SOURCES OF DATA -- MAMMALIAN DISTRIBUTION

Museum records

     Alfred Godin's (1977) book Wild Mammals of New England constitutes the
only region-wide source of mammalian range data for New England Gap Analysis.
This work contains range maps coded with species-by-county occurrences as
documented via actual or reported musem specimens.

     We incorporated Godin's data into Gap Analysis distribution maps by
digitizing the by-county occurrences and subsequently merging them with other
data sources.  Godin's species maps were digitized by selecting counties
on-screen, which corresponded to counties marked on Godin's maps as having
documented museum specimens.  An AML wrote FIPS codes of selected counties to
a textfile along with the species ELCODE.  This textfile was then loaded into
an INFO datafile so that the data could be graphically displayed in ARC/INFO.
By-county occurrences were translated to by-hexagon occurrences according to
a single decision rule:  If any portion of a hexagon fell within a county,
the hexagon was coded as "species present."  

Vertebrate Characterization Abstracts (VCA)  Data

     VCA data contribute substantially to range data for three New England
states.  These abstracts, along with Godin's data, make up all of the source
data for distribution of mammals in Connecticut, Rhode Island, and
Massachusetts. Range data for Vermont also incorporates VCA data.  Like
Godin's museum records, these data consist of species-by-county occurrences,
but the source of VCA data is variable, from a mix of literature citations.
These VCA databases vary in size with the Connecticut, Massachusetts, Rhode
Island, and Vermont databases containing 116, 370, 63, and 590 mammal records,
respectively.  The decision rule described above also applies to the
contribution of these databases to our range data.  

Vermont Small Mammal Atlas Data

     Chipman's (1994) atlas project strengthens our distributional data for
small mammals in Vermont.  This project consists of trapping data (1988-1989)
and a compilation of historical records documenting the distribution of sixteen
species of shrews, mice, and voles.  Five habitat types in all six
physiographic provinces of the state are represented in the atlas trapping data.
Sampled habitat types include two unique and fragile habitats (alpine and bog)
in addition to softwood forest, hardwood forest, and field cover types.  The
historical records compilation draws on the Zadock Thompson collection at the
University of Vermont, the Lyndon State College Collection in Lyndon, Vermont,
the Vermont Fish and Wildlife Department Heritage Database, Godin (1977), and
data from unpublished sources (Chipman 1994).  

     We generalized the by-town occurrence records taken from the atlas project
to hexagon-level occurrence records.  Counties and hexagons received a
species-present code when any portion of a species-present town polygon fell
within their boundaries.

New Hampshire Fish & Game Department Data

     Small mammal distributions for New Hampshire reflect State Fish and Game
Department data in addition to Godin's (1977) data.  These data represent three
databases provided to us with permission for their use by Shirley Ahern.
Datafile INVNTORY contains 158 records of mammal species-by-town occurrences.
These records are taken from published scientific literature or from resource
inventory investigations.  GODIN contains 526 species-by-town occurrences that
are taken from Godin (1977).  WNGSNH contains 380 records (species-by-town
occurrences) of observational sightings made by trained field biologists.

     These NH Fish & Game Department datafiles were acquired in DBASE III
format and were subsequently converted to INFO format.  NH Fish & Game standard
species codes were replaced with the ELCODEs used in the rest of our data.  We
populated hexagons and counties according to the decision rule given above: 
any portion of a species-present town polygon within the boundaries of a
hexagon or county resulted in a species-present code for that hexagon or county.

Maine data

     Godin's (1977) data for Maine is augmented by range data supplied by the
Maine Fish and Wildlife Cooperative Research Unit.


                            LITERATURE CITED

Chipman, R. B.  1994.  Distribution, relative abundance, and habitat use by
     small mammals in Vermont.  M.S. Thesis, Univ. of Vermont, Burlington.
     184 pp.

Godin, A. J.  1977.  Wild Mammals of New England.  John Hopkins Univ. Press,
     Baltimore, Maryland.  304 pp.