Data from: Estimating densities and spatial distribution of a commensal primate species, the long-tailed macaque (Macaca fascicularis)

Knowledge about distribution of primate species and their densities is
crucial for conservation and management. However, such information is
often lacking or anecdotal, even for seemingly abundant species.
Long-tailed macaques (Macaca fascicularis) are distributed across
Southeast Asia and recognized by the IUCN SSC PSG as both widespread and
rapidly declining. Precise local density and abundance data are scarce
across their range. To provide density and abundance estimates for a
long-tailed macaque population we conducted line transect distance
sampling throughout Baluran National Park (250km2), East Java, Indonesia
covering all habitats. Long-tailed macaque density was 41.4ind/km2 (95%CI
23.04 – 74.39), with an estimated abundance of 10350 individuals (95%CI
5760 – 18598). A density of 41.4ind/km2 is lower than previous estimates
for other sites in Java. Species distribution and habitat suitability
analysis revealed a macaque preference for areas close to or on roads and
trails, invasive acacia and/or native savannah. Long-tailed macaques were
provisioned with human food by commuters and tourists along roads and
trails, probably structuring their distribution/habitat use. To evaluate
if long-tailed-macaques have been overestimated for years, we also
conducted a non-random point distance sampling survey according to macaque
presence restricted to roads and trails. This survey provided density and
abundance results much higher than the line transect distance sampling
survey. Our study provides much needed baseline data for this species.
Baluran National Park management and management in other areas can use
these results to create informed management decisions regarding
long-tailed macaques. We recommend conducting systematic surveys of
long-tailed macaques throughout their range, and possibly reassessing
conservation status, and conservation and management measures for
long-tailed macaques.