Abstract: The decay of organic matter is a complex process with many co-existing species involved. Many studies in recent years focused on the species diversity of dead plant organic matter like dead wood and litter. From these studies, we learned that fungi and bacteria communities are highly diverse and specialized with respect to their hosts and hence are the main drivers of the decay process. However, our knowledge about the microbial diversity of dead animals (carrion) and its driver is limited. Here we used a large real-world experiment and exposed 10 different carcass species under various environmental conditions. We asked whether carcass host characteristics (phylogeny, trophic mode, mass, decay stage) are more important for diversity than the abiotic environment (season/temperature, elevation) as shown from dead wood.
Gamma diversity was higher for fungi than for bacteria. Fungi and bacteria gamma diversity were highest on Red Fox. The number of fungal species was driven by environment (temperature and elevation) and decay stage but not by carcass host species. The number of bacteria species was mainly driven by the decay stage. These effects were also found when focusing on beta diversity. We found no significant relationship between fungi community versus carcass phylogenetic distance; the effect was significant but weak for bacteria. The low level of specialization of fungi and bacteria to their hosts was supported by a low specialization index. These results are in strong contrast to findings observed in other necromass systems like dead wood. A low level of specialization and the stronger influence of the environment on microbial diversity might be attributed to the rapid turnover and temporal limited access to resources caused by competing animal organisms like mammals and insects.
