Earlier this month (July 2012), the National Academy of Science & Technology discussed the ecological importance of biodiversity in Philippine freshwater lakes and marshes.
Two lakes (Laguna de Bay and Lake Lanao) and one marsh (Agusan Marsh) were used as examples to illustrate the concept of productivity.
All three were shown to have high secondary productivity in terms of fish biomass, although these three aquatic ecosystems were not quantitatively compared with each other.
If these three ecosystems are compared, I would expect Agusan Marsh to have the highest natural production of fish per unit area.
This is because of the presence of crocodiles in this marsh, and the absence of these top predators in the other two lakes. A research project should be able to demonstrate this fact.
Crocodiles, despite the negative bias of many people, are very useful group of species, in that they recycle the nutrients from their prey through the large amounts of wastes they produce.
Their prey consists of animals from terrestrial and aquatic habitats, thus, serving to connect terrestrial and aquatic habitats.
The nutrients in the water of lakes and marshes become part of the food chain from plankton to fish. This explains why aquatic environments where crocodiles are present are very productive.
Crocodiles, because of their large biomass at the top of the food chain, have a large impact on the aquatic environment.
They have been called keystone species because they structure aquatic and adjacent terrestrial biotic communities.
It is unfortunate that many of our people tend to look only at the destructive effects of crocodiles on people, and ignore the benefits from their presence in our environment.
These destructive effects are not entirely of their own making; they are due to the encroachment of humans in areas where they used to be found.
Fortunately, some of our people have lived side by side with crocodiles without serious problems.
To give some examples, people in Ligawasan Marsh have co-existed with crocodiles for centuries. Ligawasan Marsh is a very productive area with a high biodiversity. I am told that some tribal groups have also been living in the same forest environment together with crocodiles in the Agusan Marsh.
On Siargao Island, people have lived in the vicinity of an extensive area of mangroves, which produce large fishery yields as a result of the presence of crocodiles.
Some islands south of Palawan have crocodiles and people living together.
We, humans, of a higher intellectual capacity, should find ways to exist side by side with the ancient survivors or living fossils such as crocodiles that have existed since 200 million years ago, by finding ways to allow these species to survive and to continue to benefit our country and the world.
In the Philippines, the Department of Environment & Natural Resources, and the Protected Areas & Wildlife Bureau are the government agencies charged with the responsibility of managing and protecting the species of wildlife that are considered by the country and the international community as seriously threatened with extinction.
These two agencies work concerned with crocodiles such as the IUCN and the Crocodile Specialist Group.
The two Philippine crocodile species are examples of these threatened species. Let us all follow the directives of the national and international agencies with regard to matters having to do with crocodiles, the living fossils among our biodiversity species.
