MEASUREMENT AND FIELD METHODS LAB
Ecology is about making sense out of what we see in the world, finding patterns and interpreting them. “Science is about
organizing experience and predictive power” (from Allen & Hoekstra. 1992. Toward a Unified Ecology).
Well-documented, repeatable science gives information credibility. Some have called this quantitative ammunition.
Quantitative measures can be part of a description (so many centimeters or inches tall, a certain percentage of a
community in terms of density or coverage, etc.) or a test of an hypothesis. Hypotheses reveal what is not true by the
process of elimination. As more hypotheses reveal more untruths, more certainty accumulates.
Measures of attributes can allow you to make comparisons:
a. Differences or similarities with respect to space: plant geography
b. Differences or similarities with respect to time: succession
REFER TO THE LAB REPORT FORM FOR SUBMISSION GUIDELINES. DO NOT HESITATE TO CALL OR WRITE WITH
QUESTIONS.
Part 1. Measurements, Dimensional Analysis, Growth
A. Measurements
The world can be observed in two ways, qualitatively or quantitatively.
Qualitative is the related word to quality. These observations describe phenomena, which cannot be measured
objectively. Examples are colors (each individual’s eye sees differently), flavors, cuteness. Qualitative measurements
are not easily repeated and can demonstrate bias based on emotions or culture.
Quantitative is the related to the word quantity. These observations describe phenomena, which can be measured
objectively. This is the type of observation science is bases upon. Examples are numbers of objects, temperatures,
distances.
Even when qualitative measurements are employed, accuracy of these figures depends on absence of human error
and preciseness of measuring devices. There is no perfect instrument for measuring. And of course, humans cannot
see all of what is, anyway.
Give two examples of qualitative observation and two of quantitative observation. Add to Lab Report Form on
page 8.
Qualitative
1.
2.
Quantitative
1.
2.
B. Dimensional Analysis
Dimensional analysis can be used to convert one type of unit to another using a fraction called a proportion. This is
a useful tool! Some references are based on the metric system, most often used in science, and other in the English
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system. If one cannot understand metric units of measurement, then how can critical thinking be applied? Having
some familiarity with these conversions gives you confidence interpreting data.
1. Study these steps to use dimensional analysis to convert units of measurement from one type to another.
Step 1
Identify units to be converted.
Example
Convert 10 miles to kilometers.
Step 2
Find equivalent conversion units.
1 kilometer = 0.62 miles
Step 3
Set up proportions using multiplication
or division so that unwanted units
will be eliminated.
10 miles X 1 kilometer
0.62 miles
Step 4
10 miles X 1 kilometer
Solve and cross out matching unit labels.
0.62 miles
You will see that an answer with the correct units.
= ?
= 16.13 kilometers
2. Solve these conversion problems.
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

Use help from the Internet, but you must show your work.
Space out as needed.
Add to Lab Report Form on page 8.
1.
2.
3.
4.
5.
It is 4 miles from here to Thumb Butte Park. What is this distance in kilometers?
A certain species of beetle weighs 0.5 grams. How many ounces does she weigh?
How many milligrams does this same beetle weigh?
A four-pound bass weighs how many grams?
A forest snail travels at 5 inches in one minute. Convert this to centimeters per minute.
C. Linear vs. Exponential Growth
When linear growth is occurring, a given condition increases by a specific amount per time period. Exponential
growth occurs when a condition increases by a percentage of the previous period’s amount. In other words, in
exponential growth, the growth amount compounds because each step is based on previous increases. Exponential
growth is the more common type in ecological systems.
Solve this growth problem by constructing line charts (sometimes called line graphs).
You were offered a job and your potential supervisor said, “We can pay you in two different ways: you can
earn $6.00 a day with a $6.00 a day raise, or you can earn $1.00 a day with a 25% increase each day. Carry
out to at least 35 days. Answer these questions:
1. Which earning strategy is the most profitable?
2. Which would have seemed most profitable if you had stopped at six days?
Add answers to questions and graph to Lab Report Form on page 8.
To construct the charts, consider these options:
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Make a spreadsheet in Excel for each type of growth. Then, from the Excel toolbar, convert each to a line
chart. Be sure to label the two types of growth.
Use regular graph paper to graph them, save and scan. You can find printable graph paper here,
http://incompetech.com/graphpaper/. Print graph paper or use some you already have, draw in your
information and scan.
Part 2. Measurements of Biodiversity, Field Methods
Add responses to this part (photos and answers to Analysis Questions) to your blog site as “Field Methods Sampling
Report.”
