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Swinging to uncertainty
Published on: Sunday, March 19, 2017

By David Thien
KALIMANTAN in Indonesian Borneo has been regularly for decades been contributing greatly to a haze that affects the region.

So bad is the phenomenon within the Kalimantan provinces that huge numbers of apes, notably Orangutans and Proboscis monkeys have seen their numbers dwindle.

Concerned researchers like Stan Lotha of the Czech University of Life Sciences call for updated proboscis monkey population surveys and protecting their habitats that are also being destroyed for shrimp (prawn) and milkfish farming.

“Proboscis monkeys are one of the fastest disappearing animal species in Kalimantan,” he said.

“The implication is serious. We need to maximise efforts to protect the remaining undisturbed and unburnt forest which represent a crucial proboscis monkey habitat.

“We need to protect regenerating burnt and secondary forest as they represent a suitable habitat that can contain significant population of proboscis,” he said.

As an example of the seriousness of the situation, the South Kalimantan population of the threatened species in Pulau Kaget Nature Reserve is no more!

Until 1997, this small, isolated population estimated at 300 had been pushed towards the fringes of the reserve by illegal agricultural expansion.

As food sources became depleted, the population apparently exceeded the decreasing carrying capacity of the reserve and was reported to be starving to death.

As a fast-track solution, 84 remaining proboscis monkeys were translocated to nearby, unprotected sites, resulting in 13 fatalities.

An additional 61 proboscis monkeys were taken to a zoo, where 60 per cent died within four months of their capture.

There was neither a proper pre-translocation assessment of the suitability of the release site nor a proper post-translocation monitoring programme for the released proboscis monkeys.

“The population is more fragmented than we thought, is harder to protect than we thought, and is faster declining than we thought,” Stan said.

It is very difficult to keep proboscis monkeys in captivity because they are highly sensitive creatures and few zoos have been successful. However, with very careful husbandry, it is possible keep them in captivity.

Problems in Kalimantan have been made worse by access roads, which fragment populations and increases inbreeding. Also, many plantations have put up electric fences around them.

Selective logging sometimes destroys preferred sleeping and feeding trees.

After logging, forests are sometimes poisoned to prevent undesirable vegetation from regrowing with the goal of increasing timber productivity as the forest regenerates.

This likely affects proboscis monkeys adversely and prevents them from living in those habitats.

In addition, human immigration from other areas is increasing land use and other sources of disturbance.

In some areas, proboscis monkeys are persecuted as crop raiders and are poisoned.

In some regions, they are hunted for food, and in others, they are hunted recreationally, and as bait or feed for lizards, snakes and crocodiles

Their sleeping habits near rivers also make them especially susceptible to hunting from boats.

In riverine areas of increased human activity, pollution may increase, especially due to spilled oil and fuel from boats, but also from human septic waste. All of these types of pollution have the potential to alter proboscis monkey habitats.

Activities of humans, such as fishing, fish-salting and smoking, trapping, and encampments, all disturb proboscis monkeys, keeping them away from preferred areas along rivers.

Other activities that also disturb proboscis monkeys include rattan collection, the collection of honey from bees, and firewood gathering.

Further, increasing boat traffic, sometimes as a result of gold extraction along rivers, disturbs proboscis river crossing behaviour and causes declines in population density and group size.

Also, increased boat traffic threatens proboscis monkeys due to the potential for collisions while they are crossing rivers.

Kalimantan is Indonesia’s best success story in human transmigration which sadly led to the decline of the proboscis monkey population due to the indifference of politicians who get no votes from primates.

One of the fatal mistakes people – having no idea of the proboscis diet – make is to feed them bananas.

This is due to the mistaken belief that all monkeys love bananas.

Oswald Braken Tisen of the Sarawak Forestry Corporation (SFC) said bananas bloat their digestive organs with adverse reactive complications, leading to death.

Proboscis, unlike their Orangutan and rhesus cousins, are leaf-eating monkeys who thrive on forest produce and young mangrove leaves.

“They are protected under the Wildlife Protection Ordinance 1998 (WPO 1998) of Sarawak and the penalty under its Section 29 (1) (b) provides for two-years imprisonment and RM30,000 fine for infringement.”

