DENR-XI airs concern over spread of invasive species
by RG Alama
Davao City (25 May) -- The Department of Environment and Natural Resources is worried over an emerging alien invasion.
This is not the science-fiction kind but rather the proliferation of non-native species of flora and fauna which are threatening endemic plants and animals, thus affecting biodiversity.
DENR-XI Regional Technical Director Emmanuel Isip said that in order to be considered invasive, non-native species must have the following characteristics; they have the ability to reproduce quickly, can superbly adapt to a new environment and is a voracious eater.
Invasive species are also grouped into marine and terrestrial. Among considered as marine invasive species include the janitor fish, carps, big mouth bass, African catfish. Terrestrial invaders include ipil-ipil (leucaena leucocephala), African Tulip, Hagonoy (Chromolaena odorata), Lantana (Lantana camara), golden kuhol snails.
According to Isip, these species compete and kill out native plants and animals. He said for example Hagonoy or bitter bush which is similar to an eggplant in appearance is a pest in pasture lands as these are toxic to livestock when eaten. "pag makain ng baka or kambing ang hagonoy. Nagkakasakit yan sila, mga iba namamatay." (if hagonoy are eaten by cows and goats they become sick and some would die.)
Invasive species like Hagonoy and Lantana has allelophatic effect on surrounding organisms. Allelophaty is biological trait which a certain species can control the growth of surrounding species. Hagonoy and lantana have the ability to choke off surrounding vegetation.
Isip said that climate change is advantageous to the proliferation of these invaders as they could well adjust to the environment while native species are stressed with the warming climate.
These invaders were brought over either natural migration through bodies of water or vectors like migratory birds or they were brought by man as exotic pet or ornamental collections.
He said that some known invasive species have been brought over to develop agriculture such as carps, golden snails, catfish and tilapia. Isip said that those who are introducing new species to bear in mind that there should be precautionary measures to protect other native species.
He cited that golden kuhol snails which were introduced for food is a pest in many rice farms, carps are threatening populations of native fishes in Cotabato and salt-water Tilapia poses a threat to other native saltwater fishes.
DENR-XI Regional Executive Director Jim Sampulna said that introduced invasive fishes are threatening the freshwater fish Tabong, which is endemic in Cotabato. Director Sampulna describes Tabong as a very tasty and delicious fish which is in danger from being wiped out by introduced species like carps and big-mouth bass.
Isip also appealed to pet shop owners especially fish collectors to avoid disposing unwanted collections into bodies of water. He cited the case of janitor fish which was once an aquarium fish. When it was released into the wild, these fishes grew and multiplied so quickly that they became pest. Agusan marsh is threatened by these fishes which is voracious eater devouring eggs of native fishes and wiping out their food supply.
Among the remedies to control these invaders are strict quarantine and utilizing the beneficial usage of these species. He cited that the skin of American frogs are being used as leather while golden kuhol are being used as feeds for ducks. (PIA XI) [top]