Which one of the following approaches does not belong to ex situ conservation strategy?

Wildlife sanctuaries

The correct answer is Option (2) → Wildlife sanctuaries 

Ex-situ conservation involves removing threatened animals and plants from their natural habitat and placing them in specialized facilities or locations where they can be protected and given special care. Examples of ex-situ conservation methods include zoological parks, botanical gardens, wildlife safari parks, gene banks, germplasm banks, and seed banks.In recent years ex situ conservation has advanced beyond keeping threatened species in enclosures. Now gametes of threatened species can be preserved in viable and fertile condition for long periods using cryopreservation techniques, eggs can be fertilised in vitro, and plants can be propagated using tissue culture methods. Seeds of different genetic strains of commercially important plants can be kept for long periods in seed banks.

In situ conservation strategies involve the protection and conservation of species and ecosystems within their natural habitats. In-situ conservation is a set of methods aimed at preserving all living species, particularly wild and endangered ones, within their natural habitats and environments. This approach involves the protection and management of biodiversity in its original ecosystem. Examples of in-situ conservation strategies include biosphere reserves, national parks, wildlife sanctuaries,sacred groves, biodiversity hotspots  and other protected areas that aim to maintain the ecological integrity and diversity of the region. These designated areas serve as havens for various plant and animal species, ensuring their survival and contributing to the overall conservation of biodiversity.