One measure of the health of a community is the vitality of its main streets. Every summer, Gazette reporters are dispatched to the three Island downtowns to cover the opening of new restaurants and shops and the closing of others, and to talk to merchants about the current business climate.

Rarely, however, do we focus on the owners of properties that line Martha’s Vineyard’s main streets, the people behind the bricks and mortar that in some cases house their own small businesses, in other cases are leased to tenants and in a few instances lie vacant and unkempt.

Who these people are is the focus of a special report in this week’s edition that plumbed publicly available assessors’ records and corporate databases to determine who owns the main streets of Edgartown, Oak Bluffs and Vineyard Haven. All told, they control properties valued at $272 million.

The answer is as varied as the downtowns themselves.

Many of the longtime businesses considered fixtures in Vineyard Haven and Oak Bluffs are in buildings owned by the people who have run them for many years. Much of Edgartown, and some of the other downtowns, is owned by just two sets of landlords: Geno and Barbara Courtney and Benjamin and Brian Hall. A surprisingly small number of properties have changed hands in the last decade, but the new guard of owners have already begun to put their stamp on the Island’s downtowns.

Some 30 years ago, a series in the Gazette chronicled the decline of the Island’s central business districts, recording the exodus of key businesses from the main streets. Today, the Island’s downtowns are full of vibrancy, in part due to proactive efforts by business associations and the towns themselves to create environments that draws shoppers and diners in. But the health of main street is also a function of its property owners, as several people pointed out in interviews for this special report.

With real estate values soaring, property owners have reason to protect their investments by upgrading their properties, but they also have a responsibility to maintain them — or sell them if they cannot.

As one business owner said, “When you buy a property within a community, you belong to something, it’s not just that something belongs to you.”