Our Blog: Plants and other Stories
Summer Flower Watch in Lower Sabie, Kruger National Park
DEC 18, 2020 | Written by Joseph White & Laurence Kruger. Photos by Joseph White & Laurence Kruger.
Kruger National Park
Above: The tall sword lily (Gladiolus varius) adds a burst of pink to the landscape. Photo: Joseph White.
The silent battle on our savannas between majestic trees and determined grasses has intrigued us for a long time – and meant that plenty of us have overlooked the non-grassy herbaceous plants (forbs) that make up a considerable and unique element of the savanna’s understory.
In fact, forbs tend to go under-researched and under-valued worldwide. But they are certainly part of an international research and education programme called BROWSE (Biodiversity Research on Wildlife and Savanna Ecosystems) that is looking at long-term drivers of savanna dynamics, including fire, megaherbivores such as elephant and buffalo, drought, climate change – and plant diversity including forbs.
Top and above: The inconspicuous Chlorophytum cooperi, one of the spider plant family, becomes noticeable in the post-fire landscape. Photo: Joseph White.
One of the BROWSE research sites is on the rich, red plains with basalt soils in the northern Lebombo bushveld of the Kruger National Park. This provides an ideal open habitat where many forbs can flourish.
BROWSE aims to consider the impacts of ecosystem change on all taxa. Around Lower Sabie, you may see its many 70-metre-square fenced plots. They are designed to exclude megaherbivores and allow researchers to track which plants thrive and which might struggle without their impact.
Left: The bushveld chincherinchee (Albuca seineri) exploding into flower after the first Lowveld rains. Photo: Joseph White. Right: The contrasting green and lilac flowers of a Ledebouria species. Photo: Joseph White.
Several necessary fires went through these exclosure plots and the surrounding area in autumn. Good early summer rains followed and forbs responded strongly.
Anywhere between 12 and 24 species were counted inside a single exclosure. Just outside the plots, it was a treat to find that the patient, large bulbs of a few special spring-flowering members of the amaryllis family (Amaryllidaceae) had burst into life under the fire-scorched thorn trees (Senegalia).
During their fleeting appearances after fire or drought, forbs can outnumber tree and grass species richness in savanna and grasslands. But their visible domination of the diversity in the herbaceous layer is brief.
Top and above: Stenostelma capense produces distinctive milkweed pods that split open to release its fluffy seeds inside to the wind. Photo: Joseph White.
This seasonal nature and challenges surrounding their identification means that until recently, forbs have often been left out of savanna research and management plans. As a result, there are several gaps in our knowledge and understanding of forbs in the understory. But long-term research projects, such as the BROWSE plots in Lower Sabie, can provide crucial progress.
Ultimately, BROWSE hopes to build a more comprehensive understanding of the dynamics between trees, grasses and forbs in the savanna, as well as providing research opportunities for our future botanical leaders.
Top: An inviting patch of the widespread, summer-growing blood lily (Scadoxus multiflorus subsp. multiflorus) with its large spherical, bright-red flowerheads. Above: Dr Laurence Kruger caught botanising the showy blood lily, also known as isiphompo. Photo: Joseph White.
Our Guest Bloggers
Joseph White, a plant ecologist with a focus on plant-animal interactions and spatial ecology, is currently a postdoctoral researcher at the University of the Witwatersrand working on large-scale impacts of woody-plant encroachment on ecosystem services and biodiversity.
Based in the Kruger National Park, Laurence Kruger is director of Organization for Tropical Studies South Africa programmes and the Nsasani Trust. Both organisations run human-capital development programmes focusing on field-based, experiential environmental education and long-term research.
For more about the importance of forbs in the Kruger National Park, see ‘Special green gifts’ in Veld & Flora, December 2020
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