Community Ecology BDC321 Pt2 Mark J Gibbons, Room Z108, BCB Department, UWC Tel: 021 959 2475....
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Transcript of Community Ecology BDC321 Pt2 Mark J Gibbons, Room Z108, BCB Department, UWC Tel: 021 959 2475....
Community Ecology
BDC321 Pt2
Mark J Gibbons, Room Z108, BCB Department, UWC
Tel: 021 959 2475. Email: [email protected]
Image acknowledgements – http://www.google.com
Some Definitions
Environmental Condition
Physical environmental variable or factor, that varies in space and time, and to which organisms respond
Examples include:
Temperature, salinity, moisture, elevation, depth, nitrogen concentration of water, beach grain size etc etc etc
Environmental Gradient e.g. Temperature
Per
form
ance
or
Ab
un
dan
ce
Species ASpecies BSpecies CSpecies DSpecies ESpecies FSpecies GSpecies HSpecies ISpecies J
Resource
Something that is required or used by an organism, the
quantities of which can be reduced by the organism
Examples include:
Dissolved oxygen, sunlight, water, carbon dioxide, mineral
nutrients, organisms as food
Population
A group of individuals of the same species that coexist in space and/or time
Population size / density
Rat
eBirth
Death
K
Born
Population size / densityN
um
ber
s
Dying
Difference = NET Recruitment
0
200
400
600
800
1000
1200
1400
1600
1800
1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106
Time
N
S-Shaped Growth Curves
Characteristic of intra-specific competition
0
5
10
15
20
25
0 200 400 600 800 1000
Population Size
Net
Rec
ruit
men
t
N - Shaped
K
Community?
A group of interacting populations of different species that coexist in time/space
Outcomes of interactions between two species
Inter-specific Interactions
-+Predation
--Competition
0+Commensalism
0-Amensalism
Species BSpecies A
++Mutualism
A community as viewed from a predator-prey perspective
A group of interacting populations of different species that coexist in time/space
A number of other trophic based units also used
Community subsets
Guild
Communities can have very many interacting populations
of different species and to study all of them requires a
suite of expert taxonomists at the very least.
Community ecologists tend to get around this issue by
studying subsets of the community
Taxocene
Morpho-species
How big is a community? ANY SCALE
Broad patterns in terrestrial vegetation can be recognized at the global scale - BIOMES
At this scale, climate is the overwhelming factor that limits vegetation
How small is a community?
Regional Species Pool
Evolutionary Processes
Physiological Constraints
Historic Events
Habitat Selection – Habitat Species Pool
Dispersal Ability – Geographic Species Pool
Local Community
Inter-specific Interactions
Rules – a species will only be present if:
a) It can disperse there
b) Conditions and resources allow it to survive
c) Predators and competitors etc don’t preclude it
Determinants of Community Composition and Structure
Course Aims and Structure
Objectives:
•To train students in the basic theories of community ecology
•To provide students with the necessary skills to enable them to undertake surveys and identify biological communities
•To provide students with the necessary skills to enable them to determine those environmental factors contributing to community structure
Required Background:
Any course on community ecology requires a certain level of background theory and skills - if it is to be successful. For this course, they include a working knowledge of:
Measures of central tendency and dispersionMSExcel
It is also assumed that students are able to build simple single-species models of population growth and that they have a knowledge of intra-specific competition.
As many of you may lack this background, it will be necessary to spend a short period of time completing this work.
Approach:
The course is a balance between theory, laboratory and
field: any person that goes on to work (e.g.) in nature
conservation needs to know why data on communities need to
be collected, they need to know how to collect the data and then
how to analyse the data. They may also need to make informed
decisions (often of a management nature) based on the data. As
a consequence, any course on community needs to include
elements of theory, fieldwork and laboratory simulation, and
here the theory and laboratory simulation go very much hand in
hand.
NB: It is not possible to cover everything in the theory AND
develop your field, analytical and report-writing skills. As a
consequence, some areas of theory are ignored entirely or are
glossed over very superficially.
