The Malay Archipelago

I live on the fringes of the Malay Archipelago. At least that’s what the naturalist Alfred Russel Wallace called it. In his famous book of that name, he wrote:

The Malay Archipelago extends for more than 4,000 miles in length from east to west, and is about 1,300 in breadth from north to south. It would stretch over an expanse equal to that of all Europe from the extreme west far into Central Asia, or would cover the widest parts of South America, and extend far beyond the land into the Pacific and Atlantic oceans. It includes three islands larger than Great Britain; and in one of them, Borneo, the whole of the British Isles might be set down, and would be surrounded by a sea of forests. New Guinea, though less compact in shape, is probably larger than Borneo. Sumatra is about equal in extent to Great Britain; Java, Luzon and Celebes are each about the size of Ireland. Eighteen more islands are, on the average, as large as Jamaica; more than a hundred are larger than the Isle of Wight; while the isles and islets of smaller size are innumerable.

Wallace claimed to have fond a line running through the Malay Archipelago that separates islands with Asian flora and fauna from those with plants and animals more like those of Austalia. This is now called the ‘Wallace Line’. It runs between Bali (on the western, Asiatic side) and the lesser-known nearby island of Lombok (on the eastern side).

Why does the Wallace Line run right between these two nearby islands? Wallace had a theory: it’s because the ocean between them is very deep! Even when sea levels were much lower—for example during the last ice age—and many islands were connected by land bridges, Bali and Lombok remained separate. Indeed, all the islands on one side of the Wallace Line have been separate from those on the other side for a very, very long time.

How long? Maybe forever, since Australia used to be down near Antarctica. I don’t really know. Do you? I’ve brought Wallace’s book to read with me, but that’s probably not the best way to find out. It should be easy to look up.

However, everything gets more complicated when you examine it carefully. Now the Wallace Line is just one of several important lines dividing biogeographical regions in the Malay Archipelago:

Sundaland is the land shelf containing the Malay Peninsula, Borneo, Java, and Sumatra. Sahul, also known as Australasia or simply Australia, is the land shelf containing Australia and New Guinea. Wallacea is a group of islands between Sundaland and Sahul—islands that haven’t been haven’t been recently connected to either of these land shelves.

The Wallace line is the western boundary of Wallacea, separating it from Sundaland. The Lydekker line, named after Richard Lydekker, is the eastern boundary of Wallacea separating it, from Sahul.

Wallacea is the red, heart-shaped region here:

The blue line through Wallacea is called the ‘Weber line’. Max Carl Wilhelm Weber argued that this line, not the boundary between Bali and Lombok, mark the major boundary between Asiatic and Australian organisms.

I bet the real truth is even more complicated.

Anyway, today my wife and I are going to Lombok. We’ll say there until the 21st, based in Senggigi; then we’ll go to Bali and stay in the town of Ubud until the 25th. So, we’ll have a good chance to see the difference between Asiatic and Wallacean flora and fauna.

17 Responses to The Malay Archipelago

  1. John Baez says:

    Due to the resounding lack of interest in this blog entry, I’ve added some more material on the Wallace Line, Weber Line and Lydekker line. I would like to understand how sharp these lines are. if we drew the frontier of each species, how much would they bunch up along a few key lines?

    • Florifulgurator says:

      No lack of interest, rest assured.

      The first thing I would look for when taking a closer look (iff time allows) would be the island of Flores. A remote relative had speciated there: homo floresiensis. There are other examples of insular dwarfism found on Flores.

    • The first map has made me muse quite off on a tangent: How do ice ages end? Methinks the core ingredient is fire: Despite the glaciation there’s lots more land for plant life, particularly forests. Plus, the (albeit smaller) ocean has higher phytoplankton activity (cf. thermocline). Thus more oxygen. Result: Increasing forest fire frequeny. I’m not sure about the nitrogen (oxide or not). It seems there could be less in the air (nitrogen fixating plants plus nitrogen adsorption by char coal) – less fire suppression. Since CO2 is a trace gas, it can accumulate from forest fires unabated until the climate/biophysical system flips and oceans go rising again.

