This document provides information on various ecological sampling techniques used in field investigations and population ecology studies. It discusses the importance of sampling, as counting every individual in a population is usually impossible. Common sampling methods include quadrats, transects, and capture-recapture. Quadrats involve counting organisms within a defined area, while transects sample along a line or belt. Capture-recapture allows estimating population size by marking and recapturing individuals. Factors like habitat, organism size, and sampling goals determine the appropriate sampling method and unit size. Population attributes like density, birth and death rates can provide insights into how environmental factors regulate population sizes.

1. 1

2. BIO 300
BIOLOGICAL TECHNIQUES AND SKILLS
SARINI BINTI AHMAD WAKID
FACULTY OF APPLIED SCIENCE
2

3. Techniques in field investigation
3

4. Population Ecology
Population—
A group of individuals of the same species
living in a particular geographic area
Population Ecology—
Concentrates mainly on the factors that
affect how many individuals of a particular
species live in an area
4

5. What is a sample?
“A portion, piece, or segment that is
representative of a whole”
5

6. Why do we sample?
Because it is usually impossible to
count all the plants or animals present
in a given area
– e.g. # dragonfly larvae in a pond
– e.g. plant cover on a river terrace
– e.g. species of plants in the estate
6

7. NON-INVASIVE SAMPLING
Avoid any degradation of the habitat when
sampling
􀁺 Removal of whole or parts of organisms
should be limited to species that can quickly
recover
7

8. REPRESENTATIVE
SAMPLING
Take a number of samples from around the
sampling site so as to be reasonably sure
that the samples represent the site in general
Necessities…
􀁺 the samples represent the whole
– It is necessary to take enough samples so
that an accurate representation is obtained
– It is necessary to avoid bias when sampling
8

9. SAMPLING UNITS
Type determined by the organisms and the
physical nature of the habitat being sampled
– Area of ground surface
– Volume of air, water or soil
􀁺 Standard units enable comparison of results
9

10. QUADRATS
A standard, area sampling unit consisting of a square frame
􀁺 Consistent size and shape is essential for comparing samples
from different places and/or times
Quadrat size
Chosen to suit sampling goals
􀁺 A balance between what is best and what is practical is always
necessary
􀁺 Should suit:
– practical constraints
– habitat
– organism
10

11. Quadrat Method
 A Quadrat is a sampling area of any shape
randomly deployed. Each individual within
the quadrat is counted and those numbers
are used to extrapolate population size.
 Example: a 100 square centimeter metal
rectangle is randomly thrown four times and all
of the beetles of a particular species within the
square are counted each time: 19, 21, 17, and
19. This translates to 19 beetles per 100 cm2
or 1900 per m2.
11

12. QUADRAT & TRANSECT
ACTIVITIES
How, Where & Why Scientists Do Sampling
Scientists often collect data “in the field” which could
mean underwater, in a forest, in a cave, on a reef, or
even the moon! Two essential methods to gather
ecological information in a standardized way are:
Transect Sampling (using a single line) and
Quadrat
Sampling (counted within a grid). These sampling
methods provide more accurate data than random
sampling or simply guessing, but they take less time
than counting every specimen in a certain area.
12

13. Quadrats
- a sturdily built
wooden frame,
can be folded for
easy transport and
storage
13

14. Using a quadrat along
a belt transect
Quadrats
- When placed on the ground, the species
present within the frame are identified and
their abundance recorded
- Sampling could be random or systematic
14

15. Practical Constraints
Small quadrats are quicker to survey but yield a
smaller individual sample of habitat
– Often require a larger # of samples to
represent the habitat
􀁺 Large quadrats require more time and effort
to survey but provide a larger individual
sample of habitat
– Often require a smaller # of samples to
represent the habitat
15

16. Habitat size
Appropriate sample unit size depends on size scale of
the habitat
– Small scale habitats require smaller sized samples
􀁺 Ex. Boulders
– Large scale habitats require larger sized samples
􀁺 Ex. Forests
16

