances of small mammal species
living in widely separated boreal landscapes. A copy of those data are listed
below. Be sure to take notes on the description of sampling protocols for each
project. Working in teams, summarize the biodiversity of each community and
evaluate, as a class, each of following:
1. Within each landscape, which location, habitat, transect and plot had the
greatest diversity of small mammals species? Justify your answer.
2. Assess the "repeatability" of the small mammal assemblies. What
are the implications to studies of biodiversity?
3. Briefly criticize (both positive and negative aspects) 1, the concept of biodiversity, and 2, the suggestion that areas of high biodiversity receive priority for preservation.
Small Mammals in Different Ontario Transects
| TRANSECT | HABITAT | Bb | Cg | Tm | Mc | Mp | Ni | Pi | Pm | Sc | Ts | Zh |
| 1 | Forest | 0 | 4 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| 1 | Cutover | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 |
| 2 | Forest | 0 | 6 | 0 | 0 | 0 | 0 | 0 | 2 | 0 | 0 | 1 |
| 2 | Cutover | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 1 |
| 3 | Forest | 0 | 5 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 3 | Cutover | 0 | 0 | 1 | 0 | 5 | 0 | 0 | 0 | 0 | 0 | 1 |
| 4 | Forest | 0 | 3 | 0 | 0 | 0 | 0 | 0 | 3 | 0 | 0 | 0 |
| 4 | Cutover | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 5 |
| 5 | Forest | 0 | 2 | 0 | 0 | 0 | 0 | 0 | 2 | 0 | 0 | 1 |
| 5 | Cutover | 0 | 0 | 7 | 0 | 2 | 0 | 0 | 0 | 1 | 2 | 1 |
| 6 | Forest | 0 | 9 | 1 | 1 | 0 | 0 | 0 | 6 | 0 | 0 | 5 |
| 6 | Cutover | 0 | 4 | 5 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 2 |
| 7 | Forest | 0 | 6 | 1 | 0 | 0 | 2 | 0 | 1 | 0 | 2 | 1 |
| 7 | Cutover | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 0 |
| 8 | Forest | 0 | 5 | 0 | 0 | 0 | 0 | 0 | 13 | 0 | 1 | 0 |
| 8 | Cutover | 0 | 1 | 0 | 0 | 6 | 0 | 0 | 0 | 0 | 3 | 13 |
| 9 | Forest | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 7 | 0 | 0 | 0 |
| 9 | Cutover | 0 | 0 | 3 | 0 | 4 | 0 | 0 | 0 | 0 | 0 | 3 |
| 10 | Forest | 0 | 9 | 0 | 11 | 0 | 2 | 0 | 2 | 1 | 2 | 2 |
| 10 | Cutover | 0 | 2 | 1 | 3 | 6 | 0 | 0 | 1 | 0 | 0 | 2 |
| 11 | Forest | 0 | 8 | 0 | 0 | 0 | 4 | 0 | 1 | 0 | 0 | 0 |
| 11 | Cutover | 0 | 2 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 4 |
| 12 | Forest | 0 | 5 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 0 |
| 12 | Cutover | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 |
| 13 | Forest | 0 | 6 | 0 | 0 | 0 | 0 | 0 | 4 | 0 | 7 | 0 |
| 13 | Cutover | 0 | 5 | 1 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 1 |
| 14 | Forest | 0 | 5 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 0 |
| 14 | Cutover | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 |
| 15 | Forest | 1 | 7 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 2 |
| 15 | Cutover | 1 | 5 | 7 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 |
| 16 | Forest | 0 | 7 | 0 | 4 | 0 | 0 | 0 | 5 | 0 | 0 | 0 |
| 16 | Cutover | 0 | 0 | 2 | 0 | 1 | 0 | 0 | 3 | 0 | 0 | 1 |
| 17 | Forest | 1 | 8 | 0 | 3 | 0 | 0 | 0 | 2 | 0 | 0 | 0 |
| 17 | Cutover | 0 | 0 | 0 | 0 | 14 | 0 | 0 | 0 | 0 | 0 | 0 |
