Effects of elk and bison carcasses on soil microbial communities and ecosystem functions in Yellowstone, USA

Abstract

Carrion is long recognized as important to scavengers. How carrion may affect soil microbial biodiversity and ecosystem processes in natural systems is comparatively unknown, but is important for the intersection of vertebrate food webs, below‐ground processes and ecological heterogeneity. We assessed in situ soil and plant responses to wolf‐killed mammal carrion in Yellowstone National Park, USA. Bison and elk carcasses increased soil respiration and vegetation nutrient concentration and the carcasses contain altered bacterial and fungal communities compared to control plots. The ‘fingerprints’ of soil microbial taxa associated with bison compared to elk carcasses differed considerably and taxa are found dependent upon abiotic gradients and soil properties. We found evidence that soil microbial community changes associated with carcasses may not be as generalizable as previously thought, which is important for a mechanistic understanding of the links between carrion and soil heterogeneity and potentially for applications in forensic science. This work demonstrates the importance of carrion studies in natural systems. Our findings show that carrion creates distinct ecological patterns that contribute to both above‐ and below‐ground biological heterogeneity, linking carrion distribution dynamics with soil microbial biodiversity and ecosystem functions.

A methodological roadmap to quantify animal‐vectored spatial ecosystem subsidies

“…egesta, excreta, carcasses) as well as the magnitude of nutrient influx into the surrounding environment through in situ measurement of various soil and plant properties (e.g., pH, soil texture, plant community composition, soil and plant nutrient content) at sites of animal activity (i.e. see Bump et al, 2009, Risch et al 2020. Finally, given that stable isotope that come from animal tissues and excreta are isotopically enriched compared to their diet, enriched plant and soil materials surrounding the deposition can indicate deposition and use of animal-vectorized subsidies (Bump et al 2009a).…”

“…These sites can be compared to measurements collected in randomly selected points, which may serve as a control treatment. Assessing the plant community composition and cover will help identify whether killing behaviour of predators leads to changes in plant composition, while soil samples collected below carcasses can be used to compare microbial activity and nutrient availability between carcass and control sites (Metcalf et al 2016;Risch et al 2020). Both total soil and plant nutrient concentration as well as enriched δ 15 N in plant and soil samples can be used to identify and quantify the impact of this animal vectorized subsidy (Bump et al 2009b;Holtgrieve et al 2009;Barton et al 2016).…”

“…egesta, excreta, carcasses) as well as the magnitude of nutrient influx into the surrounding environment through in situ measurement of various soil and plant properties (e.g. pH, soil texture, plant community composition, soil and plant nutrient content) at sites of animal activity (see Bump, Webster, et al, 2009;Risch et al, 2020). When experimental analyses cannot be conducted, the total biomass of nutrients deposited can be calculated using previously determined chemical analysis of various deposited materials (Brodie & McIntyre, 2019;Flueck, 2009;Holdo et al, 2011).…”

Landscapes shaped from the top down: predicting cascading predator effects on spatial biogeochemistry

“…But predators influence rates of prey mortality and where prey die on the landscape, thereby determining the quantity and spatial distribution of decomposing carcasses in ecosystems (Bump et al 2009a). Predation can thus increase small‐scale heterogeneity by concentrating nutrients and physical disturbance at kill sites, altering local biogeochemistry and community composition of plants and soil organisms (Holtgrieve et al 2009, Barton et al 2013a, b2013b, Risch et al 2020).…”

Comparative Decomposition of Humans and Pigs: Soil Biogeochemistry, Microbial Activity and Metabolomic Profiles

“…Because of challenges in obtaining, and/or restrictions on use of, human cadavers, many forensic taphonomy studies use animal carcasses as proxies. Therefore, much of our knowledge of decomposition timing and processes have relied on various animal carcasses, including pigs ( Hopkins et al, 2000 ; Wilson et al, 2007 ; Howard et al, 2010 ; Meyer et al, 2013 ; Pechal et al, 2013 ; Forger et al, 2019 ; Matuszewski et al, 2020 ), mice ( Metcalf et al, 2013 ; Lauber et al, 2014 ), rats ( Carter et al, 2010 ), dogs ( Reed, 1958 ), and other vertebrate wildlife ( Towne, 2000 ; Parmenter and MacMahon, 2009 ; Macdonald et al, 2014 ; Risch et al, 2020 ). Domestic pigs ( Sus scrofa ) are often cited as the most useful analog for humans in decomposition studies, given their physiological and anatomical similarities, including mass, hairiness, and pigmentation ( Schoenly et al, 2007 ; Matuszewski et al, 2020 ).…”