ALL LECTURES AND SUPPLEMENTARY MATERIAL WILL BE PROVIDED ON THE INTERNET AFTER THEY HAVE
BEEN PRESENTED
Defining a community
Summarizing characteristics
Examining links
Introduction: Definitions
Inte
r-sp
ecif
ic In
tera
ctio
ns
I:C
om
pet
itio
n
Inte
r-sp
ecif
ic In
tera
ctio
ns
II:P
red
atio
n
Community changesin space and time:
SuccessionDisturbance
Effect of Competition in structuring communities
Effect of Predation in structuring communities
Contents
Field & Analytical
Theory & Modeling
Theory, Modeling and Field
Timetable
There will be three lectures per week and two practical
classes. ALL classes will take place in Z29: it may be
necessary to schedule additional classes on Saturday
mornings: such classes to start at 08h00. Please note that
some official classes will be rescheduled.
IT IS EXPECTED THAT YOU WILL ATTEND ALL CLASSES
ON TIME
Day Week Date Period Official Type Duration Topic Assignment dateTues 1 23-Mar-10 pm P 3 Introduction, Aims, Definitions ETCThurs 1 25-Mar-10 2 L 1 MSExcel & Population Dynamics: AssessThurs 1 25-Mar-10 3-4 P 2 Community Properties; Area problems
Fri 1 26-Mar-10 1 L 1 Community Properties; diversity indicesMon 2 29-Mar-10 1 L 1 How to ID Communities: Conceptual overviewTues 2 30-Mar-10 pm P 3 How to ID Communities: similarity matrices by handThurs 2 01-Apr-10 2 L 1 How to ID Communities: drawing dendrograms by handThurs 2 01-Apr-10 3-4 P 2
Fri 2 02-Apr-10 1 L 1Mon 3 05-Apr-10 1 L 1Tues 3 06-Apr-10 pm P 3 How to ID Communities: drawing dendrograms by hand ETCWed 3 07-Apr-10 pm P 3 How to ID Communities - PRIMER & CorrelationThurs 3 08-Apr-10 2 L 1 Competition - MechanismsThurs 3 08-Apr-10 3-4 P 2 Competition - Simple 2 spp Models
Fri 3 09-Apr-10 1 L 1 Competition - Summary: Niche widthMon 4 12-Apr-10 1 L 1 Predation - Types & Effects Prelim REPORT DeadlineTues 4 13-Apr-10 pm P 3 Predation Models: Simple 2 spp models - exponentialThurs 4 15-Apr-10 2 L 1 Predation Models: Simple 2 spp models - logisticThurs 4 15-Apr-10 3-4 P 2 TEST 1
Fri 4 16-Apr-10 1 L 1 Predation Models: Simple 2 spp models - exponential with refugesMon 5 19-Apr-10 1 L 1Tues 5 20-Apr-10 pm P 3Thurs 5 22-Apr-10 2 L 1Thurs 5 22-Apr-10 3-4 P 2
Fri 5 23-Apr-10 1 L 1 POSTER Deadline 1Mon 6 26-Apr-10 1 L 1 Succession - Markov ChainMon 6 26-Apr-10 4 L 1 Succession - biological mechanisms I: Markov ChainsTues 6 27-Apr-10 pm P 3Wed 6 28-Apr-10 pm P 3 Go through test, report back on posterThurs 6 29-Apr-10 2 L 1 Succession - biological mechanisms II, Climax conceptThurs 6 29-Apr-10 3-4 P 2 Analyse data on succession from literature
Fri 6 30-Apr-10 1 L 1 Disturbance POSTER Deadline 2Mon 7 03-May-10 1 L 1 Disturbance in Markov Chain ModelsMon 7 03-May-10 4 L 1 Disturbance in Markov Chain ModelsTues 7 04-May-10 pm P 3 Analysis of Field DataWed 7 05-May-10 pm P 3 Competition and Communities - IThurs 7 06-May-10 2 L 1 Null ModelsThurs 7 06-May-10 3-4 P 2 Null Models
Fri 7 07-May-10 1 L 1 Predation and Communities - I Final REPORT DeadlineMon 8 10-May-10 2-pm ALL 7 REVISIONTues 8 11-May-10 2-pm ALL 7 REVISION
Public HolidaysMJG AwayExtra Lessons
Assessments and Deadlines
Evaluation will take the form of continuous assessment. This continuous assessment is broken up as follows:
Class test (33%) + Practical work (67%) = Course Mark
Class Tests
The Class test will be held on Thursday 15 April 2010 during
periods 2-4: Z29. Students will be tested on ALL material
covered up to and including that of Tuesday 13 April 2010.
