GIS Methodologies for Developing Conservation Strategies Part 7 doc

140 Lambert and Carr

hoped that analysis and mapping of a corridor network would assist Central

American governments and nongovernmental organizations in the identification

and prioritization of key areas for preservation and protection. A spin-off benefit

of this project is a preliminary GIS database of the entire Central American

isthmus which has been shared with many government agencies in Central

America, other scientists, land use planners, and conservation organizations

that are also working to preserve and manage the natural treasures of Central

America.

Database Development and Evaluation

The GIS database development component of the corridor study was designed

as a two-phase process to complement the preliminary and more detailed analy￾sis efforts. Initially, due to limited funding, only the data layers that were re￾quired to support the preliminary corridor potential study would be developed.

Subsequently, with additional funding, the team would develop more compre￾hensive databases to support more detailed study of specific potential linkages.

The logical first step for the team was the identification and collection of

existing digital data sources that could be obtained inexpensively. Unfortunately,

the team found that, although there were several GIS projects being conducted

in Central America, the GIS databases these projects were creating varied widely

in scale, projection, content, theme, date, and digital format. There were appar￾ently no regional efforts being made to develop a standardized database for the

entire isthmus.

Fortunately, an affordable source for base map features called the Digital

Chart of the World (DCW) had just become available (ESRI 1993). The DCW

provides base map features such as roads, hydrography, political boundaries,

population centers, and topography (at 1,000-foot intervals) for the entire world.

This database was created by digitizing the U.S. Defense Mapping Agency’s

1:1,000,000 scale Operational Navigation Chart map series. A license for the

ARC/INFO version of the DCW database was purchased from Environmental

Systems Research Institute, Inc. (ESRI) in the fall of 1992. At first, the team was

skeptical about the suitability of this database because the scale of the source

data limits typical spatial accuracy to approximately plus/minus one kilometer.

However, the alternative of digitizing base map features for all of Central

America motivated the team to test the database. After working with the data￾base, the team found the DCW’s spatial and attribute accuracy to be quite

adequate and appropriate for the objectives of this preliminary, multinational

study.

An important point to make about the DCW is that its availability allowed

The Paseo Pantera Project 141

the planning team to concentrate its own limited funding on the generation of

the new databases required for analysis and on the preliminary design of the

corridor rather than on the digitizing of base map feature layers. However, a

second important advantage to using the DCW was that it allowed the team to

get off to a quick start. All too often in the past, ambitious GIS managers have

promoted this technology successfully to their cautious colleagues, only to find

themselves explaining later, to now impatient colleagues, why it takes so long to

demonstrate any substantial results from a technology that was supposed to save

time and increase productivity. Being aware of this potential scenario, and the

fact that GIS technology and methods are still new to many of the participants in

the Paseo Pantera project (especially some of the cooperating institutions in

Central America), the corridor planning team recognized the need to demon￾strate the utility of GIS as quickly as possible to its sponsors. The DCW made this

possible. Although the DCW will not be appropriate for all projects, this project

demonstrates the potential value of the DCW to those faced with continental￾scale environmental problems and dwindling budgets.

The second step in the initial phase of GIS database development involved

the team in a process of weighing the costs of producing each new data layer

against the relative potential contribution of that data to the preliminary analysis.

Several new data layers were subsequently developed, including boundaries

of existing and proposed protected areas; forested/deforested areas; potential

biological communities based on the Holdridge system of life zone classifications

(Holdridge 1967); population density and major population centers; and areas

occupied by indigenous populations. The GIS data layers listed above represent

the conversion of more than seventy-five source maps to digital format. It is

important to point out that these data sets represent only a preliminary effort,

limited by modest funding, and that the study team recognizes the need for

much more detailed information as it enters the second phase of this study.

Once the databases described above were developed, the team explored ways

to use them to analyze the potential for a continuous biological corridor. The

following four criteria were selected for use in the model based on the evaluation

of the available data: (1) size of protected areas, (2) uniform national designation

of protected areas, (3) population densities, and (4) forested/deforested areas.

The protected areas were divided into two size classes—large (50,000 hectares

and greater) and small (less than 50,000 hectares). These classes were based on

suggestions for minimum core area size in Noss (1991).

Because of the variations in terminology used by each country to classify its

protected areas, the team developed a set of “uniform national designations”

based on current management practices. These designations were: national park

(or equivalent), anthropological reserve, extractive reserve, private reserve, and

proposed reserve. “Uniform national designation” was selected as an important

criterion because the management practices used in each protected area deter-