PT  - JOURNAL ARTICLE
AU  - Kempel, Anne
AU  - Allan, Eric
AU  - Gossner, Martin M.
AU  - Jochum, Malte
AU  - Wardle, David A.
TI  - Plant-invertebrate interactions across a forested retrogressive chronosequence
AID  - 10.1101/2022.03.30.486383
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2022.03.30.486383
4099  - http://biorxiv.org/content/early/2022/03/31/2022.03.30.486383.short
4100  - http://biorxiv.org/content/early/2022/03/31/2022.03.30.486383.full
AB  - In the long-term absence of disturbance, ecosystems often enter a decline or retrogressive phase which leads to reductions in primary productivity, plant biomass, nutrient cycling and foliar quality. However, the consequences of ecosystem retrogression for higher trophic levels such as herbivores and predators, are less clear. Using a post-fire forested island-chronosequence across which retrogression occurs, we show that nutrient availability strongly controls invertebrate herbivore biomass when predators are few, but that there is a switch from bottom-up to top-down control when predators are common. This trophic flip in herbivore control probably arises because invertebrate predators respond to alternative energy channels from the adjacent aquatic matrix, which were independent of plant biomass. Our results suggest that effects of nutrient limitation, following ecosystem retrogression, on trophic cascades are modified by independent variation in predator abundance, which requires a more holistic approach to trophic ecology to better understand herbivore effects on plant communities.Competing Interest StatementThe authors have declared no competing interest.