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We investigate agroecosystem energy flows in two Upper Austrian regions, the lowland region Sankt Florian and the prealpine region Grünburg, at five time points between 1830 and 2000. Energetic agroecosystem productivity (energy contents of crops, livestock products, and wood per unit area) is compared to different types of energy inputs, i.e., external inputs from society (labor, industrial inputs, and external biomass inputs) and biomass reused from the local agroecosystem (feed, litter, and seeds). Energy transfers between different compartments of the agroecosystem (agricultural land, forest, and livestock) are also quantified. This allows for delineating an agroecosystem energy transition: In the first stage of this transition, i.e., in the nineteenth century, agroecosystem productivity was low (final produce ranged between 14 and 27 GJ/ha/yr), and local biomass reused made up 97% of total energy inputs in both regions (25–61 GJ/ha/yr). In this period, agroecosystem productivity increase was achieved primarily through more recycling of energy flows within the agroecosystems. In the second stage of the agroecosystem energy transition, i.e., after World War II, external energy inputs increased by factors 2.5 (Sankt Florian) and 5.0 (Grünburg), partly replacing local energy transfers. Final produce per area increased by factors 6.1 (Sankt Florian) and 2.9 (Grünburg). The difference in the resulting energy returns on investment (EROI) owes to regional specialization on cropping versus livestock rearing and to increasing market integration. Our results suggest that sustainable land-use intensification may benefit from some regional specialization harnessing local production potentials based on a mix of local and external inputs. Electronic supplementary material The online version of this article (doi:10.1007/s10113-017-1145-1) contains supplementary material, which is available to authorized users.

Biomass turnover time is a key parameter in the global carbon cycle. An analysis of global land-use data reveals that biomass turnover is almost twice as fast when the land is used to enhance terrestrial ecosystem services. The terrestrial carbon cycle is not well quantified1. Biomass turnover time is a crucial parameter in the global carbon cycle2,3,4, and contributes to the feedback between the terrestrial carbon cycle and climate2,3,4,5,6,7. Biomass turnover time varies substantially in time and space, but its determinants are not well known8,9, making predictions of future global carbon cycle dynamics uncertain5,10,11,12,13. Land use—the sum of activities that aim at enhancing terrestrial ecosystem services14—alters plant growth15 and reduces biomass stocks16, and is hence expected to affect biomass turnover. Here we explore land-use-induced alterations of biomass turnover at the global scale by comparing the biomass turnover of the actual vegetation with that of a hypothetical vegetation state with no land use under current climate conditions. We find that, in the global average, biomass turnover is 1.9 times faster with land use. This acceleration affects all biomes roughly equally, but with large differences between land-use types. Land conversion, for example from forests to agricultural fields, is responsible for 59% of the acceleration; the use of forests and natural grazing land accounts for 26% and 15% respectively. Reductions in biomass stocks are partly compensated by reductions in net primary productivity. We conclude that land use significantly and systematically affects the fundamental trade-off between carbon turnover and carbon stocks.

Assessments of land-system change have dominantly focused on conversions among broad land-use categories, whereas intensity changes within these categories have received less attention. Considering that both modes of land change typically result in diverse patterns and trajectories of land-system change, there is a need to develop approaches to reduce this complexity. Using Europe as a case study, we applied a clustering approach based on self-organising maps and 12 land-use indicators to map (1) land-system archetypes for the year 2006, defined as characteristic patterns of land-use extent and intensity, and (2) archetypical change trajectories, defined as characteristic changes in these indicators between 1990 and 2006. Our analysis identified 15 land-system archetypes, with low-intensity archetypes dominating (ca. 55 % coverage) followed by high-intensity archetypes (ca. 26 %). In terms of change, we identified 17 archetypical change trajectories, clustered in four broad categories. Stable land systems were most widespread (ca. 40 % of the EU27), followed by land systems characterised by land-use conversions (ca. 26 %), de-intensification trends (ca. 18 %), and intensification trends (ca. 15 %). Intensively used and intensifying land systems were particularly widespread in Western Europe, whereas low-intensity and de-intensifying land systems dominated in Europe’s east. Comparing our archetypes with environmental and socio-economic factors revealed that good accessibility and favourable topographic, climatic, and soil conditions characterised intensively managed areas. Intensification was also most common in these areas, suggesting an ongoing polarisation of intensification in favourable areas and de-intensification and abandonment trends in more marginal areas. By providing spatially and thematically improved maps of land-use patterns and changes therein, our archetypes could serve as useful inputs for more detailed assessments of ecosystem service demand and supply, as well as explorations of land-system change trade-offs, especially with regard to land-use intensity. Further, they could serve useful for identifying regions within which similar policy tools could be valuable to develop regionalised, context-specific land-management policies to steer European land systems onto desired pathways.

