Temporal interactions and moon illumination effect on mammals in a tropical semievergreen forest of Manas National Park, Assam, India

• Published in: Biotropica Vol. 53; no. 3; pp. 831 - 845
• Main Authors: Bhatt, Urjit, Singh Adhikari, Bhupendra, Habib, Bilal, Lyngdoh, Salvador
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01-05-2021
• Subjects: Behavioural responses; Carnivores; Carnivorous animals; Dimensions; Diurnal; Dominant species; facilitation; Foraging; Lunar rhythm; Mammals; mesopredator release; Moon; moon phase; Moon phases; National parks; Nocturnal; Predator-prey interactions; Predators; Prey; Records; suppression; Sympatric populations; Tropical climate; tropical forest; Tropical forests; India
• ISSN: 0006-3606; 1744-7429
• DOI: 10.1111/btp.12917

Species interactions play a vital role in structuring mammalian communities by stimulating behavioral responses in varied niche dimensions that affect sympatric associations and predator–prey relationships. We determined temporal overlap and effects of the moon cycle on dominant and sub‐dominant mammalian assemblages in Manas National Park, India. A total of 36 species were captured, with 24,865 independent records over 11,294 trap nights. We collected 1,130 photographs of five large‐ and medium‐sized carnivores and 1,541 photographs of 12 small carnivores. Fifty‐one percent of records were detected during diurnal period, followed by 38% in nocturnal phase, and 11% during twilight. Small carnivores such as Prionailurus bengalensis and Viverridae spp. were strictly nocturnal, whereas Martes flavigula and Herpestidae spp. were diurnal. Medium‐sized carnivores were either nocturnal (Neofelis nebulosa) or diurnal (Cuon alpinus), whereas large‐sized carnivores (Panthera tigris, Panthera pardus, and Ursus thibetanus) were cathemeral. A high degree of temporal overlap (>0.75) was found between most sympatric carnivores with distinct activity peaks, while a low overlap (<0.50) was observed between different body‐sized carnivores. Viverrids’ activity was negatively correlated (r = −0.44, p < 0.01) with lunar cycles, perhaps to increase foraging efficiency or as an anti‐predator strategy. Large prey (μ = 133.23°) and small prey (μ = 131.35°) activity were high during brighter nights due to better visual detection in detecting or avoiding predators. Dominant species activity was least affected by the lunar cycle among forest‐dependent mammals, whereas subdominant species activity was either lunarphobic or lunarphilic. The study demonstrates the use of passive camera traps in understanding the behavioral rhythms of tropical mammals.
We investigated the activity patterns of tropical mammals in terms of effects of lunar cycles as manifestations of interactions amongst dominant species over subdominant counterparts. Increased activity under brighter conditions (visual acuity hypothesis), as well as an increased activity under darker conditions (dominant predator avoidance hypothesis), was tested. We found that temporal segregation facilitates the coexistence of the tropical carnivore community. Predators synchronize their activities with those of their potential prey. Moonlight strongly influenced the foraging patterns of prey species. The activity of both large‐ and small‐sized prey was higher during the full moon nights. Temporal partitioning within and amongst trophic levels play an important role in facilitating carnivore coexistence.