A century of woody plant encroachment in the dry Kimberley savanna of South Africa (original) (raw)
Related papers
Land Use Policy, 2008
The Brazilian Cerrado, a biodiverse savanna ecoregion covering $1.8 million km 2 south and east of the Amazon rainforest, is in rapid decline because of the expansion of modern agriculture. Previous studies of Cerrado land-use and land-cover (LULC) change imply spatial homogeneity, report widely varying rates of land conversion, use ambiguous LULC categories, and generally do not attempt to validate results. This study addresses this gap in the literature by analyzing moderate-resolution, multi-spectral satellite remote sensing data from 1986 to 2002 in two regions with identical underlying drivers. Unsupervised classification by the ISODATA algorithm indicates that Cerrado was converted to agro-pastoral land covers in 31% (3646 km 2 ) of the study region in western Bahia and 24% (3011 km 2 ) of the eastern Mato Grosso study region, while nearly 40% (4688 km 2 and 5217 km 2 , respectively) of each study region remained unchanged. Although aggregate land change is similar, large and contiguous fragments persist in western Bahia, while smaller fragments remain in eastern Mato Grosso. These findings are considered in the current context of Cerrado land-use policy, which is dominated by the conservation set-aside and command-control policy models. The spatial characteristics of Cerrado remnants create considerable obstacles to implement the models; an alternative approach, informed by countryside biogeography, may encourage collaboration between state officials and farmer-landowners toward conservation land-use policies. r
Journal of Ecology, 2018
The Cerrado Domain of central Brazil houses the largest extent of savanna in the Neotropics, but despite its simple characterisation as a giant savanna, it contains considerable vegetation heterogeneity that is poorly understood. 2. We aimed to determine how vegetation types in the Cerrado diverge in their tree species composition and what role ecological factors play in driving compositional patterns. 3. We used a dataset of 1,165 tree species inventories spread across the Cerrado Domain, which come from six vegetation types that have a substantial arboreal component: woody savannas, dystrophic cerradão, mesotrophic cerradão, seasonally dry tropical forests, semideciduous forests and evergreen forests. We found three extremes in terms of tree species composition, with clear underlying ecological drivers, which leads us to propose a ternary model, the 'Cerrado Vegetation Triangle', to characterize woody vegetation in the Cerrado. At one extreme, we found that semideciduous and evergreen forests are indistinguishable floristically and are found in areas with high water availability. At another extreme lie seasonally dry tropical forests which are found on more fertile soils. At the third extreme, we found that all types of savanna, and dystrophic cerradão, are highly similar in tree species composition and are commonly found in areas of poor soils and high flammability. Mesotrophic cerradão is transitional in tree species composition between savannas and seasonally dry tropical forest. 4. The lack of variation in tree species composition attributed to climatic variables indicates that within homogeneous macroclimatic zones, many types of forest and savanna co-exist due to complex mosaics of local substrate heterogeneity and fire history. 5. Synthesis. Our findings highlight the complexity of forest-savanna transitions in the Cerrado Domain, with relevance for understanding the future of Cerrado vegetation under environmental change. If nitrogen deposition is extensive, some savannas may be more likely to transition to mesotrophic cerradão or even seasonally dry tropical forest whereas if water availability increases these same savannas may transition to semideciduous or evergreen forest. 2 Our 'Cerrado Vegetation Triangle' model offers a simple conceptual tool to frame discussions of conservation and management.
Journal of Agricultural Science, 2019
This work investigates the spatial-temporal dynamics of land use and vegetation covers in a conservation area of Cerrado, in the county of Currais, Piauí, in which the economy depends on large agricultural projects. We used maps of a 32-year time series (1985 to 2017) of land use and cover provided by the Brazilian Annual Land Use and Land Cover Mapping Project (MapBiomas). We assessed six classes of land uses and vegetation covers: forest, savanna, grassland, agriculture/pasture, non-vegetated area, and water bodies. There was a fast increase in pressure on natural ecosystems from 1985 and 2017, primarily from 2000. The land use for agriculture and pasture increased from 0.26% (726.93 ha) in 2000 to 16% (50,772.63 ha) in 2017. During this period, the native vegetation decreased 15.90%, with savannas suffering the largest loss in hectares of vegetation (41,663.73 ha), followed by the forests (9,837.35 ha). The grassland cover, non-vegetated area, and water bodies remained unchanged....
