Protecting threatened Over-seas biodiversity

Tests on Niaouli seeds in Guyana

Since April 2021, GEPOG has been carrying out tests on Niaouli seeds in order to better understand the germination factors of these and to adapt the techniques and periods of control to exhaust the seed bank following interventions of ‘slaughter. These tests complement the tests already carried out on the Niaouli plots by GEPOG in 2020.

Charles-Élie in the greenhouse provided by the Kourou Agronomic Campus © GEPOG

A university student at the helm

In order to move forward on this subject, GEPOG entrusted this first study on the biology of Niaouli in Guyana to Charles-Élie MARGIER, intern of the Master 2 BEE – Plant Biodiversity & Tropical Ecosystem Management at AgroParisTech / University of Montpellier.

For 6 months, Charles-Élie will carry out the tests in a greenhouse provided by the Kourou Agronomic Campus (UMR EcoFoG).

The first experiment will aim to determine the influence of the height of the niaoulis and the relative age of the inflorescences on the production of seeds and their germination capacity.

Tests on Niaouli seeds © GEPOG

The second experiment will focus on a period of 2 months to measure the influence of brightness (shade / light) and substrate (savannah soil / forest soil) on germination rates. The dry and wet seasons as well as the transitions between them are also simulated by differently regulated sprinkler systems within the greenhouse.

Finally, tests will be carried out to determine the impact of prolonged flooding on seedling survival and the impact of fire on breaking dormancy. These data will make it possible to adapt the felling period in order to exhaust the seed bank present in the soil or resulting from the post-treatment seed rain.

Le Niaouli, at the gateway to the savannahs

The Niaouli is considered to be one of the most problematic invasive alien plant species for the conservation of Guyanese coastal savannas. Imported from Australia in the 1970s, this species darkens open spaces and invades savannas.

Its capacity to resist fires and to produce more than 20,000,000 seeds per year makes Niaouli a formidable and invasive species, threatening the Guyanese savannas.

See you in September 2021 to take stock of the results of this study.