Anjana Devkota

Seed germination responses of the medicinal herb Centella asiatica

The effect of several environmental factors on germination of medicinal herb Centella asiatica was investigated. Freshly harvested seeds of C. asiatica did not germinate even after gibberellic acid (GA3) treatment and exposure to different treatments with light qualities, while two-three months old seeds exhibited germination (82%) without pre-treatment at warm environment (25 -30oC). GA3 treatment induced germination by two weeks earlier than in control. Germination was significantly (p=0.001) higher in red and white light than in blue and far red light. In addition, germination of C. asiatica was sensitive towards the salt stress and was significantly inhibited at 6500 ppm NaCl. The leaf leachates from invasive weeds Chromolaena odorata, Ageratum conyzoides, Parthenium hysterophorus and Xanthium strumarium showed inhibitory effects on seed germination of C. asiatica. Parthenium hysterophorus had significant effect (p<0.001) on seed germination. These data contribute for the establishing of an efficient protocol for C. asiatica cultivation.

Community perception and prioritization of invasive alien plants in Chitwan-Annapurna Landscape, Nepal

The management of invasive species is a complex, yet an essential component of biodiversity conservation and environmental management for sustainable futures. Despite a well-established linkage between biological invasions and human activities, the social dimension of invasive species management is less explored as compared to the ecological aspects. In recent years, the active participation of local communities, such as assessing levels of awareness and the selection of targeted species prioritized by communities, has been considered as a crucial element for managing invasive species. We conducted 32 focus group discussions (FGDs) including 218 participants in Chitwan-Annapurna Landscape (ChAL) of central Nepal, to assess knowledge and perceptions of agrarian and forest-dependent communities about invasive alien plants (IAPs), document the efforts of the community management of IAPs and prioritize IAPs for management. In the prioritization exercise, participants of each FGD were asked to rank three IAPs using scoring methods and to express their experience about the effects of the selected IAPs on humans and the environment. We found that communities had a living memory of the arrival of some of the IAPs in their locality without knowing the exotic nature of IAPs. Biodiversity loss, livestock poisoning, reduced agricultural production and forage supply, and negative impact on forest regeneration were reported as major negative impacts of IAPs. Communities also reportedly utilized IAPs for medicinal purposes, making compost by using biomass, and controlling floods and landslides. None of the government and non-governmental organizations working in the sectors of biodiversity conservation and environmental management has informed local forest-dependent agrarian communities about the consequences of biological invasions and management of IAPs. However, local communities had already started controlling the spread of some IAPs through manual uprooting. They were able to spot, identify and prioritize IAPs for management and some of the prioritized species were among the worlds worst invasive species. Ageratum houstonianum was the top-ranked worst invasive species in agroecosystems while Chromolaena odorata and Ageratina adenophora were the top-ranked worst species in natural ecosystems. Our findings will be useful for guiding community education programs as well as the management of IAPs through formal policy and management plans, such as Nepals National Biodiversity Strategy and Action Plan.