Population Ecology I

1
Population Ecology I Population structure and
distribution life-history trade-offs and
reproductive strategies
Opening photo, Unit 2. Cain et al. (p. 153)
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Unitary and modular organisms What is an
individual?
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Examples of modular organisms
Fig. 9.1, Smith Smith, 6th ed. (p. 187)
A quaking aspen (Populus tremuloides) genet
A shoal grass (Halodule beaudettei) genet
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How might modularity affect population
studies? All the trees in this photo are
trembling aspens. How many individuals do you
see here?
Photo by Loraine Yeatts
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How might modularity affect population
studies? Apart from the dark green conifers, most
of the trees in this photo are trembling aspens.
How many individuals are there in this population?
Photo by Loraine Yeatts
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An expanding population of a clonal plant New
ramets are initially physiologically dependent on
the parental ramet, but later often become
self-sufficient.
Fig. 9.2, Smith Smith 6th ed. (p. 188)
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Two examples of modularity in animals Clones of
(a) a coral and (b) a sponge
Fig. 9.3, Smith Smith 6th ed. (p. 188)
Fig. 9.2, Smith Smith (5th ed), p. 172
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Distribution, Dispersion, andAge Structure
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Most species have relatively small geographic
ranges as illustrated by (a) 1,370 spp of North
American birds, and (b) 1,499 spp. of British
vascular plants.
Fig. 50.27, Campbell Reece, 6th ed. (p. 1118)
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Geographic range of the red maple (Acer rubrum)
Fig. 9.4, Smith Smith, 7th ed. (p. 185)
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Geographic range and relative abundance of the
Carolina wren (Thryothorus ludovicianus)
Fig. 9.5, Smith Smith, 5th ed. (p. 175)
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General representation of the dispersion of
individuals in a population within its local
distribution (or, range)
Fig. 9.3, Smith Smith, 7th ed. (p. 185)
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Distribution of the moss (Tetraphis pellucida) at
several spatial scales
Fig. 9.5, Smith Smith 7th ed. (p. 186)
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Distribution of the horned lark (Eremophila
alpestris) at several spatial scales What
factors might promote patchiness in distribution
at each scale?
Fig. 9.6, Smith Smith (5th ed), p. 176
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Distribution is partly a matter of
dispersal Human-assisted dispersal of kudzu
(Pueraria montana)
Theres a kudzu photo in your text (p. 196), but
this one is more dramatic.
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Boom-and-bust populations Gypsy moth (Lymantria
dispar), scourge of the Eastern deciduous forests
of North America (Coming soon to a forest near
you??)
Fig. 1 (Ch. 9), Smith Smith 6th ed. (p. 201)
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Boom-and-bust populations Gypsy moth (Lymantria
dispar), scourge of the Eastern deciduous forests
of North America (Coming soon to a forest near
you??)
Fig. 1 (Ch. 9), Smith Smith 6th ed. (p. 201)
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Boom-and-bust populations Gypsy moth (Lymantria
dispar), scourge of the Eastern deciduous forests
of North America (Coming soon to a forest near
you??)
Temporal and spatial changes in population
distribution of gypsy moth.
Fig. 9.17, Smith Smith 7th ed. (p. 194)
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Spatial dispersion of individuals within a
population What might promote a specific pattern
in a particular species population?
Fig. 9.8, Smith Smith 6th ed. (p. 191)
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Spatial dispersion of individuals within a
population What might promote a specific pattern
in a particular species population?
Fig. 52.2, Campbell Reece (6th ed)
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An example of uniform dispersion shrubs on the
Kara Kum desert
Fig. 9.9, Smith Smith 6th ed. (p. 192)
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Clumped dispersion within a uniform
dispersion the shrub Euclea divinorum growing in
the shelter of Acacia tortilis trees
Fig. 9.10, Smith Smith 6th ed. (p. 192)
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Why all the clumping?
Fig. 52.1, Campbell Reece, 6th ed. (p.
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Age structure (and recruitment?) in an oak
(Quercus) population in Sussex, England
Fig. 9.15, Smith Smith 6th ed. (p. 198)
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Reproductive StrategiesLife-history trade-offs
in patterns of reproduction
Opening photo for Ch. 8 in Smith Smith 7th ed.