      • Frederik De Roo says:

        Florifulgurator said:

        lots more land for plant life, particularly forests

        Are you sure? I thought that most climates during glacials were drier, and that there were less forests.

        See e.g. Last glacial maximum, Wikipedia:

        In warmer regions of the world, climates at the Last Glacial Maximum were cooler and almost everywhere drier. In extreme cases, such as South Australia and the Sahel, rainfall could be diminished by up to ninety percent from present, with floras diminished to almost the same degree as in glaciated areas of Europe and North America. Even in less affected regions, rainforest cover was greatly diminished, especially in West Africa where a few refugia were surrounded by tropical grassland.

        Most of the world’s deserts expanded. Exceptions were in what is now the western United States, where changes in the jet stream brought heavy rain to areas that are now desert and large pluvial lakes formed, the best known being Lake Bonneville in Utah. This also occurred in Afghanistan and Iran where a major lake formed in the Dasht-e Kavir. In Australia, shifting sand dunes covered half the continent, whilst the Chaco and Pampas in South America became similarly dry. Present-day subtropical regions also lost most of their forest cover, notably in eastern Australia, the Atlantic Forest of Brazil, and southern China, where open woodland became dominant due to drier conditions.

        I don’t understand how you conclude that oceans would have had higher productivity during glacials. Could you expand your line of thought?

  2. Graham says:

    One species wouldn’t bunch up. A big animal managed to get across the sea around 50,000 years ago.

  3. John Baez says:

    My wife Lisa and I are on the west coast of Lombok, the island due east of Bali. Yes, it’s a beautiful tropical paradise! But since I’m interested in climate science, I can’t help noting that it gets quite dry at this time of year—as witnessed by the dry grass near the coast:

    The cattle are thin, grazing on what little they can find. But later in the autumn the rains come, and the grassy hillsides spring to life!

  4. Tom Leinster says:

    I have a bit of a soft spot for Wallace. Among other things, his 1878 monograph Tropical Nature, and Other Essays contains the following description of a tropical forest:

    If the traveller notices a particular species and wishes to find more like it, he may often turn his eyes in vain in every direction. Trees of varied forms, dimensions and colours are around him, but he rarely sees any one of them repeated. Time after time he goes towards a tree which looks like the one he seeks, but a closer examination proves it to be distinct. He may at length, perhaps, meet with a second specimen half a mile off, or may fail altogether, till on another occasion he stumbles on one by accident.

    This beautiful short passage is so evocative that it’s been quoted several times in theoretical papers on the measurement of biodiversity.

    • John Baez says:

      I’m greatly enjoying Wallace’s book The Malay Archipelago. But there’s certainly no shortage of things that make me notice how sensibilities have changed. The first thing he does with any interesting bird or mammal is try to shoot it. He’s very impressed by orangutans—for example, how they keep struggling to climb despite severe gunshot wounds. Also, he’s convinced that the colonial powers have a parental duty to discipline the natives, for their own benefit.

      Of course, people will look back on us and find us equally offensive.

  5. John Baez says:

    A bit of amateur anthropology:

    On Sunday we saw four wedding processions here in Lombok—that’s the day people have them. These processions cap off what sounds like a long and complicated process. First the man and woman agree to get married. Then the man ‘steals’ the woman from her family… they sneak off. Then he agrees to pay the price demanded by her family—though if my understanding of local culture is any guide, some bargaining might be involved. A well-educated woman can cost a lot, because high school and college are not free here, and the woman’s family wants to recoup the money they spent on raising her. Younger, less-educated wives are cheaper.

    The grim, ashen-faced fellow at left is the groom. He was on the verge of tears. We never found out why.

    Q from “finch wench”: Is the demand for the more mature educated woman higher than for the younger “investments?”

