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Study Number:
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1002 |
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Project Title:
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Habitat suitability and the
distribution of species. |
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Investigator(s):
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Dr. Ron Pulliam
E-Mail
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Tel. 706.542.6010 |
Biographical Sketch |
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Affiliated Institution(s): |
University of
Georgia |
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Address: |
University of
Georgia
Institute of Ecology
710 Biological Sciences Bldg.
Athens, Georgia 30602
USA |
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Study Type:
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Terrestrial |
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Project Type: |
Coweeta
Core Research |
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Study Period:
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06/1998 - 07/2006 |
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Status/Notes: |
Research complete.
Type 1 |
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Funding Sources: |
National Science
Foundation,
DEB-9632854
(Text Version) and
DEB-0218001
(Text Version)
to Coweeta LTER. |
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Abstract:
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Metapopulation theory posits that
suitable habitat may frequently be
unoccupied because it is isolated and has never been colonized or has
been
colonized followed by local extinction and has not yet been recolonized. This research addresses the question of how to identify
suitable, unoccupied habitat and distinguish it from unsuitable habitat.
We
are studying a group of six species of forest understory herbs chosen to
represent a broad range of habitat distribution and dispersal
characteristics.
Our aim is to quantify the fundamental niche of these
species (sensu Hutchinson 1957), in terms of variables such as soil
moisture and temperature, by developing a set of habitat specific
demographic stage transition models (i.e. conditional on such
environmental
variables) for these species. These models, in combination with data
from
field surveys of the local distribution of the species, will be used to
develop testable predictive maps of the distribution of suitable habitat
which can be compared to the observed distribution of the plants.
We
hypothesize that both dispersal ability and the distribution of suitable
habitat are important determinants of the actual distribution of
species.
The goal of this research is both to further our conceptual understanding of
the relationships between habitat requirements and species
distributions,
and to provide a practical approach to operationalizing the concept of
"suitable habitat."
 Resources
for students about terms used in this study:
On the
relationship between niche and distribution - Pulliam, Ecology
Letters
Metapopulation Theory - Science Magazine
Ecosystems, Biomes and Habitats - The Franklin Institute
Population Modeling
- Sharov, Virginia Tech University |
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Location(s), Described:
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Grid
1 ("grid 36A"): cocentric with Dr. Allen Yeakley's sites 36G,
36A, 18H, and 18C, respectively.
Grid
2 ("grid 36G"): cocentric
with Dr. Allen Yeakley's sites 36G, 36A, 18H, and 18C, respectively.
Grid
3 ("grid 7"): is at the top of
Watershed 2. From 751 turn
right onto 751A; follow this to where road maintenance ceases. Site is
just south of this point.
Grid
4 ("grid 18C"): cocentric with Dr. Allen Yeakley's sites
36G, 36A, 18H, and 18C, respectively.
Grid
5 ("grid 18H"): cocentric with Dr. Allen Yeakley's
sites 36G, 36A, 18H, and 18C, respectively.
Grid
6 ("grid 12"): is near the intersection of 83 and 752. Site is just
south of 752 near where it enters 83, near a steel observation tower. |
Location(s):
Elevation
Decimal Degrees
UTM, Zone 17, NAD83 |
|
gridcode |
grid |
crnr |
direction |
degrees |
minutes |
seconds |
elevation (m) |
|
1 |
36A |
A12 |
N |
35 |
03 |
28.2 |
1035 |
|
1 |
36A |
A12 |
W |
83 |
28 |
0.2 |
1035 |
|
2 |
36G |
A12 |
N |
35 |
3 |
33 |
1142 |
|
2 |
36G |
A12 |
W |
83 |
28 |
3.8 |
1142 |
|
3 |
7 |
A1 |
N |
35 |
4 |
11 |
997 |
|
3 |
7 |
A1 |
W |
83 |
26 |
13.9 |
997 |
|
4 |
18C |
A12 |
N |
35 |
2 |
49.6 |
945 |
|
4 |
18C |
A12 |
W |
83 |
26 |
2.6 |
945 |
|
5 |
18H |
_ |
N |
35 |
2 |
56.3 |
1045 |
|
5 |
18H |
_ |
W |
83 |
26 |
5.1 |
1045 |
|
6 |
12 |
_ |
N |
35 |
2 |
18.9 |
1059 |
|
6 |
12 |
_ |
W |
83 |
27 |
32.9 |
1059 |
|
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Location(s),
Download GPS: |
ArcView Shape Files (shp.):
UTM, NAD83, Zone 17 |
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Location(s),
Online Maps: |
 Online Map |
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Methods/Experimental Design: |
In order to quantify the niche
requirements of our study species, we are
simultaneously tracking their year-to-year demography and the
environmental
conditions to which they are subject. Environmental variables of
interest
include soil moisture, soil temperature, light levels, and soil
chemistry.