17. Organism size and density
Depends on size and density of organisms
– Small, dense organisms require smaller
samples
􀁺 Ex. grass
– Large, scattered organisms require larger
samples
􀁺 Ex. Trees
17

18. TYPES OF SAMPLING
 􀁺 Systematic
 􀁺 Stratified
 􀁺 Random
18

19. SYSTEMATIC SAMPLING
 􀁺 Often used when the area being studied is
varied, not very large, or
 when time is available
 􀁺 Samples are taken at fixed intervals
19

20. How to sample systematically
Systematic samples are usually taken along a transect
line marked by a tape measure
􀁺 Transect- a line laid across an area
20

21. Sampling along gradients
Transects are set
up along a
environmental
gradients
– down a hillside
– across a streambed
– out from a source of
pollution
21

22. Types of transect sampling
 􀁺 Line transect
 􀁺 Belt transect
22

23. Line transect method
A measured line is laid
across the area in the
direction of the
environmental gradient
– The species touching the
line can be recorded
along the whole length of
the line (continuous
sampling) or at specific
points along the line
(systematic sampling)
23

24. Line Transect
- useful where a transition of flora and/or fauna
occurs
- a string or tape is stretched out along the
ground in a straight line;
record the organisms touching or covering
the line all along its length or at regular
intervals
- Profile transect: when there is appreciable
height change along the transect and thus
affecting the distribution of its species
24

25. Belt transect method
Similar to line transect but
widens the sampling area
– Transect line is laid out
– Samples are taken by
determining abundance or %
cover in an area that is a
defined distance from the line
– Samples can be taken all the
way along the line, at specific
intervals or even randomly
25

26. Using a quadrat
along a belt transect,
e.g. ladder transect
(every 5m)
Belt Transect
It is a strip, usually a metre wide, marked by putting a
second line parallel to the other. The species
between the lines are carefully recorded, working a
metre at a time.
Alternatively, a frame quadrat in conjunction with a
single line transect could be used. 26

27. Point Frames
- for grassland field study of dense vegetation
27

28. STRATIFIED SAMPLING
􀁺 Often used when
there are small
areas within a
larger habitat that
are clearly different
􀁺 Strata- major
differences within
communities
recognized before
sampling begins
28

29. RANDOM SAMPLING
􀁺 Often used when the area being studied is
fairly uniform, very large, or when there is a
limited amount of time available
􀁺 Random = chosen by chance rather than
according to a plan; all outcomes are equally
likely
􀁺 Samples are taken from different positions
within a habitat and those positions are
chosen randomly
29

30. How to sample randomly
Choose individuals or Place
“sampling units” haphazardly
– This is rarely completely
random
􀁺 OR…
􀁺 Assign numbers to the
areas
or individuals to be sampled
– Use a random number
table to
select which areas or
individuals
will be sample
30

31. Population Attributes
 Density – size of a population in relation to a definite unit of
space
 Affected by:
 Natality – the reproductive output (birth rate) of
a population
 Mortality – the death rate of organisms in a
population
 Immigration – number of organisms moving
into the area occupied by the population
 Emigration – number of organisms moving out
of the area occupied by the population
31

32. Population Density
Four primary population parameters:
32

33. Two Types of Density
Estimates
• Absolute Density – a known density
such as #/m2
• Relative Density – we know when one
area has more individuals than
another
33

34. Measuring Absolute Density
 Total Count – count the number of
organisms living in an area
 Human census, number of oak trees in a
wooded lot, number of singing birds in an area
 Total counts generally are not used very often
 Sampling Methods – use a sample to
estimate population size
 Either use the quadrat or capture-recapture
method
34

35. Measurement of Environmental Parameters
Abiotic factors are important in determining
both the distribution of the organisms and
their physical and physiological adaptations.
Temperature
- diurnal and seasonal temperature variations
are significant in affecting different species of
plants and animals
- equipment: mercury thermometer,
maximum-minimum thermometer,
miniaturized thermistor
35

36. pH meter in use
pH
-measure pH of a solution by universal
indicator, pH paper, pH meter, etc.
Light
-measure its duration and intensity; duration
by predication from Royal Observatory;
intensity by photographic light meter
36