| 18 | Forest | 0 | 12 | 0 | 4 | 0 | 1 | 0 | 3 | 1 | 0 | 1 |
| 18 | Cutover | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 10 | 0 | 0 | 0 |
Bb - Blarina brevicauda
Cg - Clethrionomys gapperi
Mc - Microtus chrotorrhinus
Mp - Microtus pennsylvanicus
Ni - Napaeozapus insignis
Pi - Phenacomys intermedius
Pm - Peromyscus maniculatus
Sc - Sorex cinereus
Tm - Tamias minimus
Ts - Tamias striatus
Zh - Zapus hudsonius
Small Mammals in Different Alberta Plots
| LOCATION | PLOT | Cg | Ta | Ml | Pi | Pm | Sc | Zp |
| WI | Wet 1 | 1 | 7 | 0 | 0 | 0 | 3 | 0 |
| WI | Wet 2 | 6 | 4 | 0 | 0 | 0 | 3 | 0 |
| WI | Dry 1 | 0 | 14 | 0 | 1 | 3 | 0 | 0 |
| WI | Dry 2 | 0 | 5 | 0 | 1 | 4 | 4 | 0 |
| SE | Wet 1 | 9 | 0 | 0 | 0 | 0 | 0 | 0 |
| SE | Wet 2 | 12 | 0 | 0 | 0 | 0 | 2 | 0 |
| SE | Dry 1 | 13 | 0 | 0 | 0 | 5 | 3 | 0 |
| SE | Dry 2 | 9 | 0 | 0 | 0 | 2 | 1 | 0 |
| LU | Wet 1 | 10 | 4 | 0 | 0 | 0 | 1 | 0 |
| LU | Wet 2 | 17 | 3 | 0 | 1 | 0 | 2 | 0 |
| LU | Dry 1 | 5 | 1 | 0 | 0 | 2 | 0 | 0 |
| LU | Dry 2 | 5 | 2 | 0 | 0 | 2 | 0 | 0 |
| SB | Wet 1 | 13 | 1 | 0 | 1 | 6 | 8 | 0 |
| SB | Wet 2 | 8 | 6 | 0 | 2 | 4 | 7 | 1 |
| SB | Dry 1 | 13 | 7 | 0 | 1 | 2 | 5 | 0 |
| SB | Dry 2 | 14 | 7 | 0 | 2 | 5 | 3 | 0 |
| KE | Wet 1 | 16 | 4 | 0 | 2 | 7 | 4 | 1 |
| KE | Wet 2 | 20 | 1 | 0 | 1 | 7 | 3 | 1 |
| KE | Dry 1 | 11 | 3 | 0 | 0 | 0 | 2 | 0 |
| KE | Dry 2 | 13 | 2 | 0 | 0 | 0 | 0 | 0 |
| FT | Wet 1 | 6 | 7 | 0 | 0 | 5 | 7 | 0 |
| FT | Wet 2 | 17 | 10 | 0 | 0 | 0 | 18 | 0 |
| FT | Dry 1 | 10 | 1 | 0 | 0 | 20 | 1 | 0 |
| FT | Dry 2 | 14 | 6 | 0 | 0 | 10 | 4 | 0 |
| HD | Wet 1 | 4 | 7 | 0 | 0 | 1 | 13 | 0 |
| HD | Wet 2 | 2 | 13 | 0 | 0 | 0 | 6 | 0 |
| HD | Dry 1 | 0 | 1 | 0 | 0 | 4 | 2 | 1 |
| HD | Dry 2 | 0 | 5 | 0 | 0 | 2 | 4 | 2 |
| EL | Wet 1 | 9 | 3 | 0 | 0 | 0 | 2 | 0 |
| EL | Wet 2 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| EL | Dry 1 | 0 | 2 | 5 | 0 | 0 | 4 | 0 |
| EL | Dry 2 | 0 | 2 | 0 | 0 | 0 | 13 | 1 |
| WG | Wet 1 | 11 | 15 | 0 | 0 | 18 | 1 | 0 |
| WG | Wet 2 | 12 | 11 | 0 | 0 | 14 | 5 | 0 |
| WG | Dry 1 | 2 | 10 | 0 | 0 | 26 | 1 | 0 |
| WG | Dry 2 | 0 | 7 | 0 | 0 | 24 | 0 | 0 |
Cg - Clethrionomys gapperi
Ml - Microtus longicaudus
Pi - Phenacomys intermedius
Pm - Peromyscus maniculatus
Sc - Sorex cinereus
Ta - Tamias amoenus
Zp - Zapus princeps
Use the single-species continuous and discrete logistic growth models in "POPULUS" to simulate different kinds of population dynamics. You can do this by manipulating the input parameters in the models. Manipulate only single parameters before you begin to manipulate several. Explore the results of each simulation carefully and be certain to note how different manipulations influence the pattern of population dynamics. For each simulation, vary the starting densities to evaluate how susceptible the dynamics are to initial conditions. Why is it important that ecologists understand the behaviour of these simple models? For additional insights into population variability and persistence, try other combinations of parameters, and use comparable values in the discrete growth model. When you have created each pattern, move on to “inter-specific competition”.
