Deforestation Effects on Sedimentation of Watersheds and ...
Transcript of Deforestation Effects on Sedimentation of Watersheds and ...
Deforestation Effects on Sedimentation of Watersheds and Marine Environments:
MaMaBay, Madagascar
Shreya Basu, Dani Ewert, Rachael Maingot, Jing Wang
Methodology
Determine the existence and extent of
deforestation from 1990 to 2010.
Evaluate the extent and quantity of erosion and
sedimentation in watersheds from 2000 to 2010.
Illustrate that the rate of change of sedimentation
entering the bay ecosystem related to
deforestation and erosion from 2000 to 2010.
Study Area
MaMaBay is comprised of two parks (Makira and
Masoala protected in 2009 and 1997, respectively)
and Antongil Bay. The concern for this area is the
effect of deforestation for agricultural purposes and
illegal logging may lead to biodiversity loss and land
degradation. This area maintains 1% of the earth’s
biodiversity. This ecosystem is the home of several
plant and animal species (including humans), and is
in need of further protection to ensure the health of
the land and water ecosystems are maintained.
Data Area C: This watershed area has seen most of its deforestation
occur between 2000 to 2010, with the maximum deforestation of
12-15% per watershed. This area of deforestation occurs mostly
outside the protected MaMaBay boundary, but is contributed to the
second largest plume in the bay within the MaMaBay boundary.
Area D: Maximum deforestation of about 12-15% per watershed
has occurred within the protected areas of the peninsula between
1990 to 2010. The shallows bordering this land mass is home to
shallow, fertile reef systems.
Further Research: Examine villages and roads as driver variables
to deforestation. Collect soil samples and cropping samples to
validate current research.
Main Findings
Revised Universal Soil Loss Equation= R*K*L*S*C*P,
where R is the rainfall and erosivity index, K is the soil
erodibility factor, L is the slope length factor, S is the slope
steepness factor, C is the cropping factor, and P is the
conservation practice factor.
This equation estimates the average potential soil loss
within the MaMaBay boundary. The average soil loss
between 2000 to 2010 is 0 to 500 tons per hectare
per year. Potential soil loss is at greatest risk in the
forest north of Antongil Bay and northeastern region
of the Masoala National Park, at a potential rate of 61
to 140 tons per hectare per year.
Erosion Risk Map
Deforestation, Potential Soil Loss, and Sedimentation In region ① , the rate of deforestation per watershed varies between 6 to 15% of the entire watershed,
and is increasing non-forest coverage from 1990 to 2010. As seen in the potential soil loss image,
region ① also is at risk of 36 to 140 tons per hectare per year of soil loss. The largest sedimentation
plume in Antongil Bay was found in the estuary of region ① , and has a strong correlation of
continuously increasing throughout 2000 to 2010. There are also high rates of deforestation occurring
in region ② with 6 to 15% deforestation occurring per watershed, and this change has occurred mostly
between 2000 to 2010. The second largest sedimentation plume in the bay is found here, with a
comparable magnitude of continuously increasing similar to the northern plume. Throughout the entire
Antongil Bay, there is an continuously increasing trend of sedimentation through 2000 to 2010.
Deforestation Deforestation
1. Used 3 Landsat-7 images to classify
landscape into Forest, Non-forest and Water
for 2010.
2. Reclassified CI map to show land change in
1990, 2000, and 2005.
3. Corrected missing values in 2010 with
previous CI maps.
Soil Erosion
1. Generated 6 factors with rainfall, soil,
elevation, and vegetation data.
2. Estimated of soil loss throughout MaMaBay
boundary from 2000 to 2010.
3. Derived watershed map using DEM.
Sedimentation
1. Used MODIS Level 3- 16 day product
aggregated into a monthly product showing
ocean color anomalies.
2. Conducted a times series analysis used to
show overall variance in ocean color
anomalies from 2000 to 2010.
Research Objectives
1990 to 2000: Deforestation occurred mainly along the
northern border of the MaMaBay boundary, and between
the villages bordering the north section of the bay and
forest just north of the villages.
2000 to 2005: The total amount of deforestation
exceeded the amount in the previous ten years with
annual deforest rate tripled from 1,246 ha/yr to 3,628
ha/yr. New areas of deforestation are located along the
northern and southern boundary of Masoala, the core
forest between the villages and northern MaMaBay
boundary, and along the east coast of bay.
2005 to 2010: Deforestation continues to increase
effecting core and edge forest within the entire study
area.
①
②
12,461
18,138
21,125
1,246
3,628
4,225
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
0
5,000
10,000
15,000
20,000
25,000
1990-2000 2000-2005 2005-2010
Deforestation (1990-2010): Hectares
Total Deforestation
Deforestation per year
Data Source
Range
Units Resolution/MMU
Range
(values) (time)
Landsat ETM+ NASA
0-1
Meter 30 m
Date: 09/06/2010
Path: 158 Row:71
Date: 09/06/2010
Path: 158 Row:70
Date: 04/11/2011
Path: 158 Row:70
Bands
1-5,7
Conservation International
Maps
Conservation
International N/A Meter 30m 1990, 2000,2005
Shapefiles from WCS
Wildlife Conservation
Society Various Various Various Various
SRTM DEM SRTM data warehouse 0 - 2000 Meters 90m 2000
FAO Soil Data
FAO Institute,
GeoNetwork N/A N/A N/A 1978, updated 2003
Antalaha Rainfall Data
National Climatic Data
Center CSB N/A mm/hr N/A 1997-2010
MODIS CMG Monthly
NDVI NASA, Clark Labs 0 - 1 Degrees 0.5°x0.5° 2000 - 2010
MODIS, MCD43A4 NASA Bands 1, 3-4 Meters 500m 02/14/2000-12/27/2010
Area A: This watershed area lies mostly within the protected
MaMaBay boundary. Maximum deforestation of 12-15% per
watershed has occurred within the protected areas between 1990
to 2010. Average potential soil erosion of 61 to 140 ton per
hectare per year may occur in this area within the boundary. The
largest plume discovered in the bay receives sediment from this
entire area. This plume has been continuously increasing in
sedimentation with only a 1% probability this happened by
chance.
Area B: This watershed area is split between being inside and
outside the MaMaBay boundary. Maximum deforestation of about
12-15% per watershed has occurred within the protected areas
between 1990 to 2010. Average potential soil erosion of up to 61
to 140 ton per hectare per year may occur in this area within the
boundary. The shallows bordering this land mass is home to
shallow, fertile reef systems.