Ecology, Environment and Conservation Paper

DYNAMICS OF GRASSHOPPER COMMUNITY ON A GRASSLAND ECOSYSTEM AND INFLUENCE OF ABIOTIC FACTORS ON POPULATION

C.M. Muralidharan

Abstract

The study conducted during 2002-04 in a grassland ecosystem (Banni grassland, lies between latitude of 23° I 9' to 23° 52 N and east longitude of 68'56' to 70° 32, covers an area of 2900 km2 is a part of Kachchh district) revealed the presence of 17 grasshoppers species which were active from July to March with peak period of activity in the month of December. No species was observed from April to June.Among the different species, Phlaeoba cinc-talis and Recognizable Taxonomic Unit (RTU —unidentified specimen) were most dominant.The activity of the species viz. Chrotogonus oxypterus, Sphingonotus sayignyi, Heteracris pulchra and Acroty/us sp.were very meager The seasonal abundance mainly depends on the prevailing weather conditions.The rainfall and maximum temperature had a negative effect on abundance (non-significant).1n general. the incidence of grasshoppers started after the onset of monsoon and the insufficient and delayed monsoon greatly hampered the emergence and abundance of the most grasshopper species. The total grasshopper population irrespective of species was at a higher level, during !ate monsoon period i.e. October to January matching with the plenty of food material.Thus, temperature and rainfall as individual weather factor did not exert significant influence on abundance of grasshoppers directly, but relative humidity, which is a result of both of these factors, showed a significant positive correlation .Hence, from the present study, it can be stated that the rainfall and rainy days play a key role in abundance, as these parameters indirectly helped in the availability of food and has a delayed effect on population