Factors influencing scavenger guilds and scavenging efficiency in Southwestern Montana

Morgan A. Walker,Maria Uribasterra,Wayne M. Getz,Jason K. Blackburn,Sadie J. Ryan,José Miguel Ponciano,Valpa Asher

doi:10.1038/s41598-021-83426-3

Morgan A. Walker, Maria Uribasterra + Show 5 more

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https://doi.org/10.1038/s41598-021-83426-3

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Abstract

Scavenging of carrion shapes ecological landscapes by influencing scavenger population demography, increasing inter- and intra-specific interactions, and generating ecosystem services such as nutrient cycling and disease moderation. Previous research found the cues promoting, or the constraints limiting, an individual’s propensity or ability to scavenge vary widely, depending on anthropogenic and environmental factors. Here we investigated differences in scavenging patterns in a complex scavenger guild in Southwestern Montana. We used camera traps established at 13 carcass sites to monitor carcass detection, visitation, and consumption times, during 2016–2018 and generalized linear models to explore the influence of carcass characteristics, habitat features, and seasonality, on carcass selection and scavenging efficiency. We found that scavenger species diversity was higher at higher elevations and in grassland habitats. Scavenging efficiency was influenced inter alia by seasonality, distance to water, and elevation. We found that most carcass consumption was via facultative scavengers (bears, wolves, magpies, Corvus spp.) rather than turkey vultures, the only obligate scavengers in the study area. However, growing populations of turkey vultures may lead to increased competition with facultative scavengers over carrion, and could have cascading effects on food webs in this ecosystem.

Highlights

Scavenging of carrion shapes ecological landscapes by influencing scavenger population demography, increasing inter- and intra-specific interactions, and generating ecosystem services such as nutrient cycling and disease moderation
Parameter estimates from this model indicated more scavenger species were present at carcass sites at higher elevations (p = 0.03; Table 2)
The compositions of scavenger guilds worldwide are affected by a host of environmental and anthropogenic factors, including NDVI, human footprint, habitat type, aquatic trophic conditions and s eason[32,33,34,35,36]

Summary

Introduction

Scavenging of carrion shapes ecological landscapes by influencing scavenger population demography, increasing inter- and intra-specific interactions, and generating ecosystem services such as nutrient cycling and disease moderation. The possible factors influencing carrion use include the characteristics of the carcass itself[16,21] (species, spatio-temporal location, disease status or cause of death), the ecology of the scavenging animal (species, body size, sociality, inter- and intra-specific dynamics), and abiotic factors[18,19] (season, weather, habitat). This study provides insight into the biotic and abiotic factors influencing the diversity of vertebrate scavengers and their behavior and scavenging efficiency in southwestern Montana, USA. This northern temperate ecosystem supports one of the few intact carnivore guilds in North America[27] but is a system shown to be highly

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