Identification and chemical composition analysis of salt licks used by Sumatran Elephants Elephas maximus sumatranus in Tangkahan, Indonesia

Abstract

A crucial aspect of successful conservation strategies is the identification of critical aspects of local habitats required for species preservation in a given region, such as salt licks. Tangkahan is adjacent to the Gunung Leuser National Park in North Sumatra, Indonesia. The park collaborates with the Indonesia Conservation Response Unit using captive Sumatran Elephants Elephas maximus sumatranus for forest patrols, mitigation of human-elephant negative interactions, public education, and ecotourism in the area. An initial study on the daily activities of captive Sumatran Elephants revealed their search for salt licks, which are essential for maintaining their optimal daily sodium intake. Information on salt licks in Tangkahan is limited and deserves further investigation. Ethical clearance is deemed unnecessary, as the research employs a non-invasive approach, exclusively observing the natural behaviors, and daily activities of elephants. The well-being of the elephants takes precedence over invasive technologies, with continuous monitoring ensuring their care throughout the research process. The study utilizes a descriptive-analytic methodology, tracking the daily movements of Sumatran Elephants to identify the locations of salt licks in the area. Four salt licks—Encepan-1, Encepan-2, Namo Cencen, and Hot Spring—were identified by participating in the elephants’ territorial exploration. Although the salt licks were located adjacently, Encepan-1 was most frequently visited by the elephants. The salt licks were characterized as waterholes containing Na+ (Sodium ion) rich waters from springs. However, according to the atomic absorption spectrophotometry (AAS) method, the sodium concentration in these salt licks ranged 34–55 ppm, which is estimated to be insufficient for the physiological requirements of the elephants. Therefore, further investigations are needed to explore other complementary salt licks and the incidence of geophagy to support the mineral needs of Sumatran Elephants in the Tangkahan region.