U.S. Geological Survey, Biological Resource Division's
National Wetlands Research Center and Louisiana Cooperative Fish and Wildlife
Research Unit
Publication_Date: 1999
Title: Predicted Distribution Model Maps
Geospatial_Data_Presentation_Form: Digital
map
Description:
Abstract:
This data set consists of the predicted
distribution of terrestrial vertebrates in Louisiana; it was created in
a GIS modeling process using species habitat association rules in combination
with species geographic range and land cover/use map of Louisiana. The
attributes describe the predicted presence or absence of a species. Range
maps, which rely on the location of specimens, merely convey the geographic
extent of an animal's distribution; they do not include information about
current conditions within the range which may favor or preclude a species
from an area. Habitat features, such as vegetation, can enhance any portrayal
of an animal's distribution despite some limitations (Scott, et al. 1993).
In the GAP Analysis, all of the species are combined to calculate an area's
specific values of species richness, a measure of biodiversity. Beside
GAP Analysis, predicted distribution maps may be used to develop a wide
variety of management or research plans relating to each species or any
combination of terrestrial vertebrates.
Purpose:
The intended purpose of this data set
was to provide information about the current distribution of a species,
filtered by the knowledge of the distribution of its suitable habitat.
Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date:
1999
Currentness_Reference:
Publication Date
Status:
Progress:
Complete
Maintenance_and_Update_Frequency:
No current
plans for updating distribution data, but may be updated as new data becomes
available.
Any downloading and use of these data signifies a user's agreement
to comprehension and compliance of the NWRC Standard Disclaimer. Insure
all portions of metadata are read and clearly understood before using these
data in order to protect both user and NWRC interests. See section 6.3 Distribution
Liablity.
Use_Constraints:
Acknowledgement of the National Wetlands Research Center and the
Louisiana Cooperative Fish and Wildlife Unit as a data source would be
appreciated in products developed from these data, and such acknowledgment
as is standard for citation and legal practices for data source is expected
by users of this data. Sharing new data layers developed directly from
these data would also be appreciated by NWRC staff. Users should be aware
that comparison with other data sets for the same area from other time
periods may be inaccurate due to inconsistencies resulting from changes
in mapping conventions and digital conversions over time. These data are
not legal documents and are not to be used as such. The data set was produced
with the intention of application at the state or eco-region level. The
data provide a course-filter approach to analyses, therefore not every
occurrence of animal or plant habitat is mapped, only large, generalized
distributions are mapped, based on the USGS 1:100,000 mapping scale in
both detail and precision. This data set can be used to provide context
for finer level maps or applications. Appropriate uses include: 1. Statewide
biodiversity planning; 2. Regional and large area resource planning; 3.
Coarse-filter evaluation of potential impacts or benefits of major projects/initiatives
on biodiversity, such as utility or transportation corridors, wilderness
proposals, open space or recreation proposals; 4. Environmental impact assessment
for large projects such as military activities; 5. Education at all levels
for both students and citizens; 6. Estimation of potential economic impacts
from loss of biological resource based activities; 7. Determining relative
amounts of management responsibility for specific biological resources among
land stewards to facilitate cooperative management and planning; 8. Basic
research on regional distributions of plants and animals and to help target
both specific species and geographic areas for needed research. Inappropriate
uses of these data include: 1. Generating specific measurements from the
data finer than the nearest thousand hectares; 2. Establishing exact boundaries
for regulation or acquisition; 3. Establishing definite presence or absence
of any element; 4. Determining abundance, health, or condition of any element;
5. Establishing a measure of accuracy of any other data by comparison with
this data set; 6. Combining these data with any other data finer than 1:100,000
scale for analysis; 7. Use of these data to map small areas (less than thousands
of hectares) typically requiring mapping resolution at 1:24,000 scale and
using aerial photographs or ground surveys; 8. Altering the data in any
way and redistributing it as a GAP product.
The National Wetlands Research Center and the Louisiana Cooperative
Fish and Wildlife Unit would like to acknowledge the following agencies
for their participation in the development of the data set: U.S. Forest Service,
U.S. Army Corps of Engineers-New Orleans, Environmental Protection Agency,
Natural Resources Conservation Service, National Marine Fisheries Service,
U.S. Fish and Wildlife Service, U.S. Geological Survey.
Native_Data_Set_Environment:
The computer operating system platform was Windows NT Grid. Specifically,
processing and data development phases used an installed Windows NT software
package of ARC/INFO (Version 7.1 and 7.2). All GAP coverages are stored
in ARC/INFO format and map layout.
Cross_Reference:
Citation_Information:
Originator:
Lousiana Gap Analysis Project, United States Geological Survey, Biological
Resources Division's, National Wetlands Research Center
Publication_Date: 19980101
Title: Louisiana Gap Analysis Project
Edition: First Geospatial_Data_Representation_Form: document
Publication_Information:
Publication_Place: Lafayette, Louisiana
Publisher:
U.S. Geological Survey Biological Resources Division
Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
Assessing the accuracy of the predicted vertebrate distributions
is subject to many of the same problems as assessing land cover maps, as
well as a host of more serious challenges related to both the behavorial
aspects of species and the logistics of detecting them. The goal was to
produce maps that predict distribution of terrestrial vertebrates and from
that, total species richness and species content with an accuracy of 80%
or higher. No formal accuracy assessment of predicted vertebrate distribution
maps of the Louisiana GAP Project because no set of species occurrence
data, independent of the Louisiana GAP Project was available for comparison.
