Urban Jungle

PUBLISHED : Friday, 30 May, 2008, 12:00am
UPDATED : Friday, 30 May, 2008, 12:00am

This week: habitat conservation

One of the misconceptions about vets is that we know everything science has to offer about animals in general, at least the warm-blooded varieties. The animal kingdom is so large that there are many specialised fields. So even though I have dealt with animals every day for more than 10 years, I am still constantly learning about animal matters far afield from my world of small-animal medicine. One of my hobbies is to keep abreast of new scientific findings, not only in veterinary medicine but also in other fields of animal, plant and environmental science. It helps me put my knowledge into perspective, not to mention satisfy the childhood curiosity that led me along the road of science to my vocation.

Everyone has heard about the extinction of the dinosaurs, and some more zoologically minded readers may know there have been other major but not so famous extinction episodes in the past. One that comes to mind is the loss of all the trilobites that once dominated the world before the age of the dinosaurs. These events are still a mystery to science but we can safely say they were the result of natural disasters of some sort.

What is astonishing and horrifying is the new extinction episodes we are facing now. A study by the Zoological Society of London reports that since the 1970s, humans have been responsible for the extinction of a quarter to a third of the world's wildlife. Populations of land-based species have fallen by 25 per cent, marine by 28 per cent and freshwater by 29 per cent, the study says. We are killing 1 per cent of all species annually. It doesn't take a rocket scientist to figure that at this rate, biodiversity is going to be dangerously low in a few decades.

The world's wildlife has always lived harmoniously in a natural equilibrium, with a sufficient buffer to survive most disasters. The secret to this buffer is biodiversity. It is this diversity of animal species that prevents any one pest species from dominating and destroying the environment.

For humans, the loss of biodiversity means the loss of potentially life-saving medicines, an increase in pests affecting our food supply, deterioration in water quality and supply and a world that is more susceptible to the adverse affects of global warming and other natural disasters. The arrogance of humans has led to the deaths of billions of animals. How will we be judged by future generations? As decadent, greedy and short-sighted, I would guess.

What is encouraging is the constant string of findings in the area of zoology. New species are discovered all the time. Recently in Laos a rock rat the locals call kha-nyou has been discovered. Paleontologists at the Carnegie Museum of Natural History immediately identified it as a previously described fossilised species called Laonastes aenigmamus, or stone-dwelling enigmatic mouse in plain English. This was like finding a dinosaur in our backyard, or the catching of a living coelacanth (an ancient fish thought to be extinct) by fishermen in the Indian Ocean near Cape Town in 1938. Another recent discovery was a species of jellyfish that looks more like a flat worm, discovered by the Townsville Aquarium in Queensland, Australia.

These seemingly inconsequential findings are not just scientific curiosities; they highlight how little we really know about the living world. And by patching these bits of information together we hope one day to arrive at an overarching view of the intricate network of life in the complex ecosystems of our planet.

There has been another astonishing find by the University of California, Berkeley. Looking at DNA, scientists have identified an evolutionary effect called parallelism, where organisms independently come up with the same adaptations to environmental stimuli. What this means is that animals we previously thought were members of the same species could actually be several species that have made the same evolutionary alteration to ensure survival. This means we may actually be underestimating the world's biodiversity. For example, there are some 500,000 African elephants in the wild. However, while the elephants that dwell on the savannahs and those that live in the forests look the same, they are actually two different species.

Another recent discovery was of hundreds of new species of animals in the western region of Papua New Guinea. Due to the area's extreme remoteness, they have survived in a pristine time capsule. But with the encroachment of man on the area, we risk the loss of many valuable discoveries that could help save mankind from itself.

So I beseech the people of Hong Kong to think conservation, not only of individual species, but of their habitats as well. Every species we save means maintaining biodiversity, which in turn will help other species survive, which will help us to survive.