Monday, 25 January 2010

January Research Colloquium: Thai Bats, past, present, and future

This year’s series of monthly research presentations started with a very interesting report by Alice Hughes, who is a PhD student at the University of Bristol and one of our volunteers.
Bats as a group are hard to study, as they are hard to locate or observe, and are consequently much neglected even in areas where there is a lot of interest. The UK for example has a well-developed network of bat study groups – I went on a bat walk led by one towards the end of last year where we used bat detectors to track Common Pipistrelles and Noctules in the middle of Bristol. The only tropical bats that have been studied in much detail are the various fruit bats, and they are not typical of the majority of species, being mostly large, vegetarian, and roosting in many species in large colonies in the open.

The current list of species known from Thailand is 121, and many more probably remain to be identified (many bat species can only be told apart by their ultrasonic calls without DNA analysis). Each of these species has its own preferred set of environmental conditions, which explains their often restricted ranges. Alice has been studying the bats of Thailand in order to obtain a predictive envelope of the various conditions required, to enable the extrapolation of how species will fare in the future, and have fared in the past, under different climate conditions. Probably the most well known is the Bumblebee Bat, Craseonycteris thonglongyai. Interestingly, the Thai population appears to have slightly different requirements to the one in nearby Myanmar, which is also genetically distinct, although whether this means there are actually two species or simply local subspecies is unclear.

One of the features of Thai geography is that in the centre of the country is a pinch point, the Isthmus of Kra, which is the location of one of the invisible dotted lines on the map which define two different zoogeographical regions, in this case the boundary between species found in mainland South East Asia and the islands of the Sunda Shelf, which at times in the past when sea level was lower was a large exposed landmass. This boundary has persisted in the fossil record for many millions of years, despite no obvious reason for animals to be restricted to one side or the other. The study on bat species indicates that the species on either side do have some different ecological requirements, which may reflect the difference between a maritime and continental climate regime.

The results so far indicate that the future of the more specialised Thai bat species does not look good in the case of major climate change. Some generalist species on the other hand are actually predicted to increase in range, at least for some decades, as they are able to cope with a wide range of conditions. Far more work needs to be done however, even on such basics as species identification, and the recordings Alice has made of various species in flight will do a lot to further the state of understanding of South East Asian bats.

The next research colloquium should be on the first Wednesday in February. It is open to the public, so if any reader is in Bristol feel free to come along. Unfortunately this year’s series of projects has not been finalised, but for further information on our research projects the page on the Bristol Zoo website is here:

Coming up: New butterfly species, new arrivals in Twilight World, and a series on the various pigeon and dove species kept at Bristol.

Image from the Edge blog here:

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