37. Humidity
Relative humidity: the water content of a
given volume of air relative to the same
volume of fully saturated air
- equipment: whirling hygrometer
37

38. Wind and Water Speed
- wind speed:
- anemometer or wind
gauges
- water speed:
- time the movement of a
floating object over a
measured distance
38

39. Salinity
- using a conductivity meter: greater salinity has
greater conductivity
Oxygen Level
- using an oxygen meter or chemical method
(Winkler method)
39

40. Collecting Methods
Collecting all organisms within a habitat is normally
impractical and therefore small areas are selected.
Remember to return all material to its original position
after searching & collecting sufficient specimens.
Some collecting apparatus for general use are listed
below:
40

41. 1. specimen tube
2. screwed-topped jars
3. polythene bags
4. forceps
5. paint brush
6. bulb pipette
7. pooter
41

42. 8. widger 9. sieve 10. hand lens
11. enamel dish 12. beating tray 13. light traps
14. Tullgren funnel 15. Baermann funnel 16. mammal traps
17. pitfall traps 18. netting
42

43. Estimating Population Size
The exact methods used for
estimation depend not only the
nature of the habitat but also on
the organisms involved,
e.g. animals - population ;
plants - percentage cover
43

44. Using Quadrats
- By sampling an area using quadrats and
counting the number of individuals within
each quadrat, it is possible to estimate the
total number of individuals within the area
- confined to plants and sessile, or very slow-
moving animals;
- fast-moving animals are disturbed and run
away
44

45. Capture-recapture Techniques
- useful for mobile animals which can be marked
- capture, marked, released, randomly recaptured
and marked individuals recorded
no. of marked individuals recaptured total no. of individuals in 1st sample
-------------------------------------------- = ------------------------------------------
total no. of individuals in 2nd sample estimated size of population
(the Lincoln Index)
45

46. Capture-recapture Techniques
Factors affecting the accuracy of the estimation:
deaths, migration, individuals become more liable to
predation, etc.
Examples:
- arthropods marked on their backs with non-
toxic paint,
- fish have tags attached to opercula,
- mammals have tags clipped to their ears,
birds have their legs ringed
46

47. Capture-recapture Method
 Important tool for estimating density, birth
rate, and death rate for mobile animals.
 Method:
 Collect a sample of individuals, mark them,
and then release them
 After a period, collect more individuals from the
wild and count the number that have marks
 We assume that a sample, if random, will
contain the same proportion of marked
individuals as the population does
 Estimate population density
47

48. Assumptions For All Capture-
Recapture Studies
 Marking technique does not increase
mortality of marked animals
 Marked individuals are allowed to mix with
population
 Marking technique does not affect catch
probability
 Marks are not lost or overlooked
 No significant immigration or emigration
 No significant mortality or natality
48

49. Peterson Method or Lincoln Index
Marked animals in Marked animals in
second sample first sample
=
Total caught in Total population
second sample size
5 = 16 N = (20)(16) N = 64
20 N 5
49

50. Some Indices Used
 Traps  Number of Artifacts
 Number of Fecal  Questionnaires
Pellets  Cover
 Vocalization Frequency  Feeding Capacity
 Pelt Records  Roadside Counts
 Catch per Unit Fishing
Effort
50

51. Abundance Scales
The population size may be fairly accurately determined by
making some form of frequency assessment.
These are subjective and involve an experimenter making some
estimate of the number of individuals in a given area, or the
% cover of a particular species.
This is especially useful where individuals are very numerous,
e.g. barnacles on a rocky shore, or where it is difficult to
distinguish individuals, e.g. grass plants in a meadow.
51

52. The assessments are usually made on an
abundance scale of 5 categories:
 Abundance,
 Common,
 Frequent,
 Occasional,
 Rare.
Barnacles exposed at
low water
52

53.  Environmental resistance are the factors
which limit the growth of a particular
population,
 e.g. predation,
disease,
availability of light, food,
water,
oxygen and shelter,
the accumulation of toxic wastes and
even the size of the population itself.
53

