Assessing the role of a mammalian frugivorous species on seed germination potential depends on study design: A case study using wild samango monkeys

Stringer, S.D.; Hill, R.A.; Swanepoel, L.; Dalrymple, S.E.; Linden, B.; Koyama, N.F.

Abstract

Frugivory and seed dispersal contribute to the maintenance and regeneration of plant communities through transportation of seeds and enhancing germination through seed processing mechanisms. The effects of mammalian frugivore seed processing mechanisms on seed germination are generally well studied and the potential benefits include disinhibition (pulp removal), scarification (gut passage) and fertilisation (from faecal matrix). Nevertheless, our review found that there is bias in the comparative treatments included in seed dispersal studies through exclusion of entire fruit control groups and the fertiliser effect. In this study, we aimed to address such bias by using ecologically relevant experiments to investigate the influence of seed processing mechanisms on germination probability and latency of selected locally abundant fleshy-fruiting plant species, common in the diet of samango monkeys (Cercopithecus albogularis schwarzi), who are seed-spitters (disinhibition) and seed-swallowers (gut-passage and fertiliser effects). We designed experiments to isolate the cumulative effects of seed processing mechanisms and tested the effects of five treatments and one control treatment (entire fruit). We further assessed if exclusion of ecologically relevant seed treatments or relevant controls would affect our interpretation of the impact of the disperser on seed germination. Comparing gut passage and disinhibition indicated negative effects, whereas comparing gut passage and entire fruit controls indicated neutral effects in one species. Compared with gut passage alone, the fertiliser effects indicated positive or neutral benefits on germination probability. Our study demonstrated that the impacts of mammalian frugivores on germination may be under- or over-estimated in ecological literature where relevant treatments and meaningful controls are excluded.

Citation

Stringer, S., Hill, R., Swanepoel, L., Dalrymple, S., Linden, B., & Koyama, N. (2020). Assessing the role of a mammalian frugivorous species on seed germination potential depends on study design: A case study using wild samango monkeys. Acta Oecologica, 106, Article 103584. https://doi.org/10.1016/j.actao.2020.103584

• Journal Article Type: Article
• Acceptance Date: Apr 22, 2020
• Online Publication Date: May 30, 2020
• Publication Date: Jul 31, 2020
• Deposit Date: Apr 22, 2020
• Publicly Available Date: May 30, 2021
• Journal: Acta Oecologica
• Print ISSN: 1146-609X
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 106
• Article Number: 103584
• DOI: https://doi.org/10.1016/j.actao.2020.103584
• Public URL: https://durham-repository.worktribe.com/output/1265748