Analysis of Land Cover Changes of a Cerrado (Tropical Savanna) Area in the Centre-West of Brazil
Anuário do Instituto de Geociências - UFRJ, 2016
Resumo O objetivo do presente trabalho foi produzir uma análise multitemporal da cobertura do solo em uma área no centro-oeste do Brasil, em duas diferentes épocas, em 1966 e 2001, utilizando uma imagem de satélite e uma carta topográfica em ambiente SIG (Sistema de Informações Geográficas). A carta de cobertura do solo de 1966 foi obtida pela vetorialização da carta topográfica SE-22-Y-A-V (IBGE), enquanto que a carta de cobertura do solo de 2001 foi obtida através de uma classificação automática supervisionada da imagem do satélite Landsat 7 ETM+ órbita/ponto 224/073 de agosto de 2001. A análise mostrou as alterações da cobertura natural para antrópica. Em 1966, a cobertura natural representava 90% ou mais da área estudada (principalmente por cerrado sentido restrito e formações florestais), enquanto que em 2001, a cobertura natural havia diminuído para 24%, sendo substituída principalmente por áreas de agricultura e pasto.
Understanding patterns of land-cover change in the Brazilian Cerrado from 2000 to 2015
Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 2016
Clearing tropical vegetation impacts biodiversity, the provision of ecosystem services, and thus ultimately human welfare. We quantified changes in land cover from 2000 to 2015 across the Cerrado biome of northern Minas Gerais state, Brazil. We assessed the potential biophysical and socio-economic drivers of the loss of Cerrado, natural regeneration and net cover change at the municipality level. Further, we evaluated correlations between these land change variables and indicators of human welfare. We detected extensive land-cover changes in the study area, with the conversion of 23 446 km(2) and the natural regeneration of 13 926 km(2), resulting in a net loss of 9520 km(2) The annual net loss (-1.2% per year) of the cover of Cerrado is higher than that reported for the whole biome in similar periods. We argue that environmental and economic variables interact to underpin rates of conversion of Cerrado, most severely affecting more humid Cerrado lowlands. While rates of Cerrado reg...
The Brazilian Cerrado Vegetation and Threats to its Biodiversity
The Brazilian cerrado (savanna) biome covers 2 million km# representing 23 % of the area of the country. It is an ancient biome with rich biodiversity, estimated at 160 000 species of plants, fungi and animals. There are about 800 species of trees and large shrubs in the savanna vegetation and several times that number of ground species (herbs and subshrubs). When the flora of gallery forests, mesophytic forests and other habitats occurring in the biome are included, the total number of vascular plant species is estimated to reach about 10 000. During the last 25 years modern agriculture has been developed in the cerrado to produce soya, maize, rice, etc and enormous numbers of cattle are raised in planted pastures. Charcoal production for the Brazilian steel industry also causes great destruction of the cerrado. By 1994 an estimated 695 000 km# of cerrado (representing 35 % of its area) had been converted to ' anthropic landscape '. This compares to the destruction of about 400 000 km# of Brazilian Amazonian forest representing 12 or 13 % of the area of this biome. Conservation initiatives are now desperately needed. Only 1n5% of the cerrado biome is preserved as Federal Reserves and this area needs to be at least tripled. Surveys of the vascular flora aimed at discovering biogeographic patterns are now in progress with the objective of choosing representative areas and biodiversity ' hot spots ' for conservation. # 1997 Annals of Botany Company
Little is known about the threat levels and impacts of habitat loss over the Cerrado Squamate fauna. The region is under severe habitat loss due to mechanized agriculture, accelerated by changes in the Brazilian National Forest Code. The Squamate fauna of the Cerrado is rich in endemics and is intrinsically associated with its surrounding microhabitats, which make up a mosaic of phitophysiognomies throughout the region. Herein we evaluate current conservation status of Squamate biogeographic patterns in the Brazilian Cerrado, the single savanna among global biodiversity hotspots. To do so, we first updated point locality data on 49 endemic Squamates pertaining to seven non-random clusters of species ranges in the Cerrado. Each cluster was assumed to be representative of different biogeographic regions, holding its own