Malaysian Borneo; first impressions

I have just come back from a couple of very interesting (and enjoyable) weeks in northern Borneo, in the Malaysian states of Sabah and Sarawak. It was an unexpected trip, in that I was asked to accompany a natural history tour for reasons that are of no great interest to anyone else in this context. My explorations beyond Australia (other than a time in Europe over 30 years ago) have hitherto been limited to South America and Africa, so this was a real opportunity for me to see a part of the world with a very different biological history. 

Doubtless I'll be returning to Borneo in future postings here, but I've been asked to offer something of an overview while it's all still fresh in my mind, and so here it is. Firstly, in case you're not very familiar with the mighty island, here is where it is and how it's divided up.

My trip was limited to the 25% of the island which comprises the two Malaysian states of
Sabah (in the north-east) and Sarawak (in the north-west). The boundary between them is just to
the east of the tiny Sultanate of Brunei, which appears above as a rough W on the north coast.
The southern 75% of the island comprises Indonesian Kalimantan.
Map courtesy of Wikipedia.

It is the third largest island in the world (other than continents, including Australia, only Greenland and New Guinea are larger). Crucially, in terms of understanding its biology, it lies immediately to the west of Wallace's Line, named for the great 19th century English biologist Alfred Russell Wallace who recognised the clear distinctions between the fauna of Asia and Australia-New Guinea. Put simply, to the west of the line we find primates and hornbills, which to the east are replaced by possums and cockatoos. The line corresponds to deep-water trenches which mean that the land masses on either side of them have never been connected during glacial periods of low sea level. Of course things are never that clear cut in the real world, and in Sulawesi immediately to the east (on the edge of the map above) there are elements of both faunas, but it's a very useful rule of thumb. 

Thomas Huxley - the zoologist contemporary of Wallace, who coined the term Wallace's Line in 1868 - had it
running west of the Philippines, but now we recognise Ernst Mayr's version, which excludes
the Philippines from Wallacea. Wallacea is a region of somewhat mixed faunas between the largely 'pure'
Asian region and Australia.
Map courtesy of Wikipedia.

And to a visitor from Australia the 'exotic' nature of the fauna is very evident. (Reiterating, this is just an overview and I'll be revisiting these wonderful organisms in future postings.)

Rhinoceros Hornbill Buceros rhinoceros, Sepilok, Sabah.
A truly thrilling sight for a new-comer; apart from being so 'different' to our eyes, it
is quite enormous - up to 1.25 metres long.

Proboscis Monkey Nasalis larvatus, Labuk Bay, Sabah.
Another very special moment - this is one of the many Bornean endemics.

There are several major habitat types, with their own distinctive species, but the majority of the island is - or was - dominated by rainforest. I have to insert the proviso into that sentence because according to one apparently knowledgeable local we spoke to, 55% of the rainforest has disappeared in just the last 20 years, and most of the blame must be allocated to the pernicious palm oil industry. Any drive in Borneo will expose you to seemingly endless kilometres of the monoculture. It is not the only reason that the Sumatran Rhinoceros is now extinct in the wild in Borneo, but it is certainly a contributing one.

Rainforest, Sepilok, above and below.

Rainforest anywhere carries its challenges for birders - and I had to rely on my own resources for bird identification, and of course didn't know the calls - but for some reason Borneo seems to demand especially hard work to find birds. It seems that although the diversity is undoubtedly there (over 670 species recorded), overall numbers are strangely low. Various theories have been offered, but none of them seem very convincing; it really is quite odd.

It's not just rainforest either; it's strange to see no lapwings along roadsides, no kites or vultures overhead and no ducks. (They exist, but I saw one flying overhead in my entire time there.) Gardens,even near rainforests, are also surprisingly quiet.

In addition to the lowland forests shown above, there are montane forests on the mountain ranges too.

Lianas in montane forest, Kinabalu National Park Headquarters (1560 metres above sea level).

Chestnut-hooded Laughing-thrush Garrulax treacheri, a widespread and most attractive
bird of the montane forests.

Rajah Brooke Birdwing Trogonoptera brookiana, also at the Kinabalu NP HQ.
An incredibly dramatic inhabitant of the dark rainforest where the electric blue shines against the
black of its forewings.
(I am actually a little perplexed by this one; it is described as having 'electric green' flashes on the wings and this looks more like T. trojana, but that is endemic to the Philippines. Any pointers gratefully received!)

 Higher up still are the misty cloud forests; the best-known - and some of the best - examples are to be found on Mount Kinabalu, but we were there only days after the tragic earthquake and landslides closed the upper mountain for months.

Mount Kinabalu above Kundasang; the scars on the slopes mark where landslides destroyed the forests.

Cloud forest on Gungung Alab, Crocker Range, Sabah.

Bamboos in the same cloud forest.

A diverse understorey including ferns, orchids and lycopods on Gungung Alab.

Scattered around the coast are low-nutrient peat swamp forests, which are low in wildlife diversity even by Bornean standards, but which have their own specialist species.

Klias Peat Forest, Sabah.

Among the specialties of these nutrient-poor soils are the wonderful pitcher plants, which supplement their nitrogen intake by trapping and digesting small animals (which can include smaller vertebrates).

Nepenthes bicalcarata, Klias Peat Forest.
These amazing plants warrant - and will receive - their own posting in due course, but briefly,
the pitcher forms from an extension of the leaf mid-rib beyond the end of the leaf.
The lid keeps the liquid within from being too diluted; it is both sweet to attract insects, and with surface
properties that prevent insects from climbing out.
Moreover the inside is coated with waxy material almost impossible to climb, and the rim can
have downward-pointing spikes around it. The liquid is not digestive; the victim simply drowns and decomposes.
Borneo is pretty much the world hot-spot for them.

Adjoining the peat forests are mangroves, almost all around the coast (originally at least).

Mangroves, Pulau Tiga, an island off the coast of Sabah.
Proboscis Monkeys, among many other species, are mangrove specialists.

For the traveller - including naturalists - infrastructure is generally good, with an excellent road system and good hotels and lodges. People are friendly and food is excellent. By western standards things are pretty cheap, at least away from the tourist honey-traps. For some strange reason, though Sabah and Sarawak are just two states of the same country, travelling between them involves all the rigmarole of international travel, including having passports stamped by immigration officials; allow time for this!

Well, I think that will do for an overview; more detail in weeks to come. But if the opportunity arises to go there, please seize it!

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