A. Measurements of Biodiversity
A variety of objective measures have been created in order to empirically measure biodiversity. The basic idea of a
diversity index is to obtain a quantitative estimate of biological variability that can be used to compare biological
entities in space or in time. It is important to distinguish ‘richness’ from ‘diversity’. Diversity usually implies a
measure of both species richness and evenness. In this lab, we will deal with richness.

Species richness is a measure for the total number of the species in a community. However, complete
inventories of all species present at a certain location, is an almost unattainable goal in practical
applications.

Species evenness is a measure of how evenly the individuals in a community are distributed among the
different species.
.
Figure 1. A visualization of the species richness: with, respectively, 5 and 10 species.
.
Figure 2. A visualization of the evenness of 5 species.
B. Field Methods.
One of the first things a field ecologist will want to know about an animal or plant species is: How dense is the
population? Units of density are number of individuals or colonies, etc. per unit area or volume.
Another important question is: How are the organisms dispersed within the habitat? Dispersion is the pattern of
distribution in space.
In most cases it is impossible, because of the time, effort or money involved, to count every individual or plot their
location on a map. If we did so, it would be a census. So it would be useful if there were some way that we could get
an accurate representation of some spatial characteristics of the population without having to map every organism.
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By sampling the population we can do this, but the sampling must be done properly, if we want our representation
to be valid. To insure an adequate representation, some guidelines must be followed. You will use these methods in
most of the rest of your labs this semester.
Choosing Sample Sites: Random vs. Haphazard
Experimenter bias in sampling is a common hazard and must be continuously guarded against. For example, “It’s
late, and this rock is too hard to look under, so it wouldn’t hurt to sample under this smaller rock.” To obtain an
unbiased estimate of the population, sampling should be done at random, which means the sampling should be
conducted in such a way that the probability of each individual being selected in the sample is the same. There are
several ways of insuring this criterion is met or at least closely approximated.
Random numbers are series of numbers such that the chance of selecting, for example, any digit (0 – 9) is equal at
any point in the sampling procedure. If the random numbers can be assigned to organisms or to locations in the
habitat, they can be used to select the sample from the population. A fast and simple method is to use a random
number table. You can use the numbers in the table to select sampling positions (e.g. paces along a trail, GIS
coordinates, termite holes in a wall that you have numbered etc.). Most calculators and spreadsheet applications
also have random number generating functions,
Often a person will think that they can make up random numbers and/or sample “randomly” without recourse to
the use of some randomizing method. This rarely works to produce a random numbers or a random sample. Such
samples are termed haphazard.
Commonly Used Methods for Spatial Sampling
There are three general types of sampling methods used to select individuals from a population situated in space:
quadrats transect lines, and plotless techniques. In this lab, we will address the quadrat and transect.
1. A quadrat is a frame (usually a square or a circle) of known area used to isolate a subset of the population.
This subset will comprise one sample. The size of quadrat selected is determined by features of the
organisms in the population to be sampled. A postage stamp-size quadrat might work well for mites on a
leaf but will be hard to use on elephants. The use of a quadrat is very simple. It is placed randomly in the
sampling area (the habitat of the species of interest), and all the individuals within the quadrat are counted
and/or measured.
Exactly what the sampling area is, how its limits are determined, and how the quadrats are placed, are all very
important points in using this method. Quadrats are most useful when the area is fairly uniform and movement
within the area is easy.
Determining density from quadrats may seem straightforward, but you must be aware (and should investigate
as part of the exercise) how quadrat size and number of samples can influence your results.
2. The transect method is most useful when the area to be sampled is zoned in some way or has some sort of
gradients running through it. Think of the intertidal habitat on a small scale or the vegetation running up the
side of a mountain on a larger scale. Transect lines, often in the form of 100-meter measuring tape, are
stretched along a zone.
Once the line has been randomly laid, points along the line are selected. The points might be randomly or
uniformly placed, depending on the question being asked. In this way the distribution of a species across (or
within) the environmental gradient can be determined. For our purposes in this exercise, you are asked to
record every species that contacts the line.
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Density and dispersion patterns
As noted earlier, the number of individuals per unit area is termed the density and the units are things like; trees acre2,
moose km2, zooplankton m3, etc. Dispersion is the pattern of the distribution of organisms in space. There are three
basic dispersion patterns: random, clumped, and regular.
Random
Clumped
Regular
A random dispersion pattern means that there is an equal probability of an individual occurring at any point in the
habitat and that the presence of an individual does not influence the probability of occurrence of another individual.
Clumped dispersion patterns are those where the presence of an individual increases the probability of finding another
one near by. Regular dispersion, indicated by more even spacing that would be predicted by a random dispersion may
suggest territoriality or some limiting resource.
