title: A nature-based approach for managing the invasive weed speciesGutenbergia cordifoliafor sustainable rangeland management.
abstract: BACKGROUND
  The invasive weed speciesGutenbergia cordifoliahas 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 ecologically diverse ecosystem. Hence, a nature-based approach is urgently needed to manage its spread. We tested twoDesmodium sppextracts applied toG. cordifoliaand 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 byDesmodium uncinatumleaf extract (DuL), particularly under higher concentrations (≥75 %) rather than lower concentrations (≤62.5 %). Likewise, in both laboratory and screen house experiments, germination 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 thanD. uncinatumroot extract,Desmodium intortumleaf extract orD. intortumroot 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.
  
  
  CONCLUSIONS
  Our study shows a novel technique that can be applied whereG. cordifoliamay be driving native flora and fauna to local extinction. Our data further suggest that this innovative approach is both ecologically safe and effective and thatD. uncinatumcan be sustainably used to manage invasive plants, and thus, to improve rangeland productivity.
authors: Department of Sustainable Agriculture, Biodiversity and Ecosystem Management, School of Life Sciences and Bio-Engineering, The Nelson Mandela African Institution of Science and Technology, P.O. Box 447, Arusha, Tanzania ; Ministry of Natural Resources and Tourism, Wildlife Division, Tourism Hunting, Photographic Tourism and CITES Office, P.O. Box 1541, Arusha, Tanzania.
authors: Issakwisa B
authors: IB
authors: Ngondya
authors: Department of Sustainable Agriculture, Biodiversity and Ecosystem Management, School of Life Sciences and Bio-Engineering, The Nelson Mandela African Institution of Science and Technology, P.O. Box 447, Arusha, Tanzania.
authors: Linus K
authors: LK
authors: Munishi
authors: Department of Sustainable Agriculture, Biodiversity and Ecosystem Management, School of Life Sciences and Bio-Engineering, The Nelson Mandela African Institution of Science and Technology, P.O. Box 447, Arusha, Tanzania.
authors: Anna C
authors: AC
authors: Treydte
authors: Department of Sustainable Agriculture, Biodiversity and Ecosystem Management, School of Life Sciences and Bio-Engineering, The Nelson Mandela African Institution of Science and Technology, P.O. Box 447, Arusha, Tanzania.
authors: Patrick A
authors: PA
authors: Ndakidemi
keywords: Allelopathy; Bioherbicide; Desmodium; Ecological invasions; Ngorongoro