Super-scavengers: Vertebrates outperform invertebrates and microbes at
removing carrion from a tropical forest
Abstract
Scavenging by vertebrates is an important ecosystem service as they are
known to remove carrion more efficiently than other taxa. How long would
carrion persist bereft of vertebrate scavengers? Our study addresses
this question in a forested landscape, by comparing carrion utilization
by vertebrate scavengers, invertebrates, and microbes (decomposers). To
understand carrion removal, we used experimental placement of chicken
carcasses in a dry deciduous forest near Panna Tiger Reserve, Madhya
Pradesh, India. Carcasses were placed under different treatment
conditions (vertebrate scavenging, invertebrate scavenging, microbial
decomposition and control to account for moisture loss), by
experimentally excluding other scavengers. The daily rate of carcass
utilization and proportion of carrion biomass remaining differed between
treatments. Vertebrates consumed carcasses at the highest rates,
removing 83% of carcass biomass in one day (CI 95%), followed by
invertebrates (7.3%) and microbes (3.9%). Additionally, desiccation
accounted for another 3.6% weight loss per day. The study showed
drastic differences in carrion removal rates between taxa, indicating
the irreplaceable role of vertebrates in the scavenging community of
tropical forests, without whom carcasses would persist over prolonged
periods. Our results support earlier studies that found overwhelming
influence of vertebrate scavengers on carrion removal compared to other
scavenging guilds.