The islets of Adralaid and Puhtulaid were taken under protection for the first time in 1939, the prohibited botanical-zoological area of Virtsu-Laelatu-Puhtu was founded in 1957 and Puhtu-Laelatu Nature Reserve was first founded in 2003.
The wooded meadow of Laelatu is considered one of the most species-rich communities in Europe with more than 400 species of vascular plants and 30 species of moss growing there. In addition, 2/3 of all the orchid species growing in Estonia have been found in the wooded meadow.
The most noteworthy community is the deciduous forest with the majority of linden and oak trees on Puhtu peninsula a.k.a. the islet of Puhtu where more than 60 different tree and shrub species grow. Puhtu peninsula is also one of the most known areas for observing migrating birds in Estonia. Millions of arctic water birds, for example long-tailed ducks, common and velvet scoters, red- and black-throated loons, transit the narrow migration corridor of the strait of Suur Väin during spring migration. Stopovers during migration are made there also by greater scaups, smews, whooper, tundra swans and many others.
Many species of wild birds are also permanently living on the nature reserve. The coast and the islets are amongst others a habitat for the dunlin, ruff, smew and black-tailed godwit, the shady reedbeds of the bay are good nesting spots for the Eurasian bittern, water rail, spotted crake and western marsh harrier, forests near the shore are a home for the white-tailed eagle.
Puhtu-Laelatu Nature Reserve is one of the most thoroughly researched areas in Estonia. There are biology stations that are linked to study and research work in the University of Tartu and the Estonian University of Life Sciences. Basic researches with worldwide value have also been made in the nature reserve.
There are internationally important areas in the nature reserve: the Ramsar site of Puhtu-Laelatu-Nehatu, both the Väinameri area of conservation and hosting birds as well as the Väinameri Sea that is an area of the Helsinki Convention but also an important bird area (IBA) belong to the Natura 2000 network.