Further insights into the dynamics of single-species population models can
be gained via the age-structured population growth simulator in
"POPULUS".
INTER-SPECIFIC COMPETITION
Lotka-Volterra competition theory demonstrates that the outcome of
inter-specific competition depends on two characteristics of the species
involved. 1. Each species' carrying capacity. 2. The per capita effect
that individuals of each species have on the population growth rate of the
second species.
Use the Lotka-Volterra competition model in "POPULUS" to simulate four different common outcomes of competitive interaction between two species (hint: only one has global stability). Use the phase-plane to interpret the dynamics of each pattern.
Write a 6 paragraph report consisting of:
A short introduction on why it is important to model species interactions.
4 separate brief paragraphs describing each scenario of competition. Each paragraph should end with a single sentence providing a short biological explanation of the dynamics.
A concluding paragraph summarizing the importance of the different outcomes to our understanding of the role of competition in ecological communities.
PREDATOR-PREY INTERACTIONS
The Lotka-Volterra predator-prey equations contain numerous assumptions that
are biologically unrealistic. Nevertheless, the models are valuable heuristic
and pedagogical tools that enable ecologists to ask a variety of important
questions about the nature of predator-prey interactions. The models suggest,
for example, that time lags in predator responses to prey density act to
destabilize predator-prey dynamics. Knowing this, ecologists can ask whether or
not real predator-prey systems "contain mechanisms" that tend to stabilize
population dynamics. Do real predators, for example, forage in ways that
increase the stability of the predator-prey interaction? Do prey species
exhibit strategies that reduce the effectiveness of predators at low population
sizes?
Evaluate the role of predator behaviour in determining
the stability of predator-prey dynamics. Assess how different types of
functional responses act to stabilize or destabilize the predator-prey
interaction. Illustrate your answer by drawing appropriately labelled
predator and prey isoclines. Briefly describe the stability of, and provide a brief
biological interpretation for, each scenario that you draw.
You can use the "POPULUS" simulator to help you with this
assignment. The theta-logistic predator-prey model, and the discrete predator-prey
models, allow you to explore three forms of functional responses.
In one paragraph, indicate why it is important that ecologists understand
the dynamics of simple two-species models.
OPTIONAL - Do Not Submit for Grading: Please take time to explore how changes in theta (the nature of density-dependence
in prey) affect the shapes of peak densities in prey. Can you conceive of a way
to use this information to test for the relative roles of predators and food in
the regulation of cyclical species?
Any given ecological community represents a sample of the various species available to occupy the assembly, plus potential bias in sampling by field ecologists. Despite these problems, ecologists frequently wish to know whether different communities have similar or divergent patterns in their diversity. One way to assess such questions is through the use and analysis of null models and their associated randomization procedures. Randomization tests use high-speed computers to simulate the expected outcome if the ecologist was to obtain and analyze a large number of replicate samples (usually a minimum of 1000). Resampling alogorithms can be used to solve a variety of problems including such things as patterns in species diversity, probabilities of species co-occurrence, niche overlap, size distributions, and statistical tests. Many ecologists create their own resampling and simulation programs (now made much easier by using spreadsheets such as Excel or Minitab), and students can learn a great deal by creating their own algorithms.
Two types of “canned” software are readily available. Some is proprietary, and must be purchased. Fortunately, an increasing number of ecologists have made their software freely available on the internet. Some of the more popular packages include:
Proprietary:
RAMAS EcoLab A series of professional software programs capable of simulating and analyzing numerous problems in population, landscape, and conservation ecology. Suitable for teaching, research, and application.
EcoBeaker A series of simulation laboratories suitable for both secondary and university students. The programs can also be used to create “personalized” simulations.
