From afar, the sight of the green, leafy, free-floating aquatic plants over vast water bodies add aesthetic value to nature’s serenity. However, at a closer look, the fear of the unknown suddenly kicks in. And it is not for a good reason.
What appears to be naturally occurring, the water hyacinth, which is native to tropical and subtropical South America, has broad, thick, glossy, ovate leaves. This pervasive plant can rise above the surface by as much a meter in height.
Unlike kangkong, or water spinach, a nutritious vegetable Filipinos eat, water hyacinth is not edible and causes adverse impact on people and the environment.
Just last month, the Pasig River Rehabilitation Commission (PRRC) revived the Task Force Hyacinth and started removing hundreds to thousands of sacks of water hyacinth.
According to PRRC, said 4,120 sacks of water hyacinth were removed on June 10, and there is no letup in the harvesting of this invasive alien species.
Besides causing flooding, water hyacinth affects the mobility of people traveling via boats, including fishers whose livelihoods are severely affected by its adverse environmental impact.
Executive Director Jose Antonio E. Goitia said: “Rain or shine, PRRC’s clearing operations will continue not just across the Pasig River, but also in the esteros and creeks to prevent flooding.”
Invasive alien species
The Convention on Biological Diversity (CBD) describes invasive alien species as “plants, animals, pathogens and other organisms that are nonnative to an ecosystem, and which may cause economic or environmental harm or adversely affect human health. In particular, they impact adversely upon biodiversity, including decline or elimination of native species—through competition, predation, or transmission of pathogens—and the disruption of local ecosystems and ecosystem functions.”
In the Philippines, invasive alien species like the water hyacinth are slowly creeping, menacing one ecosystem at a time, including otherwise healthy water bodies like Pasig River and Laguna de Bay and Agusan marsh, undermining their productivity.
Worse, invasive alien species are considered a major driver of biodiversity loss, as they tend to compete and displace native species and cause ecological imbalance.
Invasive alien species are hard to eliminate, control or manage, like a pest that requires a science-based solution.
IAS Congress 2019
Timely enough, the Philippines hosted the Invasive Alien Species Conference 2019.
Held from July 8 to 12 at the Diamond Hotel in Pasay City, the conference, titled “Research and Development Congress on Invasive Alien Species in the Asia Pacific,” gathered 200 local and foreign researchers, scientists, academics, policy-makers, and guests to discuss recent status, control and management in the region.
Ecosystems Research and Development Bureau (ERDB), the research and development (R&D) arm of the Department of Environment and Natural Resources (DENR), took the lead to raise the IAS biosecurity approach within the entire stretch of the Pacific.
The conference aimed to contribute to the Aichi Biodiversity Target 9 in reducing the direct pressures of IAS on environmental sustainability. It’s objective is to help ensure that by 2020, “invasive alien species and pathways are identified and prioritized, priority species are controlled or eradicated, and measures are in place to manage pathways to prevent their introduction and establishments.”
Aichi Biodiversity Target 9 is part of the Aichi Biodiversity Targets, 20 in all, that were agreed upon by governments in October 2010, at the 10th meeting of the Conference of the Parties to the CBD in Nagoya, Aichi Prefecture in Japan.
A threat to ecosystems, biodiversity
According to experts, invasive alien species raise countless threats to biodiversity.
The DENR’s ERDB said their proliferation could consequently wipeout endemic and native species of a country.
“With the introduction of alien species to a new environment, the indigenous flora and fauna become vulnerable to risks,” Dr. Carmelita I. Villamor, overall coordinator and chief of ERDB’s Coastal Zone and Freshwater Ecosystems Research Division (CZFERD), said.
“Invasive alien species can occur in different taxonomic groups and may pose great threats across all ecosystems. They could also spread in ways destructive to human and the society at large,” she said.
Causing massive extinction
Quoting a CBD report, the ERDB said since the 17th century, IAS has been contributing to massive extinction on the world’s fauna at about 40 percent.
These species continue to trigger competition, predation and massive transmission of pathogens, which then increase the stakes for survival among native species like the water hyacinth.
Due to its rapid spread, water hyacinth has aggressively invaded tropical regions. Its thick cover on waterways can cause blockage, oxygen depletion and fish kills, such as what recently happened in Laguna de Bay.
Another priority species is the African tulip tree growing in the tropical forests of the South Pacific.
The African tulip tree crowds out native species and is extremely difficult to remove as it can easily regrow from its root fragments and wind-dispersed seeds.
ERDB Director Dr. Sofio B. Quintana acknowledged IAS threats as a top concern for the bureau.
“We are always keeping a close eye on invasive alien species to secure and sustain our ecosystems. Our time is changing and we don’t want to compromise the survival of our native species any further due to invasive threats,” Quintana said.
Massive infestation
According to Asean Centre for Biodiversity Executive Director Theresa Mundita S. Lim, more than 200 nonnative species have already been recorded to have been introduced in the Southeast Asian region alone.
“More than 40 of these [nonnative species] are listed in the IUCN [International Union for Conservation of Nature] as the world’s worst invasive alien species,” Lim, a former director of the DENR’s Biodiversity Management Bureau (BMB), said.
