COOCCURRENCE  - generated by Complex Systems Research Center, UNH, 10/9/01.

Data is a vector coverage, registered to NH State Plane feet, NAD83.  It
was generated by overlaying 7 data layers, as follows:


1.  Wildlife/Vernal pools:		Select by:  VERNALPOOLFLAG = 1

    Data sources:
    a)  Potential vernal pools from Deming, L., T. Diers, and J. Kanter.  1999.  
    Great Bay Reptile and Amphibian Habitat Protection Project Final Report.  
    Audubon Society of New Hampshire, Concord.  22pp.  
    b)  US Fish & Wildlife Service, National Wetlands Inventory (NWI), 1:24,000

    The above report identified which NWI wetland types represented high 
    and moderate probability indicators of vernal pools.  This set of wetlands 
    was further subset to include just those wetlands that are 
    hydrologically isolated. 

2.  Wildlife/RARP data:			Select by:  BIRDS-id ge 1 or HERPS-id ge 1

    Data sources:
    a)  Reptile and Amphibian Reporting Program (RARP) , NH Fish & Game.
    b)  NH Bird Records, NH Audubon Society
    c)  US Fish & Wildlife Service, National Wetlands Inventory, 1:24,000

    Again, the RARP and Bird Record data was used to identify the appropriate set of 
    NWI wetlands to include in the study.

3.  Large wetlands w/100' buffer	Select by:  NWIBUF = 1 for 100' buffer on wetlands 10+ acres
                                	NWIBUF = 2 for wetlands 10+ acres
                                	NWIBUF = 3 for other

    Data source:
    US Fish & Wildlife Service, National Wetlands Inventory, 1:24,000


4.  Surface water w/100' buffer		Select by:  HYDROBUF = 1 for 100' buffer around hydro polygons
					HYDROBUF = 2 for the water bodies
					HYDROBUF = 3 for other	

    Data source:
    US Geological Survey Digital Line Graphs, 1:24,000

5.  Unfragmented tracts>500 acres:	Select by:  UNFRAG = 1 for all unfragmented tracts 500+ acres
                                	UNFRAGCLASS = 1:  unfragmented tracts > 500 and < 1000 acres
					UNFRAGCLASS = 2:  unfragmented tracts >= 1000 and < 1500 acres
 					UNFRAGCLASS = 3:  unfragmented tracts >= 1500 and < 2500 acres
					UNFRAGCLASS = 4:  unfragmented tracts >= 2500 and < 5000 acres
					UNFRAGCLASS = 5:  unfragmented tracts >= 5000 and < 10000 acres
					UNFRAGCLASS = 6:  unfragmented tracts >= 10000 acres

    Data sources:
    a)  US Geological Survey, National Land Cover Data Set, 1992
    b)  NH Department of Transportation, road centerline data, June, 2001


6.  Conservation lands 1/500' buffer	Select by:  CONSBUF500 = 1 for 500' buffer around parcel
                                	CONSBUF500 = 2 for valid conservation parcel
					CONSBUF500 = 3 for other (outlots)

    Data source:
    GRANIT Conservation/Public Lands data layer, 1:24,000, summer, 2001.

7.  TNC Portfolio feature:      	Select by:  TNC_FLAG = 1

    Data source:
    TNC matrix forest matrix blocks and important biodiversity points, 
    summer, 2001.


The VALUE attribute theoretically ranges from 0 to 7, and reflects how many
of the above layers co-occur at any location.  The value of "7" never occurs
in this study area, however.