Beginning with Habitat


Land Use Ordinance Tools

1. Introduction | 2. Wildlife Habitat Overlay District | 3. Transfer of Development Rights | 4. Open Space Impact Fees | 5. Conservation Subdivision Ordinance | 6. Land Use Ordinance Performance Standards

Hessel's HairstreakConservation Subdivision Ordinance


Subdivision ordinances are a common regulatory tool among most Maine towns. When a division of land meets the state definition of a subdivision (generally the creation of 3 or more lots within a 5-year period, see Title 30-A M.R.S.A. 4401), locally adopted subdivision ordinances typically dictate the number of units that can be placed on the land based on parcel acreage (residential density), and the ordinances set a variety of performance standards including minimum lots sizes, road frontage and sideline setback requirements, etc. Many towns have adopted local subdivision ordinances that allow "open space" approaches to subdivision design. The intent of the open space subdivision approach (often referred to as "clustering") is to create a compact development that establishes protected green space through the development process. This green space is often owned by the subdivision homeowners association and may include neighborhood trails and provide some habitat benefit, but more often this land's primary value is as a buffer between neighboring developments.

From a habitat conservation perspective, however, most typical open space subdivisions provide limited value. Many of the open space subdivision ordinances crafted in the 1980's and 1990's simply established a fixed percentage of land required to be set aside that may have varied depending on the designated land use zone. The requirement of open space set-asides was typically written in a way that provided little guidance or direction to the developer regarding what types of land should be protected, and what the objectives were in terms of overall town open space protection goals. Over time, towns began to realize the limited benefits provided by many of the early open space subdivisions once they were built. The open space land set aside in these projects was usually the unbuildable wetlands and slopes located in random pockets throughout the project. Many municipal open space subdivision ordinances have now been revised to require that the dedicated open space be tied to community values identified in local open space plans or comprehensive plans. Several towns have also required that wetland and other sensitive acreage be subtracted from allowed development density calculations (see net residential density) and required that the designated open space calculations be based on a percentage of the remaining buildable acreage.

More recently, communities have started to adopt the "conservation" subdivision approach. This enhanced approach to the open space subdivision process is designed to go one step further in terms of encouraging development projects that take into consideration the surrounding landscape and do not simply focus on the specific project parcel. As you will see in the attached example, Falmouth has indentified six defined priorities for land to be set aside in the subdivision process. These priorities include Beginning with Habitat topics such as landscape connectivity (both for wildlife and human use in the form of trail connections), retention of large unfragmented blocks (requiring dedicated open space to abut existing open space), and habitat for rare species. By defining these conservation land priorities in the ordinance, the town is in a better position to negotiate just how future development will fit into its rural landscape and maintain town-wide landscape-level habitat benefits.

How This Ordinance Works

The Falmouth approach, like the wildlife habitat overlay district, creates an overlay district. In Falmouth's case, this district covers most if not all rural districts in the town (those outside of the designated growth zone) and, unlike the wildlife habitat overlay ordinance that regulates based on "disturbance", requires that any new subdivisions choose an approach of either "Conservation", or "Country Estate Lot" subdivisions. Under the first option, the applicant is required to set aside a given amount of conservation land based on a percentage of the net residential acreage. To be accepted, the conservation lands must be screened against certain conservation priorities set by the town and based on identified concerns in the town's comprehensive plan and open space plan. The ordinance also establishes a specific 4-step design process that each subdivision project must complete prior to final review. Alternatively, a developer can opt to follow the "County Estate Lot" approach. Under this alternative scenario, the number of possible lots that can be expected based on parcel acreage is cut significantly (8-acre density requirement). The Town of Freeport has taken a similar approach. In Freeport, applicants can either opt for an open space approach to subdivision or they are limited to one unit per 5-acres.

A Word of Caution!: Down zoning, or increasing the minimum lot size requirement is typically controversial and may not be the best approach for a municipality if one of the local goals is to protect unfragmented habitat. A requirement for larger lot sizes may result in less homes within a given area, but the homes become more spread out often resulting in significantly more "edge" habitat and less potential for "interior" habitat associated with unfragmented blocks (refer to Beginning with Habitat's Our Wildlife Legacy, page 12, for a further discussion of "edge effect"). This approach can actually contribute to sprawl by leap frogging and further decentralizing development. If a town is to pursue this approach, it is important to consider what larger lots, with longer roads and driveways will look like on the landscape.

For the purposes of this document, the Falmouth ordinance has not been included in its entirety. Standard subdivision design and performance sections that do not have direct habitat implications have been omitted. The complete text can be found on the Town of Falmouth's web-site (

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