Proboscis have a large and swollen stomach that is made up of chambers containing a special cellulose digesting bacteria that helps to break down the leaves.

The proboscis monkeys supplements its diet by eating other plant matter including shoots, seeds and unripe fruits along with edible insects on occasion and does so predominantly in the trees, preferring not to come down to the ground. The destruction of forests trapped some of them in mangrove areas.

Proboscis monkeys live in family groups of up to 12 females and one dominant male, while younger males live together in bachelor groups until they are ready to challenge an older male for his harem.

In Sarawak, hunting, and habitat loss – land clearing for agriculture schemes and logging are the main threats to the survivability of proboscis monkeys.

Proboscis monkeys in Sarawak, like elsewhere, are also under continued threat of deforestation to make room for increased oil-palm plantations and aquaculture schemes as they are unable to cross the plantations, greatly disrupting their foraging, social structure, mating patterns, and wild habitat.

Heavy habitat fragmentation hinders their ability to disperse, mate, interchange its gene pool, and acquire adequate food resources.

Compared to Sabah’s estimated 6,000 proboscis monkeys based on 10-year-old data, Sarawak admits having less than 1,000 proboscis monkeys.

The most controversial conservation strategy to protect the proboscis monkey is the translocation of wild populations.

The increasing and seemingly inevitable (unless immediate action is taken) loss of suitable habitat could lead to the translocation of individuals who are at risk of local extinction.

However, as seen in zoo translocation failures, this species is highly sensitive and tend to have high mortality rates when moving.

Translocation can also introduce new diseases and parasites to once unaffected areas, disrupt the ecosystem and food resources, and unsettle the monkey’s social structure.

Even if these risks are avoided, the real problem lies in the translocation destination.

Borneo’s rainforest, like so much other tropical rainforest in the region is under constant threat of destruction.

If translocation were deemed absolutely necessary, the specie’s final home should not only be appropriate to the monkey’s various needs – but entirely safe from habitat destruction.

With its many risks, this debatable method is extremely irresponsible unless the necessary precautions have been considered.

Through analysis of the conservation actions, it is clear the monkey’s long-term survival is dependent on the protection given by gazetted parks and wildlife sanctuaries.

“In Sarawak, the breakdown estimates of the proboscis monkey populations are 160 in Maludam, less than 200 in Sarawak Mangrove, 106 to 144 in Bako National Park where tourists visit to sight the proboscis monkeys, and about 300 along the whole of Brunei Bay areas including Limbang and Lawas.

“As steps to control hunting, the Wild Life Protection Ordinance 1998 introduces a total ban of all commercial sales of wildlife and wildlife products, if taken from the wild.

“The supporting legal rules have very strict controls for any captive-bred wildlife, to stop farms being a conduit for animals hunted in the wild,” Oswald said.

Wildlife included in the trade ban is “all wild mammals, birds, amphibians and reptiles”.

The continuing loss of riparian-riverine forest, coastal lowland forest, peat swamp, freshwater swamp forest, and mangroves. Their diet is mostly folivorous and frugivorous, as it prefers unripened non-fleshy fruits and young leaves but it does fluctuate throughout the year depending on local availability.

The rather lethargic behaviour of this species makes it more vulnerable to poaching, which can lead to whole populations going extinct with little effort by hunters.

Along with being hunted for food as bush meat this species is also hunted for bezoar stones, which are masses usually stuck in the stomach believed to have healing powers in traditional folk medicine.

Due to all of these threats, in the past 35-40 years, the populations have declined by more than 50 per cent.

The threats the proboscis monkey faces are clear and imminent. In the global conservation of the proboscis monkey, the species is listed under Cites Appendix I.

Appendix I lists the species which are most endangered among Cites-listed plants and animals and are therefore prohibited from all international trade. In addition to its listing under Cites, the proboscis monkey is also protected by law throughout its native Borneo range, although enforcement of laws is much to be desired.

Oswald suggested that Sarawak’s Limbang to Lawas existing troops of proboscis monkeys should be managed in conservation with nearby Brunei’s to better enhance their gene pool interchange and long-term survival in protected areas in matters of transboundary and connectivity cooperation even with Sabah’s Klias population.

There was no speaker on the Brunei situation at the workshop conference although a presentation slot was listed.

Brunei has only one population in their riverine estuaries.

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