Planners have rejected proposals to build 19 retirement bungalows on Marton Moss saying it would constitute "significant over-development".
The outline application for land between Midgeland Road and Kitty Lane was a resubmission of plans after a previous bid for 23 homes was withdrawn.
Town hall planning officers had recommended refusal which was backed by members of the council's planning committee.
Resident Barbara Fish, who addressed a meeting of the committee, said Kitty Lane was not wide enough to accommodate additional traffic which would also cause a danger to the many horse riders who use the lanes on the Moss.
She said: "The land that is now the Moss is gradually being eroded from the St Annes end by housing, and should this application succeed it will open the floodgates for developers and we will see an end to this rural part of Blackpool."
In their report to the committee, planning officers said the scheme was "considered to constitute significant over-development of the site given the nature of the surrounding area."
The report added: "It would have a fundamental, irrevocable and detrimental impact upon the character of the area and the quality of the Marton Moss Conservation Area as a heritage asset.
"It is not anticipated that the site could adequately accommodate the
quantum of development sought.
"The applicant has failed to demonstrate that biodiversity would be adequately safeguarded."