Plants disperse over the agricultural landscapes mainly through seed vectors, the latter being transported either by fauna, gravity, water or wind. Seed dispersal contributes to the spread of invasive species, crop contamination by weeds or biodiversity conservation. Especially for hydrochorous species, i.e. plants whose seeds are dispersed by water flows, there is a complex link between the plant, the seeds and the water dynamics that needs to be disentangled. Indeed, these different plant patterns induce diverse effects on mean water velocity and turbulence fields, largely determining all types of solid transport. However, this potential of plant biodiversity for controlling these transport properties is for the moment largely unknown and under-exploited.
The two main objectives of the project are resumed as follow :
* Testing innovative methods for the characterization of water mean velocity and turbulence fields, applied to seed transport in vegetated channels
* Conducting an integrated analysis for the understanding of water dynamics and seed transport induced by biodiversity (different morphotypes and plant spatial organizations)
Two types of seed release‘ experiments were conducted in the experimental channel : (i) The first one aimed at characterizing the retention rate of seeds in patches of vegetation with constant lengths in order to assess the effect of density, species and discharge on seed retention (ii) In the second experiment, the same plant density was planted on one to height panels in order to characterize the effect of the length of the patch on the retention and test the hypothesis of additivity of seed retention.
The results showed that the density, the discharge or the type of species significantly affect the rate of seed retention. Based on significant additive effect of the length of vegetated channel on the rate of seed capture, we proposed an additive model of recapture following a power law.
The project ECOFLOW, by using an innovative experiment, paves the way to a better understanding of hydrochorous dispersal in ditches, with consequences on the management of weeds in agricultural watersheds.
Project Number : 1702-008
Year : 2017
Type of funding : AAP
Project type : AAP YOUNG SCIENTISTS
Research units in the network : G-EAU
Start date :
01 Apr 2019
End date :
31 Oct 2019
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