basins of rivers entering estuaries, can be affected by these activities (Simenstad et al 1997). Oil spills are a potential major threat to habitats on the west coasts of Vancouver and the Queen Charlotte Islands, since tankers from Alaska routinely transit the offshore waters, en route to refineries in the State of Washington (Waldichuk, 1990).
In this paper we describe some recent advances in methodology useful for integrated coastal zone management in B. C. Technical staff responsible for management of coastal environments and habitats need tools to assist them in their task to keep track of changes in coastal regions. In particular, quantitative data on habitat loss and gain are required when monitoring estuarine habitat restoration using vegetation transplants or other habitat recovery techniques (Levings 1995, 1996). Some of the most important techniques involve the rapidly evolving field of Geographic Information Systems (GIS). Although GIS has been used widely to assist in terrestrial habitat management for wildlife (Burrough 1986), its application to coastal zone management in our region has been limited. There is a great potential to use GIS to organize, analyze, and present basic data required by fish habitat managers under the fish habitat management policy of the Department of Fisheries and Oceans (DFO, 1986). These data include:
a. what is the location of the habitat, usually in relation to planned industrial activity?
b. what is the area of the habitat?
c. what is the ecological value of the habitat?
d. how much of this habitat will be lost if an industrial activity is permitted?
e. if a habitat restoration or compensation project has been conducted, did it meet the prescribed target in terms of area?
Habitat managers need to keep track of relatively small bits of habitat, particularly in the intertidal zone and in shallow water (< 20 m) since these nearshore areas are where most of the land use changes (diking, port development, urbanization) are occurring. For seagrass habitat, for example, as a general policy about 100 m2
is the minimum area of concern in our region. This requires mapping at a much larger scale than needed for broad scale planning or oil spill contingency plans - other agencies in our region have developed habitat maps for the latter purposes (e.g. Howes and Wainwright 1993). It is necessary to keep track of the cumulative total of small habitats in particular areas, in order to avoid insidious losses of the estuarine environment that have occurred on many coastlines (Odum 1970). New technology that enables rapid and accurate quantification of these habitat measurements, in a cost effective manner, is of obvious direct use for integrated coastal zone managers.
B. Data Availability
In the past two decades there has been very rapid growth in data banks and technical report literature on coastal areas, especially reports written and maps produced by government agencies and private consultants. Many of these data are difficult to locate for use in decision making since they do not enter the usual scientific literature data bases such as the Aquatic Scientific and Fisheries Abstract service. In order to improve their availability it is necessary to launch specific searches for the information. Once found, the awareness of the information can be enhanced through publication of bibliographies listing reports, data, and maps. As an example, we have recently published an annotated bibliography for fish habitat maps in the Strait of Georgia (Lessard et al 1996a). We have also created an Internet home page with this information
(http://www.ios.bc.ca/ios/mehsd/coast).
C. Spatial Positioning
Decisions on habitat are particularly sensitive to locations relative to legal, zoning, and ecological boundaries. Given the high economic and ecological values involved, it is important to make sure that positions are accurate. There are no published standards available on this matter for work in the coastal zone. Based on recommendations from the manufacturer and B. C. Surveys and Resource Mapping Branch, if at least 180 readings are taken with a Differential Global Positioning System (DGPS) instrument (Trimble Navigation, Pathfinder Basic Plus), point measurements have an error of < 5 m. This is probably sufficiently accurate for most decisions. We have not made comparisons of locating habitats using conventional surveying methods such as laser transits.
