Any reason why birds are not many at Man Sagar lake as compared to their diversity and number about a decade ago? Loss of aquatic vegetation while desilting had been executed by the Government and later by the PPPmode. The vegetation got uprooted. Nearly 150 truck loads of vegetation had then been fetched from Bharatpur and introduced in this lake. Results were heartening – birds started reporting in numbers. The fish contractor had introduced two invasive species in the lake – Tilapiya and Mangur, for more gains.
The contract was got cancelled. Culling stopped. Fish population multiplied to an extent that the fish became stronger competitor to birds, for the aquatic vegetation, micro- organisms etc. They remain competitors but here the fish assumed lion’s share. To over come such an imbalanced situation we undertook a survey which revealed the species present in the lake (June 2016).
Mr. Bijendra Singh, a Naturalist at the Keoladeo National Park, Bharatpur, having field experience of more than 35 years in identifying flora and fauna, led the survey team, which included:
Mr. Govind Yadav, who has been volunteering at this lake for about two decades to examine its birds, Mr. Nishant Nath Shukla, who has experience of around eight years at this lake, and Mr. Mukesh Khatri, a new entrant in conservation. Arundo donax, Scirpus tuberosus, Polygonum glabrum, Paspaldium punctatum, Vetiveria zizanioides, Sesbania sp.,
Ipomoea carnea, Paspalum distichum, Cynadon dactylon, Heliotropium indicum, Achyranthes aspera, Phyla nodiflora, Physalis minima, Abutilon indicum, Xanthium strumrium, Laggera aurtia, Cassia occidentalis, Croton boneplandianum, Dicanthium annulatum and Alternanthera paronychioides. The quantity of such species was difficult to be assessed yet it was estimated that it was too small as compared to carrying capacity of this 1.5 sq km area of the lake.
It was discussed that these plants would not suffice needs of feed for ducks which require floating vegetation, which was found to be totally missing over the water surface of this lake. The aquatic vegetation plays consequential role in all water bodies and also contributes to its natural maintenance. It helps generate micro-organisms in water which are staple diet of birds, swimming and diving ducks, waders etc.
Aquatic plants are plants that have adapted to living in aquatic environments, referred to as hydrophytes or macrophytes. These plants require special adaptations for living submerged in water, or at the water’s surface. They include tiny floating leaves. They are a common component of wetlands.