The present study was carried out in apond at Nal village located at North-West of Bikaner District of Rajasthanduring September 2010 to November 2011. The main objective of the study was toknow the impact of abiotic factors on gastropods population. During the study three species of gastropods Gabbia orcula, Digoniostoma pulchella and Indoplanorbis exustus were recorded. Among these Digoniostoma pulchella show significantcorrelation with pH, Gabbia orcula showhigh significant correlation with water temperature and significant correlationwith Electrical Conductivity and Total Dissolved Solid of soil. Indoplanorbis exustus significantlycorrelated with pH of water.
Total gastropods population show significantcorrelation with EC and TDS of soil. Desert waters always have high electrolyteconcenteration, but this study revealed that gastropods species in desert pondundergo some adaptations and even survive during dry period of pond. Keywords:gastropods, pond, species, abiotic factor, desertINTRODUCTIONPhylummollusca occupy diverse group of animals having different shape, sizes, habitand habitat (Subba Rao, 1993). Around 8,765 species of fresh water molluscsavailable in all over world, of which 284 species are reported from India andadjacent countries.
Among them, 171 species are of class gastropods(Punithavela and Raghunathan, 2006) found in India. This is one of theimportant components of aquatic food chain, acting as an energy flow bridge inaquatic ecosystem because of detritus feeding habits. The ultimate extirpationand extinction of molluscan populations have profound effects on the widerecosystem (Sharma et al. 2010).
Freshwater molluscs are the bioindicators offreshwater pollution (Harman, 1974).Freshwater gastropods species have some economical and biological importance.Economy of North-West of state partially based on dairy farming, and snailsalso acts as intermediate hosts for Platyhelminthes parasites of animals,birds, men, fishes and other trematode infection (Kandel, 1954). This causedmorbidity and mortality in livestock and creates economic burdens on farmers.Paststudies on molluscs in Jodhpur wascarried out by Ray& Mukherjee (1969), Rathore& Bohra (1987). In Bikaner region Singh et al. (2007) and Rathore et al.
(2007) studied growth rate insome gastropods and its ecological aspects. Khatri et al. (2007) studied the incidence of trematode infestation insnail Indoplanorbis exustus. Singh et al. (2010) studied the ecology anddiversity of prosobranch snails of Indian desert. Khanam (2012), Khanam &Singh (2012 a, b) studied the ecology, population density and biometery of prosobranchsnails of desert region. Sharma et al.
(2013) studied seasonal variation in populationdensity of gastropods.Theaim of the study was to know the impact of abiotic factors on gastropodspopulation in desert pond in District Bikaner of Rajasthan. MATERIALS AND METHODSTUDY AREARajasthanthe Desert state, lies between 2303′ to 30012′ Nlatitudes and 69030′ to 78017′ E longitudes, havinglargest area (132,139 mi2) among all Indian states. Bikaner, a part north-westdesert region having geographical location 28o N and 75o 17’E,MSL 228 m. The present study was carried out from September 2010 to November2011, in Nal pond located at E 73012? and N 280 4? and MSL 229m in BikanerDistrict of Rajasthan, covering an area of 2300 m2. During the studyperiod water depth of the pond was 6.
09 meter. The pond remains dry in duringsummer months May and June every year. It is situated in low land, and receivesrain water from surrounding areas. For Physico-Chemical analysis of watersample APHA-AWWA-WPCF (1981) and Saxena (2001) were followed. Sampling wasconducted monthly as well as seasonally between 7 A.M. to 2 P.M.
Forgastropod identification soil samples were collected from three location of thepond with the help of quadrate having dimensions 25 × 20 × 10 cm and sievedmesh size 2 mm, the methods prescribed by Saxena (2001) and Sharma et al. (2013). For qualitative analysis,stereo microscope and for identification bull lens and standard keys (SubbaRao, 1989) were followed. Populationdensity was calculated by formulae prescribed by Saxena (2001).