10 August 2009

Mangroves in the Mizzle: Pasir Ris

The weather was cranky. It couldn't make up its mind. Should it pour or be hazy? Or just be muggy and humid?
Eventually it settled on a mizzle (miserable drizzle) as Marcus and I headed out to check up some mangroves at Pasir Ris.

First stop, the Pisang pisang (Kandelia candel). Ooo, it has grown four new leaves! Yes, this poor plant is in a very sad state. Even more tragic, I get the sense that this is our only Kandelia, on the mainland at least.
Well at least it's still alive. And I'm glad to see it, even though it had no flowers or propagules today. Looks like the bunch of flowers I saw on the last trip here in May didn't set. Sigh.

But on to a happier sight to check out the large magnificent Bakau mata buaya (Bruguiera hainesii). It was still flowering, but not as profusely as in May.
And I double checked the tree trunk. No lenticles (corky bumps) unlike the descriptions generally given for this species. Hmm. Well, there are variations. Doesn't help that there are so few of this special tree left in Singapore.

We look for propagules too. And find something that might be a B. hainesii propagule.
We know the first three skinny bendy propagules are probably Bakau putih (Bruguiera cylindrica), and the last thick propagule is probably Tumu (Bruguiera gymnorrhiza). And from other propagules of B. hainesii we've seen, the brownish maroon one should be it. It was stuck in the mud and when I dug it up the portion in the mud had been eaten away! I saw a similar situation with a Tumu propagule that was stuck in the mud. What is eating up the propagules?

Both Kandelia candel and Bruguiera hainesii are listed as 'Critically Endangered' in our Red List.

Another plant that is listed as 'Endangered' on our Red List is Lenggadai (Bruguiera parviflora) which is also easily seen at Pasir Ris. Today, it is full of propagules, I counted at least ten on the tree. But no flowers.
On this dreary drippy day, these startling scarlet 'flowers' brightened up the back mangroves! It is the 'Mickey Mouse' plant (Ochna kirkii). This plant is an exotic from tropical Africa and is apparently cultivated as an ornamental. The real flowers are bright yellow and what we see today are the red bracts under the green berries. The berries turn black as they ripen, and with two black berries in the right position, I guess the entire 'fruit' might resemble Mickey Mouse?
While Marcus was busy photographing all kinds of strange bugs, beetles and creepy crawlies, I found a nice patch of Love-in-the-mist (Passiflora foetida). A common vine with pretty but stinky flowers, the fruit is an orange berry held in a basket of moss-like leaves. The berry contains many seeds in a milky pulp and are edible when ripe. But they may contain hydrocyanic acid so don't eat too many.The mangroves are full of life! On sandier areas there's lots of Sand bubbler crabs (Scopimera sp.). Challenging for me to shoot with my increasingly cursed zoom lens.
And lots and lots of fiddler crabs too! I notice that there seem to be several different kinds of them. The top two from left to right are possibly the Porcelain fiddler (Uca annulipes) and the Orange fiddler (Uca vocans).
But the ones on the bottom row I have no idea what they might be. The crab experts have mentioned that the crabs we treat as Orange and Porcelain fiddlers might actually comprise many different species! More study is needed to sort them out. Wow! We certainly can't take any identifications as written in stone, and IDs will change as more study is done on our wildlife.

Mud means mudskippers! And there were lots today. The tide wasn't low so the fishes were quite close to the high shore. While the photo on the right is of a Gold-spotted mudskipper (Periophthalmus chrysospilos), I don't know what the other one is.
As I was stalking the fishes, the water suddenly wooshed in and all the fishes swam right past me!
Out in the distance, a Grey heron (Ardea cinera) was stalking confidently in the soft soft mud.
Deeper in the mangroves are all kinds of special snails. Marcus spots this handsome large snail creeping boldly on the mud.
If this snail reminds you of our common garden snail, you will not be far wrong. This is a Belokeng (Ellobium sp.) which like the garden snail breathes air (instead of through gills like most other marine snails). It is quite happy on land.

This particular bunch of Belokeng had a kind of white ridge around one side of the shell. Like others in its family, it doesn't have an operculum.
Another related snail is the Cat's ear mangrove helmet snail (Cassidula aurisfelis). It's much smaller.
Of course, there are lots of other mangrove trees and plants at Pasir Ris. What is nice is the stretch of Perepat (Sonneratia alba) trees found right on the beach. One was flowering and fruiting very low, easy to observe. Unfortunately, the leaves are not normal (see the dark veins on a lighter background?). I've been told by those who know mangroves that this means the tree is probably stressed.
Marcus also points out that most of the Perepat trees on the shore have stumpy pneumatophores (breathing roots). And indeed, the trees closer to the waterline are suffering from erosion of the sand, and some have already fallen over.
This is what the pneumatophores of a Perepat usually look like. Pointy cone-shaped things.
The park was busy despite the drizzle and early morning. There were lots of campers and all kinds of group activities. On the shore there were people fishing, cast-netting or digging up worms and other stuff.
We came across these large holes dug up in the mangrove area.

Our mangroves and shores are special and interesting. I guess it requires more outreach to help people understand the need to appreciate our shores gently.

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