Lemessa (2020). A Robust Method of Computing the Annual Rate of Land Use/Land Covers Change in
Landscapes. African Journal of Sciences (2020) Volume 14 (2) 163-168
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A Robust Method of Computing the Annual Rate of Land Use/Land Covers Change in
Debissa Lemessa, Ethiopian Biodiversity Institute, Addis Ababa, Ethiopia
Background: Several earlier studies have used different formulae to compute the annual rates of land
use/land covers changes in landscapes. Moreover, the magnitudes of the land use changes from two time
points (i.e., initial and recent) only have been used to compute the annual rates. However, the use of
different formula by itself is confusing and the failure to take into account the instantaneous changes in
magnitude of the land use changes from the intermediate time points along the time period may lead to
either overestimation or underestimation of the annual rates.
Objective: A formula to compute the annual rate of change in land use/land cover in a robust method
was suggested based on the property of the function of instantaneous change in slope and law of
compound interest in economics.
Materials and methods: The property of instantaneous changes in slope was integrated with the
formula of compound interest in economics to derive the formula of calculating the interest rate of
change in land use. With the application of this approach, the differential effects of the drivers of land use
change along long temporal scale can be taken into account by converting the magnitude of the changes
into change factors. Here, data are “scaled” to change factors from the ratios of the mid points (tangent
lines) to the consecutive intermediate initial time points along the time period and these change factors
are again averaged over number of time intervals of change detection to enhance the precision of
calculating annual rates.
Result: The annual rate of change in land use should be computed as,
Conclusion: For both short and long time periods, the present formula can be applied as standard and
such computation is an ideal input for planning biodiversity conservation and development strategies.
Keywords: Change factors; Compound interest; Instantaneous changes; Time period