Identification of Distribution of Lantana camera (Exotic Invasive Species) and its impacts on Udawalawa National Park, Sri Lanka

摘要

The Exotic Invasive Species are spreading rapidly disturbing other native living organisms in a particular area. Especially this topic has been discussed often with the environmental disturbances arising due to climate changes and human activities. Lantana camera is a destructive exotic invasive plant that spreading rapidly in tropical countries destroying natural habitats. Udawalawa National Park of Sri Lanka is one of the world famous Asian elephant habitats that located in Dry zone of Sri Lanka. Elephants in this national park are often suffering from Malnutrition due to drought impacts. This situation has been worst as rapid distribution of the Lantana camera. This research planned to find an inexpensive method to identify the distributed area of Lantana camera in Udawalawa National Park to make a better plan for the clearing purposes. And this research secondly focused to identify the impacts of Lantana camara on natural habitats. Landsat 08 satellite images were used for this research which can be downloaded free from USGS (United State Geological Survey) website. Resolution of this satellite image is 30m x 30m. Three handheld Global Positioning System (GPS) devices were used to get the accurate locations of 25 sampling sites. Arc GIS 10.4 software was used for the supervised classifications to identify the distribution of Lantana camera with reflectance values. Further verifications were done by observing selected locations by field visit. Major impacts of Lantana camara were identified by field observation and discussions with Wildlife officers. Total land extent of the Udawalawa National Park is 31067 ha. According to the result, Lantana camera has been invading the extent of 2,650 ha of the national park. Rapid spreading of Lantana camara, degradation of biodiversity, reduction of species richness and reduction of food productivity were the major impacts of this invasive plant that national park has been affected. Output of this research is very important to identify the invaded extent of the Lantana camera and its impacts on National Park. As a developing country Sri Lanka does not have a capability to use high resolution images for such studies spending big amount of money. Thus as an inexpensive method to identify the distribution of invasive plants, this research methodology is really applicable for such conditions in tropical developing countries as well.