Hi!
Well, woke up at 6 today for the opening of Bishan Park 1, or Pond Gardens. :) Haha, had to lead Deyi around for the trail and here are some of the interesting Aquatic Snails found there. And of course, many other photos :)
So this is it, the Cleansing Biotope. Some of the plants incuded are the water canna, papyrus, paper reed, pickerel weed etc. These plants arre able to absorb the chemicals and convert it. Cool eh? the water comes from the main river of which some is diverted over here to be cleansed.
Some mini flowers spotted on the floor, took some up for a snapshot.
Mrs Low Mei Choo, our Science HOD, recieving the certificate of our adoption of the Bishan River! YAY. Thats Miss Azura talking to her. Really cool because we've been working on this project for more than a year so far. :)
SNAIL EGGS!!! These belong to the Giant Apple Snail,
Pomacea canaliculata. We had to constantly remind the public NOT to step on these things!!!
Haha! A unidentified shell. Probably of the common lawn snail, native to Singapore.
AAHHH!!! The final product of the Cleansing Biotope!!! The water is so clean! essentially, the water is about 1m deep from at the banks and 2 m deep in the middle. Cool eh?
Looks like a scene from a chinese movie, somewhat like Jiang Nan or similar. This is near the amphitheatre. There was a performance behind and the participants did not want to pay attention to us! :(
Another shot from the amphitheatre.
These are the apple snails that i was talking about before. It is doot to note the 2 different varieties present, the Common Apple Snail, 4 out of the 5 are Common Apple Snails due to their darker shell colour and the Golden Apple Snail, which is the one which has a yellowish coloured shell. All of these were alive:D
The Snail again...
Nice shot? I managed to get the flowers and snapped a photo . :)
The Apple Snail extending its feelers. It is one of the most common animals in the river, along with the Tilapias and Guppies. All these animal are however, non-native...
The Apple Snail again...
This is the outlet for the water.
And a cute Molly is spotted too! it was the most colourful of them all and i quickly got a shot of it.
The clean water of the cleansing biotope. I guess this is a real success because the water managed to maintain its clarity despite it running for long time.
Haha, we got some goodie bags at the and a small bucket too. Probably for collecting seashells. Despite not finding any shells today, i guess this was a fruitful trip. I did manage to collect Apple Snail shells though during the last few visits. Another place i would recommend to collect Freshwater Snail shells would be Bedok reservoir. Managed to collect come Japanese Trapdoor Snail shells there after my cross country race last year. :D Enjoy
From post: "It is doot to note the 2 different varieties present, the Common Apple Snail, 4 out of the 5 are Common Apple Snails due to their darker shell colour and the Golden Apple Snail, which is the one which has a yellowish coloured shell."
ReplyDeleteALL of the snails shown in the photo are Pomacea canaliculata (aka Golden/Channelled Apple Snail). The shell colour in this species range from yellowish/golden to dirty brown & even greenish -- with or w/o distinct spiral bands. Size-wise, mature specimens can reach 10cm across, depending on food availability.
From post: "These belong to the Giant Apple Snail, Pomacea canaliculata. We had to constantly remind the public NOT to step on these things!!!"
For info, Pomacea canaliculata is categorized as a globally-invasive species that is very well-adapted to degraded, poor-quality freshwater habitats. In other words, you are unlikely to spot this snail species within S'pore's nature reserves (eg. in forest streams) -- unless the habitat there is deteriorating & has become prone to invasion by opportunistic species.
An aggressive & voracious herbivore, P. canaliculata is regarded as an agricultural pest & environmental threat in several parts of the world. Its bright pink egg-clutches (200-1,200 eggs each) are deposited on rocks or other solid surfaces above the water-line. These eggs are avoided by almost all types of animals due to their bad taste, as well as the presence of indigestible proteins & neurotoxins lethal to mammals. In addition, the snail itself is a known host of parasitic worms that can infect humans.
