Ascertain territory overlap among neighboring gibbon groups for the studied species

Ascertain the extent of territory overlap between neighboring groups of northern grey gibbons (Hylobates funereus) at Danum Valley Conservation Area and southern yellow-cheeked crested gibbons (Nomascus gabriellae) at Jahoo, given that territory sizes for both species are not well-known and overlap is unclear, to better interpret spatial heterogeneity in detected calling activity.

Background

While mapping detections across autonomous recording units, the authors observed substantial within-site variation in calling activity. They note that duet structure and calling rates can vary by pair and can be influenced by ecological and social factors, complicating interpretation of spatial patterns.

A critical ecological parameter affecting these patterns—the degree of territory overlap among neighboring groups—remains unclear for both studied species, limiting the ability to relate call densities to group distributions and territories.