Sunday, December 26, 2010

Bukit Timah Does Not Have More Plant Or Tree Species Than North America

I have been hearing or reading about it so many times that it's beginning to get on my nerves.

No doubt, I love Bukit Timah (the dipterocarps, the colugos, pangolins!!!), and I think being so highly urbanised, Singapore still has a rather high plant diversity and that is really something. However, I think it is really embarrassing that so many publications and websites, including those by NParks and unfortunately, even NUS, gave the wrong information that Bukit Timah has more tree or plant species than the whole of North America.

In some websites and publications, it was said that a 2ha plot in Bukit Timah has more than 350 tree species, and this is more than all the tree species ever recorded in the whole of North America. However, a search using the Internet shows that according to Elbert L. Little Jr.'s Checklist of United States Trees (Native and Naturalized), published in 1979 as Agricultural Handbook 541 by the United States Department of Agriculture, USA alone has 747 species of native trees (including Alaska but excluding Hawaii)! That means, North America certainly has a lot more tree species than the 2ha plot.

Some other websites claimed that Bukit Timah has more tree species (not just the 2ha plot) than the whole of North America. According to NParks, Bukit Timah has more than 840 species of flowering plants, including the various shrubs and herbs. Even if we were to outrageously assume that there are only about 100 shrubs and herbs, and the rest are all trees, USA alone with 747 native tree species will still have at least the same, if not more than what Bukit Timah has.

Going to the total number of plant species. According to some websites, Dr David Bellamy, a renowned conservationist, once pointed out that the number of plant species growing in the Bukit Timah Nature Reserve is more than that in the whole of North America. We already know that Bukit Timah has 840 species of flowering plants (hence excludes the gymnosperms and ferns etc), but finding the total number of plant species in USA proved to be a challenge. I managed to find the USDA website, and just looking at the list of threatened plants in Florida, North Carolina and California, there are already 1,085 species! Obviously if you include the non-threatened ones, the list will be a lot longer.

Update: Thanks to Pat, who highlighted that discounting Hawaii, continental USA (including Alaska) has ~17,000 species of vascular plants. See comments below for details.

So, Bukit Timah certainly does not have more plant species than the whole of North America. In fact, what we have is a lot less than what North America has.

However, what we can say is that we certainly have more tree species than the United Kingdom, or Canada, and possibly many other temperate countries. And if we conserve well, future Singaporeans may still be able to say that proudly in say a few hundred years' time.

Hopefully this clears things up and the embarrassingly wrong information will not be passed on to more people.


Pat said...

Thanks for highlighting this ...

Discounting Hawaii, continental USA (including Alaska) has a land area of some 920 million (=770m + 150m) hectares [1], which is occupied by ~17,000 species of vascular plants [2].

The above implies that USA has 17.9 vascular plant species per 1 million hectares, or 0.000036 vascular plant species (including trees) per 2ha.

The 2-ha survey plot in BTNR has >350 tree species. Based on the above figures, the said BTNR plot would appear to "have more" species than the whole of USA.

Might Dr David Bellamy have been referring (with or w/o explicit elaboration) to the relative species richness per acreage, but was misconstrued by his S'pore audience as talking about the absolute no. of species ?

Academia (& like-minded individuals) vs. the general population often take it for granted that each party really understands what the other is talking about -- when this is frequently not the case. To give a hilarious example, a quantum leap as scientifically known by a physicist (or physics-minded person) is the exact opposite of how the general populace popularly perceives the same term. (I won't even go into the details unrelated to physical distance.)

There are many everyday subtleties in science & statistics that academia may not have thought of explaining further, because they think the lay population already knows. And when the academia do take the initiative & pains to elaborate, the latter often thinks academia are a long-winded bunch !

[1] Lubowski, Ruben, et al. (2006-07-21). "AREI Chapter 1.1: Land Use", 5th para.

[2] Morin, Nancy. "Vascular Plants of the United States". Plants. National Biological Service, pg 200.

Ron Yeo said...

Thanks Pat for the information on the no. of species of vascular plants in USA!

Word for word, what Dr Bellamy said was, "There should be a sign in Changi Airport that says, 'We have a piece of forest with more plant species than the whole of North America!'"

Unfortunately, many of the publications and websites I mentioned earlier were published by the academia and like-minded individuals. I happened to come across a recent article written by a university professor, who is also a renowned botanist in the region, that said Bukit Timah has more tree species than the whole of North America.

The biggest problem is that when the experts gave the wrong information, everyone believes without doubt.

Pat said...

Was the Changi Airport statement ever recorded on video or tape ? It's rather odd that a professional botanist (even though he hails from the UK) would actually claim that the entire North American continent (which includes Canada) has fewer than 350 plant species.

Having not heard or seen the original statement, I'd always thought Dr Bellamy was referring to the relative plant species richness of the bountiful tropics, in comparison to the temperate zone.

Perhaps expecting the facts to be self-evident to most, he might have dropped some key words for the sake of dramatic brevity. Or maybe the quote was taken out of context -- he could have provided the relevant key details before or after the more famous statement. Or the listener might have engaged in partial listening (ala the humorous Class 95 FM ad on TV). And of course, it's also possible that the speaker himself did not really understand what he was saying ...

Whatever the cause that led to the ongoing misunderstanding, I suppose this is a good lesson that one should avoid taking it for granted that info propagated by the "experts" is always right. From past experiences, I have encountered professional-sounding nonsense coming from the mouths of PhDs, & it is indeed frustrating trying to explain the real facts after the damage is done. It's great that you pointed out the incongruity of the "myth". Hopefully, the misinformation can be corrected henceforth.

If anyone has Dr Bellamy's contact, & for the sake of curiosity & fairness, it might be worthwhile to ask him what he actually said (or meant to say).