If a re-test is necessary (i.e. more than 35% of the class failed
the first test), this will be held on Saturday 8 May 2010 at 08h00
in Z29. ONLY those students that failed the first test will be
eligible to sit the re-test, and the better of the two marks will be
taken into consideration. Students will be tested on ALL
material covered up to and including that of Friday 7 May 2010.
Course Mark (60%) + Exam (40%) = Final Mark
Prac Exam (30%) + Theory Exam (70%) = Exam Mark
Practical Work
In this course, the practical component will comprise two
evaluations. These are listed below:
PLEASE BE ADVISED THAT FACULTY RULES REGARDING
PLAGIARISM AND THE SUBMISSION OF LATE
ASSIGNMENTS WILL BE UPHELD
You will be expected to use Turnitin
Poster – 40% towards Practical Mark
Preliminary Deadline – Friday 23 April 2010
Final Deadline – Friday 30 April 2010
Report - 60% towards Practical Mark
Preliminary Deadline – Monday 12 April 2010
Final Deadline – Friday 7 May 2010
Create a poster (size A0) in MS PowerPoint to illustrate one
of the following topics:
POSTER
1. Mutualism2. Commensalism3. Amensalism4. Parasitism
The audience is undergraduate students – Teaching Tool
The poster should be based on a published, peer-reviewed
scientific paper that CLEARLY illustrates the concept
behind the topic OR that CLEARLY shows how the
concept can influence biological community structure
The poster MUST be professional in appearance
The poster will be assessed using a rubric and ALL TEXT must be submitted to Turnitin and the
report attached
TITLE
CONCEPT NOTE & DEFINITION
Article Details
METHODS
RESULTS & DISCUSSION
Legend
*Legend
Legend
LegendAcknowledgements
REPORT
Rocky shore communities along the NW
coast of False Bay, South Africa
Prepare a 2 000 word paper on the above topic for
submission to the African Journal of Marine Science. The
instructions for authors and an exemplar manuscript have
been provided to assist you prepare your paper. READ
them thoroughly!
Reports MUST make reference to at least three journal
articles, and CAN refer to a maximum of three text book
articles and a maximum of one internet article. Copies of
ALL the cited journal articles, appropriate sections of text
books and internet sources should be attached to the
submitted essay, and the relevant sections (i.e. those
pieces of information referred to in the report) MUST be
highlighted. Failure to attach supporting documentation
will result in the report being returned to the student, with
concomitant penalties for late submission being then
enforced.
The data set that you will use for this exercise was
collected from the shore at Dalebrook. ALL the data, in a
raw state, can be accessed from the www site. Tide data
You must prepare the data for analysis yourselves but in
so doing, beware of possible species misidentifications.
ONE other issues are worth mentioning. How will you deal
with replicates from each station samples along the
shore?
Your report should include (at the very least), a
description of changes in animal and plant abundance or
cover and diversity across the shore as well as a
description of changes in communities across the shore.
Credit will be given to those students, whose reports
investigate some of the links between community
members in a quantitative way.
YOU MUST SUBMIT YOUR REPORTS TO TURNITIN
BEFORE FINAL SUBMISSION (report from Turnitin must
be attached) – AND YOU ARE ADVISED TO USE THE
WRITING CENTRE IN ADVANCE!
Suitable references could include:
Branch, GM and Branch, M (1983) The living shores of
southern Africa. Struik
Lewis, JR (1964) The ecology of rocky shores. English
Universities Press
Little, C and Kitching, JA (1998) The biology of rocky
shores. Oxford
McQuaid, CD and Branch, GM (1984). Influence of sea
temperature, substratum and wave exposure on rocky
intertidal communities: an analysis of faunal and floral
biomass. Marine Ecology Progress Series, 19: 145-151
McQuaid, CD and Branch, GM (1985). Trophic structure of
rocky intertidal communities: response to wave action and
implications for energy flow. Marine Ecology Progress
Series, 22: 153-161
Stephenson, TA and Stephenson, A (1972) Life between
tidemarks on rocky shores. Freeman.