54. Density-dependent Growth
 A population is a density-dependent when its size
(or density) affects its growth rate because of
density-dependent factors such as food availability
and toxic waste accumulation.
Density-independent Growth
 In this type of growth a population increases until
some factor causes a sudden reduction in its size.
 Its effect is the same regardless of the size of the
population, e.g. temperature, fires, floods, storms,
etc.
54

55. Regulation of Population Size
 Fecundity is the reproductive capacity of individual
females of a species.
 Birth rate or natality is used to measure fecundity.
 Death rate or mortality is the number of individuals
of a species which die per unit time.
 Immigration occurs when individuals join a
population from neighbouring ones.
 Emigration occurs when individuals depart from a
population.
 A cycle occurs when the size of a population
fluctuates on a regular basis
55

56. Ecological Sampling
56

57. Why Do We Sample?
 Determine presence and/or abundance
 Monitor population fluctuations
 Assess ‘ecological damage’
 Assess quality of habitat
 Assess population responses
57

58. What Do We Sample?
 Physical Environment
 Temperature, DO, pH, salinity, clarity, flow,
sediment
 Biotic Environment
 All living things
58

59. Physical Habitat
 Temperature
 Mercury thermometer
 Electronic thermometer
 Long-term thermometers
 Dissolved Oxygen
 Winkler method (titration)
 DO meter (electrode)
 pH
 Litmus paper
 pH meter (electrode)
 Salinity
 Salinity Meter YSI 550A DO Meter w/12' cable
59

60. Water Clarity
Secchi Disk
 Disk is attached to a calibrated rope. The disk
is lowered into the water until the white parts
can no longer be seen. Secchi disk depth is
then recorded and serves as the waters
transparency index. The clearer the water, the
greater the secchi disk depth.
Secchi Disk 60

61. Current Velocity (flow)
 Floating-orange method.
 Put an orange (or something else that floats
just below the water surface) and measure the
time it takes it to float across a known distance.
 Odometer-type flow meter
 Number of revolutions the propeller makes for
a given time is calibrated to flow velocity.
61

62. Sediment
 Sediment size is important to many
aquatic organisms.
 Sieve’s are used to separate and grade
sediment samples.
 Percent of each size grade can be determined
62

63. Water Sample
 Water and plankton from various depths
can be collected.
 A trigger mechanism is used to close the
sampler.
 Sample is then brought back to the surface
63

64. Small Mammals
 Mouse/rat Traps
 Fatal
 Pit Falls
 Bucket is placed in the ground
 Sometimes have ‘leads’ to the buckets
 Live traps
 Havahart
 Sherman
 Spot-light
Havahart trap Sherman trap
64

65. Birds
 Stick-under-the-box method
 Bird-trap
 Works like a minnow trap
 Mist net
 Captures birds in flight
 Rocket net
 Uses a propellant to throw a net
over birds
65

66. Terrestrial Insects
 Sticky paper
 flies
 Baited Traps
 Fire ants
 Nets
 butterflies
 Foggers
 Collect insects from tree canopies
66

67. Aquatic Insects
 Drift Net
 Place net in flowing water
 Kick Net
 ‘Kick’ sediment upstream
from block net and the flow
will wash them into the net
 Wash bucket
 Serber or Hess Sampler
 Stir up known area of
sediment
 Animals are collected by a
catch net
 Multi-plate Sampler
 Become colonized
67

68. Crawfish and Crab Traps
68

69. Fish Larvae
 Light Traps
 Larvae are attracted to the light
 Ichthyoplankton nets
 Can be towed at various depths
 Fish collect at the ‘cod’end
69

70. Fish
 Lift net
 Net is placed down, and after
a set amount of time it is
quickly lifted
 Pop-net Pop-net
 Similar to a lift net, but floats
are attached to a framed net. Lift net
 Operated by a trigger
mechanism
 Throw net
 A net attached to a heavy
frame is thrown and every
thing inside is netted out Throw net
70

