Paper 28
Pielou, E.C. 1977. The latitudinal spans of seaweed species and
their patterns of overlap. Journal of Biogeography 4:299-311.
Blog by Kaitlyn Sullivan
Paper Author: Evelyn C. Pielou
(Commentary by Christy M. McCain)
Christy M. McCain
·
Ph.D. from University of Kansas
·
Associate Professor and Curator
of Vertebrates Dept. of Ecology & Evolutionary Biology and University of
Colorado Boulder Natural History Museum
Research interests:
“I
am interested in the mechanisms producing and maintaining patterns of species
distribution, abundance, and diversity. To address these processes, I consider
three levels of ecological organization to be equally important: species-level
autecology, population-level dynamics, and community-level processes and interactions.
My research so far has highlighted small mammal range dynamics, abundance
patterns across altitudinal ranges, and species richness patterns along
latitudinal and elevational gradients. I particularly exploit mountain systems
as natural experiments to look at how evolutionary history, ecological
processes, and future climate change influence species populations. My
overarching goal is to strive for quantitative, general theories applicable to
both the advancement of ecology and the improvement of our conservation
strategies. I use multiple tools at various spatial scales to address research
questions, including field studies, synthesis of collection and historical
data, comparative analyses, null models, GIS, and simulation modeling.”
Christy M McCain.
(n.d.). Retrieved January 30, 2017, from
http://www.colorado.edu/ebio/christy-m-mccain
Evelyn C. Pielou
·
Ph.D. from University of London
·
Professor of Biology at the
Queen's University, Kingston (1968-71)
·
Professor at Dalhousie University
in Halifax, Nova Scotia (1974-81)
·
Oil Sands Environmental Research
professor at the University of Lethbridge, Alberta (1981-86)
·
Died July 16, 2016
Research
Interests:
E.C. Pielou was a Canadian-born,
British-trained Evolution and Ecology Biologist who significantly contributed “to
the development of mathematical ecology, the
mathematical modeling of natural systems.”
Mostly self-taught, she began her career in 1963 as a research scientist
for the Canadian Department of Forestry, then transferred into the Department of
Agriculture in 1964. Starting in 1968,
Pielou spent the rest of her career as a research professor at three
distinguished universities. During that
time, she wrote and published 10 books and over 60 articles, of which earned
her a Ph.D. from the University of London.
Throughout her lifetime, Pielou was the recipient of many awards
including :
·
Fellow, Royal Society of Arts
·
George Lawson Medal (Canadian
Botanical Association), 1984
·
Eminent Ecologist Award
(Ecological Society of America), 1986
·
Distinguished Statistical
Ecologist Award (International Congress of Ecology), 1990
·
Several honorary degrees and
memberships
She recently
passed away in her home town of Comox, British Columbia, Canada.
Evelyn C.
Pielou Evolution and Ecology. (n.d.). Retrieved January 30, 2017, from
http://www.science.ca/scientists/scientistprofile.php?pID=208
Paper- Summary/Main points:
The purpose of this paper is to describe a
method of analyzing species’ ranges by depicting each species as a line on a
map. When all species are included in
the map, the ranges are shown as a sheaf of lines. “Each line relates to a single species: the
location and length of the line show the position and the extent of that
species’ range. The sheaf as a whole
shows the wat in which the several species’ ranges overlap.”
·
“Species range limits and size”
·
“Patterns of overlap among
closely and distantly related species”
·
“The latitudinal gradient in
species richness”
·
Testing two conflicting
hypotheses of overlap
(1) “The range
limits of congeneric species are independently located”
·
Species that are closely related
should overlap due to shared ancestry.
·
The unconditioned hypothesis – “locations of the northern and southern
limits of the s spans are entirely at
random.”
·
Lengths of span are undefined
(2) “The ranges
themselves, assumed to have their observed lengths, are independently located.”
·
There will be minimal overlapping
due to competitive exclusion among closely related species.
·
The conditioned hypothesis – “takes into account the lengths of the s spans and the availability of
shoreline length where they must be located.”
·
Lengths of spans are based off
actual, observed lengths which are assumed to be independently and randomly
located within the given space.
Methods
·
Data was based off literature
with previously recorded northern and southern limits of algae occurrence.
·
684 species of benthic marine
algae.
o
395 species of Rhodophyta
o
174 species of Chlorophyta
o
115 species of Phaeophyta
·
It was assumed that the span of
each species was defined by its northern and southern (latitudinal) limits.
Results/Conclusions
·
“It was concluded that
competition between related algal species has no effect on the locations of
their spans, and hence on their geographical zonation patterns. [However,] the local, as opposed to
geographical, pattern of seaweed distribution, in contrast, appears to be
strongly affected by competition.” In
other words, overlap in range limits is much more prevalent among congeneric
species than was previously predicted by competitive exclusion. Also, across the latitudinal gradient,
species ranges were distributed independently.
·
She observed that while completion
highly influences the distribution of local algae, the same is untrue of
geographical distribution.
·
“She attributed her results to
allopatric speciation followed by rampant marine dispersal.”
·
Results follow two commonly
accepted macroecological patterns
o
“Most common range sizes are the
smallest”
o
“Latitudinal patterns in
diversity are unimodal”
Questions
·
What are mid-domain effects and how
did Pielou’s set of analyses influence it?
·
If allopatric speciation does not
account for speciation among benthic algae, have other mechanisms been
determined to cause sympatric speciation in this class of plants?
·
In recent years, have
improvements to Pielou’s methodology been made in an effort to generate data
with greater biogeographic significance?