A green lung September 6, 2015, Sunday Mary Margaret
The mud lobster’s burrowing habit recycles nutrients and allows aerated water into the soil.
THE wooden boardwalk flows through the 24ha Kota Kinabalu Wetlands, one of the last remaining remnants of the formerly extensive mangrove forest that lined and protected much of the coastline around Sabah.
This relatively stable wetlands with a large number of species is nestled at the foot of Signal Hill and a mere 15-minute drive from the heart of Kota Kinabalu. Here it is possible, for a short while any way, to imagine people of Sabah slogging their way through the tangle roots. That is until you catch sight of the almost indestructible plastic bags, slippers or containers … or look up to see the skyscrapers circling this green lung.
Between 1980 and 1990, individuals interested in nature discovered that this patch of mangrove was in relatively good condition. The Kota Kinabalu Bird Sanctuary was created in 1996. The Likas Wetlands Management Committee was formed in the same year to administer this much-needed green patch. Then in 1999, it was declared a Cultural Heritage Site. Kota Kinabalu Wetlands was opened to the public in 2000.
The management of the site was taken over by the Sabah Wetlands Conservation Society in 2006. This society has the overall objective to conserve and manage Sabah’s wetlands through advocacy, education and research, including the management of Kota Kinabalu Wetlands.
This wetlands area is an easy entry into a forest type that is often mistakenly thought to be smelly and muddy wastelands. Mangrove forests are the opposite — they are teeming with life; their complex intricately connected food webs include surrounding forests, grasslands and water.
The mangrove forest perches on a complex web of intertwined stilt roots that lift it above the muddy soil.
The mangrove forest is striking as it perches on a complex web of intertwined stilt roots that lift it above the muddy soil. It occupies a harsh salty oxygen-starved but fertile environment.
Mangroves refer to different species that have adapted to survive and thrive in this harsh environment. In these salty conditions, which can be inundated with seawater twice a day, species generally use one of three adaptations to survive. Some exclude the salt by having root cells filter it out. Some accumulate salt in the tissue, while others excrete salt through, for example, dead leaves.
The 10 mangrove tree species found in the Kota Kinabalu Wetlands provide the physical link between the land, the tidal waters and the variety of animals that occupy ecological niches. The boardwalk enables visitors to see and experience first-hand the diversity and beauty of the forest.
The Sabah Wetlands Conservation Society has installed a series of information boards on the invertebrates (micro-organism, insects, molluscs, crustaceans), fish, amphibians, reptiles, birds and mammals, as well as the plant life. These informative boards provide insights to the forest, its ecology and inhabitants.
Ninety species of migratory and resident birds have been documented in the Kota Kinabalu Wetlands. Abundance of roosting, nesting and feeding sites bring in the birds. The brilliant white egrets, one of the three species frequently sighted, are easily seen against the dark green of the leaves. Key differences, as suggested by their name, Little Egret (Egretta garzetta), Intermediate Egret (Egretta intermedia) and Great Egret (Ardea alba) are the size. Another easily recognisable resident and largest bird found in the wetlands is the Purple Heron (Ardea purpurea). It nests among the fern, Piai Raya (Acrostichum aureum) a member of the Pteridaceae family that can be found in an area away from the sea.
Kota Kinabalu Wetlands has recorded 20 species of fish, 13 mollusc species, 14 crustacean, nine insects and five different species of reptiles. The affect of mud lobsters, a crustacean, which is not a lobster but more closely related to shrimps, demonstrates the complex interaction between species.
Mud lobsters (Thalassina sp) are members of the Thalassinidae family, which are sometimes called the farmers of the mangrove. These shy creatures build strange volcano-like mounds of mud as they burrow through the soil. It is believed that they eat organic matter in the mud as they dig their way through. The processed or recycled mud develops into the strange mounds, which then provide quarters for snakes, ants, crabs, spiders, warms, molluscs and shrimp.
Mudskippers and other aquatic animals take shelter in the pools during low tide that are created by the mud lobsters’ burrowing habit. Collared kingfisher (Todiramphus chloris) have been known to nest on the large mounds. Plants also grow on these mounds.
The mud lobster’s burrowing habit recycles nutrients and allows aerated water (water with oxygen) into the soil. Some plants grow better on mud lobster-tilled soils including mangrove seedlings. Mud lobsters are part of the food chain and eaten by other animals including birds. In the tropical Pacific they are hunted as food, however, this has fortunately not caught on in other areas. Mud lobsters are considered a pest because their burrowing habit weakens the bunds or edges that form the basis of lobster or shrimp farming ponds.
The ecological role of mud lobsters in the mangrove forest is a single example of the complexity and dependence of the fauna and flora of mangrove forests. As mentioned, the mangrove forest provides the link between the land and the sea, but they too benefit from the activities of the inhabitants that take up residence. The influence and the benefits of the ecological diverse mangrove forests extend far beyond their boundaries.
For information on Kota Kinabalu Wetlands read ‘The Mangroves of Kota Kinabalu Wetlands’, Sabah Society Journal Vol. 28 by Lee Young Ling 2011; and ‘Mangrove Fauna and their Adaptations in the Kota Kinabalu Wetlands’, Sabah Society Journal Vol. 28 by Lee Ka Han, 2011.
Collared kingfisher have been known to nest on the large mounds created by mud lobsters.