Here in urban S'pore, P. canaliculata directly competes with native freshwater snails for living space & food resources. In fact, it is so widespread that the similar-looking native snail Pila scutata (Shield Apple Snail) has significantly declined in population & is rarely seen nowadays. In contrast to the prominent pink eggs of the invader-snail, the egg-clutches of Pila scutata are whitish in colour, smaller in cluster size, deposited on muddy banks, & often hidden amongst vegetation.
Whilst no native aquatic snail species have been observed at Bishan Park's river, this man-made waterway is however severely infested with P. canaliculata, so much that there are volunteer groups which help to periodically remove this fast-growing snail species from the river. Example of a recent effort: 'Saturday morning at Bishan-Ang Mo Kio park' (The Green Volunteers - 13 May 13).
For more info:
* Pomacea canaliculata (Invasion Biology - Columbia University)
* Pomacea canaliculata (Global Invasive Species Database)
* Pomacea canaliculata (AppleSnail.net)
* Observation of Land Snails feeding on the eggs of Pomacea canaliculata (Nature in S'pore -- 04 May 2011)
* Pila scutata (AppleSnail.net)
* Pila scutata & Pomacea canaliculata (S'pore Biodiversity: An Encyclopedia of the Natural Environment -- edited by Peter Ng, et al., 2011 )
Hi Pat,
DeleteYes, it is true that the Apple snail is listed as one of the 100-top invasive species globally and I do acknowledge that there are social groups that embark on frequent visit to our local waterways to remove these animals. I would actually like to clarify my point regarding the appeal to the public on not stepping on the eggs. Basically, the idea of appealing to the public to not step on these eggs was actually meant to cultivate a sense of care for the environment and it's inhabitants. Personally, the removal of the eggs, as you have kindly pointed out, should be left to these social groups. For us, we may be able to identify these eggs as those belonging to the Apple Snail but the public may not. Thus, for the benefit of other organisms, we would rather appeal to the public to protect our natural environment and spread the basic knowledge of our local biodiversity, and then further strengthen their knowledge on which creatures are harmful, invasive, etc. Hope this answers your question. :)
From post: "The clean water of the cleansing biotope. I guess this is a real success because the water managed to maintain its clarity despite it running for long time."
ReplyDeleteJust to note that water quality is not measured just by turbidity vs. visual clarity alone. Other important water quality indicators include biological & chemical parameters.
Biological parameters are determined by bio-assessments. For instance, a good-quality freshwater habitat is populated by a wide range of native aquatic organisms -- as opposed to being dominated by a less diverse community of exotic/ invasive species & possibly a few highly-tolerant native species adapted to degraded/ urbanized sites.
The presence of aquatic macroinvertebrates typically indicates a clean & healthy water habitat. In particular, mayflies (Ephemeroptera) are an accurate indicator of good water quality, because the larvae are very sensitive to environmental stressors like contaminated sediments & low dissolved oxygen.
In contrast, the widespread presence of hardy, opportunistic exotic/pest species (eg. non-native/ invasive fishes, chironomids, etc.) signifies sub-optimal to poor water quality. Also note that non-native minnows (ie. small freshwater fishes from the Poeciliidae family, eg. Molly, Guppy, Mosquito Fish) are not indicator species, because they are tolerant of varying water conditions.
Some chemical indicators of water quality include pH level, as well as the concentration of toxic contaminants such as PCBs & heavy metals (eg. copper, cadmium, iron, mercury, lead, zinc, etc.) None of these chemical parameters can be determined visually, but have a significant impact on the health of aquatic organisms.
Hi Pat,
ReplyDeleteThank you for your feedback. Well, it is true that water quality is determined by chemical factors. the presence of heavy metals would also adversely affect the biodiversity as well. However, the cleansing biotope is actually meant to provide a basic introduction for the general public on how plants and other bedding materials are able to clean the water such that it is visually clean. I do agree that non-native fauna such as the mosquito fish is not a clear indication on our local diversity but this blog post was actually aimed at giving the public once again a general sense on what animals the Bishan Park has to offer. Thank you for pointing out these obsecurities. :)