Transcript Niger Nigeria - drylandsforum

Regreening the Sahel and
Farmer Managed Natural Regeneration:
What the Satellite Imagery Shows
First Drylands Week
June 10-17, 2011
Dakar, Senegal
Gray Tappan, U.S. Geological Survey
Earth Resources Observation and Science (EROS) Center
Sioux Falls, South Dakota USA
[email protected]
U.S. Department of the Interior
U.S. Geological Survey
The U.S. Geological Survey’s Earth Resources
Observation and Science (EROS) Center’s vision
is to be the world’s leading source of land
information for exploring our changing planet.
Many thanks for funding and support:
U.S. Agency for International Development
CILSS (Permanent Interstate Committee for Drought Control
in the Sahel)
African Regreening Initiative
Centre de Suivi Ecologique, Senegal
Institut des Sciences de l’Environnement (ISE/UCAD), Senegal
Challenges in Monitoring Agro-Environmental Transformations
 Farmers don’t tell you when they’ve made land improvements
 Biophysical changes occur on a vast geographic scale
 Distinguishing climate versus anthropogenic factors is complicated
 Visual evidence of benefits often not apparent in less than 3-4 years;
 Significant biophysical changes may take a decade or more
 Time-series mapping of land cover is technically challenging
Remote Sensing: A Definition
Remote sensing is the science and art
of acquiring information about the
Earth’s surface without being in physical
contact with it.
Image Courtesy of NASA: SeaWiFs
Remote Sensing Advantages
•
•
•
•
Synoptic perspective
Unique vantage point
Extra-visual information
Historical and permanent record
Image Courtesy of NASA: SeaWiFs
Remote sensing systems that
provide coverage of West Africa
• Meteosat
• SeaWIFS
• MODIS
• SPOT Vegetation
• NOAA-AVHRR
• Landsat
• Corona
• ASTER
• SPOT 5
• IKONOS
• Quickbird
• Historical Aerial Photography
• Recent Aerial Photography
• Aerial Videography
SeaWIFS Image
Approach to Mapping, Monitoring, and Modeling LULC
*Levels of Data Collection
 Satellite level
 Aerial level
 Ground level
*All data collected
through time
Field Data Collection:
1982 – 1984
Dicrostachys
glomerata
Permanent Monitoring Sites in Senegal
(Established in 1982-1983)
Field Data Collection:
• Determining vegetation
structure for mapping
• Species-level inventories
to monitor biodiversity
• Biomass and carbon
measurements
Revisited Ground
Sites to Document
Changes in Natural
Resources
1983
1994
1996
1998
1983
1996
Jan 1983
Monitoring on-farm
trees in the
Peanut Basin:
28-year comparison
Feb 2011
1984
Protection of an
ecosystem:
(Niokolo-Koba, Senegal)
Woody Species at Site 487:
1984
2007
Bombax costatum
Annona senegalensis
Combretum crotonoides
Combretum geitonophyllum
Combretum glutinosum
Combretum micranthum
Combretum nigricans
Crossopterix febrifuga
Danielia oliveri
Detarium microcarpum
Gardenia erubescens
Hexalobus monopetalus
Hymenocardia acida
Lannea acida
Ostryoderris stuhlmannii
Piliostigma thonningii
Pterocarpus erinaceus
Stychnos spinosa
Terminalia avicennioides
Terminalia macroptera
Vitex madiensis
Ximenia americana
Cordyla pinnata
Entada africana
Sterculia setigera
Bombax costatum
Annona senegalensis
Combretum crotonoides
Combretum geitonophyllum
Combretum glutinosum
Combretum micranthum
Combretum nigricans
Crossopterix febrifuga
Danielia oliveri
Detarium microcarpum
Gardenia erubescens
Hexalobus monopetalus
Hymenocardia acida
Lannea acida
Ostryoderris stuhlmannii
Piliostigma thonningii
Pterocarpus erinaceus
Stychnos spinosa
Terminalia avicennioides
Terminalia macroptera
Vitex madiensis
Ximenia americana
Cordyla pinnata
Entada africana
Sterculia setigera
2007
Aerial Surveys with the Centre de Suivi Ecologique (CSE)
A powerful combination: Airplane, GPS and a camera
Landsat Image: Mangroves,
Protected areas, and Cropland
Mapping and Monitoring:
The Senegal Experience
• Mapped the Land Resources of Senegal (1982 1985)
• Monitored land cover trends with CSE through four
decades (completed in 1999)
• Built on results for quantifying carbon stocks in soils
and vegetation (completed in 2003)
• Currently assessing and mapping land resources in
the Kedougou and Casamance Regions
Published Vegetation Map of Senegal
(1986)
Soils of Senegal
Seasonal
Vegetation
Patterns
NOAA-AVHRR
NDVI (vegetation index or greenness)
Satellite observed greening trend
Trends in NDVI 1982 – 2006 corrected for the effects of rainfall:
Source: Herrmann et al., 2005
Tree Parkland Dominated by Faidherbia albida:
Leaf-off Stage in the Rainy Season
Enlargement from a Landsat Image, October 2000:
Tree parklands not visible (south of Aguié, Niger)
0
5 km
Niger Land Cover in 1975
Niger Land Cover in 2000
Southern Niger in the 1980s
Southern Niger in 1997: Early Evidence of FMNR
Preparing for flight
at Tahoua, Niger
Tahoua Region, Niger in 2005: Well established FMNR
Parkland Renaissance: trees are young and growing
Agricultural Parkland east of Matamèye
Impact of trees on crop growth
Impact of a single F. albida tree on crop growth
(radius of high productivity: 5 m around a small tree)
Quickbird Image of Medium Density Tree Parkland
East of Maradi, Oct. 2005
1955
Landscape Dynamics
Southwest of Zinder
1975
2005
1955
Landscape Dynamics
Southwest of Zinder
1975
2005
Percent Tree Cover Trend in the Study Area
(Mirria-Magaria-Matameye Triangle)
General Extent of Farmer-Managed Natural Regeneration
Is It Increased Rainfall?
