24 January 2009

Pulau Ubin mangrove delights

Super low tides during Lunar New Year was the routine in past years. This year, strangely, there isn't a very low spring tide.Undeterred, a bunch of die-hard shore explorers decided to have a look at some shores on Pulau Ubin. Despite all our many travels, I'm rather embarassed to say I've never done this stretch of shore before. The tide was low enough, at least to look at the mangroves!

Since going to Pulau Semakau with Dr Jean Yong, I've got bit by the mangrove bug! Pulau Ubin sure has lots of interesting mangrove trees.Among the prettiest mangrove trees must be Tumu (Bruguiera gymnorrhiza) or as Dr Jean says, the tree 'with lipstick'! There are quite a few of these trees on the shore today.Another common Bruguiera is Bruguiera cylindrica or Bakau putih in Malay. It has delicate white flowers and develops slim propagules with sepals that are bent upwards towards the stalk.
There are also all the common Rhizophora or Api-api. Since Dr Jean's explanation, I can't forget how Rhizophora apiculata develops long prop roots that form a skirt around the stilt roots! There were also a few pretty Rhizophora stylosa and Rhizhophora mucronata trees.We also came across a lot of Xylocarpus trees. Some were growing among the other mangrove trees, so we had to look carefully to sort out the different trees. This one had elegant snaky buttress roots. They all had flaking bark. So they are probably Xylocarpus granatum. We couldn't find any fruits or flowers so we can't be very sure.There was a very pretty Ceriops tagal tree festooned with long propagules like a green Christmas tree!From Dr Jean's field explanations, we recall that Ceriops tagal has a smooth brown fruit and a white collar around the propagule. On the right are the pretty flowers of this dainty tree.And what a pleasant surprise to find several Ceriops zippeliana trees! These have brown fruits with textures. We couldn't find any with propagules though.These are the flowers of Ceriops zippeliana. They are quite small and seem less numerous than those of Ceriops tagal.And what a superb delight to encounter a large old Penaga laut (Callophylum innophylum) tree in full bloom! The sprays of white flowers looked like sparkling stars against the dark green glossy leaves.Here's a closer look at the delicate flowers of this ancient tree.On the high shores, there was a small patch of shrubby Lumnitzera littorea with its bright red blossoms. After seeing these short plants, I am in awe of the tall trees of L. littorea at Pulau Semakau!
There were also a few stands of Nipah palms (Nypa fruticans). The photo on the left appears to be a bunch of flowers about to 'bloom'. The ball-shaped one are the female flowers, while the male flowers appear on a long stalk, golden with pollen, and will emerge from the sheaths besides the ball-shaped bunch. On the right are fruits at various stages of development.

Nipah palm leaves are of course the source of thatching for attap huts, while the developing seed is eaten as 'attap chee' in our favourite desserts, and 'gula melaka' or brown sugar is made from the sap extracted from the palm.Sadly, one of the palms had a rope tightly tied around it. What a way to treat a plant that is so useful to us.The mangroves of Pulau Ubin are teeming with all kind of animals. We came across quite a few spiders. This one might be the Mangrove big-jawed spider (Tetragnatha josephi) which was named after Joseph Koh, our dear friend and spider expert who wrote the Guide to Spiders of Singapore.And this pretty spider with a special web is probably the Mangrove St. Andrew's Cross spider (Argiope mangal) which was described by Joseph Koh.Here's a closer look at the spider. Only the female Argiope mangal builds webs. These are contain only 2 white zig-zag lines, called stabilimentum. Argiope versicolor, which is found inland, makes the "full" cross with 4 stabilimentum.
Earlier in the forested area, we came across a large Golden web spider. She was busy wrapping up her catch, which looked like a butterfly.
A closer look suggests she is the Batik golden web spider (Nephila antipodiana) as she had all black legs (no red or yellow 'knees') and also from the pattern on her abdomen. Like other Golden web spiders, little red spiders (Argyrodes sp.) not only live in her web but may also steal her food.
Here's the team taking photos of the Golden web spider. Today, we are glad to have Brandon gamely join us. While Chay Hoon took the opportunity to bring her new camera for a test run. We were very fortunate to have Andy join us as he was very familiar with the mangroves here so we didn't miss the exits for an easy departure.As we were leaving, we spotted a humungous hornets' nest high up a mangrove tree.Here's a closer look at it. I wished John our wasp expert was with us. I'm sure he would have found this interesting. But we just tip toed quietly away.

6 comments:

  1. A great delight in reading this post, especially the accounts on the mangrove plants. I know very little about these plants. Thanks for the great write-up.

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  2. Thank you for the encouragement Federick! Actually, I know very little about mangroves. Am continuously learning as we explore, with much patience from teachers such as Dr Jean :-) Mangroves are quite fun as I find out more about them.

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  3. erm sorry ria but i think that api-api is avicennia :)
    http://mangrove.nus.edu.sg/guidebooks/text/1049.htm

    I think Rhizophora is bakau(?) :)
    http://www.naturia.per.sg/buloh/plants/rhizophora.htm

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  4. Thanks for that correction November.

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  5. Hello, i think the Nephila in your photos is not N. antipodiana but N. pilipes because she has red palps. The picture acutally shows yellow spots behind her knees too.

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  6. Thank you for that correction! And for sharing the information about this fascinating animal. There sure is a lot to learn about our wildlife!

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