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In 2005, another comprehensive example of the use of GIS, this time with aerial photography rather than satellite imagery, came to the writer's attention. In this study, a Brown University student's undeergraduate thesis, conditions favoring surival of an increasingly rare wildflower on Block Island, RI are defined and mapped using GIS.


A GIS APPROACH TO PRESERVING A RARE FLOWER HABITAT IN BLOCK ISLAND, RHODE ISLAND

This page will try to reconstruct an innovative application of GIS to a very specific topic. The work reported on was part of a Senior-Honors thesis done by Matthew A. Vadeboncoeur at Brown University who graduated with a Sc.B in Environmental Science in 2003 . His thesis title is Using GIS to prioritize Land for Management in the Conservation of a Rare Species: A Landscape-based Metapopulation Method for Northern Blazing Star on Block Island, RI. His goal was to identify areas on the island of optimal suitability for preservation of the wildflower as an aid to decision making by the citizenry and the Nature Conservancy regarding future land development. A summary of his project is presented on hiswebsite.

Liatris scariosa var. novae-angliae is a beautiful wildflower whose English name is Northern Blazing Star found over much of New England but which is disappearing from Rhode Island. Block Island, RI is still a favored habitat. Two views of this lovely flower are seen below:

A stalk of Liatris scariosa. Individual blooms of Liatris.

The flower favors grasslands and meadows, and at times near swampy growth. Here is a typical habitat on Block Island and a picture showing its occurrence in grassweed growth.

Typical habitat of Liatris in tall grass.

Liatris along a walking path.

The entire state of Rhode Island is shown in this Landsat image. Block Island lies within Long Island Sound about 20 km (12 miles) south of Naragansett Bay.

Rhode Island, with Block Island at the bottom, seen in this Landsat image.

An aerial oblique photo shows the entire island. Beneath that is a map of the island, which is about 11 km (7 miles) long

Aerial view of Block Island.

Map of Block Island.

Block Island is a smaller version of Martha's Vineyard in Massachusetts in that it has permanent residents, residents in summer homes, and many tourists. This view shows much of the island (in winter) including the Great Salt Pond with most homes near shore but some inland.

Panoramic view of Block Island.

The next three pictures help to give a flavor to the setting and scenery of Block Island. Read their captions

Old Harbor Landing.

Typical shore area facing southh towards Long Island Sound.

Summer bathers along the beach.

The material exposed at the cliff in the second picture is stratified to unstratified glacial drift. Block Island is the remnant of a glacial moraine deposited in the Pleistocene. The island's soils are thus derived from transported drift.

As is characteristic of most of southern New England, there has been significant, sometimes drastic, conversion of land use as more people flock to seashore environments for part to full time living. Compare the land use maps for Block Island for 1939 and 1999, a 60 year span.

Land cover map on Block Island, 1939

Land cover for 1999.

As expected, the largest change has been the conversion of natural cover to residential land and associated landscaping. This of course is encroaching on the habitat of the Northern Blazing Star:

House taking up land that is favorable to Blazing Star, a patch of which appears pink in this photo.

Matt Vadeboncouer approached the problem of selecting and recommending parcels of land for limitations on residential use by using a combination of false color aerial photography, maps made by Soil Conservationists, and field work.

False color aerial photo of part of Block Island.

Primary input maps were made using the ESRI ArcInfo GIS system. The first of these digitized a general rating of the Land Protection status as of the start of the project.

Land Cover Protection status.

The second map is a detailed reclassification of land use in the early 2000s made by Vadeboncouer (using 1999 data).

Revised Land cover map for 1999.

Next, a land cover suitability map was generated, in which the highest suitability pertained to favored Blazing Star environments.

Land cover suitability.

Next, a soil classification using earlier work was put into the GIS theme map base.

Soil classification for Block Island.

From this and other data, a soil suitability map was derived in which category 4 indicated soils best for supporting Liatris scariosa; category 3 was also within an acceptable level.

Soil suitability map.

Using appropriate probability functions, a Total Suitability Score was assigned to the cells containing the land parcels.

Total Suitability Score.

From these and other map inputs the final output was a map denoting Conservation Action by Parcels. Those in blue identified land where the island decision makers could choose to limit development in order to better preserve and manage natural conditions including those that protect continued presence of the cherished Blazing Star plants.

Conservation Action Priority map.

The map below is not from Vadeboncouer's study but is a recent one referred to by the developers for managed land use and open space which could eventually be reallocated to human use.

Recent generalized Land Use Map for Block Island.

This study is both a tribute to the capabilities of GIS and to how a college student's work can actually be turned to benefits for one's fellow citizens while maintaining aspects of the natural environment.

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