The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008
74
http://www.odyssey.ursus.maine.edu/gisweb/gisabout.html).
Definitions can change rapidly and they vary according to who
is giving them. The definitions of the early 1990s were
functional in nature. They focused on what a GIS could do and
what it would produce. Now definitions tend to address issues
like “information strategies” and adding values to data. The
range of views of GIS has increased over the last few years, in
response to the expansion of the market for GIS and the
applications to which it has been applied (Heywood et al,
1998).
1.3 The Role of Geographic Information Systems (GIS)
When the habitat requirements of a species includes several
factors, the information about habitat requirements may be
combined by computer maps of each required habitat
characteristic, using geographic information systems. This
allows us to see the habitat patches as perceived by the species.
In various case studies, we used this approach to model
metapopulations of threatened species.
Current GIS applications in conservation biology and wildlife
management include various aspects of habitat description,
delineation and monitoring. Conservation biologists and
wildlife managers are concerned with questions that involve
predicting the future of endangered and threatened species
(Akçakaya, 1992). Such questions include:
• Is it better to prohibit hunting or to provide more habitat
for African elephants?
• Is captive breeding and réintroduction to natural habitat
patches a viable strategy for conserving black-footed ferrets? If
so, is it better to reintroduce 100 black-footed ferrets to one
habitat patch or 50 each to two habitat patches?
• Is it worthwhile to relocate endangered helmeted
honeyeaters from their current populations to empty habitat
patches to spread the risk of local extinctions?
• Is it better to preserve one large fragment of old-growth
forest, or several smaller fragments of the same total area?
• Is it better to add another habitat patch to the nature reserve
system, or enhance habitat corridors to increase dispersal among
existing patches?
To use GIS to determine the spatial structure with this approach,
first it is necessary to distinguish the habitat characteristics
important for the species. That can be done by collecting habitat
and species occurrence data at a large number of locations in the
landscape. The data then may be analyzed with multiple
regression, which gives a function (called the habitat suitability
function) that links the habitat characteristics to the suitability
of the habitat. In the case of the helmeted honeyeater for
example, the variables of this function will be the presence of
ground water, density of Eucalyptus trees, and the amount of
decortication of their bark
(http://www.ramas.com/gisworld.htm).
1.4 Applications of GIS technology 2
GIS are now used extensively in government, academic, non
profit and business for a wide range of environmental resource
analysis and landuse planning applications. GIS technology
employs computer software to link tabular databases to map
graphics, allowing users to quickly visualize their data. This can
be in the form of generating maps, on-line queries, producing
reports, or performing spatial analysis
(http://www.sara.nysed.gov/pubs/gis/sevencon.htm)
2 See Appendix 2
2. THE MODEL
Preparing data for Animal Movement is relatively “easy”. The
program can directly utilize Point Shape files, which can import
point data from delimited text, dBase files, SQL databases, and
many CAD and GIS file structures. Each model consists of
several elements:
1) A transforming surface - a GIS layer based on a single
environmental feature such as elevation, streams, roads,
etc.;
2) A weighting protocol - weights are assigned to each
element on the transforming surface based on a
preconceived concept on the ecological impact of that
feature on animal dispersal;
3) A cost surface - a surface created by the GIS that defines
each pixel on the transforming surface based on it’s
cumulative weight (cost) from a chosen starting point like
a population center, to a specific endpoint; and
4) A dispersal path—a route drawn across the cost surface
based on choosing the lowest cumulative cost to move
between two specified points on that surface.
Digital databases to be used in the models include digital
elevation model (DEM), digital line graph (DLG), vegetation
(based on Soil Conservation Service DLG data), and landuse
boundaries
(http://www.absc.usgs.gov/glba/gistools/Anim_Mov_UseMe.pd
f; http://www.ncgia.ucsb.edu/conf/SANTA_FE_CD-
ROM/sf_papers/gillian_bowser/ncgia2.html).
2.1 Main Constraints and Problems 3 with the Current
Use of GIS
(Bretas, http://www.idrc.ca/books/focus/766/bretas.html)
2.1.1 Cost
Costs are currently the main constraint to the use of GIS.
Software is relatively expensive in relation to the budgets.
Expansion of GIS use will probably decrease its cost. In the
meantime, a compromise would be to use available shareware,
or to have a software tailored for use in control programs by a
nonprofit organization.
2.1.2 Adequate Training
There exists at present a lack of trained personal. The new
windowed interfaces, however, are easier to use and will speed
up the process of training. Computing skills are useful in the
labour market; consequently, staff from control programs
should be willing to be trained.
2.1.3 GIGO (Garbage in, Garbage out)
GIS is not a tool designed to increase the quality of data.
Frequently, much of the data collected is not used. GIS use
could lead to a relaxation in data collection and consolidation. It
is necessary to review all the steps in the information flow to
guarantee quality and adequacy.
2.1.4 Misinformation and Misinterpretation * •
3 Some other factors driving the Environmental Industry
(http://www.esri .com/industries/environment/trends. html)
• Economic Uncertainty
• Pollution Prevention
• Cost and Services
• Federal Markets
• Commercial Markets
• Project Cost, Length, and Size
• Maturation
