Geography Reference
In-Depth Information
Rather than appreciate the services the near-sighted mammals do—tilling
and aerating the soil, eating harmful grubs—they see only the messy dirt
mounds that multiply each night. Traps are set. Moles die. Lawns remain
green and tidy, but there is a hidden cost.
Some animals cause real problems in cities; beavers destroy valuable trees
and l ood urban streams, overabundant deer harbor ticks that spread disease,
cougars and bears occasionally attack humans, and the bite of a black mamba
can kill or maim. It is possible to coexist with some of these problems. For
example, nonlethal beaver deceivers—devices that limit the amount of water
held back by the animals' dams—allow beavers to live safely among us. We can
also learn how best to behave around dangerous wildlife and reduce the attrac-
tiveness of our yards and neighborhoods to large predators. But sometimes we
just need to remove the animal. If a black mamba gets into my house, I'm calling
a snake charmer!
Thick skin is an author's armor, but the lack thereof is another reason am-
phibians struggle in subirdia. Pesticides, herbicides, pharmaceuticals, and
salts and other chemicals we use to de-ice roadways readily dif use through
the moist skin of a frog or salamander. These environmental stressors, along
with increased exposure to ultraviolet radiation, which has increased as ozone
levels have been reduced, interact to lower an amphibian's ability to i ght of
disease and parasites. Frogs compromised by ultraviolet radiation and pesticide
contamination, for example, are less able to i ght of infections by parasitic
l atworms. The worms, which are superabundant in overly fertile ponds, de-
form the frogs' legs, often leading to grossly misshapen or extra appendages.
Amphibians soak in all manner of environmental challenge through porous
skin that evolved to help them live a simple, passive life in a less toxic world.
