11.4

Question 1

when a nature reserve is managed for its wildlife’s benefit, scientists need to be able to…

Answer 1

measure the type and numbers of the organisms found there

make measurements of the physical and chemical factors that may have an effect on the plant and animal communities

Question 2

These measurements allows the reserve to be…

Answer 2

managed to meet the habitat requirements of the organisms living there

Question 3

Changes in the size of populations of animals and plants can be used to find out…

Answer 3

how successful in a particular management technique has been and whether extra effort needs to be made to conserve a species/habitat

Question 4

It is impossible to identify and count every organism present within a particular habitat so samples are taken, which are thought to be..

Answer 4

representative of the whole habitat

Question 5

Sampling a small area of the ecosystem or habitat enables us to…

Answer 5

estimate the numbers of organisms living in a much larger area

Question 6

Sampling can be carried out

Answer 6

randomly

systematically

Question 7

Random ensures that every organism in the sampling grid has an…

Answer 7

equal chance of being sampled, helping to remove sampling bias

Question 8

To increase the reliability of the results obtained via systematic many samples should be taken from each grid. A variety of measurements will be taken at each sampling point:

Answer 8

• abiotic factors (that can influence the numbers and types of organisms present)
• biotic factors (make up the living part of the organism’s environment)

Question 9

The biotic factors measured at the sampling points may include the:

Answer 9

• Numbers of a particular species present
• Numbers of different species present
• The % cover of plant species present
• The relative abundance of a particular species

Question 10

Random sampling technique:

Answer 10

study area is divided into a grid system

random numbers are used to generate sampling coordinates within the grid

each number must have an equal chance of being chosen

a sample is taken at the intersection of each pair of coordinates

Question 11

what does the random sampling technique assume?

Answer 11

that the samples are representative of the whole population

Question 12

Systematic sampling technique:

Answer 12

the area is divided into a grid system

sampling points are located at regular intervals

Question 13

what are the 7 abiotic factors:

Answer 13

light intensity
pH
temperature
oxygen
relative humidity
levels of ions
soil moisture

Question 14

how to measure light intensity

Answer 14

light meter

Question 15

how to measure pH

Answer 15

soil pH test or electronic probe

Question 16

how to measure temperature

Answer 16

thermometer

Question 17

how to measure oxygen

Answer 17

oxygen probe

Question 18

how to measure relative humidity

Answer 18

hygrometer

Question 19

how to measure levels of ions

Answer 19

soil test or electronic probe

Question 20

how to measure soil moisture

Answer 20

soil tests

Question 21

what are the 6 sampling techniques:

Answer 21

quadrat
transect
sweep netting
kick sampling
trapping
indirect methods

Question 22

what is quadrat ?

Answer 22

using a metal frame to mark out a small area within a grid - samples animals and plants within the small area

Question 23

what is transect sampling?

Answer 23

mark out a line or a narrow belt and study along it -samples organisms living in an area where abiotic conditions change with distance along the transect

Question 24

what is sweep netting?

Answer 24

sweep a sampling net through water or plants such as grasses - samples freshwater organisms

Question 25

what is kick sampling?

Answer 25

kick stones on a river bed and catch the disturbed organisms with a net placed downstream - samples freshwater invertebrates

Question 26

what is trapping?

Answer 26

pitfall traps - crawling insects
longworth traps - small mammals
light traps - moths and other night-flying insects

Question 27

what are indirect methods?

Answer 27

count droppings, dead animals, nest sites, burrow entrances - samples larger organisms that are hard to sample by any of the direct methods

Question 28

when using a quadrat: the species present are identified and their abundance recorded using 3 methods:

Answer 28

1) density of a species - calculating the mean density (total number of individuals counted/number of quadrats x area of each quadrat)
2) Percentage cover (estimation useful for clump-forming species)
3) abundance scales (subjective)

Question 29

When are point quadrats useful?

Answer 29

vegetation is dense as they can sample at many different levels

Question 30

when are transects used?

Answer 30

where conditions and organisms change over distance

Question 31

How can reliability of data be improved for transects?

Answer 31

using 3 or more parallel transects carried out across the same habitat

Question 32

A line transect records the organisms that lie…

Answer 32

underneath a string or tape that is stretched out across the ground

Question 33

a belt transect is a strip across the species occurring…

Answer 33

within the belt are recorded - a quadrat can also be placed alongside a transect and the species within it recorded

Question 34

if the transect is short, sampling can be…

Answer 34

continuous along its entire length

Question 35

if large distances are involved then samples are taken…

Answer 35

at intervals along the belt