Density and microhabitat use of Bengal slow loris in primary forest and non-native plantation forest.

The extent of planted forests has greatly increased in the tropics, but their conservation value while assumed to be low, is largely unknown. We compared the density and microhabitat selection of a nocturnal arboreal primate, the Bengal slow loris (Nycticebus bengalensis), in mostly undisturbed, evergreen tropical forest to those in 15-18 year old Acacia/Leucaena plantations with significant secondary regrowth, and <15 year old plantations with little regrowth. Based on estimates derived from distance sampling, loris densities in older plantations were nearly identical to primary forest (4.26 vs. 4.00 lorises per square kilometer), although encounter rates were three times higher in the older plantations probably owing to the lower detection probability in the more complex vegetation of the primary forest. The mean density estimate for the younger plantation was one-third of the above habitats (1.27 lorises per square kilometer), although not statistically different. Lorises tended to use larger diameter and taller trees, with a greater crown depth than randomly sampled trees, and tended to avoid habitats with sparsely crowned trees. The older plantations had trees with lower basal area and shorter stems than the primary forest; however, the older plantations contained higher densities of Bauhinia lianas, a commonly eaten food source and did not contain the red giant flying squirrel (Petaurista petaurista), a potential competitor. Although it is unknown whether the Bengal slow loris would persist without the presence of primary forest in the landscape, we suggest that older plantations have conservation value for at least selected species and as such, could be better managed to increase this value.