Due to its unique and diverse habitats, the Caspian Sea has become home to many rare species of flora and fauna. In connection with an increase of the Caspian Sea level during the period of 1994 – 1996, habitats for rare species of aquatic vegetation have drastically decreased. This can be attributed to a general lack of seeding material in newly formed coastal lagoons and water bodies.
Many rare and endemic plant species of Russia are associated with the intra-zonal communities of the Volga delta and riparian forests of the Samur River delta as well as to the Sarykum barkhan which is a unique refuge for flora adapted to the loose sands of the ancient Central Asian Deserts. The principal limiting factors to successful establishment of plant species are hydrological imbalances within the surrounding deltas, water pollution, and various land reclamation activities. The water level change within the Caspian Sea is an indirect reason for which plants may not get established. This affects aquatic plants of the Volga delta, such as: Aldrovanda veiculosa and Nelumbo caspica. About 11 plant species are found in the Samur River delta, of which some form a unique liana forest that dates back to the Tertiary period.