Skip to main content
×
Home

Stability of wooded patches in a South African nutrient-poor grassland: do nutrients, fire or herbivores limit their expansion?

  • Anja A. Mourik (a1) (a2), Frank van Langevelde (a1), Esther van Tellingen (a1), Ignas M. A. Heitkönig (a1) and Ian Gaigher (a3)...
Abstract

Patches of wooded vegetation in nutrient-poor grassland characteristically contain high soil moisture and nutrient availability compared with surrounding grassland. These ‘islands of fertility’ appear stable in size, suggesting that tree recruitment at the patch boundary is limited. We hypothesize that tree establishment in adjacent grassland is limited by (1) competition for resources, (2) fire or (3) herbivory. In a South African grassland, we measured moisture availability and conducted a bioassay experiment to analyse whether soil nutrient limits tree recruitment at the patch boundary. We thus measured nutrient concentrations of maize plants grown in patch, boundary and grassland soil. To investigate whether browsing or fire affected tree seedlings at the patch boundary, we burned plots including patches, and used fences to exclude browsers. Neither soil moisture nor nutrient availability at the boundary differed from inside the patches, suggesting that tree recruitment at the boundary is not resource limited. Both fire and browsing combined caused a significantly lower tree seedling growth at the patch boundary, suggesting that these two factors can impede tree recruitment. The balance between positive feedback mechanisms facilitating tree recruitment, and the negative impact of fire and browsing can explain the apparent stability of these islands of fertility.

Copyright
Corresponding author
Corresponding author. Email: frank.vanlangevelde@wur.nl
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Journal of Tropical Ecology
  • ISSN: 0266-4674
  • EISSN: 1469-7831
  • URL: /core/journals/journal-of-tropical-ecology
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Keywords:

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 12 *
Loading metrics...

Abstract views

Total abstract views: 94 *
Loading metrics...

* Views captured on Cambridge Core between September 2016 - 18th November 2017. This data will be updated every 24 hours.