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Fire and herbivores alter vegetation structure and function. Future fire
activity is predicted to increase, and quantifying changes in vegetation
communities arising from post-fire herbivory is needed to better manage
natural environments. We investigated the effects of post-fire herbivory
on understory plant communities in a coastal eucalypt forest in
south-eastern Australia. We quantified herbivore activity, understory
plant diversity, and dominant plant morphology following a wildfire in
2017 using two sizes of exclosures. Statistical analysis incorporated the
effect of exclusion treatments, time since fire (TSF), and the effect of a
previous prescribed burn. Exclusion treatments altered herbivore activity,
but TSF did not. Herbivory reduced plant species richness, diversity and
evenness and promoted the dominance of the most abundant plants within the
understory. Increasing TSF reduced community diversity and evenness and
influenced morphological changes to the dominant understory plant species,
increasing size and dead material while decreasing abundance. We found the
legacy effects of a previous prescribed burn had no effect on herbivores
or vegetation within our study. Foraging by large herbivores resulted in a
depauperate vegetation community. As post-fire herbivory can alter
vegetation communities, we postulate that management burning practices may
exacerbate herbivore impacts. Future fire management strategies to
minimise herbivore-mediated alterations to understory vegetation could
include aggregating management burns into larger fire sizes or linking
fire management with herbivore management. Restricting herbivore access
following fire (planned or otherwise) can encourage a more diverse and
species-rich understory plant community. Future research should aim to
determine how vegetation change from post-fire herbivory contributes to
future fire risk.
112 views reported since publication in 2021.