Massachusetts Department of Fish and Game

Environmentalists have a special affinity for maps. Whether terrestrial or marine, the environment and its ills are tied to a geography that can be expressed in a rectilinear scale.

As science progresses, so do the maps. Witness the latest effort from the state of Massachusetts.

To ensure that largely private efforts to set aside land do the most public good, the state Department of Fish and Game has just unveiled the latest and most elaborate version of its online BioMap, complete with instructions on how to use it.

With both climate change and suburbanization built into the state’s biological future, the map, as its developers write in their introduction, “provides a framework for protection and stewardship of those lands and waters that are most important for conserving biological diversity.”

There are two potential audiences for the map, said Henry Woolsey, the program manager for the state’s Natural Heritage and Endangered Species Program. If you are part of a town, or a regional or a state-level agency, and set out to do land conservation, he said, the BioMap suggests what lands you should acquire.

“The Commonwealth of Massachusetts is spending $50 million a year on open space protection,” he said. “This BioMap is a major driver of where it gets invested.”

While that may be its primary use, it can also raise a warning flag for developers who may be eying a site that is the natural home of a threatened species.

What is more, the map, which went live on the Web on Thursday evening, gives a sense of how shoreline ecosystems and the marine and terrestrial life that depends on them will move should sea levels rise as much as a meter and a half as a result of climate change, Mr. Woolsey said.

It has about 500 different layers of information, 400 of them related to individual species that state officials have identified as threatened by extinction. Many of the rest deal with identifying varieties of ecosystems, from the salt marshes of the coast to the limestone wetlands of the Berkshires.

“We have about 80 or so different types of communities — salt marshes, level bogs, pitch pine scrub oak barrens,” Mr. Woolsey said. “Other levels deal with individual birds, like whippoorwills and warblers, as well as butterflies and moths.”

Yet the Massachusetts map is hardly the only graphic call to arms available on the Internet. For some years, the World Resources Institute has used maps and graphics to underline its research findings, most recently with a map designed to help Ugandan farmers decide where to concentrate their livestock infrastructure.

And the Washington-based Environmental Working Group has for years been working on perfecting the use of maps as polemics, from its immensely detailed map-based report on “Who Owns The West” to agricultural subsidy maps.

As more and more groups find ways to integrate their data with Google Maps, the cartographic products can only get richer.