Land-use has transformed ecosystems over three quarters of the terrestrial surface, with massive repercussions on biodiversity. Land-use intensity is known to contribute to the effects of land-use on ...biodiversity, but the magnitude of this contribution remains uncertain. Here, we use a modified countryside species-area model to compute a global account of the impending biodiversity loss caused by current land-use patterns, explicitly addressing the role of land-use intensity based on two sets of intensity indicators. We find that land-use entails the loss of ~15% of terrestrial vertebrate species from the average 5 × 5 arcmin-landscape outside remaining wilderness areas and ~14% of their average native area-of-habitat, with a risk of global extinction for 556 individual species. Given the large fraction of global land currently used under low land-use intensity, we find its contribution to biodiversity loss to be substantial (~25%). While both sets of intensity indicators yield similar global average results, we find regional differences between them and discuss data gaps. Our results support calls for improved sustainable intensification strategies and demand-side actions to reduce trade-offs between food security and biodiversity conservation.
Abstract
Understanding the carbon (C) balance in global forest is key for climate-change mitigation. However, land use and environmental drivers affecting global forest C fluxes remain poorly ...quantified. Here we show, following a counterfactual modelling approach based on global Forest Resource Assessments, that in 1990–2020 deforestation is the main driver of forest C emissions, partly counteracted by increased forest growth rates under altered conditions: In the hypothetical absence of changes in forest (i) area, (ii) harvest or (iii) burnt area, global forest biomass would reverse from an actual cumulative net C source of c. 0.74 GtC to a net C sink of 26.9, 4.9 and 0.63 GtC, respectively. In contrast, (iv) without growth rate changes, cumulative emissions would be 7.4 GtC, i.e., 10 times higher. Because this sink function may be discontinued in the future due to climate-change, ending deforestation and lowering wood harvest emerge here as key climate-change mitigation strategies.
Abstract
Built structures, i.e. the patterns of settlements and transport infrastructures, are known to influence per-capita energy demand and CO
2
emissions at the urban level. At the national ...level, the role of built structures is seldom considered due to poor data availability. Instead, other potential determinants of energy demand and CO
2
emissions, primarily GDP, are more frequently assessed. We present a set of national-level indicators to characterize patterns of built structures. We quantify these indicators for 113 countries and statistically analyze the results along with final energy use and territorial CO
2
emissions, as well as factors commonly included in national-level analyses of determinants of energy use and emissions. We find that these indicators are about equally important for predicting energy demand and CO
2
emissions as GDP and other conventional factors. The area of built-up land per capita is the most important predictor, second only to the effect of GDP.
Understanding the drivers of forest transitions is relevant to inform effective forest conservation. We investigate pathways of forest transitions in the United States (1920-2010), France ...(1850-2010), and Austria (1830-2010). By combining evidence from forest inventories with the forest model CRAFT, we first quantify how change in forest area (ΔA), maximum biomass density (ΔBd
max
), and actual biomass as fraction of maximum biomass (ΔF
max
) shaped forest dynamics. Second, to investigate the connections between forest change and societal resource use, or social metabolism, we quantify the importance of selected proximate and underlying socio-metabolic drivers. We find that agricultural intensification and reduced forest grazing correlated most with positive ΔA and ΔBd
max
. By contrast, change in biomass imports or harvest did not explain forest change. Our findings highlight the importance of forest growth conditions in explaining long-term forest dynamics, and demonstrate the distinct ways in which resource use drove forest change.
This dataset includes data on the embodied human appropriation of net primary production (eHANPP) associated with products derived from agriculture and forestry. The human appropriation of net ...primary production (HANPP) is an indicator of changes in the yearly availability of biomass energy from photosynthesis that remains available in terrestrial ecosystems after harvest, under current land use, compared to the net primary production of the potential natural vegetation. HANPP is an indicator of land-use intensity that is relevant for biodiversity and biogeochemical cycles. The eHANPP indicator allocates HANPP to products and allows tracing trade flows from origin (the country where production takes place) to consumption (the country where products are consumed), thereby underpinning research into the telecouplings in global land use. The datasets described in this article trace eHANPP associated with the bilateral trade flows between 222 countries. It covers 161 primary crops, 13 primary animal products and 4 primary forestry products, as well as the end uses of these products for the years 1986 to 2013.
