136794 - Temporal partitioning of activity.pdf (3.51 MB)
Temporal partitioning of activity: rising and falling top-predator abundance triggers community-wide shifts in diel activity
journal contribution
posted on 2023-05-20, 09:48 authored by Calum CunninghamCalum Cunningham, Vincent ScoleriVincent Scoleri, Christopher JohnsonChristopher Johnson, Leon BarmutaLeon Barmuta, Menna JonesMenna JonesTop predators cause avoidance behaviours in competitors and prey, which can lead to niche partitioning and facilitate coexistence. We investigate changes in partitioning of the temporal niche in a mammalian community in response to both the rapid decline in abundance of a top predator and its rapid increase, produced by two concurrent natural experiments: 1) the severe decline of the Tasmanian devil due to a transmissible cancer, and 2) the introduction of Tasmanian devils to an island, with subsequent population increase. We focus on devils, two mesopredators and three prey species, allowing us to examine niche partitioning in the context of intra- and inter-specific competition, and predator-prey interactions. The most consistent shift in temporal activity occurred in devils themselves, which were active earlier in the night at high densities, presumably because of heightened intraspecific competition. When devils were rare, their closest competitor, the spotted-tailed quoll, increased activity in the early part of the night, resulting in increased overlap with the devil's temporal niche and suggesting release from interference competition. The invasive feral cat, another mesopredator, did not shift its temporal activity in response to either decreasing or increasing devil densities. Shifts in temporal activity of the major prey species of devils were stronger in response to rising than to falling devil densities. We infer that the costs associated with not avoiding predators when their density is rising (i.e. death) are higher than the costs of continuing to adopt avoidance behaviours as predator densities fall (i.e. loss of foraging opportunity), so rising predator densities may trigger more rapid shifts. The rapid changes in devil abundance provide a unique framework to test how the non-lethal effects of top predators affect community-wide partitioning of temporal niches, revealing that this top predator has an important but varied influence on the diel activity of other species.
Funding
Australian Research Council
History
Publication title
EcographyVolume
42Issue
12Pagination
2157-2168ISSN
0906-7590Department/School
School of Natural SciencesPublisher
Blackwell MunksgaardPlace of publication
35 Norre Sogade, Po Box 2148, Copenhagen, Denmark, Dk-1016Rights statement
© 2019 The Authors. Licensed under Creative Commons Attribution 3.0 Unported (CC BY 3.0) http://creativecommons.org/licenses/by/3.0/Repository Status
- Open