Conservation and life in Borneo

Climate change and famine in Bornean sun bears

Wong recently spoke to myself and a few others about how climate can effect the ecology of the rainforest here in Borneo during El Niño and events.

Borneo fires 1997

Borneo fires 1997

In 1997 there was an El Niño event which caused drought and forest fires in Borneo. Smoke from these fires made fig wasps (which pollenate fig trees in a special relationship called mutualism) virtually extinct in many areas here. There are more than 800 species of fig wasp on Borneo; often, a species of wasp may be associated with just one species of fig.

A female fig wasp

A female fig wasp

This was significant as sun bears and many other species need fig trees; they are opportunistic feeders and will eat figs when other fruit is scarce.

El Niño and La Niña events do not occur at regular intervals. The El Niño event of 1997 was immediately followed by a La Niña. This La Niña brought extra rains, which stopped many trees from producing fruit ( as many fruiting trees in Borneo require a period of drought to trigger a flowering). This lack of other fruits due to the absence of a drought was compounded by the lack of figs (which many forest animals, including sun bears and orangutans, fall back on when other fruit is not available.

An emaciated bear

An emaciated bear following an El nino & La Nina event

Climate data suggests an increase in average temperature of 0.4 Celsius since the mid eighties. This has increased evapotranspiration, leading to around a 20% increase in rainfall. It may be possible that increased rainfall due to climate change could increase the frequency and severity of future famines.

The worrying thing is that we now seem to be experiencing a repeat of what happened in the late nineties, as can be seen in the figure below.


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