More People – More Trees
Population
Location of 12 Terroirs Used for Comparing
Tree Density Across the Niger-Nigeria Border
Niger
• Tahoua
• Maradi
• Zinder
Terroirs
■
■
■ ■
■
■
■
■
■
■
Nigeria
■
■
0
200 km
Terroir in Niger 19 km North of the Niger-Nigeria Border
Source:
Google
Earth,
2005
Source:
Google
Earth,
2005
Terroir in Niger 8.5 km North of the Niger-Nigeria Border
Source: Google Earth, 2005
Terroir in Nigeria 1.5 km south of the Niger-Nigeria Border
Source: Google Earth, 2005
Terroir in Nigeria 38 km south of the Niger-Nigeria Border
Source: Google Earth, 2005
Comparative Overview of Terroirs on Opposite Sides
of the Niger-Nigeria Border
Niger
Nigeria
Source: Google Earth, 2005
What is the overall
extent and density
of FMNR in
southern Niger?
Quickbird image
south of Zinder
Extent and Density of Tree Cover Across Southern Niger
Maerua crassifolia
Benefits of On-Farm Trees… a Win-Win Strategy
• Firewood production
• Fodder for animals
• Increase biodiversity
• Habitat for millions of migrating birds
• Fruit production
• Traditional medicine
• Increased soil fertility
• Decreased soil erosion
• Reduced wind speed
• Increased crop yields
• Increased water infiltration
• Decrease in temperature
• Increase in rainall
• Inexpensive and easy to adopt
• Increase in biomass and carbon
• Contribute to mitigating climate change
Senegal land cover in 1975
Senegal land cover in 2000
Mature Faidherbia albida Parkland:
N. of Khombole, Peanut Basin, Senegal
Mature Faidherbia albida Parkland: 32 T Carbon / ha
Peanut Basin, Senegal
Tree Parkland Dominated by Faidherbia albida:
Leaf-off Stage in the Rainy Season (N. of Khombole)
Permanent Monitoring Sites in Senegal
(Established in 1982-1983)
Monitoring on-farm
trees in Senegal
1983
1983
1994
Peanut Basin,
20-year comparison
Site 31
1996
1998
2003
Jan 1983
Monitoring on-farm
trees in the
Peanut Basin:
28-year comparison
Feb 2011
Monitoring on-farm trees in the Peanut Basin
Feb 1998
Jan 2011
Nov 1995
Monitoring on-farm
trees in the
Peanut Basin:
15-year comparison
Jan 2011
Soil Susceptibility to Wind Erosion
Very low tree density in the Saloum
May 1983
Monitoring on-farm
trees in Senegal:
27-year comparison
Site 581:
Dépt. de Kaffrine
Mar 2010
Monitoring on-farm trees in the Saloum, Senegal
Jan 1994
Dec 2004
Senegal’s Agricultural Parkland Region and Potential
Directions of Expansion to other Agricultural Regions
Agriculture areas
Represented in yellow
Main parkland area
Outlined in green
Faidherbia albida trees in rice fields, Basse Casamance, Senegal
Final Remarks
 Time-series remote sensing imagery played a key role
in characterizing the extent and magnitude of agroenvironmental transformations
 High resolution imagery provides a practical way to
monitor FMNR
 Time-series images helped convince people that a
positive landscape changes were happening at a grand
scale
 Remote sensing provides a baseline from which to
monitor the spread, uptake and impacts of FMNR