PARENT SESSION
Oral Session # 68: Soil Ecology I: Communities, Respiration, and Nutrient Cycling.
Presiding: C Rumbaitis-del Rio
Thursday, August 7. 8:00 AM to 11:30 AM, SITCC Meeting Room 106.
Impact of drought on faunal biodiversity and functional aspects of soil in arid environment.
Tripathi, Ghanshyam*,1, Ram, Setha1, Sharma, Brij Mohan1, 1 Department of Zoology JNV University, Jodhpur, Rajasthan, India
ABSTRACT- Impact of drought on faunal biodiversity and functional aspects of soil has been studied in some selected silvipasture systems of arid zone of Jodhpur in India. The silvipasture systems were Prosopis cineraria, Acacia nilotica, Zizyphus nummularia, Capparis decidua and Acacia Senegal based having Cenchrus ciliaris, Cenchrus biflorus, Eleusine compressa or Digitaria marginatus grasses in different combinations. The period from November 2000 to October 2001 was considered non drought year and November 2001 to October 2002 as drought year depending on average rainfall. The drought caused a significant reduction in density of major groups of soil fauna. Populations of Acari, Myriapoda, Isoptera, Coleoptera, Collembola and other arthropods showed about 50% reduction in response to approximately 80% decreased rainfall in the drought year. The drought effect on soil fauna during rainy and winter seasons was more or less similar in all silvipasture systems. Though there were also some season specific minor differences in population reduction in different silvipasture systems, but the range of drought dependant decrease in faunal population never exceeded 33 to 63.95%. Maximum drought effect on Acari was found in P. cineraria field. Likewise, maximum drought effect on Myriapoda, Isoptera and Coleoptera was in A. senegal system. However, maximum effect of drought on Coleoptera and other arthropods was recorded in C. decidua field. In contrast to maximum drought effect, the least effect of drought on Acari was in A. nilotica, Myriapoda in Z. nummularia and other arthropods in A. Senegal based silvipasture field. The population of Coleoptera, Isoptera and Collembola exhibited minimum drought effect in traditional desert pedoecosystem of P. cineraria. This reflects a kind of adaptive association between desert plant and soil fauna. Some soil nutrients significantly increased during drought year. However, there was a substantial reduction in soil respiration and dehyrogenase activity. The present observation suggests that drought decreases faunal diversity and density but this reduction appeared to be silvipasture system specific.
Key words: silvipasture system, arid environment, soil fauna , drought