Data from: Carcass predictability but not domestic pet introduction affects functional response of scavenger assemblage in urbanised habitats

Urbanisation alters species richness and composition, but studies of
urbanisation effects on ecological functions have often quantified
variation in functional traits and changes in functional diversity rather
than measuring directly how ecological functions vary between rural and
urban assemblages. Consuming dead animal matter and recycling its
nutrients stabilizes and structures food webs and therefore represents a
key component of ecosystem functioning. Introduction of free-ranging
domestic pet animals adds additional scavenger species to urban habitats,
and increased predictability of carcass resources produced by human
activities characterizes urban habitats. Here, we investigate the effect
of urbanisation on the composition of diurnal and nocturnal scavenger
assemblages and on the ecological function of carcass removal by using a
carcass placement experiment in Swiss urban and adjacent rural habitats.
While diurnal and nocturnal scavenger assemblages changed considerably
from rural to urban areas by comprising particularly more domestic cats in
the latter, carrion consumption rate did not differ between the two
habitats. Predictability of carcass occurrence increased carrion
consumption rate in both, urban and rural habitats but mainly native
scavengers and not introduced domestic pets responded to the repeated
placements. These results suggest that urbanisation shapes scavenger
assemblage compositions without affecting their ecological function. The
mechanism is likely due to a behavioural change of native scavengers in
response to the occurrence of domestic pets resulting in functional
plasticity of urban scavenger assemblages. The functional plasticity might
be facilitated by the increased carcass predictability and additional
anthropogenic food resources in urban habitats exploited by nutritionally
flexible native scavenger species.