Relationships Between
Land Use/Cover and Macro-Forces of Change -- Answers to Activities
QUICK LINKS
| Activity
3.1 Number Crunching and What It All Means | Activity
3.2 Feeding the Millions |
| Activity
3.3 What Depends on What in Land Use Change? | Activity
3.4 Land Use Change and Driving Forces at Different Scales |
| Activity 3.5 Film: Banking
on Disaster | Activity
3.6 Local Change -- Global Forces |
| Activity 3.7 The
Personal Land Use Log | Activity
3.8 How Personal is Global Change? |
| Activity 3.9
What Can We Do About It Anyway? |
Activity
3.1 Number Crunching and What It All Means
Make sure students understand the concepts of coordinate system, scale
on both axes and correlation. Use the two sets of scatterplots to solidify
their understanding. The first two scatterplots don't show a clear relationship,
of the latter two, the first shows positively correlated, the other negatively
correlated values.
Perfect correlation would mean that all points fall on one straight
line, whereas not correlated variables have randomly dispersed data
points in a coordinate system.
Then let students write their rules of thumb for no correlation, positive
correlation, and negative correlation.
A No correlation -- no trend discernible
in the plotted data at all. Data points are randomly distributed.
B Positive Correlation -- as values
on the x-axis increase, so do values on the y-axis. The trend is one from
the origin of the coordinate system up and to the right.
C Negative Correlation -- as values on one
axis increase, values on the other axis decrease. The trend is, e.g., one
from high y-values near the y-axis down and to the right (low x-values).
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Activity
3.2 Feeding the Millions
Make sure students understand the distinction between a linear and a logarithmic
scale. If you do not want to use the mathematical formulations provided
in the task description for instructors, draw the two scales one above
the other on the blackboard so that the students can visualize the difference.
(Say, you have a 1 m yardstick. How many times would it fit on a logarithmic
scale between the marker for 0 and 1, between 1 and 2, between 2 and 3,
etc.?)
The graph in Figure
13 shows the population density vs. cropland per person data plotted
in a semi-log coordinate system with a "tendency" line drawn through it.
In their discussion of what the plot actually means, the students should
note the following points:
As population density increases, the ratio of cropland per capita decreases
(negative correlation) -- no big surprise. Common sense would have allowed
us to come up with this hypothesis.
But there is no perfect correlation (scatter; points don't all fall
on one line). Reasons for that include data-inherent problems, difference
in agro-technology, different levels of development of the economy, cultural
differences in values and food preferences, physico-natural differences
between ecological regions, etc.
It may be interesting to use some regional examples to illustrate the
above points; compare and contrast Nigeria and China, Europe and Asia,
Bolivia and Oceania, or North and South America.
Figure 13: Relationship
Between Cropland and Population Density, 1989 (Answer)
Source: Extracted from Sage (1994: 280; his Table 2), after World Resources
Institute (1990)
Also indicate to students that there is no one line in this hand-held
version of a correlation because people see the trends differently, but
that a quantitative approach (calculating the slope and y-axis intercept)
would result in a definitive line.
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Activity
3.3 What Depends on What in Land Use Change?
The task description for instructors already indicates the major difference
between correlation and regression. Make sure students understand the difference
between these two types of analysis.
The regression analysis for the four population/land use pairs -- with
population being the independent and the land use variables the dependent
variables -- results in the following values (Table
8):
Table 8: Results
of Regression Analysis (Population/LULC, 1961-1991)
| Regression Pair |
R2 |
Slope |
Y-intercept |
| Population/Arable land: |
.658 |
+0.02 |
1,235,125.8 |
| Population/Permanent crops: |
.616 |
+0.01 |
56,702 |
| Population/Permanent pasture: |
.675 |
+0.11 |
2,718,469 |
| Population/Forests: |
.695 |
-0.14 |
4,681,090.4 |
Students should note in their deliberations that these coefficients
are fairly large, but in and of themselves they cannot indicate whether
population is the strongest driving force (others are not analyzed, so
a comparative statement cannot be made). They should also be aware of the
fact that only six years entered into the analysis, and that statistical
significance is limited by sample size. This fact does not allow major
conclusions or inferences about causality.
Students should also demonstrate caution in interpreting the graphs
and regression coefficients. Besides assessing the correctness of their
calculations, also look for their thoughtfulness and common sense in drawing
conclusions from the statistical findings.
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Activity
3.4 Land Use Change and Driving Forces at Different Scales
The results of this activity depend entirely on the research question and
data used for the analysis. Generally, look for similar indicators as described
for the previous activity whether or not students understood the concepts
and can thoughtfully apply the analysis to a global change question. In
addition, make sure students pay careful attention to scale. Do the results
they find at different scales explain the differences? Do these explanations
make sense? Do students demonstrate an ability to assess the data they
used (to the degree possible) and do these considerations enter into the
interpretation?
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Activity
3.5 Film: Banking on Disaster
Make sure students recognize how abstract driving forces like "technological
change" or "economic development" look when grounded in a specific concept.
In the discussions students should also recognize the "human face" of land
use/cover change.
Activity
3.6 Local Change -- Global Forces
The specific results here, again, depend very much on what local example
students choose to investigate. Reiterate to students the importance of
scale in this exercise. Students should search for and use a variety of
data sources and show the necessary scepticism regarding their quality.
Note whether they have developed a sensitivity for how global forces might
affect communities, people, and the environment locally. You may also want
to include students' care and creativity in presenting their findings.
This activity is a great opportunity for the instructor to let go of
the reins. Especially if the project is for public display, students will
put in much effort and time to show off their best!
Activity
3.7 The Personal Land Use Log
Since practically everything we do and every place we go is somehow related
to land use or land cover, students should have no trouble finding many
examples to list in their one-day land use log. You might want to set a
minimum number of observations to have a basis for comparison of what students
hand in. Students should also demonstrate that they have put in some effort
to find out about the regional connections between them as users and the
places of origin of the items or products they listed. Supporting
Material 3.7 lists examples only roughly. You may want to encourage
students to present their land use log in an orderly, structured and/or
creative fashion.
Activity
3.8 How Personal is Global Change?
Students explicitly make connections between global processes and their
personal lives. This is an informal opportunity to assess students' progress
over the module, whether they understood the basic concepts, the linkages
between driving forces and land use change, and the connections across
scales.
Activity
3.9 What Can We Do About It Anyway?
This final activity is meant to be empowering as well as grounding in reality.
Learning about the macro-forces of change should not lead to a fatalistic
stance in students vis-a-vis the processes shaping their local,
social and physical environment. Rather students should understand that
what we conceptually call macro-forces are in fact the cumulative results
of many individual and community-based decisions over which people do have
control, even if they don't feel they do. Decisions about land use must
address and balance constraints and opportunities which are political,
economic, social, ethical, technological, and environmental in nature.
The group reports and the closing debriefing period should bring out this
ever-present tension between macro-forces and individual control.
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Last Revised: 6 /15/04 Robert E. Ford rford@univ.llu.edu