71. Minnow trap
 Usually use bait to attract small fish
 Light is used sometimes as an attractant
71

72. Fish
 Electrofishing
 Electricity is put into the water
 Fish are temporarily stunned and usually swim
towards the electricity source
 Usually non-fatal but may cause some damage
72

73. Fish
 Gill Net
 Gill nets resemble tennis nets
 Fish can not swim completely through the net
and get caught
 Gill nets are size selective (based on mesh size)
Square Mesh
Stretch mesh
Bar mesh
73

74. Fish
 Trammel Net
 Three panels: two large
mesh on the outside
and a small mesh on
the inside
 Fish swim through the
outer mesh, pushes the
small mesh through the
other side and
becomes entangled
74

75. Hoop nets (and other
similar nets) can have
bait or not.
Fyke nets have leads
to help guide fish to
the net.
75

76. Seine
Seines are nets that are pulled through
shallow water to catch fish.
76

77. Purse Seine
 Used to encircle entire schools of fish
 Usually involves a spotter plane and a second
boat
77

78. Trotline (longline)
 A series of baited drop lines connected to
a main line.
Can be deployed by tying
one end to the bank and
tying the other end with a
heavy weight.
78

79. Shrimp (or fish) Trawl
 Net pulled behind a
boat along the
bottom
 Either a beam or otter
boards keep the net
open
79

80. Tagging Individuals
 Coded Wire Tags
 Microwire that has a unique
label
 Magnetic wand detects the tag
 Tag retention should be
determined
 T-Bar tags
 Can be individually numbered
 External tag
 PIT tags (Passive
Integrated Transponders)
 Wand induces the tag to
transmit, individual number is
displayed
80

81. Other Tagging Methods
 Toe clip
 Amphibian and reptile
 Clip of one or more toes to
identify individuals
 Bird Band
 Place a metal band on a
bird leg
 Generally has
identification information
81

82. Preserving plant specimens
 Pressing and drying
 Long-term preservation
and storage
 Alternative drying
techniques
 Special preservation
and processing
techniques
 Mounting
82

83. Pressing and drying
 Techniques for pressing and drying specimens have been
established for many years. There are minor variations in
recommended methods, but they are essentially the same
worldwide.
 The best specimens are plants that are pressed as soon as
possible after collection, before wilting and shrivelling. Most
plants may be kept in sealed containers such as plastic bags for
up to a day if it is inconvenient to press immediately. However,
some plants show such rapid wilting, particularly of the flowers,
that such delays are best avoided. Flowers with a lot of nectar
may go mouldy very quickly if excess nectar is not shaken off
before pressing.
 Specimens are pressed flat and dried between sheets of
absorbent blotters or semi-absorbent paper such as newspaper.
Papers with a glossy surface should be avoided because they
are not absorbent enough to aid drying. The plant should be
carefully laid out between the drying sheets, as their form at this
stage largely determines their ultimate appearance. The flowers
should be spread out with the petals carefully arranged, wilted
leaves should be straightened and unnecessary shoots of
excessively twiggy shrubs may be cut away.
83

84. Microwave ovens
 Small numbers of specimens can be dried using a microwave oven. The
technique recommended in the literature is to place the specimens
between unprinted absorbent paper, for example butcher's paper, not
newspaper, which is unsuitable because the chemicals present in the
ink may cause a fire. The specimens should be put in a special press
which should be of a microwave-safe material (wood, acrylic or
polycarbonate sheeting e.g. plexiglass or perspex, NO metal
components). If such a press is not available, sheets of cardboard can
be placed above and below the specimens and then weighted down.
 Drying time depends on the power of your oven. In most cases drying is
accomplished by irradiating at maximum power for 1-2 minutes per
specimen, although it is often a case of trial and error. It is best to
process no more than 10-12 specimens of average thickness per batch.
Specimens are usually dried after the moisture that characteristically
appears on the glass door has disappeared. If the specimen is damp
when taken out of the oven, allow it to stand before re-radiating as
moisture continues to evaporate from the specimen for some time. Care
must be taken not to irradiate the specimens for too long.
 It should be noted that microwave treatment damages seeds and the
cellular structure of the plants which may reduce the long-term value of
the specimens.
84

