A new land‐cover map of Africa for the year 2000

Mayaux, Philippe; Bartholomé, Étienne; Fritz, Steffen; Belward, Alan

doi:10.1111/j.1365-2699.2004.01073.x

Cited by 446 publications

(394 citation statements)

References 18 publications

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“…6815 0 N, 980 0 E; figure 1). This is a large area classified as closed evergreen lowland forest according to the Global Land Cover 2000-map of Africa [37] with several protected areas [36]. Not all the area outside reserves that is classified as closed forest by the land cover map is structurally intact forest, but intact forests still extend far outside the protected areas (E. O. Effiom and O. Olsson 2009-2012, personal observations).…”

Section: Materials and Methods (A) Study Sitesmentioning

confidence: 99%

Bushmeat hunting changes regeneration of African rainforests

et al. 2013

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To assess ecological consequences of bushmeat hunting in African lowland rainforests, we compared paired sites, with high and low hunting pressure, in three areas of southeastern Nigeria. In hunted sites, populations of important seed dispersers-both small and large primates (including the Cross River gorilla, Gorilla gorilla diehli)-were drastically reduced. Large rodents were more abundant in hunted sites, even though they are hunted. Hunted and protected sites had similar mature tree communities dominated by primate-dispersed species. In protected sites, seedling communities were similar in composition to the mature trees, but in hunted sites species with other dispersal modes dominated among seedlings. Seedlings emerging 1 year after clearing of all vegetation in experimental plots showed a similar pattern to the standing seedlings. This study thus verifies the transforming effects of bushmeat hunting on plant communities of tropical forests and is one of the first studies to do so for the African continent.

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Section: Materials and Methods (A) Study Sitesmentioning

confidence: 99%

Bushmeat hunting changes regeneration of African rainforests

et al. 2013

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“…The strongest deviations in pCO 2 between data from this study and the modelled data from 3 were observed for the rivers (Zambezi and Congo) with extensive wetland coverage (5 and 10% of the total catchment, respectively). ) and %O 2 (%), and aboveground woody biomass (Mg km -2 ) 57 , % of dense forest cover (%) 56 , and wetland surface (cumulated surface and fraction of catchment) 58 . The strong increase in cumulated wetland surface between 200 and 700 km upstream of Kinshasa corresponds to the core of the "Cuvette Centrale".…”

Section: Ghg Flux Computationsmentioning

confidence: 99%

Globally significant greenhouse-gas emissions from African inland waters

et al. 2015

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Carbon dioxide emissions to the atmosphere from inland waters-streams, rivers, lakes and reservoirs-are nearly equivalent to ocean and land sinks globally. Inland waters can be an important source of methane and nitrous oxide emissions as well, but emissions are poorly quantified, especially in Africa. Here we report dissolved carbon dioxide, methane and nitrous oxide concentrations from 12 rivers in sub-Saharan Africa, including seasonally resolved sampling at 39 sites, acquired between 2006 and 2014. Fluxes were calculated from published gas transfer velocities, and upscaled to the area of all sub-Saharan African rivers using available spatial data sets. Carbon dioxide-equivalent emissions from river channels alone were about 0.4 Pg carbon per year, equivalent to two-thirds of the overall net carbon land sink previously reported for Africa. Including emissions from wetlands of the Congo river increases the total carbon dioxide-equivalent greenhouse-gas emissions to about 0.9 Pg carbon per year, equivalent to about one quarter of the global ocean and terrestrial combined carbon sink. Riverine carbon dioxide and methane emissions increase with wetland extent and upland biomass. We therefore suggest that future changes in wetland and upland cover could strongly a ect greenhouse-gas emissions from African inland waters.C limate predictions necessitate a full and robust account of natural and anthropogenic greenhouse-gas (GHG) fluxes, especially for CO 2 (refs 1-3), CH 4 (ref. 4) and N 2 O (ref. 5), which together accounted for 94% of the anthropogenic global radiative forcing by well-mixed GHGs in 2011 relative to 1750 (ref. 6). Inland waters (streams, rivers, lakes and reservoirs) are increasingly recognized as important sources of GHGs to the atmosphere, with global CO 2 and CH 4 emissions estimated at 2.1 PgC yr −1 (ref.3) and 0.7 PgC yr −1 (CO 2 -equivalents; CO 2 e) (ref. 4) (1 Pg = 10 15 g), respectively. Considering that the oceanic and land carbon (C) sinks correspond to ∼1.5 and ∼2.0 PgC yr −1 (ref. 7), respectively, the GHG flux from inland waters is significant in the global C budget.In a recent global compilation of inland CO 2 data 3 , <20 data points (out of 6,708, that is, <0.3%) represented African inland waters (with the exception of South Africa, which has been densely sampled), even though they account for ∼12% of both global freshwater discharge 8 and riverine surface area 3 , and include some of the largest rivers and lakes in the world. Equally for the global CH 4 database, there is a strong under-representation of tropical inland waters, whereby a recent synthesis 4 resorted to extrapolating CH 4 fluxes from temperate rivers.The prevailing large uncertainty involved in GHG flux estimates for inland waters, essentially due to the paucity of available data, is coupled to a poor understanding of underlying processes, both of which preclude gauging of future fluxes in response to human pressures. In particular, there is a need to further understand the link between inland water GHG fluxes and ...