The Asean has one of the highest proportions in endemic species on a per-country basis compared to most tropical regions, Lim said.
Vulnerable island biodiversity
Championing the mainstreaming of biodiversity conservation and protection in the Asean, Lim said some countries in Southeast Asia are with islands that are home to unique species that are found nowhere else in the world.
“The Asean also hosts a variety of forest ecosystem types, with each type having its own unique combination of species. The Philippines alone has 12 types of forest ecosystems, which include not just a forest of tall dipterocarps, but also, pygmy forests that are found on islands like Dinagat, and in mountain protected areas like Mount Hamiguitan and Mount Apo. From land to water, the region is blessed with lakes and river ecosystems that support a variety of freshwater fisheries that thrive nowhere else naturally, but in these bodies of water,” she said.
Such a situation makes the region, and island countries within the region, like the Philippines, very vulnerable to the impacts of IAS, she said.
“Introduction of exotic [nonnative] species, whether intentionally or not, has already resulted in observed depletion of our native species. Invasive alien species threaten native species by feeding on them, by competing with them for food and space or introducing pests and diseases,” she explained.
Economic, cultural impact
According to Lim, IAS not only affect the environment, but also agriculture and health, and result in significant economic losses.
“The problem is, we only start paying attention to them when their effect can be felt, which is usually already a bit late. So we need to focus as well on prevention and early detection,” she said.
The loss of the variety of food and nutritional choices on the table would be the most obvious impact of some of the most problematic IAS we have in the Philippines, she said.
According to Lim, most of the freshwater fish now commonly served for food are introduced into our water systems, like tilapia and cream dory.
“We, of course, have heard so much about increasing catch of knife fish and janitor fish in Laguna de Bay and Marikina River, where ayungin and kanduli used to thrive in abundance. We have also seen how the Brazilian mahogany, with its ‘propeller-like’ seeds and the ‘Piper aduncum’ weed can affect the regrowth and regeneration of natural vegetation for watershed areas, and for the restoration of vital ecosystems and ecosystem functions. Then, we also have the golden apple snails, the European squirrels, the cane toad, and other known ‘invasives,’ all of which are impacting our biodiversity, and in some areas, our culture and our way of life,” she said.
A cause for alarm
Assistant Secretary for Staff Bureaus Ricardo L. Calderon, the concurrent director of the DENR-BMB, said the massive infestation of ecosystems, especially in Philippine forests is a cause for alarm.
Calderon, a forestry expert, said invasive alien species have been unintentionally introduced into the wild not knowing their adverse environmental impact.
He agreed that IAS “seriously threaten our ecosystems, especially in flora. We are losing our native species because of them.”
Unintended release, unintentional effect
He said while some of IAS were introduced “in good faith” or “with good intentions” their spread, as a result of the unintended release into the wild, do more harm than good to new environments.
Calderon cited the case of the gmelina, a fast-growing tree that tends to grow from 3 meters to 30 meters tall or even higher, which have been proliferating in protection forests.
Good for production forest, gmelina tends to compete with native trees, which it outgrows and eventually kills in protection forests.
“These invasive species that were introduced in the past eliminate native species or prevent their growth. For example, gmelina is supposed to be for production forests, but not for protected areas. They have been planted in protection forests, unintentionally,” he explained.
Prevention better than cure
According to Calderon, while the problem brought by invasive alien species is not as extensive as they have been reported or believed to be, the DENR is not taking the challenge posed by their proliferation sitting down.
“We have a number of interventions and with this [18th] Congress, we hope to come up with an action plan to prevent their proliferation,” he said.
“Remember, prevention is better than cure. But since some of these invasive alien species have been introduced—and they are here now and part of the food chain—we must find a way to control it, manage it and make the most out of it,” Calderon said.
He cited, for instance, the unintentional release of pets, citing the case of the Chinese softshell turtle, which is considered a menace to fishpond owners in Central Luzon. The Chinese softshell turtle has also been spotted in Laguna de Bay and other water bodies.
The aggressive turtles grow fast and have a big appetite for fish and other aquatic life—feeding on tilapia, also an invasive alien species, and prawn being cultured by fishpond operators.
Calderon said the gathering of expert hosted by the DENR-ERDB aims to tackle invasive alien species and find ways to control and manage them, if not prevent their proliferation, hence, it is important to define, so as to identify, what is invasive alien species.
“One species may be invasive in the Philippines but not in another or other countries where they occur naturally,” he said in a mix of Filipino and English.
Maximizing economic potentials
He said identifying the various threats of invasive alien species, and how to maximize their economic benefits, would also be a bonus output of the international conference.
For the Philippines, learning how to treat IAS at the national level is a must.
But he said the Philippines is also looking forward to forging ties with its neighbors in the Asia Pacific to address the threats while exploring their potential economic benefits.
“Hopefully, the direction is to come up with a regional action plan. But first and foremost, we must have a national action plan. This is being worked out by the DENR’s various bureaus. How do we control it, and how do we prevent its entry,” Calderon said.
Image credits: PRRC