85. Alternative drying techniques
Silica gel/other desiccants & freeze drying
 Alternative methods of drying plant specimens have been used
for some time, but are mostly restricted to special purpose
collections. The main alternatives are freeze-drying and drying in
a desiccant powder such as desiccant silica gel. In general these
techniques are used where it is essential to preserve the shape
of a delicate plant of organ of the plant such as the flower.
Freeze-drying has also been used to preserve the chemical
composition of a plant as accurately as possible for later study.
 Disadvantages and special conservation problems of specimens
dried in these manners are that they are particularly susceptible
to damage. The dried parts are fragile, lack support and often
catch on packing materials. They must, therefore, be packed
especially carefully and stored in small boxes or tubes with some
appropriate packing material that does not snag and break small
projections. Acid-free tissue paper is often used. Drying in
desiccant silica gel crystals or powder can also have the
disadvantage that it is difficult to remove all traces of the silica
gel after drying.
85

86. Special preservation and processing
techniques
Wet or spirit collections
 Very fleshy or delicate structures, including small
algae and orchid flowers, are best preserved in an
air-tight glass or plastic jar with a liquid preservative
rather than by drying. The type of preservative used
should be clearly labelled in the jar. Such material is
often referred to as a spirit collection or wet
collection.
 Most material can be satisfactorily preserved in 70%
ethyl alcohol (or 70% methylated spirit or denatured
alcohol) with 30% water. Colours will fade quickly in
spirit, however, so it is a good idea to keep
comprehensive notes and photographs.
86

87. Small algae
 Microscopic algae are often collected in a jar and in the water in
which they were found. If the algae are to be stored for more
than 2-3 days, a preservative needs to be used. Traditionally this
has been the extremely toxic formalin - a small amount can be
added to the water to make a 5% final solution, and the container
labelled. This must not be sent through the post or by courier.
 There are some other equally toxic options, for example
propylene phenoxytol, but none should be sent through the post.
A safer option is to add sufficient concentrated alcohol or
methylated spirits to the water containing the algae to make a
final solution of 70% alcohol. This treatment dilutes the algae
making them difficult to find, so if they can be concentrated
somehow first (e.g. by filtering) they can be stored in much less
liquid. Another option is to fix the algae in formalin (or something
similar) first, and then prepare a microscope glass slide with a
permanent water-soluble mounting medium.
87

88. Mounting
 Mounting specimens prevents most fragile material from
fragmenting and prevents specimens becoming separated from
their labels. If the plant collection is a long-term project,
specimens should be mounted on sheets of archival (permanent)
cardboard or paper with archival-quality fixing media. These
include stitching with cotton thread, dental floss, nickel-plated
copper wire (for heavier specimens), narrow strips of archival
paper, linen tape, or by using an archival adhesive such as
methyl cellulose adhesive
 One disadvantage of mounting specimens is that it can make
parts of the specimen inaccessible for examination, so it is
essential that this be borne in mind during specimen
arrangement and mounting. For example, easily reversible
mounting media should be used, specimens should be strapped
to the sheet, rather than glued all over, and the specimen should
be carefully arranged before it is attached so that it shows all
features.
88

89.  Full-size herbarium mounting sheets are
usually about 43 cm long x 28 cm wide. The
plant name and accompanying field notes
should be transcribed on a permanent label
stuck to one corner of the herbarium sheet
(the bottom right-hand corner being the most
common) or, sometimes, annotations may be
written directly on the sheet or card.
 Small pieces of material which may have
become separated from the specimen (e.g.
seeds) can be placed in small plastic bags
and pinned to the sheet.
89

90. Long-term preservation and
storage
 The long-term preservation of dry plant
specimens is largely dependent on protection
from insect attack. Specimens collected by
Linnaeus in the eighteenth century, and by
Banks and Solander on the Endeavour voyage
in 1788, are still excellently preserved.
90