Terrestrial biomass carbon stocks (BCS) play a vital role in the climate system, but benchmarked estimates prior to the late twentieth century remain scarce. Here, by making use of an early global ...forest resource assessment and harmonizing information on land use and carbon densities, we establish a global BCS account for the year 1950. Our best-guess BCS estimate is 450.2 PgC (median of all modulations: 517.8 PgC, range: 443.7-584.0 PgC), with ecosystems in Southern America and Western Africa storing c. 27 and 16% of the total respectively. Our estimates are in line with land change emissions estimates and suggest a reduction in BCS of 8-29% compared to the median, with losses in tropical subcontinents partially offset by gains in northern subcontinents. Our study demonstrates an approach to reconstruct global BCS by triangulating different data sources and extends the study of global BCS accounts further back into the twentieth century.
Tree cover (TC) and biomass carbon stocks (CS) are key parameters for characterizing vegetation and are indispensable for assessing the role of terrestrial ecosystems in the global climate system. ...Land use, through land cover change and land management, affects both parameters. In this study, we quantify the empirical relationship between TC and CS and demonstrate the impacts of land use by combining spatially explicit estimates of TC and CS in actual and potential vegetation (i.e., in the hypothetical absence of land use) across the global tropics (~23.4° N to 23.4° S). We find that land use strongly alters both TC and CS, with stronger effects on CS than on TC across tropical biomes, especially in tropical moist forests. In comparison to the TC-CS correlation observed in the potential vegetation (biome-level R based on tropical ecozones = 0.56–0.90), land use strongly increases this correlation (biome-level R based on tropical ecozones = 0.87–0.94) in the actual vegetation. Increased correlations are not only the effects of land cover change. We additionally identify land management impacts in closed forests, which cause CS reductions. Our large-scale assessment of the TC-CS relationship can inform upcoming remote sensing efforts to map ecosystem structure in high spatio-temporal detail and highlights the need for an explicit focus on land management impacts in the tropics.
Numerous drivers such as farming practices, erosion, land-use change, and soil biogeochemical background, determine the global spatial distribution of phosphorus (P) in agricultural soils. Here, we ...revised an approach published earlier (called here GPASOIL-v0), in which several global datasets describing these drivers were combined with a process model for soil P dynamics to reconstruct the past and current distribution of P in cropland and grassland soils. The objective of the present update, called GPASOIL-v1, is to incorporate recent advances in process understanding about soil inorganic P dynamics, in datasets to describe the different drivers, and in regional soil P measurements for benchmarking. We trace the impact of the update on the reconstructed soil P. After the update we estimate a global averaged inorganic labile P of 187 kgP ha
for cropland and 91 kgP ha
for grassland in 2018 for the top 0-0.3 m soil layer, but these values are sensitive to the mineralization rates chosen for the organic P pools. Uncertainty in the driver estimates lead to coefficients of variation of 0.22 and 0.54 for cropland and grassland, respectively. This work makes the methods for simulating the agricultural soil P maps more transparent and reproducible than previous estimates, and increases the confidence in the new estimates, while the evaluation against regional dataset still suggests rooms for further improvement.
Understanding the dynamics behind forest transitions, i.e., shifts from deforestation to forest recovery, is crucial for forest conservation and climate-change mitigation i.e., carbon (C) ...sequestration. We investigated the drivers of the forest transition in the United States, which was characterized by forest thickening despite surges in industrial wood extraction. We employ the concepts of Human Appropriation of Net Primary Productivity (HANPP) and Material and Energy Flow Analysis (MEFA) to quantitatively assess changes in major provisioning ecosystem services demanded from forests, i.e., industrial wood (comprising biomass used in products such as paper and pulp), grazing, and fuelwood, and analyse substitution processes from 1870-2012 at regional, sectoral, and national scales. The share of industrial wood in total annual forest biomass harvest increased from 23% to 84% over the time-period, while fuelwood and biomass grazed declined from 63% to 13%, and 14% to 3%, respectively. Reductions in demand for fuelwood and biomass grazed were enabled by shifts in feed and energy sources, consequently allowing for increases in both livestock numbers and energy use. Feed crops increased six-fold, alleviating grazing pressure on forest ecosystems, particularly in the Eastern states. Fossil fuels replaced fuelwood, especially in the residential sector. Between 1900-2012 the final energy mix increased seventeen-fold. Thus, the increase in biomass C stocks in U.S. forests was connected to substitution of forest ecosystem services with fossil fuel-based production systems, and with manifold increases in societal resource use and C dynamics. Such shifts need to be considered when assessing the positive environmental effects of forest transitions.
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