Biodiversity in Indian Tropical Grazing Lands

Abstract

The grazing land ecosystems in Indian tropics can be recognized as Steppe formation under semi-arid climate, Dry savanna dominating central and eastern parts of Rajasthan (with 500 mm/a rainfall and 6-8 months dry spell), Shrub savanna in Deccan plateau, and Arundinella – Themeda tall savanna on wet slopes of low to medium elevations in the north India at the borders of the tropics. Among these, the Shrub savanna of Deccan plateau are rich in herbaceous and ligneous biodiversity. This contribution describes status of biodiversity in these grazing land ecosystems and growing threats to biodiversity in the post-liberalization economy. Evidently, during the past two decades, the alarmingly high neglect of ethno-scientific principles and incentive of a market economy, besides the conventional pressure of sedentary and migratory graziers, burning and agricultural extension have resulted in decline of phytodiversity, both in composition and herbage quality, leading to loss of faunal diversity and alteration in ecosystem functioning. Niches of livestock-friendly forage species like Dichanthium, Bothriochloa, Cenchrus and Chrysopogon have been occupied by non-palatable species, such as, Heteropogon contortus (L.) Beauv. ex Roemer & Schultes and Themeda quadrivalvis (L.) Kuntze, and weedy flora like Agrostis, Aerva, Eragrostis and Euphorbia. At places, these grazing land ecosystems have been used for development of human settlements and commercial orchards. In Protected Areas like Kanha National Park in Madhya Pradesh, the rich nutritious herbage sites are fully occupied by non-palatable species Saccharum sponteneum L. in particular, thus, posing a threat of decline of foraging resources for swamp deer (Rucervus duvaucelii G. Cuvier). The Great Indian Bustard (Ardeotis nigriceps Vigors) conservation areas have deteriorated rapidly due to overgrazing by Blackbuck (Antilope cervicapra L.). At sites, growth of bushes and deformed coppices of tree species have resulted in increased population of predators like fox (Volpes vulpes) that are danger to eggs and chicks of bustard. The “pockmark” sites, such as, leftover quarrying sites have been turned into market use (industrial areas), fragmenting the continuity of faunal diversity sites. It is suggested that survey of grazing lands should be continued at selected locations on long-term basis as done for silvicultural operations (using protected and marked preservation plots) in forestry. Habitat alteration activities, especially affecting RET species, must be regulated. Establishing a network of local people and experts for regular monitoring of migratory herds and wild fauna like Great Indian Burtard would help greatly in conservation of biodiversity and RET species in particular, of the tropical grazing lands at ecosystem level.