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GCE-LTER Data Set Summary
Accession:
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INV-GCEM-0209
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Research Theme:
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Aquatic Invertebrate Ecology (Monitoring)
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Contributors:
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Thomas Dale Bishop, Merryl Alber, Ken Helm, Monica Palta, Gayle Albers, Laurel Berger-Bishop, Dean Hardy
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Title:
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Crab population monitoring: Spring 2001 mid-marsh and creekbank crab abundances based on hole counts at GCE marsh, monitoring sites 1-10
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Abstract:
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There are a number of crab species that inhabit the vegetated intertidal marshes of the GCE-LTER permanent monitoring sites. The most frequently encountered species are Uca pugnax, U. pugilator, U. minax, Sesarma reticulatum, Armases cinereum, and Eurytium limosum. These species are highly mobile at various tide stages and seek the safety of burrows when not foraging. Their behavior patterns make it difficult to accurately assess their abundance within the constraints of our current monitoring activities. To do so would require a sampling program dedicated solely to that unique end. This study was designed to use counts of crab holes as a relatively quick and easy way to estimate total crab densities at the GCE-LTER sites. Such a method does not differentiate which species made a particular hole and therefore only estimates total crab abundance. Plugged holes were excluded from the counts. Our initial data yielded an average across all sites of 239 crabs (all species) m^-2. Our initial conclusion is that crab hole counts allow the estimation of crab densities and yields estimates comparable to those methods requiring extensive time and effort. This method will be used to estimate crab densities in the Spring and Fall (yearly) within the GCE-LTER domain.
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DOI:
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10.6073/pasta/014151ab4ff41c4982cb446a661762a6
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Key Words:
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Aquatic Invertebrate Monitoring, Armases, crabs, creek bank, density, Eurytium, intertidal, marshes, mid-marsh, monitoring, mud, permanent plots, population dynamics, Sesarma, spring, Uca
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LTER Core Area:
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Population Studies
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Research Themes:
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GCE2 Q2 - Domain Patterns, GCE3 Area2 - Patterns within the Domain, Aquatic Invertebrate Ecology |
Study Period:
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12-May-2001 to 18-May-2001
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Study Sites:
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GCE1 -- Eulonia, Georgia, USA
GCE2 -- Four Mile Island, Georgia, USA
GCE3 -- North Sapelo, Sapelo Island, Georgia, USA
GCE4 -- Meridian, Georgia, USA
GCE5 -- Folly River, Georgia, USA
GCE6 -- Dean Creek, Sapelo Island, Georgia, USA
GCE7 -- Carrs Island, Georgia, USA
GCE8 -- Alligator Creek, Georgia, USA
GCE9 -- Rockdedundy Island, Georgia, USA
GCE10 -- Hunt Camp, Sapelo Island, Georgia, USA
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Species References:
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Armases cinereum,
Eurytium limosum,
Sesarma reticulatum,
Uca minax,
Uca pugilator,
Uca pugnax |
Project References:
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Invasive species, Marine invertebrate monitoring |
Downloads:
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Data Table: INV-GCEM-0209 (Main data table for data set INV-GCEM-0209, 80 records)
Access: Public (released 14-Sep-2003)
Metadata: Text (ESA FLED),
XML (Ecological Metadata Language)
Data Formats: Spreadsheet (CSV) [8.70kb], Text File [6.75kb], MATLAB (GCE Toolbox) [505.48kb], MATLAB (Variables) [311.49kb], Text Report [47.54kb]
Column List:(hide)
Column |
Name |
Units |
Type |
Description |
1 |
Year |
YYYY |
integer |
Calendar year of observation |
2 |
Month |
M |
integer |
Calendar month of observation |
3 |
Day |
D |
integer |
Calendar day of observation |
4 |
Site |
None |
integer |
GCE-LTER sampling site number |
5 |
Zone |
None |
integer |
Marsh zone code (1=Creekbank, 2=Mid-marsh) |
6 |
Plot |
None |
integer |
GCE-LTER permanent plot number |
7 |
Location |
none |
string |
Geographic location code in the GCE Metadata Database for the sampling plot |
8 |
Flag_Location |
none |
string |
QA/QC flags for Geographic location code in the GCE Metadata Database for the sampling plot (flagging criteria, where "x" is Location: manual) |
9 |
Location_Notes |
none |
string |
Notes on location assignments and geographic accuracy |
10 |
Longitude |
degrees |
floating-point |
Geographic longitude in decimal degrees |
11 |
Flag_Longitude |
none |
string |
QA/QC flags for Geographic longitude in decimal degrees (flagging criteria, where "x" is Longitude: x<-180="I", x>180="I", manual) |
12 |
Latitude |
degrees |
floating-point |
Geographic latitude in decimal degrees |
13 |
Flag_Latitude |
none |
string |
QA/QC flags for Geographic latitude in decimal degrees (flagging criteria, where "x" is Latitude: x<-90="I", x>90="I", manual) |
14 |
Quadrat_Area |
cm^2 |
floating-point |
Areal measurement of the quadrat frame |
15 |
Flag_Quadrat_Area |
none |
string |
QA/QC flags for Areal measurement of the quadrat frame (flagging criteria, where "x" is Quadrat_Area: x<0="I", x>5000="Q") |
16 |
Hole_Count |
Count |
integer |
Number of crab holes recorded in 625 cm^2 quadrat |
17 |
Flag_Hole_Count |
none |
string |
QA/QC flags for Number of crab holes recorded in 625 cm^2 quadrat (flagging criteria, where "x" is Hole_Count: x<0="I", x>52="Q") |
18 |
Hole_Density |
Count/m^2 |
floating-point |
Calculated number of crab holes per meter squared |
19 |
Flag_Hole_Density |
none |
string |
QA/QC flags for Calculated number of crab holes per meter squared (flagging criteria, where "x" is Hole_Density: x<0="I", x>832="Q") |
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Statistics:
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Generate script code to retrieve data tables for analysis in: MATLAB, R, SAS, SPSS |
Citation:
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Bishop, Thomas Dale. 2002. Crab population monitoring: Spring 2001 mid-marsh and creekbank crab abundances based on hole counts at GCE marsh, monitoring sites 1-10. Georgia Coastal Ecosystems LTER Project, University of Georgia, Long Term Ecological Research Network. http://dx.doi.org/10.6073/pasta/014151ab4ff41c4982cb446a661762a6
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