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GCE-LTER Data Set Summary

Accession: INV-GCEM-0209 Research Theme: Aquatic Invertebrate Ecology (Monitoring)
Contributors: Thomas Dale Bishop, Merryl Alber, Ken Helm, Monica Palta, Gayle Albers, Laurel Berger-Bishop, Dean Hardy
Title: Crab population monitoring: Spring 2001 mid-marsh and creekbank crab abundances based on hole counts at GCE marsh, monitoring sites 1-10
Abstract: 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.
DOI: 10.6073/pasta/014151ab4ff41c4982cb446a661762a6
Key Words: Aquatic Invertebrate Monitoring, Armases, crabs, creek bank, density, Eurytium, intertidal, marshes, mid-marsh, monitoring, mud, permanent plots, population dynamics, Sesarma, spring, Uca
LTER Core Area: Population Studies
Research Themes: Q2 - Domain Patterns, GCE3 Area2 - Patterns within the Domain, Aquatic Invertebrate Ecology
Study Period: 12-May-2001 to 18-May-2001
Study Sites:
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
» Download Geographic Coverage: Google Earth, ESRI Shapefile (polygons, points)
Species References: Armases cinereum, Eurytium limosum, Sesarma reticulatum, Uca minax, Uca pugilator, Uca pugnax
Project References: Invasive species, Marine invertebrate monitoring
Downloads: Information

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],  Text Report [47.54kb],  MATLAB (GCE Toolbox) [505.48kb],  MATLAB (Variables) [311.49kb]

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")
Statistics: Generate script code to retrieve data tables for analysis in: MATLAB, R, SAS, SPSS
Citation: 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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This material is based upon work supported by the National Science Foundation under grants OCE-9982133, OCE-0620959 and OCE-1237140. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.