Harifidy RAKOTO RATSIMBA "Forest ecosystem resilience and rainfall variability in the southeastern part of Madagascar"
1. Outline
1. Context
2. Methodology
Satellite data processing
Rainfall data
Regression analysis
3. Results
2. Context Methodology Results
Madagascar
Europe
N Bonn
#
o
Bn
Sub Saharan Africa W E
S Asia
NorthAfrica
8, 7
East of Mozambique
00k
m
Sub Saharan Africa
Indian Ocean Island
#
Antananarivo Australia
0 4000 8000 Kilometers
3. Context Methodology Results
Madagascar
• Area : 587 040 km²
• Climate :
– Tropical along coast
– Temperate inland 580 km
– Arid in south 1570 km
• Elevation extremes : 0 to 2 876 m
Unique biodiversity
– Ecosystem level
– Species level
4. Context Methodology Results
Ecosystem diversity
N
W E
S
Tropical and Subtropical Dry Broadleaf Forests
Mangroves
Montane Grasslands and Shrublands
Tropical and Subtropical Moist Broadleaf Forests
Deserts and Xeric Shrublands
5. Context Methodology Results
Species diversity and endemism
Taxonomic Species Endemic % endemism
group species
Plants 13 000 11 600 89.2
Mammals 155 144 92.9
Birds 310 181 58.4
Reptiles 384 367 95.6
Amphibians 230 229 99.6
Freshwater 164 97 59.1
fishes
6. Context Methodology Results
Population
• 20 653 556 (July 2009 estimation)
• 43.5 % less than 14 years
• Infant mortality rate : 54.2 deaths / 1000
• Growth rate : 3 %
Degradation and deforestation processes
7. Context Methodology Results
Deforestation
Year Area (ha) % of Annual
country deforestation
area rate
1990 10 668 800 18.0 -
2000 9 677 701 16.3 0.83
2005 9 216 617 15.6 0.53
Harper et al., 2007 ; Rasolohery and Steininger, 2008
Deforestation + Degradation CO2 emission Potential reduction
REDD is included in the Bali roadmap (COP 13 UNFCCC)
8. Context Methodology Results
Location of the study area (yellow
field polygon) in the Region of
Anosy, Madagascar.
9. Context Methodology Results
Forest type
- Humid rain forest or evergreen rain forest : high canopy and high biodiversity
- Dry forest, dominated by Didiereaceae highly adapted to drought and whose
leaves are usually deciduous during the dry season
- Transitional forest localized between humid rain forest and dry forest with an
intermediate character
Climate observation
The rainy season has shortened and the average daily rainfall frequencies have
decreased
Main objectives
To assess resilience the impact rainfall variability on forest ecosystem
10. Context Methodology Results
Satellite data processing
• Chlorophyll activity or greenness is measured using the NDVI based on remotely
sensed Landsat images with 30m spatial resolution
• Six images in three times series were used from 1984 to 2009 capturing three
types of forests such as humid rain forest, dry forest and transitional forest
• Three images were taken during the dry season and three during the wet season
in order to consider changes in photosynthesis level linked with seasonal and
inter-annual changes in precipitation
11. Context Methodology Results
Rainfall data processing
Location of the rainfall stations
12. Context Methodology Results
Regression analysis Images acquisition
Preclassification: radiometric / atmospheric / geometric corrections
NDVI images (intra / inter annual Land cover map
Type of forest map
Sampling and NDVI value extraction
NDVI and precipitation value correlation by pixel
Spatial trend of the changes
(inter and intra annual)
13. Context Methodology Results
Wet season
1984 November 2002 January 2009 November
14. Context Methodology Results
Dry season
1991 July 2001 September 2009 June
15. Context Methodology Results
Humid forest Transitional forest Dry forest
Wet season Dry season
16. Conclusion
• Assessing the changes (potential) :
capacity of soil to retain water SLM, SFM
ecosystem impact (fragmentation)
biodiversity impact
starting point for socio ecosystem vulnerability
analysis
data availability (gaps), upscale ?
17. Contact :
Dr Eng RAKOTO RATSIMBA Harifidy
Researcher
Department of Water and Forest
School of Agronomy
University of Antananarivo
Po Box 175 – 101 Antananarivo
MADAGASCAR
rrharifidy@moov.mg
http://www.essa-forets.org