Transcript Document

“History would be an excellent
thing if only it were true”
(Tolstoy)
Sources of Historical Information
Timescale (years)
Data source
Thousands or greater
Fossil Record
Thousands
Archeological
Decades to Centuries
Museums, literature,
oral history
Decades (?) or greater
Molecular markers
Types of Historical Information
Readily available for many species
• Distributional data (species occurrences)
Potentially available/can be estimated
Life history parameters (age, growth rates)
Abundances of individual species
Estimates of population sizes
Nature of historical data
Sampling is generally biased
Preservational and/or collecting biases
Uneven spatial and/or temporal coverage
Archeological & fossil data are time- averaged
Comparing past with present
We cannot change how the past was sampled but we
can modify how we sample the present
Unbiased ecological surveys may not be appropriate!
Time-averaging can be our friend since it damps out
short term variation - pay attention to the recently
dead (e.g. Kidwell, 2001)
Developing a toolbox: much room for exploring new
statistical approaches and modeling
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http://www.biology.ucsd.edu/labs/roy/CBRISC/
Funding: UC Marine Council, The San Diego Foundation, NSF
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Human Impacts on Body Size of
intertidal invertebrates
34 o N
Los An ge le s
C ou nty
O ran ge C oun ty
S an Die go
C ou nty
33 o N
Roy et al (2003) Ecology Letters 6:205-211
Tegula aureotincta
The animals are cooked in oil and
Served in the shell, the bodies
removed with a pin as they are
eaten……..Certainly a long-lived
species such as Tegula cannot
withstand an intensive fishery
3.28
3.24
Ricketts et al. Between Pacific Tides
3.2
CNM
Field
1960-1980
3.16
Pre-1960
ln(Length)
3.32
Roy et al (2003) Ecology Letters 6:205-211
Fissurella volcano
Not known to be
harvested
3.16
3.11
CNM
Field
1960-1980
Pre-1960
3.06
Pleist
ln(Length)
3.21
Roy et al (2003) Ecology Letters 6:205-211
Why we need historical data
Lottia gigantea
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(> 50 mm)
63
Mean size
62
“When properly prepared it
is delicious, having finer
meat and more delicate
flavor than abalone…….”
61
60
59
58
Ricketts et al, Between
Pacific Tides
57
56
55
54
Pre-1960
Protected
(multi-year survey)
Unprotected
(multi-year survey)
Survey data courtesy J.M. Engle & B.J. Becker
Pleistocene/Holocene
fossil record
can provide prehuman baselines for
distributions and
relative abundance
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record can be
extraordinarily
complete
140
No. of species
e.g. ~ 80% of shallow
marine mollusks living
in California are in the
Pleistocene terraces
Newport Bay Bivalves
(~ 125 k.b.p)
120
100
80
60
40
20
0
0
10000
20000
No. of specimens
30000
40000
Museum collections
Can be used to:
quantify past occurrences of species and
identify local extinctions
study temporal changes in population size
structures as well as some aspects of life history
This example from the UC
Berkeley collections records
the presence of the owl limpet
at moonstone beach on
Santa Catalina Island in 1949.
Is the species still there?
Research papers, reports, dissertations etc.
Can supplement museum data
Often only source for some species or in countries
without extensive museum archives
The sacred chank of India (T. pyrum)
Fishery extends back to ~ 2500 B.C.
1910-1911 harvest data from Hornell 1914
No. of individuals
80000
60000
40000
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20000
0
5.5
6
6.5
7
7.5
8
8.5
Diameter (cm)
9
9.5
10
10.5
40o
N
Northeastern Pacific
Bivalves
Present range limit of
Southern extralimital species
34.5o
Species range limits shift in
response climate change
All of these species present
125,000 y.b.p.
>26% of bivalve species known
from the Pleistocene exhibit
range shifts
6
2
“Natural” local extinctions
need to be separated from those
due to human impacts
1
28o
12
1
5
1
23 o
3