Dr. Sudheera Manorama Wadisinha Ranwala
Presidential Address
Presented at 2009 Annual Sessions of the Institute of Biology, Sri Lanka
Biological invasions, one of the important components of the process of global changes, occur when organisms are introduced to new, often distant ranges where their descendants proliferate, spread and persist. Invasions are neither novel nor a human-driven phenomenon, but it has been shown that the number of biotic invasions have grown enormously as a direct consequence of expanding travel, trade and tourism in the past 200 years and especially in the last 50 yrs.
According to Williamson’s “Tens Rule”, less than 1% of species that are introduced into a new environment will become damaging pests, or cause adverse effects on biodiversity. However, the ones that do become invasive will be responsible for serious economic and environmental costs as they act on ecosystem, community and population levels wherever they invade. They could adversely affect ecosystems by dramatically altering the ecosystem functions in a multitude of ways. They do bring about alterations in light availability, nutrient cycling pattern and energy budgets, hydrological regimes, rates of sedimentation, soil erosion and intensity of wild fires. Invasions by disease-causing organisms can severely impact native species. These effects may indirectly contribute to the abundance or survival of native species including endemic and threatened species. Cumulative impacts of alien invaders on community structure and composition are immense, irreversible and irreparable. They are responsible for elimination, reduction of the number of native species in the community leading to extinctions. It is said that the estimated 80% of endangered species in the world suffer by predation by or competition with alien invaders. These changes pose a threat to global biodiversity second in impact to habitat loss and fragmentation.
Biotic invasions cause two main categories of economic impacts, through production loss in agriculture, forestry and losses that occur through recreational and tourism revenues and costs directly related to combating alien invaders including all forms of quarantine, control, and eradication. If monetary values could be assigned to the extinction of species and loss of ecosystem services, total costs from impacts of biological invasions would drastically increase. Thus, consequences of biotic invasions are often so profound and therefore new invasions should be prevented. Establishment and the spread of biological invasions should also be managed.
Strategic approaches for management of invasive alien species encompass prevention, early detection, eradication, control and containment. Screening of biological imports at the country boundaries is considered as the most cost- effective means of prevention of the arrival of pests and infectious diseases to new environments. The ability of a nation to restrict the movement of biotic invaders across its borders is governed by international treaties, key among them being the International Plant Protection Convention (IPPC) agreement that had developed International Standards on Phytosanitary Measures (ISPM) in collaboration with the Secretariat of the of the Food and Agriculture Organization (FAO) and the Secretariat of the Convention on Biological Diversity. Under this agreement, member countries including Sri Lanka can restrict movement of species that may pose threats to human, animal or plant life. Other international agreements such as World Trade Organization (WTO), South Asian Association for Regional Cooperation (SAARC) Preferential Trading Agreement (SAPTA), Convention on Biological Diversity (CBD), International Convention for the Prevention of Pollution From Ships, 1973 as modified by the Protocol of 1978 MARPOL (73/78) and International des Epizooties (OIE) have also established various standards and guidelines to be used for international trade of biological organisms and their products in order to protect human, plant and animal life.
Sri Lanka has enacted several national legislation which either directly or indirectly address the prevention of introduction and control of spread of biological invasions in Sri Lanka. Water Hyacinth Ordinance of 1909 is the first legislation implemented with regard to alien plant invaders in Sri Lanka. The Fauna and Flora Protection Ordinance, No 02 of 1937 as amended, Plant Protection Act no 35 of 1999 and the Seed Act no 22 of 2003 also make provisions for the sanitation of plants and regulate the introduction and spread of organisms harmful to existing flora of the country. The Animal Diseases Act No 59 of 1992 ensures that exotic diseases are not introduced to Sri Lanka. The amendments made to section 61 read with section 30 of the Fisheries and Aquatic Resources Act no 2 of 1996 provide restriction on import and export of certain fish species which are harmful to aquatic fauna. At present, implementation of these agreements and legislation does not totally provide effective control against introduction of potential invaders due to various limitations.
