sampling animals Flashcards
why is collecting quantitative data on animals hard
small animals will hide
large animals will run from the presence of humans
what is an invertebrate
an animal lacking a back bone. For example, a snail.
what is sweep netting
walk through a habitat with a stout net.
Sweep the net through the vegetation.
small insects or small animals will be caught in the net
why is a pooter better than sweep netting
because it catches animals before they fly away.
describe a pooter.
A pooter is a small jar used for collecting insects.
It has two tubes - one goes into your mouth so you can apply suction, and the other goes over the insect so that it is sucked into the jar.
A fine mesh over the end of the first tube stops you swallowing the insect.
It is difficult to collect from trees using a sweep net, what is a better alternative
place a white sheet under a branch and knock the branch with a stick. The branch will vibrate pushing any small animals onto the sheet.
Need to be quick to identify as they fly off
what is a pitfall trap
small container buried up to soil level, any animals moving through plants will fall into trap.
leave overnight
identify / count, (named) invertebrates
sample both areas, randomly at 5(+) sites
what can be added to a pitfall trap to avoid animals escaping
small volume of water or scrunched up paper.
Why may it be necessary to cover a pitfall trap with a stone or piece of wood
to avoid it from filling with water when it rains.
also prevents scavengers
describe the structure of a Tullgren funnel
a funnel filled with leaf litter with a mesh screen below. There is a light at the top driving the animals downwards as the light dries and warm up the litter. the animals fall into the mesh screen then into a jar underneath the funnel
what is capture mark recapture
capture an animal
mark it in a way that isn’t harmful and release it
the animals you recapture which have a mark can be recorded as c3
the animals without a mark can be marked as c2
With this you can work out total population-
c1( amount of marked individuals) X c2
divided by c3
what is the equation for total population
c1 X c2 / c3
what are the cons to capture mark recapture
animals may learn trap is harmless and has food- therefore go in there more often
animals may also dislike the experience and keep away from traps from there onwards.
