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Background: The invasive weed species Gutenbergia cordifolia has been observed
to suppress native plants and to dominate more than half of the entire crater floor
(250 km2
) in the Ngorongoro Conservation Area (NCA). As this species has been found
to be toxic to ruminants it might strongly impact animal populations in this eco logically diverse ecosystem. Hence, a nature-based approach is urgently needed to
manage its spread. We tested two Desmodium spp extracts applied to G. cordifolia and
assessed the latter’s germination rate, height, fresh weight and leaf total chlorophyll
content after 30 days in both laboratory and screen house experiments.
Results: Seedling germination rate was halved by Desmodium uncinatum leaf extract
(DuL), particularly under higher concentrations (≥75 %) rather than lower concentra tions (≤62.5 %). Likewise, in both laboratory and screen house experiments, germina tion rate under DuL treatments declined with increasing concentrations. Seedling
height, fresh weight and leaf total chlorophyll content (Chl) were also most strongly
affected by DuL treatments rather than D. uncinatum root extract, Desmodium intortum
leaf extract or D. intortum root extract treatments. Generally, seedlings treated with
higher DuL concentrations were half as tall, had one-third the weight and half the leaf
Chl content compared to those treated with lower concentrations.
Conclusion: Our study shows a novel technique that can be applied where G.
cordifolia may be driving native flora and fauna to local extinction. Our data further
suggest that this innovative approach is both ecologically safe and effective and that
D. uncinatum can be sustainably used to manage invasive plants, and thus, to improve
rangeland productivity |
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