Soil moisture will be measured biweekly during the growing season and
approximately monthly during the winters to depths of 10 and 30cm at
four
locations within each study plot, using Coweta's Tektronix TDR unit. The
cells are the 16 2x2 m monitoring cells within each 20x24 m grid.
From 2000-2006 we monitored soil temperature in Celsius and Fahrenheit on all sites by burying HOBO loggers (ONSET Computer Corporation) approximately 5 inches under the ground, near the center of each grid. Nancytown grids were monitored from their initial dates in 2001. Data was logged as an average of temperatures over a two-hour period.
Soil
chemistry variables we anticipate measuring include pH, N, and C.
Sub-canopy
light levels will be derived using hemispherical photography. The study
plots are subdivided into grids of 2x2m cells, marked with orange stake
flags.
Within these all ramets of our study species are marked with
stake
flags of various colors and given unique identifying numbers so that
their
growth and survival can be followed from year to year. Demography data from Coweeta and Whitehall sites have been taken since 1999, and data from Nancytown since 2001. In 2005 and 2006, only the intensive cells were surveyed, and surveyed for new plants. In 1999 and 2000, some grids were re-surveyed. The flower data, except from 2003 and 2006, is taken from the demography survey and not the revisit flower survey.
Variables of
interest
include plant size or leaf area, flower and fruit production, and
recruitment of new ramets. This information, along with the measures of
local environmental conditions within study plots, will be used to
construct
condition-specific demographic stage transition models, providing a
meaningful quantitative definition of habitat suitability for our six
study
species. |
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Sampling Frequency: |
Soil moisture: at least monthly
Soil temperature: continuously
Demography: approximately twice per year during growing season |
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Data Columns:
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Soil Moisture:
grid - Grid number (see Locations, above)
datetdr - Date TDR measurement was taken; Month-day-year
cell1 - Percent soil moisture
cell2 - Percent soil moisture
cell3 - Percent soil moisture
cell4 - Percent soil moisture
cell5 - Percent soil moisture
cell6 - Percent soil moisture
cell7 - Percent soil moisture
cell8 - Percent soil moisture
cell9 - Percent soil moisture
cell10 - Percent soil moisture
cell11 - Percent soil moisture
cell12 - Percent soil moisture
cell13 - Percent soil moisture
cell14 - Percent soil moisture
cell15 - Percent soil moisture
cell16 - Percent soil moisture
datestd - Date TDR measurement was taken in sequential numbering; (1 =
1/1/1900)
Soil Temperature:
tempidx - Index of all records
Date - Date the temperature was logged; Month-day-year
Time36A - Time that the temperature was logged on grid 36A; Hour-minute
C36A - Temperature in Celsius, to three significant digits
F36A - Temperature in Fahrenheit
Time36G - Time that the temperature was logged on grid 36G; Hour-minute
C36G - Temperature in Celsius, to three significant digits
F36G - Temperature in Fahrenheit
Time7 - Time that the temperature was logged on grid 7; Hour-minute
C7 - Temperature in Celsius, to three significant digits
F7 - Temperature in Fahrenheit
Time18C - Time that the temperature was logged on grid 18C; Hour-minute
C18C - Temperature in Celsius, to three significant digits
F18C - Temperature in Fahrenheit
Time18H - Time that the temperature was logged on grid 18H; Hour-minute
C18H - Temperature in Celsius, to three significant digits
F18H - Temperature in Fahrenheit
Time12 - Time that the temperature was logged on grid 12; Hour-minute
C12 - Temperature in Celsius, to three significant digits
F12 - Temperature in Fahrenheit
TimeN - Time that the temperature was logged on grid N; Hour-minute
CN - Temperature in Celsius, to three significant digits
FN - Temperature in Fahrenheit
TimeR - Time that the temperature was logged on grid R; Hour-minute
CR - Temperature in Celsius, to three significant digits
FR - Temperature in Fahrenheit
TimeSo - Time that the temperature was logged on grid So; Hour-minute
CSo - Temperature in Celsius, to three significant digits
FSo - Temperature in Fahrenheit
TimeStr - Time that the temperature was logged on grid Str; Hour-minute
CStr - Temperature in Celsius, to three significant digits
FStr - Temperature in Fahrenheit
TimeA - Time that the temperature was logged on grid A; Hour-minute
CA - Temperature in Celsius, to three significant digits
FA - Temperature in Fahrenheit
TimeB - Time that the temperature was logged on grid B; Hour-minute
CB - Temperature in Celsius, to three significant digits
FB - Temperature in Fahrenheit
TimeC - Time that the temperature was logged on grid C; Hour-minute
CC - Temperature in Celsius, to three significant digits
FC - Temperature in Fahrenheit
Time28 - Time that the temperature was logged on grid 28; Hour-minute
C28 - Temperature in Celsius, to three significant digits
F28 - Temperature in Fahrenheit
TimeExt - Time that the temperature was logged on grid Ext; Hour-minute
Cext - Temperature in Celsius, to three significant digits
Fext - Temperature in Fahrenheit
TimeRok - Time that the temperature was logged on grid Rok; Hour-minute
Crok - Temperature in Celsius, to three significant digits
Frok - Temperature in Fahrenheit
TimeE - Time that the temperature was logged on grid E; Hour-minute
CE - Temperature in Celsius, to three significant digits
FE - Temperature in Fahrenheit
Polygonatum biflorum
Demography: (Information on the demography (growth, survival, and reproduction) of 7541
individually marked Polygonatum biflorum over an 8 year period)
land - site location; (CWT = Coweeta, WH = Whitehall Forest in Athens Georgia)
grid - Grid code
ID - Individual plant ID
row - Row within grid matrix
col - Column within grid matrix
I - Indicates whether it is an intensive cell (1) or not (0). Intensive grids
are where abiotic measures (soil moisture, etc) were taken.
