Composition and species diversity of small mammals in the hilly tracts of southeastern Rajasthan

The Aravalli range diagonally bisects the state of Rajasthan and this oldest Archaean rock formation is also spread in southern and southeastern Rajasthan. The latter zone is an conglomeration of Aravallis, Vindhyans and Deccan trap and it has undergone a change in landuse pattern, from forest to irrigated crop land, during recent years. Studies were taken up in this biologically interesting hilly tract to investigate the spatial diversity of small mammals as practically no information exists on this aspect. Small mammals were trapped in 35 habitats at 11 locations during 1997-99 and 386 individuals belonging to 15 species were collected in 5210 trap days. On an overall basis, the house shrew, Suncus murinus was found to be the most abundant small mammal in all habitats at all localities. Another commensal mammal, the house rat, Rattus rattus predominated in crop fields along with the mesic species like Millardia meltada, Golunda ellioti and Bandicota bengalensis. However, the typical faunistic element of hills, the rock rat, Cremnomys cutchicus occurred in low numbers in the Vindhyan scrap and Deccan trap due to presence of cracks and crevices which are its preferred ecological niche. Six mice species preferred the Vindhyan scrap as 62 per cent of them occurred in this rock formation. Among the four rock types, Aravallis, Vindhyan scrap, Vindhyan plains and Deccan trap; the Vindhyans were the most occupied as well as species rich rock type. Among the habitats, cropfields and scrubland were most diversified (α diversity 3.17 and 2.66 respectively) and species rich habitats. The impact of transformation of forests into irrigated crop field is evident due to a significantly higher frequency of occurrence of commensal small mammals in croplands apparently due to relatively superior soil moisture regime, food resource and shelter. Resumen: La sierra Aravalli disecta diagonalmente al estado de Rajasthan; esta Antigua formación rocosa del Arqueano también se extiende en el sur y sudeste de Rajasthan. Esta última zona es una conglomeración de trapps de Aravallis, Vindhyans y Deccan y durante años recientes ha sufrido un cambio en el patrón de uso del suelo, pasando de ser bosque a ser tierras agrícolas con irrigación. Se emprendieron estudios en esta región de lomeríos biológicamente interesante para investigar la diversidad especial de mamíferos pequeños fueron capturados en 35 hábitats distribuidos en 11 localidades durante 1997-99, y se recolectaron 386 individuos pertenecientes a 15 especies en 5210 días-trampa. En terminus generales, se encontró que la musaraña doméstica, Sincus murinus, es el mamífero pequeño más abundante en todos los habitats de todas las localidades. Otro mamífero comensal, la rata doméstica, Rattus rattus predominó en campos de cultivo junto con especies mésicas tales como Millardia meltada, Golunda ellioti y Bandicota bengalensis. Sin embargo, el elemento faunístico típico de las Colinas, la rata de la roca, Cremnomys cutchincus estuvo presente con números bajos en el escarpe de Vindhyan y en el trapps de Deccan debido a la presencia de grietas y hendeduras, las cuales son su nicho ecológico preferido. Seis especies de ratones prefirieron el escarpe de Vindhyan, ya que 62 por ciento de ellos estuvieron presentes en esta formación rocosa. Entre los cuatro tipos de roca, Aravallis, escarpe de Vindhyan, planicies de Vindhyan y trapps de 26 SPECIES DIVERSITY OF SMALL MAMMALS