Freeware:
Populus A complete set of teaching simulations offered by Don Alstad (University of Minnesota).
VORTEX An individually-based stochastic simulation package designed by R. C. Lacey for Population Viability Analyses (PVA). Suitable for teaching, research, and application.
Nestedness Calculator A simulation program designed by W. Atmar and B. Patterson (Field Museum of Natural History, Chicago) that assesses the degree to which small island (or otherwise fragmented) biotas represent subsets of larger ones. Can be used for teaching, research and application.
EcoSim A set of simulation modules provided by N. Gotelli (University of Vermont) that assess hypotheses related to questions ranging from species diversity to null statistical models. This package is suitable for teaching, research and application.
Today, we will use EcoSim to re-analyze the data on small-mammal communities. Our session has two purposes, 1, to assess statistical differences in the small-mammal communities, and 2, to give you experience with “EcoSim” so that you can use it to analyze your winter bird data later in the term.
Use the help files to learn more about EcoSim. Begin your assignment by deciding how you should enter your data into EcoSim. Note that the data can be analyzed to assess differences among samples, between communities and between habitats.
Differences in sampling intensity can often bias our interpretations about patterns in ecological communities. Imagine, for example, that you collect 500 individuals from one community, and only 100 from another. Which sample is likely to be more representative of the community it is sampled from? Can you effectively compare the large sample with the smaller one? Most ecologists would agree that you cannot make a direct comparison. You can, however, compare the two communities if you could draw an equal-sized sample from each community. EcoSim provides such a “rarefaction” solution. Once you know the total number of individuals in each sample, you can ask EcoSim to randomly draw samples of different sizes from each community, and to use the results to calculate confidence intervals around your estimate of species diversity. Thus, in our hypothetical case, we would ask EcoSim to simulate 1000 samples of 100 individuals drawn at random from our 500-member community. We would conclude that the two communities have different diversities if the 95% confidence interval does not include the value calculated in the 100-member community itself.
Though both the Ontario and Alberta communities were sampled with similar live-traps, sampling intensity is unlikely to be identical and you will be unable to make direct comparisons between them. You will, however, be able to contrast the communities living in different areas, and those living in different habitats, because they have been sampled with equal effort. To begin your simulation, choose two samples in each community for comparison, and enter the data into EcoSim. Contrast both species richness, and species diversity (use Hurlbert’s PIE [Probability of Interspecific Encounter – see the help file for more details]). Repeat the process for the data comparing different habitats.
Write a report assessing species diversity in both small mammal communities. Be certain that your report gives clear answers to the following questions.
1. Was the same small-mammal community represented in different samples?
2. Were the assemblies occupying the different habitats similar or dissimilar?
3. Did any of the assemblies have higher diversity than the others?
4. How reliable are your interpretations?
5. What are the implications of the patterns you have observed to the study and conservation of ecological communities?
Each student will review a recent (no earlier than 2002,
preferably more recent) research paper in the area of community ecology.
Students must have received approval for their choice earlier in the term.
Reports, including time for questions, will be restricted to 15
minutes.
Evaluate the paper carefully and include only relevant material. Use visual
aids in your presentation (e.g., overheads) whenever appropriate. If you plan on
computer projection (e.g., MS PowerPoint Presentation), please arrange to have
a laptop computer and data projector available in the classroom for your
presentation. Concentrate on communicating the central ideas and themes
of the research or theory to your peers. Rehearse your presentation to make
sure "it works". Prepare to lead a discussion on the topic by making
a list of important or unresolved questions you would like to see addressed.
Can you articulate your perspective of the issues? Can you design a definitive
study to test the theory? What additional theoretical innovations are necessary
to facilitate empirical tests? Each student will also be required to write a
short critique of the research paper that they have reviewed for the class. The
critique should include both positive and negative aspects. The report should
concentrate on how the approach used in the reviewed paper can or cannot
contribute to future progress in understanding ecological communities. Students
should familiarize themselves with recent "notes and comments" in The
American Naturalist, or the "forum" section in Oikos for appropriate
examples of constructive critiques. Students should also be certain to review
and reference the appropriate ecological literature. The maximum length of the
written review will be four typed
pages (double-spaced, 2.5 cm margins, minimum height of lower-case letters 2
mm).