Being a member country of Convention on Biological Diversity, the government Sri Lanka has taken steps to conserve its exceptional biological wealth from the time of signing the convention in 1992. It includes all efforts that were conducted, being conducted or to be conducted in accordance with article 8 (h) of the convention which indicate that all possible mechanisms should be considered to prevent the introduction, control spread and management of invasive alien species that threaten habitat and ecosystems. The Ministry of Environment and Natural Resources as the national focal point to the CBD together with other line -departments have already developed policies, many projects and programmes to prevent the introduction, control and eradicate invasive alien species (IAS) in Sri Lanka. In addition, organization of the first national symposium on IAS in Sri Lanka by the Ministry of Environment in 1999 and three other symposia in collaboration with National Agricultural Society (in 2000), National Science Foundation and Sri Lanka Association for the Advancement of Science/ Section D (in 2008), Agriculture Extension Unit, University of Peradeniya and Institute of Biology (in 2009), strengthened the interdisciplinary corporation among various key stakeholders. These symposia also served as a venue for upgrade and exchange of knowledge among scientists and policy makers, identified gaps and loopholes and raised public awareness on the current status of biological invasions in Sri Lanka. The project on control and management of freshwater aquatic invasive alien species in Sri Lanka conducted by the Ministry of Environment with technical assistance from the Food and Agricultural Organization and Plant Protection services of the Department of Agriculture performed several activities related to the introduction of biocontrol agents for the two most serious aquatic weeds, Salvinia molesta and Eichhornia crassipes, survey of aquatic weeds in Kurunegala and Anuradhapura Districts and several awareness, training and capacity building programmes for the rural community in these regions. A draft policy on controlling invasive alien species in protected areas had also been prepared in 2005 under the Protected Area Management Project of the Department of Wildlife Conservation, Sri Lanka. The country is now stepping towards a five year project for strengthening capacity to control the introduction and spread of invasive alien species in Sri Lanka through the Global Environmental Facility and United Nations Development Programme. This has already planned the work ahead including revision of national lists of Invasive alien Fauna and Flora, revision of legal regimes, establishment of demonstration sites for effective management, analysis of economic impacts, costs and benefits of IAS, development of an Information Management System, establishment of protocols for screening of live imports of plants and animals to Sri Lanka, development of programmes to improve communication, education, training and capacity building for IAS control, enhancement of institutional coordination, policy preparation and monitoring etc, so as to fill the existing gaps that exist with regard to combating biological invasions in Sri Lanka. Department of Agriculture, the focal point to the International agreement on Plant Protection (IPPC) through various programmes significantly contributes to prevent introduction, control and eradicate species that interfere with the agro-biodiversity of the country. The Marine Environment Protection Authority (MEPA), which acts as the focal point for implementation of the MARPOL convention 73/78 has also taken steps forward to manage marine invasive species. Other government agencies such as the Department of Wildlife Conservation, Forest Department, Irrigation Department, Mahaweli Authority of Sri Lanka, National Aquatic Resources and Research Agency, Department of National Botanic Gardens, Central Environmental Authority, Universities and Research Institutes have also contributed in numerous ways for management of IAS in Sri Lanka. The Non governmental organizations such as the World Conservation Union (IUCN), Sri Lanka Nature Forum (SLNF), EML consultants (Pvt) Ltd, Eco –V, Sewalanka Foundation and several other NGOs together with various community based organizations play a key role in working towards management of alien invaders in Sri Lanka.
Prediction of invasiveness of species during import, identification of the most threatening species and the most vulnerable communities for effective control of already established IAS are not simple. The extent of spread that would be subjected for management, most effective method of control, available resources, post removal treatment for biomass, tools for monitoring of regeneration and assessment of benefits resulting from management are crucial steps in control and management of IAS. Education and awareness on invasive species is strictly necessary for vigilant early detection of IAS by the society for easy control and management. Finding uses of IAS seems attractive, particularly in the tropics where low cost and labour intensive small scale technologies are feasible, but is a challenging issue. However, a variety of possible uses including composting, paper pulping, biogas production, utilization of chemical properties etc., have been innovated by Sri Lankans for controlling some invasive alien plants, but such management measures for invasive alien fauna is still remain unexplored.
It is well understood that much of the world’s attention has been paid more to invasive alien flora than invasive alien fauna with reference to many aspects. Recent surveys on published information on invasive alien species of Sri Lanka had revealed that very limited aspects of IAS have been investigated during the past few years and many windows of opportunities exist for IAS work. Over the years, a few species were popular examples. Most of the publications were focused on terrestrial species although aquatic species were the most problematic group. Ecological impacts, control and management aspects of invasive alien species have been fairly addressed by several authors while studies that focus on economic impacts, costs and benefits of invasive species in Sri Lanka are scanty. Biological aspects such as genetics, reproductive biology, regeneration and propagation studies, assessment of distribution, spread, degree of invasiveness, allelopathic effects of plants, feeding and nesting habits of animals and their habitat characteristics have been paid little attention. Legal aspects and assessments on the public awareness status of IAS have been untouched. Identifying future invaders and predicting their likely sites of invasion are of immense scientific and practical interest. In practical terms, it could reveal the most effective means to prevent future invasions. Economic benefits from "alien invaders" should also be given priority in research. Horticulture is a key pathway for introduction of species to national borders as many of our invasive species have been introduced for ornamental use. Despite the fact that only few exotics will become invasive, disallowing the use of existing invasive species for horticultural purposes while encouraging the use of alternative native species, would provide a stronger foundation in preventing the introduction of potential alien invasive species to the country.
We, as biologists, are in a position to address all these issues and find effective solutions through scientific research, provide accurate documentation and evaluations for steps to be taken in the right direction. No matter we are physiologists, molecular biologists, taxonomists, ecologists, conservationists, GIS specialists, collaborative efforts among us would result in a significant improvement in combating biological invasions in this small island. Foremost among the responsibilities of us, as the biologists in this country, is to ensure that biological wealth is protected and being utilized in a sustainable manner. Being one of the largest group of biologists in Sri Lanka, the Institute of Biology is also in a suitable position to sensitize other societies and clubs to the issues regarding alien invaders, to work with industrialists to assist the public in safe gardening and landscaping of the environment, partner with local governmental and non governmental organizations and international agencies in the management of harmful alien invaders.
Let’s get together to combat biological invasions!
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