91. Pests and their control
 A range of pests attack dried plant material. The
most common pests are insects and fungi, though
rodents and other large animals can cause damage
in poor storage conditions. Insects eat the material,
the paper surrounding the material, and the
adhesives and mounting media.
 Such insect pests range from psocids (book lice),
which attack mainly the softer parts such as flowers
and soft fruits, to tobacco beetles and carpet
beetles, which can bore holes through the toughest
of specimens. Many insects are particularly
sensitive to relative humidity levels and do not thrive
at levels below 50%.
91

92. The most common and acceptable specimen
treatments for insect control are:
 Freezing
 Microwave
 Poisoning
 Insect deterrents
 Fungal pests
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93. Storage
 Dried and pressed plant specimens can be
stored in cardboard or plastic boxes, or tied in
bundles in light-weight cardboard folders
placed in 'pigeon holes'.
 Alternatively, they can be placed in protective
plastic jackets and displayed in ring folders
which is recommended if they are to be
frequently handled, such as for a reference
collection.
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94. Filing
 Specimens should be filed in a systematic order if a
relatively permanent collection is being made. The
major groups, i.e. ferns and fern allies, cycads,
conifers, dicotyledons and monocotyledons, are
best kept separately or according to some
classification scheme, such as that given in a flora
or handbook.
 Similarly, the genera within each family and the
species within each genus may be filed
alphabetically or following some such classification.
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95. Preservation of entire animals
 Types of collection specimens of an entire animal:
For reference collections, mammals can be prepared as a variety of
specimens. The condition of the specimen may determine possible
ways to preserve it; if for instance decomposition of the skin has
loosened the hair of a carcass so much that it can easily be pulled
out or removed by rubbing (“slipping” fur), it will be very difficult or
impossible to produce a study skin or mounted specimen.
The most usual types of specimens (based on Nagorsen and
Peterson, 1980) are:
1) entire fluid-preserved animals (for studying anatomy and
histology; fluid preservation may change the fur colour)
2) study skins with accompanying skulls / partial skeletons (some
bones remain in the skin), for studying pelage colour, hair quality
and moulting patterns,
3) mounted skins with accompanying partial or entire skeleton
(some bones may remain in the skin, dependant on the method of
preservation) or freeze-dried specimens,
4) entire skeletons, for instance for studying anatomy, geographic
variation or for age determination (entire skeletons are poorly
represented in collections, so Nagorsen and Peterson (1980)
recommend preparation of at least one male and one female
skeleton per species.
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96. Preservation of specimens in the
field
 Formalin preservation
 Preservation in alcohol
 Preservation by cooling or freezing
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97. Formalin preservation
 After weighing and measuring the animal and attaching an adequate
label very small specimens (up to 100 g) can be fixed whole by
submerging them in 10 % buffered formalin (tissue - formalin
solution ratio of at least 1 : 12). the body cavity can be filled with
formalin solution by injection until it is turgid and firm; some formalin
may also be injected under the skin, into the body cavity, larger
muscles and organs. If hypodermic needles are not available, the
body cavity can be opened ventrally by making a slit instead,
allowing the formalin to enter.
 Keeping the mouth open with a piece of wood or cotton may later
allow examination of teeth. Then the whole body can be immersed
in formalin, in the posture in which it is supposed to stay
permanently because it will harden. The ratio of formalin to carcass
must be at least 12 to 1 to assure a good fixation. Tissues can be
left in buffered neutralized formalin for several months, but formalin
hardens specimens; therefore, after fixation, longterm storage in
alcohol may be better. After preservation the carcass should
therefore be washed in water and transferred into ethanol for
permanent storage
 Disadvantages; for instance it discolours the fur, after a longish
immersion, softens the bones and prevents further examination for
microbiology.
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98. Preservation in alcohol
 After weighing, a whole animal can be
preserved in a container of alcohol (70-90%).
Removal of the intestine prior to storage of
the animal in alcohol is recommended
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99. Preservation by cooling or
freezing
 Removal of the skin with insulating fur before
cooling or freezing may help to cool the
carcass down more quickly.
 Freezing is not recommended if histological
examination is planned
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100. THANK YOU
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