M1 through M6 DESCRIPTION:
Gridded fields of changes in runoff and river flow
(discharge) due to historical and hypothetical deforestation from Douglas
et al. (2005). Scenario 1 (Sc1, historical) compared distributed runoff (RO)
and river flow (discharge, Q) generated from pre-industrial land cover (based
on WWF Terrestrial Ecoregions of the World (Olson et al., 2001) with runoff
and river flow derived from contemporary landcover. Scenario 2 (Sc2, hypothetical
future) compared distributed runoff and river flow (discharge, Q) generated
from the contemporary landcover with runoff and river flow generated from
a hypothetical future forest conversion scenario.
The contemporary landcover was developed by combining
the Global Land Cover Characteristics Database (GLCCD 2000; Loveland et al.
2000) interpreted using the International Geosphere-Biosphere Programme (IGBP)
land cover classification scheme (IGBP 1998) with cropland and cropland mosaic classes from the IFPRI
Agricultural Extent database, which is a reinterpretation of the GLCCD v2.0
dataset. This exercise identified areas, at a 1km resolution, that contain
30 percent or more agricultural activity. For details on the creation of the
IFPRI Agricultural Extent, see Wood et al. (2000) and IFPRI (2002). The Center
for Sustainability and the Global Environment at the University of Wisconsin
has developed a global pasture surface based also on a reinterpretation of
the GLCCD v2.0 data. The pasture surface represents non-forest areas that
are used for grazing (Ramankutty 2003). The agricultural extent and pasture
surfaces were superimposed on the IGBP classified GLCCD to create the contemporary
land cover surface.
The objective Scenario 2 (hypothetical future
forest conversion), was to design a hypothetical , ‘worst-case’ land cover
change experiment that explored deforestation in the most vulnerable tracts
of remaining forest, and to measure what effect this conversion could potentially
have on biodiversity, hydrological function and ultimately, on downstream
human populations. The baseline for this scenario was the contemporary land
cover surface because the contemporary land cover surface was our best available
representation of existing land cover. In Scenario 2, only existing forest
area (circa 1992/3) within the tropical forest biomes was targeted for conversion;
land cover in all remaining portions of the domain was held constant. The
global conservation status from the WWF terrestrial ecoregions database (Olson
et al., 2001) was used to identify the areas most vulnerable to change within
the tropical forest biomes; forest conversion was limited to areas. The conservation
status is an indicator of the degree and threat of change for each individual
ecosystem. The key factors defining the conservation status are the degree
of habitat loss, the level of fragmentation, remaining block size and level
of conversion. The areas classified as critical or endangered were designated
as those most threatened in terms of potential deforestation. Areas currently
under protection, as identified by The World Conservation Monitoring Centre’s
(UNEP-WCMC, 2003) protected areas database, were therefore not subject to
conversion.
DOWNLOADABLE FILES:
(M1) Scenario
1: Change in runoff (del RO, in mm/yr) due to historical forest conversion
to agriculture. Primary source: Douglas et al. (2005)
(M2) Scenario 1: Change
in discharge (del Q, in km3/yr) due to historical forest conversion to agriculture.
Primary source: Douglas et al. (2005)
(M3) Scenario
1: Relative change in discharge (ratio of del Q to Q) due to historical forest
conversion to agriculture. Primary source: Douglas et al.
(2005)
(M4) Scenario
2: Change in runoff (del RO, in mm/yr) due to hypothetical future forest conversion
to agriculture. Primary source: Douglas et al. (2005)
(M5) Scenario 2: Change
in discharge (del Q, in km3/yr) due to hypothetical future forest conversion
to agriculture. Primary source: Douglas et al. (2005)
(M6) Scenario
2: Relative change in discharge (ratio of del Q to Q) due to hypothetical
future forest
conversion to agriculture. Primary source: Douglas et al.
(2005)
REFERENCES:
Douglas,
E. M., K. Sebastian, C. J. Vörösmarty and S. Wood, 2005. The role
of tropical forests in supporting biodiversity and hydrologic integrity, Ecological
Applications, in review.
Global
Land Cover Characteristics Database (GLCCD). Version 2.0. 2001. Available
online at: http://edcdaac.usgs.gov/glcc/glcc.html.
International
Food Policy Research Institute (IFPRI). 2002. Global Agricultural Extent v2.0.
Available online at: http://www.asb.cgiar.org/BNPP/phase2/bnpp phase2 datasets.htm
International
Geosphere Biosphere Programme (IGBP). 1998. Data and Information Systems,
IGBP-DIS Global Land Cover Set DISCover.
Olson,
D.M., E. Dinerstein, E.D. Wikramanayake, N.D. Burgess, G.V.N. Powell, E.C.
Underwood, J.A. D’Amico, I.Itoua, H.E. Strand, J.C. Morrison, C.J. Loucks,
T.F. Allnutt, T.H. Ricketts, Y.Kura, J.F. Lamoreux, W.W. Wettengel, P.Hedao,
and K.R. Kassem. 2001. “Terrestrial Ecoregions of the World: A New Map of
Life on Earth” in BioScience. 51(11): 935-938.
Ramankutty,
N. 2003. Global Grazing Lands Dataset. Center for Sustainability and the Global
Environment (SAGE). University of Wisconsin, Madison. Data made available
through personal communication.
UNEP-WCMC.
2003. Prototypes of National and International Designated Protected Areas.
Description available at http://www.unep-wcmc.org/protected_areas/. Data made
available through the Millennium Ecosystem Assessment Intranet (2003).
Wood,
S, K. Sebastian and S.J. Scherr. 2000. "Pilot Analysis of Global Ecosystems:
Agroecosystems". World Resources Institute/International Food Policy
Research Institute. Washington D.C.
Additional Links:
Douglas
et al. (2005)