Cadaver decomposition islands around animal carcasses can facilitate establishment of various plant life. Facultative scavengers have great potential for endozoochory, and often aggregate around carcasses. Hence, they may disperse plant seeds that they ingest across the landscape towards cadaver decomposition islands. Here, we demonstrate this novel mechanism along a gradient of wild tundra reindeer carcasses. First, we show that the spatial distribution of scavenger faeces (birds and foxes) was concentrated around carcasses. Second, faeces of the predominant scavengers (corvids) commonly contained viable seeds of crowberry, a keystone species of the alpine tundra with predominantly vegetative reproduction. We suggest that cadaver decomposition islands function as endpoints for directed endozoochory by scavengers. Such a mechanism could be especially beneficial for species that rely on small-scale disturbances in soil and vegetation, such as several Nordic berry-producing species with cryptic generative reproduction.

On August of 2016, 323 wild tundra reindeer (Rangifer tarandus) were struck by lightning on southern Norway, killing virtually the entire herd.  During fieldwork for parallel studies in 2017, we opportunistically registered the occurrence and behavior of avian species on carcasses from this mass die-off. Several passerine species other than corvids were observed actively foraging on arthropods that are typically associated with carcass decomposition, such as blowfly (Calliphoridae sp.) adults and larvae. In decreasing order of abundance, five passerine species (excluding corvids) were observed taking arthropods at the site: the Meadow Pipit (Anthus pratensis, least concern), Northern Wheatear (Oenanthe oenanthe, least concern), Common ReedBunting(Emberizaschoeniclus, near threatened), Bluethroat (Lusciniasvecica, near threatened), and Lapland Bunting (Calcarius lapponicus, vulnerable) (status according to IUCN). Previous studies on these passerines have documented a very sharp decline in their abundance in Norway. The insect abundance associated with ungulate carcasses may provide an important food resource for such species, and may impact their life history, fitness, and eventually population dynamics. This mechanism, however, has received almost no attention from the scientific community, and warrants further investigation.