Sample size
How many samples (of any kind) will you need to take before you are confident your estimate of density or dispersal
reflects the true situation? Clearly, the larger the sample the better, but things like time, effort, and money also enter
the picture. Today, we will look at two.
Sampling
You will need a camera for this to post least four photos to your blog site. You can certainly post more if you want to.
Purpose:
 Perform two different spatial sampling techniques and compare the results in numbers of species found
 Recognize an discuss dispersal patterns
Materials:
 Relatively natural outside area with a good number of different kinds of plants. A garden, field, trail, or flower
bed work in a pinch.
 Camera
 Sun protection and water for yourself and team members (if you are working with others)
 String cut into a 16.2-meter length. Two-tenths meter is allowed for making a knot, details below.
 Other objects or more string to delineate subdivisions of your quadrat
 Random number calculator. To format your random number table, put in 16 random numbers, minimum value
1, maximum value 16, “true” to allow duplicate entries, nothing in “seed.”
Here is a link to one you might want to use: http://screencast.com/t/cf7RpVoaQFd. The page will look like this, but do
not use this one. Generate one of your own.
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Procedure:
1. Visit your natural area and choose a site in which you can situate a 4-meter by 4-meter quadrat.
2. Form your quadrat by tying the ends of your string together and forming it into a 4-meter by 4-meter square
over your area. Take a photo.
3. Subdivide the quadrat in to 16 equally sized squares. To do so, line up stones, lay down more string, place flags
of paper or cloth, or other markers to make these boundaries like these.
Take a photo of this arrangement.
4. Use the random number generator to generate 16 numbers.
5. Select the first eight numbers to designate the squares in your quadrat you will sample.
6. In each of these randomly selected squares, record the number of different kinds of species (species richness).
Do not count the number of each species.
How can you determine the different species? Give them a common name you invent (or use one you know) and
make sketches, so you can keep track of what you find.
7. Note any dispersal patterns.
8. Record these data in a table like this:
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9. Place a flag or other marker on the bottom left and the top right corners of the quadrat. Take a photo.
10. Untie the knot in the string.
11. Secure the string at the bottom left corner and extend the string through the top right corner and beyond
(about 16 meters total). Take a photo.
12. At each point where a plant intersects (where it touches, for trees where its shadow falls) this line, record the
species name (made up or otherwise).
13. Count the number of different kinds of species (species richness) the string intersects. Do not count the number
of each species.
14. Record these data as total number of species along transect.
15. Note any dispersal patterns.
16. Analysis questions.
a. This exercise did not require random sampling to chose your site. State how you chose your site, and
explain any biases you discovered in yourself while doing so.
b. Describe the differences in the number of species using each method. Which one seems to “capture” the
scene the best?
c. If you discovered any dispersal patterns, describe them.
d. Discuss what you would change for either method to determine a more accurate species count.
References:
Clark, P. J. and F. C Evans,. 1954. Distance to nearest neighbor as a measure of spatial relationships in populations. Ecol 35: 445-453.
MLA Coastal Wiki. http://www.coastalwiki.org/wiki/measurements_of_biodiversity. Accessed 2014 Jun 13.
Greig Smith 1979. Pattern in Vegetation J. Ecol. 67:755-779.
Kinzie III, R. and R. H. Snider 1978. A simulation study of coral reef survey methods. IN Coral Reef Research Methods. D. R. Stoddart & R. E Johannes eds. UNESCO Paris
Poole, R. W. 1974 An Introduction to Quantitative Ecology McGraw-Hill NY
Simberloff, D. 1979. Nearest neighbor assessments of spatial configuration of circles rather than points Ecology 60:679-685
Southwood, T. E. E. 1966 Ecological Methods. Methuen London
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LAB REPORT FORM
This report form is for Part 1 only. Please add Part 1 answers to the Submit Some Assignments link in Blackboard, post
Part 2 to your blog site. Thanks!
Quantitative and Qualitative. Write examples of qualitative and quantitative observations here.
Qualitative
1.
2.
Quantitative
1.
2.
Conversion Problem Answers. Record work and answers to conversion problems here. Conversion problems are
repeated below.
1.
2.
3.
4.
5.
It is four miles from here to Thumb Butte Park. What is this distance in kilometers?
A certain species of beetle weighs 0.5 grams. How many ounces does she weigh?
How many milligrams does this same beetle weigh?
A four-pound bass weighs how many grams?
A forest snail travels at five inches in one minute. Convert this to centimeters per minute.
Linear vs. Exponential Growth. Questions repeated here.
1. Which earning strategy is the most profitable?
2. Which would have seemed most profitable if you had stopped at six days?
3. Attach charts/line graphs here or separately.
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