FAUNAL DIVERSITY ON ARID LANDS CAVES IN THE SONORAN DESERT, MEXICO

Biospeleological studies in Mexico are scarce, particularly ones to explain the interaction between species in caves, as well as the relationship with their physical environment. The Sonoran Desert is located in the northwest of Mexico and southwest of USA, and most of this desert belong to the state of Sonora. There is a shortage of knowledge of the biospeleology from Sonora, representing only 1.2% of Mexico speleological studies. The objective of this work was to determine biotic factors that have a role in the fauna diversity in two karst caves in the central region of Sonora. In order to accomplish the objective, we surveyed the Cueva de la Mariana and Cueva El Tigre for a year (April 2015 - April 2016). Two sensors were placed in each cave in the transition zone and deep zone of the caves to determine the temperature and relative humidity; also the fauna (vertebrate and invertebrates) was collected and preserved through different methods. The climate of the caves was different, with a mean annual temperature of 26.5 °C and 52% annual relative humidity for Cueva de la Mariana and for Cueva El Tigre was 29.3 °C and 67%, respectively. The fauna found in both caves were represented by 23 orders, 38 families, 51 genera and 52 species. This cave community depends of the guano produced by seven species of bats, being the Mexican free-tailed bat (Molossidae: Tadarida brasiliensis) the most important, with a population of half of a million in Cueva de la Mariana and a million individuals in Cueva El Tigre in summer. The alteration on elimination of the bat populations inside both caves can produce local extinction of 80% of the species registered. This is the first biospeleological study on arid lands caves from Mexico.