plant - Plant species abbreviation
Xcord - Number of meters the center of the cell is to the right of 0,0
Ycord - Number of meters the center of the cell is uphill from 0,0
lf06 - Leaf number 2006
pres06 - Present (1) or absent (0) for 2006
length06 - Leaf length 2006; millimeters (mm)
width06 - Leaf width 2006; millimeters (mm)
fruit06 - Number of fruits produced 2006
flwr06 - Number of flowers produced 2006
lf05 - Leaf number 2005
pres05 - Present (1) or absent (0) for 2005
length05 - Leaf length 2005; millimeters (mm)
width05 - Leaf width 2005; millimeters (mm)
neighID05 - ID number of the closest neighbor to a new plant for 2005
neighdist05 - Distance in centimeters to the closet neighbor (not exceeding 20
cm) for 2005
fruit05 - Number of fruits produced 2005
flwr05 - Number of flowers produced 2005
lf04 - Leaf number 2004
pres04 - Present (1) or absent (0) for 2004
length04 - Leaf length 2004; millimeters (mm)
width04 - Leaf width 2004; millimeters (mm)
fruit04 - Number of fruits produced 2004
flwr04 - Number of flowers produced 2004
lf03 - Leaf number 2003
pres03 - Present (1) or absent (0) for 2003
length03 - Leaf length 2003; millimeters (mm)
width03 - Leaf width 2003; millimeters (mm)
neighID03 - ID number of the closest neighbor to a new plant
for 2003
neighdist03 - Distance in centimeters to the closet neighbor (not exceeding 20
cm) for 2003
fruit03 - Number of fruits produced 2003
flwr03 - Number of flowers produced 2003
lf02 - Leaf number 2002
pres02 - Present (1) or absent (0) for 2002
length02 - Leaf length 2002; millimeters (mm)
width02 - Leaf width 2002; millimeters (mm)
fruit02 - Number of fruits produced 2002
flwr02 - Number of flowers produced 2002
lf01 - Leaf number 2001
pres01 - Present (1) or absent (0) for 2001
length01 - Leaf length 2001; millimeters (mm)
width01 - Leaf width 2001; millimeters (mm)
fruit01 - Number of fruits produced 2001
flwr01 - Number of flowers produced 2001
lf00 - Leaf number 2000
pres00 - Present (1) or absent (0) for 2000
length00 - Leaf length 2000; millimeters (mm)
fruit00 - Number of fruits produced 2000
flwr00 - Number of flowers produced 2000
lf99 - Leaf number 1999
pres99 - Present (1) or absent (0) for 1999
length99 - Leaf length 1999; millimeters (mm)
fruit99 - Number of fruits produced 1999
flwr99 - Number of flowers produced 1999
Polygonatum Demography Data Codes: (denote the different status of the plants from year to year)
m - a missing plant; we found the flag marking a plant's location, but no plant
e - an empty cell
nl - a "no leaf" plant; a stalk in the present year that has shed all of its leaves
fnf - "flag not found"; no sign of the plant was found in the survey
x - a row could well be deleted, either because it is an "Info" or filler row whose purpose is served after a plant has been found in that cell, or investigations have determined that the plant is actually a specimen of
Uvularia.
na - individual grids that were not surveyed in a certain year
Missing Data Codes:
N/A |
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Publications: |
Pulliam, H. Ronald. 2000.
On the relationship between niche and
distribution. Ecology Letters. 3: 349-361. |
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Data Restrictions:
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Users must
adhere to the Coweeta LTER Data Policy. |
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Metadata:
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EML Format (XML Schema) |
Information
about EML |
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Data Downloads:
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Soil Moisture:
Microsoft® Excel (.xls)
| Text Comma
Delimited (.csv) | DBase (.dbf)
Soil
Temperature:
Microsoft® Excel (.xls)
|
Text Comma
Delimited (.csv) |
DBase (.dbf)
Polygonatum biflorum
Demography:
Microsoft® Excel (.xls)
|
Text Comma
Delimited (.csv) |
DBase (.dbf) |