Suchergebnisse

Shade covers for pitfall traps can be used to reduce the amount of solar
radiation penetrating to the bottom of pitfall buckets, thereby reducing the
number of captured animals dying from heat-stress. We tested the effectiveness
of a variety of shade covers for reducing temperatures in pitfalls and trap
mortality of small vertebrates, and examined the effect of one cover design on
trap success in arid landscapes. Shade covers made of insulation foil were
found to reduce core pitfall temperatures by 20–22˚C compared with
uncovered buckets, which reached temperatures greater than 66ºC. Other
cover types tested (plastic lid or cardboard) were found to be less effective:
core bucket temperatures still reached 48–53ºC. While foil covers
do reduce temperatures and therefore the probability of heat-stress-related
mortality, above-ground foil covers also influence trap success. Traps with
above-ground foil covers caught 39–43% fewer small vertebrates
and 7–42% fewer species than uncovered traps. Above-ground foil
covers had the greatest influence on the sampled abundance of scincid lizards
(reduced by 50–52%), reduced the sampled abundance of most other
lizard families and mammals, but increased capture success for snakes. If
shade covers are required to minimise heat stress and mortality in pitfall
buckets we recommend foil covers placed inside the bottom pitfall buckets as
they significantly reduce pitfall temperatures and are likely to have minimal
influence on trap success. However, regular checking of traps is still one of
the most reliable ways to reduce heat-stress- related and other deaths in
pitfall traps.