Rain forest understorey ferns facilitate tree seedling survival under animal non-trophic stress
Article first published online: 7 MAR 2012
© 2012 International Association for Vegetation Science
Journal of Vegetation Science
Volume 23, Issue 5, pages 847–857, October 2012
How to Cite
Song, G.-Z. M., Yates, D. J., Doley, D. (2012), Rain forest understorey ferns facilitate tree seedling survival under animal non-trophic stress. Journal of Vegetation Science, 23: 847–857. doi: 10.1111/j.1654-1103.2012.01398.x
- Issue published online: 4 SEP 2012
- Article first published online: 7 MAR 2012
- Manuscript Accepted: 14 JAN 2012
- Manuscript Received: 1 APR 2011
- Rainforest CRC, Australia
- Oppenheimer Memorial Trust (Johannesburg, South Africa)
- Australian rain forest;
- Litter stress;
- Plant–plant interaction;
- Species trait;
- Vertebrate disturbance
Although forest ecosystems harbour many animal species and animal non-trophic effects are as ubiquitous as trophic effects, few studies have examined animal non-trophic effects on plant–plant interactions. Can animal non-trophic behaviour influence plant–plant interactions and thus, change the net effect of interactions, especially those between understorey vegetation and tree seedlings? How do the species traits of understorey vegetation and animals contribute to their interactions with seedlings?
The Main Range National Park, southeast Queensland, Australia.
Seedling survival related to the cover of understorey vegetation (mainly the fern Lastreopsis decomposita) was monitored in a 0.5-m wide and 200-m long transect for 2 yrs. Ten per cent of the transect was caged to estimate the effects of non-trophic disturbances from two pheasant-size, ground-dwelling birds (Menura alberti and Alectura lathami) for 1 yr. Two hundred plastic tags (5 × 5 cm) were placed in the transect to quantify bird disturbance and litter input.
The negative effects of the fern understorey on seedlings were increased light deficits, greater risk of herbivory and wilting or rotting; the positive effects were reduced uprooting and litter smothering due to abiotic and bird disturbances. Notably, the exclusion of bird activity changed the net effect of the fern understorey from positive to neutral, and seedling survival was positively correlated with fern cover.
The net effect of plant-plant interactions is subject to change when additional species are involved. In addition to trophic effects, non-trophic effects are such that they can change interactions between plants. A conceptual model of species traits contributing to interactions is presented.