7-days of FREE Audio papers, translation & more with Prime
7-days of FREE Prime access
7-days of FREE Audio papers, translation & more with Prime
7-days of FREE Prime access
https://doi.org/10.1111/j.1442-9993.2012.02454.x
Copy DOIJournal: Austral Ecology | Publication Date: Oct 18, 2012 |
Citations: 19 |
AbstractImpacts of large herbivores (>5 kg) on woody plants in African savannas are potentially most severe among plants shorter than 1.6 m. It is well established that severe browsing leads to longer shoots, yet prevents saplings from recruiting into adult size‐classes in African savannas. Increased shoot length, indicating faster shoot growth, is often associated with reduced concentrations of tannins and increased nutrient concentrations, suggesting carbon limitation. We hypothesized that, on average, large herbivores suppress stem height or circumference, but increase shoot length. We also hypothesized that if there were concomitant positive effects on nutrients, or negative effects on tannin concentrations, they would be greatest early in the wet season. We sampled saplings of four deciduous woody species (Acacia grandicornuta, Dichrostachys cinerea, Combretum apiculatum and Grewia flavescens) at different stages of the wet season in a large‐scale, long‐term herbivore exclusion experiment in Kruger National Park, South Africa. Plant height, shoot length and stem circumference were generally not adversely affected by large herbivores, suggesting C limitation is rarely present among deciduous saplings in semi‐arid African savannas, allowing them to tolerate browsing. Time since first rainfall emerged as a predominant factor consistently affecting nutrient and tannin concentrations, rather than large herbivores. Nitrogen and phosphorus generally decreased (by 20–50%), while condensed tannin concentration increased (150–350%) during the wet season, except for one species. We postulate that A. grandicornuta is less prone than other species to accumulating tannins during the wet season because of high investment of C in spines. Although nutrient and tannin concentrations were generally not affected by large herbivores, species‐specific responses were evident very early in the wet season, which is when herbivore populations are most likely to be affected by differential forage quality among plants.
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.