REPORT POSTER TEST EXAM Attendance N Mark % Pass Pass Mark
REPORT 9 45.4 33.3 58.6
POSTER 0.54 9 58.1 77.8 61.8
TEST -0.20 0.09 9 49.5 44.4 58.4
EXAM 0.57 0.09 0.08 9 55.0 88.9 58.5
Attendance 0.60 0.21 0.05 0.93
Pass or Fail?
A student is deemed to have passed the course if her/his Final mark (i.e. Coursework + Exam) is ≥50% AND the Exam mark is ≥40% AND the Practical mark is ≥50%
Should a student obtain a Final mark of ≥50% AND have a Practical mark of ≥50% BUT have an Exam mark <40%, then that student will get an opportunity to write a Supplementary Exam*
Should a student obtain a Final mark of 45-49%, AND the Practical mark is ≥50%, then that student will have an opportunity to write a Supplementary Exam*
Should a student obtain a Coursework mark (i.e. Class tests + Practical) of ≥50% AND have a Practical mark of ≥50% AND have an Exam mark of ≥30% then that student will get an opportunity to write a Supplementary Exam*
A student who does not meet the above grades fails and is not eligible to sit the Supplementary Exam.
A student who fails to get a mark of 50% in the Practical work automatically fails, regardless of the Coursework or Exam mark – such a student not being eligible to sit the final exam.
Similarly, a student that fails to obtain a course-work mark of less than 40% is not eligible to sit the final exam.
* - Supplementary exams will be held at the end of the examination period. This exam will test the student on ALL the work undertaken in the module.
Readings
Although there are no prescribed books for this course, the following texts are recommended (especially those in bold-typeface): all are currently placed on short-loan at the UWC library.
•Begon, M., Harper, J.L. and Townsend, C.R. (1990). Ecology: Individuals, Populations and Communities. Blackwell Scientific Publications, 945pp.
•Begon, M. and Mortimer, M. (1986). Population Ecology: A Unified Study of Animals and Plants. Blackwell Scientific Publications, 220pp.
•Krebs, C.J. (1999). Ecological Methodology. Benjamin Cummings, 620pp.
•Morin. P.J. (1999). Community Ecology. Blackwell Science, 424pp
•Zar, J.H. (1984) Biostatistical Analysis. Prentice-Hall
Nt+1 / Nt = R = R / {1 + [Nt.(R-1)/K]}
For a population of organisms showing discrete breeding
and a fundamental reproductive rate (R) of 1.41 (per year),
determine when the population will reach its carrying
capacity of 643 215 individuals if the initial population size
in 2007 is 12 individuals.
Nt+1 = Nt R / {1 + [Nt.(R-1)/K]}
REFRESHER……
10 minutes…..
R 1.41
K 643215t N R
2007 12 1.4099892008 16.91987 1.4099852009 23.85676 1.4099792010 33.63752 1.409972011 47.42789 1.409957
2012 66.8713 1.40994
2013 94.28451 1.4099152014 132.9332 1.4098812015 187.4199 1.4098322016 264.2305 1.4097632017 372.5022 1.4096652018 525.1035 1.4095282019 740.1482 1.4093352020 1043.117 1.4090632021 1469.817 1.408682022 2070.503 1.4081422023 2915.561 1.4073842024 4103.315 1.4063222025 5770.581 1.4048332026 8106.7 1.4027512027 11371.69 1.3998532028 15918.69 1.3958372029 22219.89 1.3903082030 30892.5 1.3827712031 42717.25 1.3726252032 58634.76 1.35922033 79696.35 1.3418342034 106939.3 1.32002
2035 141162 1.2936022036 182607.5 1.262992037 230631.4 1.2292832038 283511.4 1.194192039 338566.4 1.1597212040 392642.5 1.1277482041 442801.8 1.0996282042 486917.2 1.076032043 523937.6 1.0569952044 553799.6 1.0421252045 577128.5 1.0307962046 594901.7 1.0223292047 608185.2 1.0160912048 617971.4 1.0115442049 625105.1 1.0082552050 630265 1.0058892051 633976.6 1.0041942052 636635.4 1.0029832053 638534.7 1.002122054 639888.6 1.0015062055 640852.3 1.0010692056 641537.5 1.0007592057 642024.4 1.0005392058 642370.2 1.0003822059 642615.6 1.0002712060 642789.8 1.0001922061 642913.4 1.0001362062 643001 1.0000972063 643063.2 1.0000692064 643107.4 1.0000492065 643138.7 1.0000352066 643160.9 1.0000242067 643176.6 1.0000172068 643187.8 1.0000122069 643195.7 1.0000092070 643201.3 1.000006
0
100000
200000
300000
400000
500000
600000
700000
2007
2011
2015
2019
2023
2027
2031
2035
2039
2043
2047
2051
2055
2059
2063
2067
2071
Year
Nu
mb
ers
Assuming that you can ALL project
populations growing under the
influence of intra-specific
competition into the future……..