    A: Good question! I don’t really know. Our guide told us that most couples marry at the age of 20-23, and do this in order to “have fun”: in the villages, at least, premarital sex is a serious no-no. This doesn’t suggest a high overall demand for more mature, educated women. But there must be lots of different social strata with different habits. For example, only 15% of the people in Lombok are Balinese, but they’re very wealthy and powerful: the Balinese invaded Lombok some centuries ago and though they’ve been pushed back by the native Sasaks, they’re still play an important role.

    (The Balinese are Hindu, the Sasaks are Muslim. I’m sort of bummed that I missed going to the only temple in the world where Hindus and Muslims both worship! That would have been interesting.)

    In a wedding procession on Lombok, the bride’s family officially ‘meets’ the groom’s family—though they’ve actually spent the previous evening partying together. So it actually starts as two separate processions, walking toward each other down the street. And each one has a band! Above you can see two guys playing electric guitar—but at left, hard to see, there’s a guy playing keyboard. There’s also a singer, not shown here—and in front of the whole crew, kids gyrate wildly to the deafening music.

    All this is a substitute for the more traditional gamelan. We saw one of those at the wedding procession of a more wealthy couple.

    Q from Harrison Brown: Is there any attempt by these bands to imitate the traditional gamelan sound? Or is the music they play more Western-influenced?

    A: These bands don’t seem to be imitating gamelan music at all. Different bands I heard played in different styles. This particular one sounded a bit like Indian pop music to my uneducated ear. However, there are many styles of Indonesian pop music, as you’d expect from an ethnically diverse country with hundreds or even thousands of islands… and I’m sure they were playing one of these styles.

    Later our guide took us to Mataram, the capital of Lombok, and we bought a pirated DVD containing 13 CD’s worth of Sundanese gamelan music for the equivalent of $1.20. I love this Sundanese stuff.

    Our guide had a DVD of “pop Sunda”, which is strongly gamelan-influenced music played on modern instruments—somewhat cheesy synthesizers and drum machines, but still fascinating. I was unable to copy it, but now I’m in Ubud and I’ll try to buy some CD’s of this.

    Here’s the singer of that band, surrounded by a scrum of motor scooters. On Sundays, these wedding processions bring traffic to a halt in small towns all over Lombok. Even though our driver had been a cabbie in Malaysia—which sounds like the ultimate qualification for fighting through crowds—he gave up and pulled over. So we hopped out and photographed these scenes.

    Here’s the keyboard player for that wedding procession band. What’s cool is that the synthesizer is connected to a sound board and bank of speakers… all on a wheeled cart! The band has its name emblazoned on the front of the cart.

    This appears to be typical gear for weddings here on Lombok.

  6. John Baez says:

    On our first night in Lombok, Lisa and I met a guy named Han who offered to show us around for a reasonable fee. On Monday he took us up to town of Senaru, on the northern slope of the big volcano called Gunung Rinjani that dominates the island. From there we hiked to two waterfalls.

    Here you can see Han and Lisa walking along one of canals that carries cold, clear water down from the volcano’s jungle-covered slopes to the complex irrigation system that waters the terraced farms of Lombok:

    It should remind you of the irrigation system on Bali, which I showed you in “week303”.

    Here’s the first waterfall we saw. It bursts spectacularly out of the jungle foliage:

    It’s called Sendang Gila, and it’s a popular tourist attraction because it’s only a 20 minute walk from the village of Senaru. Not too crowded, though.

    Getting to the second waterfall was considerably more work. After a bit of steep hiking we had to cross the Bridge of Horrors, shown here:

    Well, that’s just my own name for it, because I have a bit of acrophobia. It has a railing on one side but not the other—and it has large holes, which reveal its true purpose: it’s an aqueduct! The canal I showed you earlier flows through this bridge across the deadly, fearful chasm below.

    After gazing dizzily downwards for a minute—it’s really further down than it looks here—I got a mental grip on myself, repeated the mantra don’t look down, and crossed with no problem.

