Collaborative removal of an invasive alien aquatic weed by volunteering university students in collaboration with multiple stakeholder groups around Lake Biwa, Japan

Author(s): Haruka Tsujino
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Institution or organization of origin:  International Volunteer Student University Association (IVUSA)
Country: Japan


Explosive growth and propagation of Water primrose Ludwigia grandiflora subsp. hexapetala, an invasive alien aquatic weed introduced from South America, has caused serious problems such as competitive exclusion of native species, obstruction in operation of commercial fisheries, and increased risk of river flooding. IVUSA (International Volunteer University Student Association), is a pioneering volunteer group in the removal of this invasive weed since 2013. We have carried out 62 removing activities so far, with participation of a total of 12,275 local people from governments, fisheries cooperatives, environmental NPOs, and individual residents. In Lake Biwa, Shiga Prefecture, the area of the lake surface covered with this invasive weed once reached almost 300,000 ㎡ in 2016. A variety of stakeholders have carried out activities for its removal, resulting in a marked decrease to some 30,000 ㎡ by the end of FY 2018. We will make continuous efforts toward the extermination of this invasive weed, In this presentation, we will make a historical review of our activities, highlighting the removal methods, the results of activity sequence, and the challenges in collaboration with various stakeholders.

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