(p. 158)
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Precocity vs. delay
Precocious reproduction in dandelion (Taraxacum
officinale)
What ecological circumstances might favor each of
these strategies?
Delayed reproduction in red oak (Quercus rubra)
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Semelparity vs. iteroparity
Fig. 52.6, Campbell Reece 7th ed. (p. 1141)
Agave (Agave sp.) a semelparous plant
What ecological circumstances might favor each of
these strategies?
Sugar maple (Acer saccharum) an iteroparous plant
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Semelparity vs. iteroparity
Fig. 7.11, Cain et al. (p. 162)
Agave (Agave sp.) a semelparous plant?
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Fecundity vs. parental care
What ecological circumstances might favor each of
these strategies?
Fig. 52.8, Campbell Reece 7th ed. (p. 1142)
a. Dandelion (Taraxacum officinale) High
fecundity, little parental care per individual
embryo.
What animal species have life-histories
characterized by these strategies and the ones in
the preceding slides?
b. Coconut palm (Cocos nucifera) Much lower
fecundity, much greater parental investment in
each embryo.
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Contrasting life history strategies in two
salamander species with overlapping ranges
Left spotted salamander (Ambystoma maculatum)
Fig. 8.17, Smith Smith, 7th ed (p. 176)
Right redback salamander (Plethodon cinereus)
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Evidence for the trade-off between fecundity and
parental care Inverse relationship between mean
seed weight and fecundity in a variety of
herbaceous plants.
Fig. 7.15, Cain et al. (p. 165)
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Evidence for the trade-off between fecundity and
parental care Inverse relationship between mean
seed weight and fecundity in goldenrod.
Fig. 8.12, Smith Smith, 7th ed (p. 170)
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The cost of reproduction in lesser black-backed
gulls Effects of experimental manipulation of
brood size on survival of offspring
Fig. 7.14, Cain et al. (p. 165)
Fig. 52.7, Campbell Reece 7th ed. (p. 1142)
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The cost of reproduction in European
kestrels Effects of experimental manipulation of
brood size on survival of parents
Fig. 52.7, Campbell Reece 7th ed. (p. 1142)
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Cost of reproduction in red deer on the island of
Rhum in Scotland Effects of reproduction on
mortality of females
Fig. 52.5, Campbell Reece 6th ed. (p. 1157)
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Another way to look at the metabolic cost of
reproduction Relationship between fecundity and
size of big-handed crabs in New Zealand
Fig. 8.13, Smith Smith, 7th ed. (p. 171)
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Another way to look at the metabolic cost of
reproduction Relationship between fecundity and
size of European red squirrels
Fig. 8.13, Smith Smith, 7th ed. (p. 171)
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Using mark-recapture sampling to estimate animal
populations (or, How to determine populations of
uncooperative organisms)
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Using mark-recapture sampling to estimate animal
populations
Imagine you are studying a particular species of
fish, and there is a population of 10,000 of
these fish living in a lake so N 10,000
individualsbut you dont know this! You capture
250 of fish and mark them in some way so that you
will know if you catch them again in the future
so M 250 fish, and the proportion of marked
individuals in the population is But you dont
know this, either!! Now imagine you allow those
marked fish to mix in with the population again,
and then you capture another batch. This time
you catch 360 fish so C 360 fish. Based on the
ratio of M to N (0.025), how many of those 360
individuals would you expect to be
recapturesi.e., fish that you marked in the
first capture?
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Using mark-recapture sampling to estimate animal
populations
where, N population M number of
individuals marked in initial trapping C
number of individuals captured in census
trapping R number of marked individuals
recaptured in census trapping
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Using mark-recapture sampling to estimate animal
populations

• After rearranging to solve for N, this becomes
• Example
• Imagine you capture and mark 150 fish in a lake.
  (This must be a random, representative sample.)
• You release them back into the lake, allowing
  enough time for them to remix with the
  population.
• You then trap another 220 fish, of which 25 are
  recaptures (i.e., marked from the initial
  trapping).
• What is your estimate of the total population of
  fish in the lake?