set of species, herein mapped according to their extent of occurrence (EOO). We then contrasted these data in four different scenarios, according to the presence or absence of habitat loss and the presence or absence of the current protected area (PA) cover. We searched for non-random patterns of habitat loss and PA coverage among these biogeographic regions throughout the Cerrado. Finally, with the species EOO as biodiversity layers, we used Zonation to discuss contemporary PA distribution, as well as to highlight current priority areas for conservation within the Cerrado. We ran Zonation under all four conservation scenarios mentioned above. We observed that habitat loss and PA coverage significantly differed between biogeographic regions. The southernmost biogeographic region is the least protected and the most impacted, with priority areas highly scattered in small, disjunct fragments. The northernmost biogeographic region (Tocantins-Serra Geral) is the most protected and least impacted, showing extensive priority areas in all Zonation scenarios. Therefore, current and past deforestation trends are severely threatening biogeographic patterns in the Cerrado. Moreover, PA distribution is spatially biased, and does not represent biogeographic divisions of the Cerrado. Consequently, we show that biogeographic patterns and processes are being erased at an accelerated pace, reinforcing the urgent need to create new reserves and to avoid the loss of the last remaining fragments of once continuous biogeographic regions. These actions are fundamental and urgent for conserving biogeographic and evolutionary information in this highly imperiled savanna hotspot.
Understanding patterns of landcover change in the Brazilian Cerrado from 2000 to 2015 Mário
2016
Clearing tropical vegetation impacts biodiversity, the provision of ecosystem services, and thus ultimately human welfare. We quantified changes in land cover from 2000 to 2015 across the Cerrado biome of northern Minas Gerais state, Brazil. We assessed the potential biophysical and socio-economic drivers of the loss of Cerrado, natural regeneration and net cover change at the municipality level. Further, we evaluated correlations between these land change variables and indicators of human welfare. We detected extensive landcover changes in the study area, with the conversion of 23 446 km and the natural regeneration of 13 926 km, resulting in a net loss of 9520 km. The annual net loss (21.2% per year) of the cover of Cerrado is higher than that reported for the whole biome in similar periods. We argue that environmental and economic variables interact to underpin rates of conversion of Cerrado, most severely affecting more humid Cerrado lowlands. While rates of Cerrado regeneration...
Conservation of the Brazilian Cerrado
Conservation Biology, 2005
The Cerrado is one of the world's biodiversity hotspots. In the last 35 years, more than 50% of its approximately 2 million km 2 has been transformed into pasture and agricultural lands planted in cash crops. The Cerrado has the richest flora among the world's savannas (>7000 species) and high levels of endemism. Species richness of birds, fishes, reptiles, amphibians, and insects is equally high, whereas mammal diversity is relatively low. Deforestation rates have been higher in the Cerrado than in the Amazon rainforest, and conservation efforts have been modest: only 2.2% of its area is under legal protection. Numerous animal and plant species are threatened with extinction, and an estimated 20% of threatened and endemic species do not occur in protected areas. Soil erosion, the degradation of the diverse Cerrado vegetation formations, and the spread of exotic grasses are widespread and major threats. The use of fire for clearing land and to encourage new growth for pasture has also caused damage, even though the Cerrado is a fire-adapted ecosystem. Ecosystem experiments and modeling show that change in land cover is altering the hydrology and affecting carbon stocks and fluxes. Cerrado agriculture is lucrative, and agricultural expansion is expected to continue, requiring improvements in and extension of the transportation infrastructure, which will affect not only the Cerrado but also the Amazon forest. Large-scale landscape modification and threats to numerous species have led to renewed interest from various sectors in promoting the conservation of the Cerrado, particularly through strengthening and enlarging the system of protected areas and improving farming practices and thus the livelihoods of local communities.