COURSE SUMMARY



COMMUNITY ECOLOGY

Biology 4113 - 2005

Instructor:

Dr. Douglas Morris

Office: CB4017

Lab: CB3019

Text:

Morin, P. J. 1999. Community Ecology, Blackwell Science.
Morris, D. W. 2005. Community Ecology: Course Guide and Notes.

Lectures:

Tuesday 08:30-10:20; AT 2003

Labs:

Thursday, 10:30-12:20, AT 3002 (or as assigned)

Office Hours:

Tuesday 10:30-11:30 & Thursday: 13:00-14:00 (4 January - 8 April only). Other Times by Appointment

Contents:

Introduction Course Objectives
Evaluation Report Format
Report Due Date Report Style
Final Term Report Oral Reports
Term Project Tentative Timetable








Introduction:

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 Format:

Read each assignment carefully and include only relevant material. Unless otherwise indicated, maximum length of reports including tables, figures, and references will be six typed pages (double-spaced, 2.5 cm margins, minimum height of lower-case letters 2 mm).

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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.

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Final Term Report:

Each student will be required to write a short (maximum 10 double-spaced typed pages, includes all tables, figures, and literature citations) report on the term project. Follow the format used for short communications in OIKOS. Be certain that your report includes the following:

TITLE:                   Short and descriptive.

KEY WORDS:            A list of six or fewer key words that could be used to index your report.

ABSTRACT:               Concise and informative.

INTRODUCTION:      Two or three engaging paragraphs that briefly review relevant literature and set the theme for the report.

METHODS:                 A concise description of essential methods. Provide just enough detail so that someone else could duplicate your study.

RESULTS:                   A concise summary of all relevant results. Whenever possible use tables and figures. Choose illustrations over tables whenever possible.

DISCUSSION:            A detailed (but not verbose) assessment of the significance of your results and their importance to the theme of your report.

Criticize shortfalls and suggest improvements only if they are likely to interest, and be of value, to your readers.



REFERENCES:           List all key references and no more. Use original sources rather than secondary reports or reviews.

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Oral Reports:

Each student will be required to review a recent (no earlier than 2002, preferably more recent) research paper in the area of community ecology. Students must receive approval of their choice, and should verify their selection with their instructor(s) early 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. 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.

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Term Project:

The entire class will participate in the term project assessing the coexistence of overwintering birds on the University campus. Pairs of students will be responsible for twice daily observations and counts of birds on campus. Observations must be recorded within one hour of sunrise and sunset. Students will record the number of all individual birds spotted while walking a standard “transect” on the University campus (the exact location will be determined in consultation with the class). Students must record, and enter the following data into an EXCEL spreadsheet that will be shared with the class. Record the date, time of observation, habitat, climatic conditions, student name, and number of individuals of each species. Be certain to enter zeroes when no individual of a particular species has been sighted. Climatic variables should include such things as temperature, per cent cloud cover, wind speed (calm, slight breeze, strong breeze, wind gusts), and precipitation (occurring or not, and type).

We anticipate that field guides and binoculars will be provided on a sign-out basis, and students are required to make them available to subsequent teams. Students will be financially liable for damage to, or loss of, guides and binoculars.

Each student will be responsible for writing a final term report, using the class data, on the structure of overwintering bird communities. The report does not need to analyze data for the entire term but it should justify whichever subset of data it uses. The report should emphasize, as much as the data allow, processes influencing patterns in the bird communities, and should not simply be a compilation or summary of bird diversity. Students should assess such things as possible mechanisms of coexistence (are there negative or positive associations among different bird species; do these vary temporally or with habitat?), differences in species composition between habitats, and possible rules of species assembly. Additional questions could include: Are the birds recorded in one site a non-random subset of those occurring elsewhere on campus? Are there repeated patterns in the assembly (e.g., guild membership rules)? Do the relative abundances of bird species vary with habitat? Are mixed flocks fortuitous aggregations of more or less randomly occurring bird species, or do they represent repeated patterns? What are the implications of any patterns to the coexistence of species? Is there any evidence that bird species vary in their tradeoffs of energy for safety?

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Tentative Timetable - 2005

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

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Return to Douglas Morris' Home Page



BIOLOGY 4113 - COMMUNITY ECOLOGY


Topic 1: Community as a Unit of Study

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.

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BIOLOGY 4113 - COMMUNITY ECOLOGY


Topic 2: Species Interactions - Competition

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.

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BIOLOGY 4113 - COMMUNITY ECOLOGY


Topic 3: Species Interactions - Introduction to Predator-Prey Dynamics

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.

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BIOLOGY 4113 - COMMUNITY ECOLOGY


Topic 4: Species Interactions - More on Predation

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.

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BIOLOGY 4113 - COMMUNITY ECOLOGY


Topic 5: Mutualism

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.

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BIOLOGY 4113 - COMMUNITY ECOLOGY


Topic 6: Host-Parasite and Plant-Herbivore Dynamics

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.

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BIOLOGY 4113 - COMMUNITY ECOLOGY


Topic 7: Resource Consumption Theory

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.

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BIOLOGY 4113 - COMMUNITY ECOLOGY


Topic 8: Niche Theory and Habitat Selection

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.

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BIOLOGY 4113 - COMMUNITY ECOLOGY


Topic 9: Coexistence and Isoleg Theory

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.

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BIOLOGY 4113 - COMMUNITY ECOLOGY


Topic 10: Large-Scale Patterns

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.

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BIOLOGY 4113 - COMMUNITY ECOLOGY


Topic 11: Alternative Processes

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.

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BIOLOGY 4113 - COMMUNITY ECOLOGY


Topic 12: Neutral Models and Species Assembly

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.

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Biology 4113 - Community Ecology


LABORATORY 1. Describing Ecological Communities

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

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BIOLOGY 4113 - COMMUNITY ECOLOGY


LABORATORY 2: Intra- and Inter-specific Competition.



INTRA-SPECIFIC COMPETITION:

Theoretical ecologists have demonstrated that even simple deterministic models of population growth can produce a variety of different patterns in population dynamics. For single-species delayed logistic growth models, these patterns depend upon the "characteristic response time" of the population. Response time can be thought of as the product of the population's capacity for increase (usually estimated by the intrinsic growth rate - r) and time lags in the response of the growth rate to population density. Four patterns are highlighted by ecologists. 1. Monotonic increase to a stable carrying capacity. 2. Damped oscillations around a stable carrying capacity. 3. Stable limit cycles in density through time. 4. Chaotic population fluctuations.

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.

 

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BIOLOGY 4113 - COMMUNITY ECOLOGY


LABORATORY 3 – Predator-Prey Interactions

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?

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BIOLOGY 4113 - COMMUNITY ECOLOGY


LABORATORY 4: Using EcoSim to Analyze Ecological Communities

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?

 

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BIOLOGY 4113 - COMMUNITY ECOLOGY


STUDENT REPORTS:

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).

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.

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