Frogs are examples of wildlife that have a wide latitudinal
global distribution from the tropics (0 to 23 degrees North and South Latitudes)
to the Arctic Circle. In the Arctic Circle, they are active at near-freezing
temperatures to higher temperatures during the brief summer period.
Our work on amphibians and reptiles inhabiting the tropical
rain forests of the Philippines has shown the narrow temperature range (few
degrees Celsius) at which they are active. Small endemic frogs occupy only
relatively cool habitats and are active only at temperatures around the lower
20s C. Similarly, small Philippine lizards are adapted to equable forest floor
habitats with temperatures in the lower 20s C. They succumb to substrate
temperatures in the higher 20s.
Amphibians and reptiles, unlike birds and mammals, do not
possess physiological mechanisms to regulate their body temperatures; they
depend on behavior to stay within their temperature limits. They are therefore
at the mercy of their surroundings, and are among the first to go extinct in the
event of elevated temperatures brought about by climate change.
To protect them, we must preserve their habitats in the
tropical rain forest, which serves to buffer atmospheric temperature changes
through such mechanisms as evaporation of water, which in turn results in
cooling.
The situation for marine species in the tropics is not too
different. These species also have a wider tolerance for the lower part of their
range than for the upper part. In other words, the temperatures to which they
are now exposed are not far from the higher limit of tolerance, so that they are
more likely to succumb to increasing water temperatures than to decreasing
temperatures. Thus, for example, fish has been observed to die from high
temperatures, which affect their bodies directly and indirectly through the
reduction of oxygen in the warm water.
Warm water holds less oxygen than cool water. Warming of
marine waters reduces marine productivity resulting in reduced marine
biodiversity.
In this case, we are practically helpless. All we can do is hope that
upwellings will bring to the surface cooler water to counteract the effects of
warm water near the surface and restore the productivity of the sea.