The closest comparable data set would be the breeding bird survey, but species
detection rates are not known for that survey and the probable vary greatly
among species. The Land Cover map for the Louisiana GAP Project exceeded
the 80% accuracy standard noted. However, some habitat classes were comprised
of highly variable types. In particular, the Agriculture/Pasture type of
the current vegetation classification scheme was problematic for modeling
vertebrates. This type was omitted from all but a few vertebrates' habitat
affinity lists.
Logical_Consistency_Report: Unknown
Completeness_Report:
Distribuiton maps are never finished products, but are continually
updated as new information is gathered. Maps of predicted distributions
of terrestrial vertebrates in Louisiana should be considered as course
depictions of probable range and relative abundance of known suitable habitats
within that range. The number of pixels of occurence within any restricted
geographic range should not be interpreted as an indicator of commonness
or abundance. This first attempt at predicting areas of high species richness
has identified more gaps in our knowledge of vertebrate distribution and
habitat affinities than gaps in protection or biodiversity. The next generation
of GAP Projects requires regional and sub-regional planning to match vegetation
class goals with current level of wildlife-habitat relationships models.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report: Not applicable
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report: Not applicable
Lineage:
Process_Step:
Process_Description:
ARC/INFO coverages were generated for each group (herps (amphibians
and reptiles), birds, and mammals); these coverages include a base map extracted
from the EPA U.S. hexagon map and a linked database containing indicators
of presence or absence within a hex of all terrestrial vertebrates in the
Louisiana GAP Project species list. Distribuiton maps for each species
were combined with three grids and a habitat affinity database to produce
a predicted distribution map. The range map (EPA hex-based) was overlaid
onto the habitat use map to select not only the used habitat cells within
the range of the species but any cell of used habitat forming a contigous
path from the distribution through to the adjacent hexagon. The distribution
maps relied on published compilations of habitat affinities; different compilations
were used for the three groups. Crosswalks were constructed to translate
these habitat characterizations into the Louisiana GAP Project land cover
types. The resulting database files link the Louisiana GAP Project species
lists to the Louisiana GAP Vegetation classes (presence or absence only).
Deviations from published habitat affinities recognized by local experts
were incorporated into habitat models.
Process_Date:
1999
Spatial_Data_Organization_Information:
Indirect_Spatial_Reference: The State of Louisiana
Horizontal_Datum_Name: North American Datum of 1927
Ellipsoid_Name: Clarke 1866
Semi-major_Axis: 6378206.4
Denominator_of_Flattening_Ratio:
294.98
Entity_and_Attribute_Information:
Overview_Description:
Entity_and_Attribute_Overview:
The vertebrate distribution maps consist of two coverages. The first
coverage contains one attribute; the values of the attribute denotes the
presence or absence of a predicted species within an given area. The "1"
grid value represents a positivie affinity, "0" a negative affinity, and
"9" adjacent to a positive affinity. The second coverage contains a set of
attribute which describes the predicted species distribution, the species
scientific and common names, GAP land cover type, hydrologic codes, etc.
The second coverage is the combined grid for all the Louisiana mammals, birds,
and herps species used in the Louisiana GAP Project.
Entity_and_Attribute_Detail_Citation:
Final Report Louisiana GAP Analysis Project - A Geographic Approach
to Planning for Biological Diversity, published by U.S. Geological Survey
Biological Resources Division
Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:
U.S. Geological Survey Biological Resource Division's National Wetlands
Research Center
Contact_Person: Steve Hartley
Contact_Position: Senior Geographer and GIS Analyst
The predicted vertebrate distribution maps created for the Louisiana
GAP Analysis Project.
Distribution_Liability:
Although these data have been processed successfully on a computer
system at the Biological Resource Division, no warranty expressed or implied
is made regarding the accuracy of utility of the data on any other system
or for general or scientific purposes, nor shall the act of distribution
constitute any such warranty. This disclaimer applies both to individual
use of the data and aggregate use with other data. It is strongly recommended
that these data are directly acquired from a Biological Resource Division
server, and not indirectly through other sources which may have changed
the data in some way. It is also strongly recommmended that careful attention
be paid to the contents of the metadata file associated with these data.
The Biological Resource Division shall not be held liable for improper
or incorrect use of the data described and/or contained herein. So, these
data are provided "as is" and without any express or implied warranties
of merchantability and fitness for a particular purpose. Also, use of trade
name or commercial products in this home page is solely for the purpose
of providing specific information, and does not imply recommendation or
endorsement by the U.S. Government. Be aware, as is possible in all government
situations, other constraints may have been required and added since the
compliation and completion of this metadata file.