NEED TO BE ABLE TO ANSWER QUESTIONS
by Whit Gibbons
November 3, 2003
Ecologists are involved in a profession that
requires answering questions. Research ecologists address questions
of how the world works. Ecologists who are college teachers answer questions
asked by students. And some ecologists today need to be able to answer
questions asked by the general public, the taxpayers who support research
and universities. As career training, my University of Georgia graduate
students occasionally try their hand at answering environmental questions
Q: Can you tell me if wildlife has any chance of surviving a wildfire,
such as the fires that have destroyed homes and forests in British Columbia
and California? Do animals try to escape the fire or are they paralyzed
with fright? Do they succumb to the lack of oxygen that results from
the fire? Do smaller animals try to burrow underground or is that area
too hot? I am not being morbid, I just care about them.
Answer by J. D. Willson (Institute of Ecology): "Humans have come
to view wildfire as a bad or destructive event, most likely as a result
of our attachment to material objects (e.g., our homes). Certainly,
when wildfire burns an area, some wildlife will die, but it is important
to keep in mind that fire is a natural part of many (maybe even most)
terrestrial ecosystems. While fire may kill a few individual animals,
it is often beneficial to animal and plant populations in an area. Fire
frees up nutrients, often resulting in an abundance of new plant growth
in subsequent years.
is actually necessary to preserve certain species. For example, redwood
trees need fire for their seeds to germinate, and the American prairies
would not exist if they were not maintained by the fires and grazing
that stop trees from invading. Fire may also be important in controlling
insect pests and the spread of disease, and can even produce specific
habitats required by some species (such as dead trees for woodpeckers).
some animals certainly die in fires, most escape. Large mammals and
birds may outrun or outfly a fire, and most small animals, including
mice, lizards, and salamanders, probably take refuge underground. **During
a fire, the temperature is not elevated even a few inches beneath the
soil. Animals that die are likely weak, old, or sick and probably would
have died soon anyway. So, yes, some animals certainly die in fires,
but fires, on the whole, probably do more good than harm to animal populations.
Some scientists have even suggested that fire suppression by humans
has done more damage to animal populations than logging."
I am doing a research paper on mosquitoes in an honor's biology course.
How do mosquitoes develop immunity to substances; can they develop immunity
to pesticides and insecticides?
by Luke Fedewa (Institute of Ecology): "Generally, animals (including
mosquitoes) within populations will have a range of tolerance to pesticides
and other environmental entities, including microbes, toxic metals,
and temperature. Immunity is a term reserved for the physiologic response
that fends off pathogens (disease-causing agents that include toxic
substances, bacteria, and viruses). Although, pesticides may stimulate
the immune system, they generally interrupt physiologic pathways or
damage internal organs in a manner that causes death through bodily
a differential tolerance occurs among individuals within populations
(collections of mosquitoes in your case), mosquitoes can adapt their
population-level tolerance to certain pesticides, assuming a differential
tolerance exists or becomes formed during exposure. For example, let's
say I use a pesticide containing a chemical that kills 90% of a mosquito
population. The next time I use this chemical it may only kill 80% and
the next time only 70%, because a greater proportion of the survivors
after each bout are those with immunity. Meanwhile, if they have produced
offspring and the immunity has a genetic basis that can be inherited,
the parents with immunity are more likely to produce offspring that
are immune. The rate of proportional immunity within the population
will depend on a number of different characteristics, including but
not limited to environmental factors, genetics, and the chemical itself.
But the general trend toward immunity can and does occur."
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