A swath of the former Riddell’s Bay Golf Course has officially become a nature reserve, according to a government notice.

A total of 16.6 acres on the southwestern portion of the land has been designated a nature reserve under a protected land agreement, signed by Walter Roban, the Minister of Home Affairs, on October 31.

The notice stated that the designation would “allow for the establishment and preservation of the land as a Nature Reserve in perpetuity wherein the land will be reserved principally for plants and habitats for local wildlife by restricting actions which can be carried out within the designated area”.

An even larger swath of land at the property covering 49.5 acres of the former golf course is subject to a conservation management plan.

The two lots make up the Riddell’s Bay Gardens and Nature Reserve, which is open to the public and includes walking trails and gardens.

A spokeswoman for Castile Holdings, the company that owns and manages the site, said last year that more than 2,000 trees had been planted at a cost of $1 million while work had also been carried out to remove invasive species.

Another 23 acres, a quarter of the site, has been divided into 18 plots of land which are being sold to buyers who want to build homes.

Mr Roban also signed off on the redesignation of 3.4 acres of land on White Crest Hill in Smith’s as an Open Space Reserve.

The designation will restrict development in the area to “site works and accessory structures which are ancillary to the enjoyment of the land as open space”.

The change is linked to a proposal to develop 13 residential plots on the property.

White Crest Hill, once known as Catchment Hill, housed a large water catchment built in the 1930s for the former Castle Harbour Hotel.

The disused and partly overgrown catchment is surrounded by woodland largely untouched since the 1920s.

A 2011 Special Development Order, which turned the area around Tucker’s Point into a battleground for conservationists, gave approval for up to 38 homes on 21.38 acres of White Crest Hill.

But representatives for the developer said a lower-density approach with more conservation space had been adopted.