3.3. Land Cover and Land Use Changes (LCLUC) and soil erosion
changes (2005 - 2015)
In ten years of study period (2005 - 2015) at the
national scale in Pakistan, overall ‘cropland’ area increased from
170,761 km2 (19.36%) in 2005 to 177,474
km2 (20.12%) while ‘forest land’ decreased from 2,000
km2 (0.23%) in 2005 and 1,604 km2(0.18%) in 2015. At the national scale, in the ‘grassland’ class 521
km2 (0.06%), in settlements LCLU class 106
km2 (0.01%) and in ‘wetlands/snow cover’ 1,532
km2 (0. 71%) increased detected between 2005 – 2015
while in ‘other’ LCLU class an overall area lost from 551,813
km2 (62.57%) in 2005 to 543,337 km2(61.61%) in 2015 (Table 5).
Through cross tabular or change matrix method, at the national scale
total 29,081 km2 (3.30%) loss while 17,506
km2 (2.00%) gain observed in LCLUC classes between
2005 to 2015. Among the LCLU classes, <2% loss and gain
detected in ten years of study period (2005 - 2015). In spatial
distribution map of LCLU, loss detected prominently in Sindh, Punjab and
Khyber Pakhtunkhwa while major gain observed in Balochistan (Table 6 and
Figure 6)
Among all six IPCC defined LCLU classes in the seven administrative
units of Pakistan, in the Sindh and Balochistan provinces, the area in
the percentage of low annual soil erosion (<1 ton/ha/year)
category was observed under the majority of the LCLU classes between
2005 to 2015. In Azad Jammu & Kashmir, Gilgit-Baltistan and Islamabad
Capital Territory, a well the distribution of each category of soil
erosion against LCLU classes were observed between 2005 to 2015. In the
forest, under the high (5-20 ton/ha/year) annual soil erosion class, in
the Azad Jammu & Kashmir, Gilgit-Baltistan, Khyber Pakhtunkhwa, and
Punjab an increasing trend detected in ten years of study period (2005 -
2015). Among all the administrative units of Pakistan, only in Azad
Jammu & Kashmir, under the very high (> 20 ton/ha/year)
annual soil erosion class, in all six LCLU classes an increment observed
in ten years (2005 - 2015) of the study period. Surprisingly, in the
settlement class in 2015, very high (> 20 ton/ha/year) soil
erosion was calculated as 10% which was zero in 2005. Even in the
Khyber Pakhtunkhwa province and Islamabad Capital Territory, under the
high (5-20 ton/ha/year) soil erosion class increase in settlement class
observed between 2005 to 2015. In the settlement class, in ten years of
the study period (2005 - 2015), no soil erosion occurred in the
Gilgit-Baltistan. In the Islamabad Capital Territory, from 2005 to 2015,
the other LCLU class completely shifter from medium (1-5 ton/ha/year) to
high (5-20 ton/ha/year) annual soil erosion category (Figure 7).
At 5km spatial resolution, bivariate analysis revealed in Pakistan
maximum areas covered by ‘no change’ between soil erosion change and
LCLUC classes. Majority LCLUC ‘loss’ detected in Balochistan, Punjab and
Sindh with no-change in soil erosion change. In the Azad Jammu &
Kashmir, Gilgit-Baltistan, Islamabad Capital Territory and Khyber
Pakhtunkhwa administrative units, ‘loss’ in LCLUC detected with ‘gain’
in soil erosion change class. Huge area in Khyber Pakhtunkhwa and
Gilgit-Baltistan spreader under ‘loss’ with few patches of ‘gain’ in
LCLUC and soil erosion change between 2005 - 2015 (Figure 8).
4. Discussion
This study provides the first soil erosion estimations and monitoring
from 2005 to 2015 at 1 km spatial resolution at the national scale and
seven administrative units of Pakistan. In this study, we adopted a
cost-effective and easily replicable methodology, used freely available
geospatial datasets (soil, precipitation, LCLU, and elevation) in the
widely adopted and proven RUSLE.