Length (mm) Frequency Table of cephalothorax of Euphausia
superba collected during February 2008 from the Weddell Sea,
Antarctica.
Calculate the mean cephalothorax
length of E. superba in the Weddell
Sea during February 2008 and
determine the standard deviation,
variance, standard error and 95%
Confidence limits around your
estimate.
ALL CALCULATIONS TO BE
CONDUCTED “LONG-HAND”
20 MINUTES……..
X F20.6 020.8 121 1
21.2 321.4 521.6 1721.8 2122 26
22.2 3722.4 4422.6 5622.8 5823 45
23.2 3223.4 1923.6 1223.8 1324 3
24.2 124.4 324.6 0
Critical values of the t distribution
Conf. Level 50% 80% 90% 95% 98% 99%One Tail 0.25 0.1 0.05 0.025 0.01 0.005Two Tail 0.5 0.2 0.1 0.05 0.02 0.01
df . . . . . .1 1 3.078 6.314 12.706 31.821 63.6572 0.816 1.886 2.92 4.303 6.965 9.9253 0.765 1.638 2.353 3.182 4.541 5.8414 0.741 1.533 2.132 2.776 3.747 4.6045 0.727 1.476 2.015 2.571 3.365 4.0326 0.718 1.44 1.943 2.447 3.143 3.7077 0.711 1.415 1.895 2.365 2.998 3.4998 0.706 1.397 1.86 2.306 2.896 3.3559 0.703 1.383 1.833 2.262 2.821 3.2510 0.7 1.372 1.812 2.228 2.764 3.16911 0.697 1.363 1.796 2.201 2.718 3.10612 0.695 1.356 1.782 2.179 2.681 3.05513 0.694 1.35 1.771 2.16 2.65 3.01214 0.692 1.345 1.761 2.145 2.624 2.97715 0.691 1.341 1.753 2.131 2.602 2.94716 0.69 1.337 1.746 2.12 2.583 2.92117 0.689 1.333 1.74 2.11 2.567 2.89818 0.688 1.33 1.734 2.101 2.552 2.87819 0.688 1.328 1.729 2.093 2.539 2.86120 0.687 1.325 1.725 2.086 2.528 2.84521 0.686 1.323 1.721 2.08 2.518 2.83122 0.686 1.321 1.717 2.074 2.508 2.81923 0.685 1.319 1.714 2.069 2.5 2.80724 0.685 1.318 1.711 2.064 2.492 2.79725 0.684 1.316 1.708 2.06 2.485 2.78726 0.684 1.315 1.706 2.056 2.479 2.77927 0.684 1.314 1.703 2.052 2.473 2.77128 0.683 1.313 1.701 2.048 2.467 2.76329 0.683 1.311 1.699 2.045 2.462 2.75630 0.683 1.31 1.697 2.042 2.457 2.7540 0.681 1.303 1.684 2.021 2.423 2.70450 0.679 1.299 1.676 2.009 2.403 2.67860 0.679 1.296 1.671 2 2.39 2.6670 0.678 1.294 1.667 1.994 2.381 2.64880 0.678 1.292 1.664 1.99 2.374 2.63990 0.677 1.291 1.662 1.987 2.368 2.632100 0.677 1.29 1.66 1.984 2.364 2.626z 0.674 1.282 1.645 1.96 2.326 2.576
X F X.F X-MEAN (X-MEAN)2 F(X-MEAN)2
20.6 0 0 -2.04 4.16 020.8 1 20.8 -1.84 3.39 3.3921 1 21 -1.64 2.69 2.69
21.2 3 63.6 -1.44 2.08 6.2321.4 5 107 -1.24 1.54 7.7021.6 17 367.2 -1.04 1.08 18.4221.8 21 457.8 -0.84 0.71 14.8522 26 572 -0.64 0.41 10.68
22.2 37 821.4 -0.44 0.19 7.1922.4 44 985.6 -0.24 0.06 2.5522.6 56 1265.6 -0.04 0.00 0.0922.8 58 1322.4 0.16 0.03 1.4723 45 1035 0.36 0.13 5.81
23.2 32 742.4 0.56 0.31 10.0123.4 19 444.6 0.76 0.58 10.9523.6 12 283.2 0.96 0.92 11.0423.8 13 309.4 1.16 1.34 17.4724 3 72 1.36 1.85 5.54
24.2 1 24.2 1.56 2.43 2.4324.4 3 73.2 1.76 3.09 9.2824.6 0 0 1.96 3.84 0
SUMS 397 8988.40 147.78Mean 22.64Variance 0.37STDev 0.61St Error 0.03t 1.96t. St Error 0.06Upper 22.70Lower 22.58
Basic Model Building……
