Impacts of invasive alien plants on ecosystem services of Ramsar lake cluster in middle mountain Nepal
H. Pathak, Dinesh Raj Bhuju, Bharat Babu Shrestha, Sailesh Ranjitkar
Abstract
Biological invasions have significant impacts on ecosystems, the services provided by ecosystems, and associated economies. In wetlands, invasion by alien plants can impact the ecosystem services that are fundamental to human well-being. We conducted a stakeholder analysis in Ramsar sites in the Pokhara Valley to understand ecosystem services, the economic valuation of provisioning services, invasive alien plants, and their impacts. We collected information from locals living near the Ramsar site using focus group discussions, key informant interviews, and household (HH) surveys. We identified five invasive alien plants in the Ramsar sites in Pokhara Valley. A total of 18 ecosystem services were recorded from discussions with residents living near the Ramsar sites. Our study found that the economic benefits generated from the provisioning service, calculated based on the market price in the year of data collection, were worth a total of International$ 9.05 million. The value of provisioning services was International$ 0.1 million HH−1 year−1. Our estimate showed that the value of provisioning services before the occurrence of invasive alien plants in 1989 was International$ 0.19 million HH−1 year−1 higher than in 2019. Those who benefit from the Lake clusters mentioned that the invasive alien plants led to a decrease in economically important plants such as medicine and fruits and decreased fish production. Other impacts have included: reduced natural beauty, loss of biodiversity, and obstruction of recreational boating, which has discouraged tourism in recent years, among other impacts. Our results show that the rampant spread of invasive alien plants has a severe impact on ecosystem services. The impact on the associated economic value is alarming. There is an urgent need for proper management of wetlands. The findings from our results can help make decision-makers aware of the need to act in order to restore and maintain the services provided by the wetlands.