Nicholas J. Gotelli and Aaron M. Ellison. 2002. Biogeography at a regional scale: determinants of ant species density in New England bogs and forests. Ecology 83:1604-1609.

Site	Code	Latitude	Longitude	Elevation	Bog Area	GSF	LAI	Bog PC1	Bog PC2	Forest PC1	Forest PC2
Tobey Pond Bog (CT)	TPB	42.00333	73	389	2877	0.049	5.368	2.87	0.96	-0.46	-0.79
Halls Brook Cedar Swamp (MA)	HBC	42.02889	70	8	11760	0.092	3.453	0.41	-1.05	-1.15	-0.48
Chockalog Bog (MA)	CKB	42.04944	71	152	7422	0.068	2.762	-1.32	-1.09	-0.94	-0.38
Shankpainter Ponds (MA)	SKP	42.04972	70	1	55152	0.219	1.587	-1.02	0.98	-0.61	0.82
Clayton Bog (MA)	CB	42.17444	73	210	73120	0.128	2.462	-2.57	1.31	-0.70	-0.37
Round Pond (MA)	RP	42.19417	72	78	10511	0.073	3.038	-2.89	0.42	-1.57	-0.72
Ponkapoag Bog (MA)	PK	42.23472	71	47	491189	0.141	3.695	-2.21	0.01	-0.14	-1.23
Otis Bog (MA)	OB	42.27139	73	491	89208	0.061	3.128	0.29	2.33	-1.09	2.08
Swift River (MA)	SWR	42.30972	72	121	19699	0.063	3.11	-1.19	0.06	-1.56	0.86
Arcadia Bog (MA)	ARC	42.555	72	95	1190	0.08	5.286	0.739	-3.27	-1.54	0.07
Bourne-Hadley Ponds (MA)	BH	42.5675	72	274	105369	0.093	2.506	0.43	0.02	-0.93	-0.50
Quag Pond (MA)	QP	42.57528	71	335	40447	0.153	2.457	-1.76	1.31	0.26	-0.08
Hawley Bog (MA)	HAW	42.68639	72	543	36813	0.121	2.822	1.14	1.44	-0.71	-0.22
Lake Jones (MA)	WIN	43.32667	72	323	84235	0.063	4.497	1.86	-0.26	-0.64	-0.45
North Springfield (VT)	SPR	44.05806	72	158	435	0.053	3.423	0.12	-0.27	-0.92	-0.44
Snake Mountain (VT)	SNA	44.28972	73	313	248	0.168	1.713	2.09	0.71	-0.56	-0.69
Peacham Bog (VT)	PEA	44.325	72	468	576732	0.077	3.993	-0.16	-3.21	1.53	2.28
Chickering Bog (VT)	CHI	44.49917	72	362	38081	0.049	3.713	-0.22	0.63	1.36	-1.08
Molly Bog (VT)	MOL	44.54528	72	236	8852	0.057	4.417	2.26	0.89	7.05	-3.38
Colchester Bog (VT)	COL	44.76278	73	30	623284	0.052	3.867	0.37	-1.58	-1.34	0.33
Moose Bog (VT)	MOO	44.95389	71	353	864970	0.062	4.795	1.20	0.84	4.79	4.57
Carmi Bog (VT)	CAR	42.00333	72	133	38023	0.059	3.047	-0.423	-1.2	-0.12	-0.19

Variable Units

Site code is used in Appendix E. Latitude and longitude are in decimal degrees; elevation is in meters above sea-level; bog area is in square meters; global site factor (GSF) is percent of available light (direct + diffuse) in the understory (see Appendix B for details of calculations); and leaf area index (LAI) is in (m² leaf tissue)/(m² ground area). Decimal fractions of longitude coordinates are not reported to protect threatened wetland habitats. Bog and forest PC scores are the first and second principal components derived from field measurements of plant species composition at each site (Appendix B, Appendix D).

Site Selection

Sites were selected in consultation with local conservation agencies (The Nature Conservancy and state Natural Heritage Programs). Criteria for selection included: high quality, relatively undisturbed bogs, presence of a population of the northern pitcher-plant Sarracenia purpurea L. (an ant predator), and representation across a variety of ecological sub-regions (Bailey 1998). Sites were spread across the states and covered all of the Vermont ecological sub-regions and 10 of the 13 subregions of Massachusetts. Pitcher-plant bogs are uncommon in Connecticut, and only one site was sampled in that state.

Measurement of Geographic Variables

At each site, latitude and longitude were determined using a Trimble Global Positioning System unit (Trimble Instruments, Sunnyvale, CA, USA). Subsequently, digital aerial photographs were obtained for each bog (from state mapping authorities), or, when digital photographs were unavailable (five sites), photographic prints (from USGS-EROS) were scanned and digitized. Aerial photographs were used to construct a set of data layers in a geographic information system (using Arc-View GIS 3.2, ESRI, Redlands, CA, USA), from which we calculated bog area and perimeter. We did not attempt to measure the area of surrounding forests, as the forest was generally continuous for at least several km² around each bog. Site elevation was determined from USGS topographic maps (using the software program Topo!, Wildflower Productions, San Francisco, CA, USA).

Literature Cited

Bailey, R.G. 1998. Ecoregions: the ecosystem geography of the oceans and continents. Springer-Verlag, New York, New York, USA.