    Here’s the second waterfall we saw in Gunung Rinjani National Park:

    It’s called Tiu Kelep. After crossing the Bridge of Horrors, we had to hike 45 minutes more to reach it. Towards the end we needed to walk through the stream. The most exciting moment was when I slipped, reached out to a large rock to steady myself, and then noticed this rock was covered with insects of a kind I’d never seen before… ants, probably, but red and white, and strangely fuzzy. They sensed my hand and mounted a massive swarming attack. A real Indiana Jones moment.

    Little things like this make reaching the final goal that much more delightful.

    Here are some more ‘artistic’ shots of Tiu Kelep. It’s wonderful how this one particular plant thrives under these stressful conditions. Do you know what it’s called?

  7. EdT says:

    Wow. More pics! :)

  8. Hey, John. Looks like you’re living in paradise!

    The map you posted rang a bell as it’s the same one I used in my blog-book. Might interest you, so here’s the link:

    I enjoyed your music, by the way. Reminds me a bit of Brian Eno’s “Music for Airports.” It’s occurred to be me that Eno’s piece might be just a bit more mathematical than yours — and I’m wondering why. :-)

    • John Baez says:

      Bali is paradise; I live in Singapore. But actually Singapore is a much better-organized and convenient place to live, and I don’t know of a ‘Bali U.’ where I could spend my days doing math research… so perhaps being able to work in Singapore and nip over to paradise for a visit now and then is the best I can hope for.

      Wow! What an interesting book! It’ll take me a while to absorb what it’s about. Have you spent time travelling around Indonesia and such places and listening to the music, or is your research mainly from afar?

      I’m glad you enjoyed my music. I should be nice to you: you’re an endangered species! What did you listen to? I imagine Flowers of Darkness sounds a bit like a blues version of Eno’s Music for Airports, though it’s actually a lot more like his album Neroli. My piece Liminal has more of the ‘aimless major’ quality of Music for Airports, but it’s a lot more chaotic.

      It’s occurred to be me that Eno’s piece might be just a bit more mathematical than yours — and I’m wondering why. :-)

      First, I’m a worse musician, and it’s just a hobby, so I tend to throw together pieces when I get the urge, instead of laboring over them as Eno usually does. Second, math is my day job: I like music because it lets me stop thinking about math. But third, my album Treq Lila was composed with the help of a cellular automaton: that’s about as mathematicial as it gets! But I let the computer do the math, while I tried to make it sound good.

      • I’m glad you find my book interesting and hope you’ll find some time to comment and/or pose questions on the blog. And no, I haven’t done all that much traveling, and hardly any field work. As I see it, Anthropology shouldn’t be all that different from physics, where you have room for both experimenters, who do the hands on stuff, and theorists, who try to organize their results and think about what it all might mean. But for most Anthropologists (and Ethnomusicologists) the hands-on stuff (field work) is the be-all and end-all, so mine is definitely an uphill struggle. Not that I wouldn’t have liked to visit all these fascinating places and people, but my life took a different course.

        I was commenting on Flowers of Darkness, but have since listened to Liminal, which I like even more. It’s an excellent example of ambient music, where you can just put it in the background of your awareness as you do other things, but when you pay attention you find interesting things to listen to. Has a kind of gamelan type feel that works quite well, very delicate. Not bad, for a physicist, I must say. :-)

  9. Sivakumar M. Maniam says:

    Interesting music John. Liminal gave me a feeling of standing in an open grassy field with mild breeze blowing. I would say more of wind chimes than gamelan.

    Singapore is a bit too organized, a little chaos is good to experience living. Bali U would be a dream come true !.

  10. Suharyo Sumowidagdo says:

    Saw this post when I google search about Sahul shelf. If you are looking for math or mathematical physics activity in Indonesia, the best place is probably Institut Teknologi Bandung. There is a theoretical-mathematical physics research group in the physics department there.

    • John Baez says:

      Thanks! Someday I’d like to visit western Java. I’ve spent a lot of time in Bali, but in Java I’ve only been to Yogyakarta and nearby attractions like Borodubur and Prambanan:

      • John Baez, diary, August 2015.

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