Mineral contents of salt-lick water and mammal visitation to salt-lick in tropical rainforests of Peninsula Malaysia

Abstract

Salt-licks are considered to be important places for conservation of animals; however, functions of salt-licks were still not well studied especially in Peninsular Malaysia. In order to examine the possible mineral-supplementing function of salt-licks of this area, we compared mineral concentration between the water from salt-licks mainly visited by herbivorous mammals to drink water and nearby streams, possible water sources for mammals at the area. We also analyzed the relationship between mineral concentration and salt-lick visit by mammals. Among analyzed minerals, only the concentrations of sodium and calcium were significantly higher in water from all studied salt-licks than those of nearby streams in both dry and rainy seasons, indicating that mammals could supplement these minerals by drinking salt-lick water. Herbivores most frequently visited the salt-lick with the sodium concentration significantly higher than other salt-licks. In contrast, omnivores and carnivores did not show such tendency. Red muntjac (Muntiacus muntjak) and sambar (Rusa unicolor), the first and second most-frequent visitors of salt-licks (41.7% and 20.8% of the visitation record by mammals, respectively), most frequently visited the salt-lick with highest sodium concentration. On the other hand, Malayan tapir (Tapirus indicus) and white-thighed langur (Presbytis siamensis), the third and fourth most-frequent visitors (15.1% and 5.4%, respectively), frequently visited the salt-lick with lower sodium concentration. The results are consistent with hypotheses that sodium supplementation is an important purpose of salt-lick visit by herbivores, and indicated that other factors which would vary by species, such as social interaction, also affect selection of salt-licks to visit by herbivores.