1) – How many tennis balls could fill this room?
You have 60 seconds to come up with an answer
How did you arrive at your answer?
Real world vs model worldResolutionAssumptions and trade-offs
2) – in groups of two, and using your PC, tell me how many tennis balls could fill this room?
You have 5 minutes to come up with an answer
How did you arrive at your answer?
A gas storage tank has a Vol of 3000 cubic m. It currently contains methane. The tank must be emptied & then cleaned before being modified for use as a milk storage vessel.
Safety regulations require that it should contain no more than 1 part in 100 of methane before it can be cleaned.
Nitrogen is available and can be pumped into an opening near one end of the tank. Another opening near the other end will let gases escape.
How much nitrogen will you need to dilute the methane effectively?
Working in groups of two, think about the problem for about 30 mins and prepare a plan, before explaning it to the rest of the class.
DO NOT solve the problem at this stage.
Solve the problem
Identifying or Delineating Communities
1 – physically defined communities
Assemblages of species found in a particular place or habitat
ARTIFICIAL?
2 – taxonomically defined communities
Identified by presence of one or more conspicuous
species that dominate biomass and/or numbers, or which
contribute importantly to the physical attributes of the
community
Topographic distributions of the characteristic dominant tree species of the Great Smokey Mountains, Tennessee, on an idealized west-facing mountain and valley
BG, beech gap; CF, cove forest; F, Fraser fir forest; GB, grassy bald; H, hemlock forest; HB, heath bald; OCF, chestnut oak-chestnut forest; OCH, chestnut oak-chestnut heath; OH, oak-hickory; P, pine forest & heath; ROC, red-oak-chestnut forest; S, spruce forest; SF, spruce-fir forest; WOC, white oak-chestnut forest.
Great Smoky Mountains Tennessee
SUBJECTIVE?
3 – statistically defined communities
Sets of species whose abundances are significantly correlated, positively or negatively, over space and/or time.
Look at numerical and specific composition of samples
Determine similarities between samples
Look for a pattern in the similarities between samples
And so identify communities OBJECTIVELY
4 – interactively defined communities
Subsets of species in a particular place or habitat, whose
interactions influence their abundance.
Only some, and perhaps none, of the species in a physically
defined community may constitute an interactively defined
community.
Hairston (1981: Ecology, 62: 65-72) noted that of the seven
species of plethodontid salamander in his study (North
Carolina, USA), only the two most common influenced each
others abundances: the balance, while ecologically similar,
remained unaffected by each others abundance.
THE END
Image acknowledgements – http://www.google.com