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“…The spatial distribution of vegetation types for the Volta watershed was based primarily on the 1 km 2 -resolution global land cover (GLC2000) map for Africa, derived from daily measurements collected during the year 2000 by the Vegetation sensor on-board the Spot-4 satellite (Mayaux et al, 2004). Through a combination of remote-sensing data and expert knowledge, Mayaux et al (2004) classify the entire continent of Africa into 27 land-cover categories.…”

Section: Vegetation In the Volta River Watershedmentioning

confidence: 99%

“…Through a combination of remote-sensing data and expert knowledge, Mayaux et al (2004) classify the entire continent of Africa into 27 land-cover categories. Four GLC2000 landcover classes constitute greater than 95% of the total vegetation in the Volta watershed although the proportions vary between sub-basins (Fig.…”

Section: Vegetation In the Volta River Watershedmentioning

confidence: 99%

“…It is associated with higher mean annual rainfall and often referred to as Guinean savanna (Mistry, 2000). Using the vegetation continuous fields product (Hansen et al, 2003), Mayaux et al (2004) estimated percentages of tree cover, shrub/grass cover, and bare soil for each GLC2000 vegetation class. Further refinements of vegetation distribution within each class were made in this study by incorporating additional information regarding the proportion of croplands in each class from a global distribution of agricultural vegetation (Wang & Veizer , 2000) and from biome-specific data (Olson et al, 2001).…”

Section: Vegetation In the Volta River Watershedmentioning

confidence: 99%

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Computing the net primary productivity for a Savanna- Dominated ecosystem using stable isotopes: A case study of the Volta River Basin

Hayford¹

2009

West African Journal of Applied Ecology

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The hydrologic systems and the terrestrial ecosystem of the Volta river basin in West Africa, play important role in the carbon cycle. This is so because of the coupling of water vapour release and CO 2 uptake during photosynthesis, expressed as water use efficiency or transpiration ratio. Hydrologic and land-cover data, together with stable isotope ratio measurements of δ 18 O and δD, and data from the global network of isotopes in precipitation (GNIP) are used to determine the net primary productivity (NPP) of the savanna-dominated ecosystem. The δ 18 O and δD values in the Volta rivers range from -4.72 to 2.37 mm -l and from -35.28 to 9.30 mm -1 SMOW, respectively. The results indicate that the vegetation is supported by 380 km 3 of rainfall, out of which 50% is returned to the atmosphere via plant transpiration. Associated with annual transpiration is the NPP of 0.170 × 10 15 gCyr -1 or 428 gCm -2 from the terrestrial ecosystem. Modelled estimates of heterotrophic soil respiration in this study slightly exceeded the NPP estimates, implying a small source of CO 2 to the atmosphere. This condition does not favour the postulated existence of a major sink of atmospheric CO 2 in the Volta basin.

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A new land‐cover map of Africa for the year 2000

Cited by 446 publications

References 18 publications

Bushmeat hunting changes regeneration of African rainforests

Bushmeat hunting changes regeneration of African rainforests

Globally significant greenhouse-gas emissions from African inland waters

Computing the net primary productivity for a Savanna- Dominated ecosystem using stable isotopes: A case study of the Volta River Basin

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