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Requests for Natural Diversity Data Base State-listed Species Reviews

DEEP’s Natural Diversity Data Base (NDDB) program performs hundreds of environmental reviews each year to determine the impact of proposed development projects on state-listed species and to help landowners conserve the state’s biodiversity. State agencies are required to ensure that any activity authorized, funded, or performed by a state agency does not threaten the continued existence of endangered or threatened species. Other applicants for certain state and local permits may also be required to consult with the NDDB as part of the permit process. The NDDB Request for Review process is designed to assist in complying with the State Endangered Species Act, but is not a substitute for actual on-site surveys that may be required for environmental impact assessment.

Maps have been developed to serve as a pre-screening tool to help applicants determine if there is a potential impact to state-listed species. Shaded areas ("blobs") on the maps depict approximate locations of state- and federal-listed species and significant natural communities. If a project falls within a shaded area the applicant must submit a Request for Natural Diversity Data Base (NDDB) State Listed Species Review Form (DEEP-APP-007), and all required attachments, including maps, to the NDDB for further review. When consulting the NDDB maps, please consider the entire area impacted by a project, including any potential runoff or other associated disturbance, not just the project's immediate footprint. A new mapping format is being employed, starting December 2012, that more accurately models important riparian and aquatic areas and eliminates the need for the upstream and downstream searches required in previous versions. Please read instructions carefully as they have changed.

The DEEP will provide recommendations for avoiding impacts to state-listed species. If we cannot make a determination based on the information provided, you may be asked to have biological surveys conducted at the site. Not all land use choices will impact the particular species that is present. Often, minor modifications to a proposed plan can alleviate conflicts with state-listed species. For this reason, applicants should apply early in the planning stages of a project.

Local planning and zoning boards are the primary authority over private development in their towns. The DEEP encourages municipal agents to use the environmental review process and to consider impacts to state-listed species when making land use decisions.


View Maps by Town

Northern Long-eared Bat Map

NDDB Freshwater Mussel Map

Instructions for Review of NDDB Freshwater Mussel Map

Request for Natural Diversity Data Base (NDDB) State Listed Species Review Form*

Word; PDF, DEEP-APP-007, 8 Pages, Rev. 03/20/20; Instructions, DEEP-INST-007, 11 Pages, Rev. 03/20/20

Frequently Asked Questions

*Be sure to read the instructions carefully. Incomplete forms or missing attachments will result in the request being rejected.

Forms should be sent to:

Central Permit Processing Unit
Department of Energy and Environmental Protection
79 Elm St.
Hartford CT 06106-5127

Or emailed to:

Please do not send duplicate copies of requests. Choose either to email the request or to send a hard copy, but do not send both.

Content last updated August 18, 2020.