The Department of Environment and Natural Resources (DENR) has completed the draft management plan on invasive alien species (IAS) to prevent its adverse impact to the environment and biodiversity.
Developed as part of the United Nations Environment Programme-Global Environment Facility Project 0515, “Removing Barriers to Invasive Species Management in Production and Protection Forests in Southeast Asia [Foris Project]”, the National Invasive Species Strategy and Action Plan (Nissap) 2016-2026 aims to provide a blueprint for various stakeholders in preventing the spread of IAS.
IAS include knife fish, janitor fish and, in the case of plants, water lily. Developed through a consultative process with various stakeholders—research and academic institutions, civil societies, private sector and government agencies—at the national and regional levels, Nissap is envisioned to cover the management of various types of IAS in areas that are most vulnerable to their impacts.
To prevent the introduction of IAS or their infestation, and to effectively manage their spread and minimize their threats, Nissap provides a framework for coordinated and multisectoral management.
Major driver of biodiversity loss
According to Biodiversity Management Bureau (BMB) Director Theresa Mundita S. Lim, IAS is a major driver of biodiversity loss and continues to threaten ecosystems, including lakes and other inland water ecosystems or wetlands.
IAS are introduced to a location through various pathways, like transported to a new location, either intentionally or unintentionally—such as in fisheries, agriculture, forestry and reforestation, trade, travel and tourism, the document said.
The exotic, or sometimes called nonnative species, displace the native ones through competition, predation, habitat alteration, diseases and parasitic infestations.
According to the DENR-BMB, studies have shown that IAS could alter the evolution of native species by competitive exclusion, which can lead to loss of genetic diversity.
The structure and functions of an ecosystem can be altered dramatically by IAS, the document pointed out.
It cited as an example the adverse impact of invasive plants that can colonize large areas, inhibiting the growth of native plants and forming monoculture that leads to the decline of watershed functions.
“Invasive aquatic plants can cover entire surface of lakes, ponds and rivers,” the document said.
On the other hand, exotic or nonnative species can carry invasive pests that can damage forestry, agriculture and aquaculture.
Climate change; economic losses
Climate change-induced alteration of ecosystems can also facilitate the spread of invasive species through the creation of habitats and conditions that suit new and already established invasive species, according to the draft Nissap.
Experts have warned against the spread of IAS because of their potential economic impact.
Because of expanding trade and globalization, the direct and indirect economic losses associated with the damages from IAS will further increase, they warned.
The global cost of IAS is pegged at $1.4 trillion.
In the Philippines, rice-productivity loss from golden apple snails, or golden kuhol, reached up to an estimated $12.5 million to $17.8 million in the 1990s.
“The Nissap aims to help policy-makers, local governments and the private sector prevent the spread of invasive species,” Lim said.
She said the Nissap 2016-2026 would be submitted to Environment Secretary Regina Paz L. Lopez for approval.
3 Mindanao lakes under threat
IAS have already affected rivers and lakes in Luzon—such as the Marikina River, Pasig River, Laguna de Bay and Taal Lake—and are now threatening three lakes in Mindanao, said Josefina de Leon, head of the BMB’s Wildlife Division.
Among those affected by IAS in Mindanao are Lake Sebu, Agusan Marsh and Liguasan Marsh.
Lake Sebu’s productivity is being undermined by water lilly, water cabbage and tilapia.
Agusan Marsh and Liguasan Marsh are affected by water lily, janitor fish and tilapia.
Lake Sebu is one of the many bodies of water supplying important irrigation to the provinces of Sultan Kudarat and South Cotabato. The lake and its surroundings are part of the ancestral domain of the T’boli and Ubo tribes, who have been the traditional dwellers of the lake.
Agusan Marsh is part of the Agusan Marsh Wildlife Sanctuary and one of the most ecologically significant wetlands in the Philippines. It contains nearly 15 percent of the nation’s fresh-water resources in the form of swamp forests.
Liguasan Marsh, meanwhile, is a key biodiversity area. It is home to unique birds and assorted native fish, and is the primary source of water and food of people living in the area.
De Leon said the reported spread of IAS in these lakes is alarming because they could affect the lakes’ productivity and affect those who depend on the lake’s bounty for income and livelihood.
Lim said a thorough assessment of the situation in the affected lakes is necessary to address the problem.
She said there is also a need to look into the condition of other economically important lakes to come up with measures to prevent invasion by nonnative species, particularly “pesky” fish.
“We need to assess the situation to come up with a plan how to contain or eliminate invasive species without harming other species,” she said.
The Bureau of Fisheries and Aquatic Resources (BFAR) had sought the help of the DENR-BMB to help address the problem confronting various stakeholders in the areas.
Monitoring lakes
Lim said the DENR field staff members, as part of their mandate, monitor lakes, particularly those frequented by migratory birds during migration, but the activities focus on averting the spread of avian influenza virus.
The official said the lakes should be monitored regularly, not just to prevent the avian influenza virus from spreading, but in order to prevent the spread of IAS that are detrimental to the environment.
Lim said lakes are important ecosystems that support a diverse species of plants, birds and animals, and ecosystem services that support the livelihood of farmers and fishermen.
IAS, like janitor fish, knife fish and tilapia, have already adversely affected the Laguna de Bay and Taal Lake for years.
Janitor fish and knife fish are ornamental fish species, while tilapia, which was introduced in the 1970s in the Philippines to boost fish production, is now part of the Filipino diet.
These invasive alien fish compete against and sometimes prey on native fish leading to their extinction.
According to Lim, the release of IAS into the wild is prohibited and punishable by the Wildlife Act because of their potential adverse impact to the environment. They also cause the extinction of native species. The official cautioned hobbyists who release their pets into the wild. Potentially dangerous species are ornamental fish and other aquarium pets, including deadly Burmese python, birds, rats and spiders.
High endemism
The Philippines is rich in biodiversity and is known for its high endemism.
It is estimated that around 45 percent to 60 percent of plants in flowering forests are endemic to the Philippines or are only found in the country.
Around 64 percent of Philippine mammals are endemic to the country, such as the Philippine Tamaraw or the Mindoro dwarf buffalo, which can only be found in the mountains of Mindoro Island.
It is also estimated that 32 percent of birds in the Philippines are endemic to the country.
The Philippines also boasts of having the highest endemism when it comes to reptiles (73 percent) and amphibians (91 percent).
Around 34 percent of freshwater fish in the Philippines are also endemic to the country.
Prevention rather than cure
The Nissap implementing guidelines is anchored on the precautionary principle, data sharing and collaboration, research and monitoring, biodiversity conservation, international cooperation, committed funding for implementation, public education and awareness, participatory and consultative approach to planning, decision-making and management, policy and institutional development, and training and capacity building.
It has nine Strategic Goals, including Leadership and Coordination; Prevention; Early Detection and Rapid Response; Control and Management; Restoration; Research and Information Management; Education and Public Awareness; International Cooperation; and Training Needs and Capacity Building.
According to Lim, four decades later, the Philippines is now feeling the impact of the introduction of tilapia.
“While it seemed to be appropriate then for food security, its introduction in our lakes and rivers have caused us to lose better-tasting native fish varieties,” Lim said.
She said prevention is always better than finding cure to a problem, citing the case of the diminishing fish variety that were replaced in the market, either by bangus or tilapia.
“If you notice, tilapia and bangus are all that you can see in the market because our native fish are nearly extinct, if not extinct already,” Lim said.
She said a thorough study should be conducted before another species of fish is introduced, intentionally to boost food production or as a biological control agent, to prevent potential adverse impact, rather than preventing a cure to a problem which can result in the extinction of native species and accelerate biodiversity loss.