African land systems play a decisive role in addressing future sustainability challenges for food and energy supply—in Africa and potentially elsewhere. Knowledge on the magnitude and efficiency of current land use and its socio-economic frame conditions is scarce but required to provide an appropriate basis for estimating production potentials and efficiency improvements. We apply the human appropriation of net primary production (HANPP) framework to analyze African land systems and their dynamics between 1980 and 2005. HANPP measures human-induced changes in ecological biomass flows and allows analyzing the efficiency with which humans use the natural resource NPP (Net Primary Production). In 2005, African HANPP amounts to 20 %, which is below the global average of 23 %, and has grown significantly (+55 %) since 1980. HANPP efficiency (i.e., the ratio of used biomass extraction to total HANPP) is low (35 %) in contrast to the global average of 48 %. Large regional variations (ranging from 18 % in Central Africa to >100 % in Northern Africa) and only small improvements of +11 % on average have been observed. In the study period, the growth of HANPP has been mostly driven by land-use expansion. We conclude that the observed low HANPP efficiency in Africa suggests that there may be potentials for improving the efficiency of biomass production on existing land-uses rather than increasing output trough further land expansion. We discuss policy implications that could help better utilizing existing potentials to increase land-use efficiency in a sustainable manner.

Understanding patterns, dynamics, and drivers of land use is crucial for improving our ability to cope with sustainability challenges. The human appropriation of net primary production (HANPP) framework provides a set of integrated socio-ecological indicators that quantify how land use alters energy flows in ecosystems via land conversions and biomass harvest. Thus, HANPP enables researchers to systematically and consistently assess the outcome of changes in land cover and land-use intensity across spatio-temporal scales. Yet, fine-scale HANPP assessments are so far missing, an information important to address site-specific ecological implications of land use. Here, we provide such an assessment for Europe at a 1-km scale for the years 1990, 2000, and 2006. The assessment was based on a consistent land-use/biomass flow dataset derived from statistical data, remote sensing maps, and a dynamic global vegetation model. We find that HANPP in Europe amounted to ~43 % of potential productivity, well above the global average of ~25 %, with little variation in the European average since 1990. HANPP was highest in Central Europe and lower in Northern and Southern Europe. At the regional level, distinct changes in land-use intensity were observed, most importantly the decline of cropland areas and yields following the breakdown of socialism in Eastern Europe and the subsequent recovery after 2000, or strong dynamics related to storm events that resulted in massive salvage loggings. In sum, however, these local dynamics cancelled each other out at the aggregate level. We conclude that this finding warrants further research into aspects of the scale-dependency of dynamics and stability of land use.

In life cycle assessment (LCA), the impact assessment on natural resources is still in the early stages of research, and the impacts of biotic resources are usually not evaluated. The human appropriation of net primary production (HANPP) is a well-known indicator of land use impacts, but it cannot be easily implemented in LCA. The objective of this paper was to create a life cycle impact assessment (LCIA) method on land use impacts on net primary production (NPP) based on the HANPP approach. To create an operational LCIA method, the midpoint characterization factors (CF) were calculated by comparing the NPP of plants occurring under current land uses with a baseline scenario, i.e., the NPP of potential natural vegetation. For the endpoint CF, we considered the backup technology concept and included in the calculation the marginal cost for additional biomass production through algae cultivation in the ocean. Site-generic and site-specific midpoint and endpoint characterization factors (CF) were created in a global scale for 162 countries and for four types of land uses (cropland, pasture, infrastructure, and wilderness). For cropland, we also created biomass-specific CF for ten particular crops in a global scale. The LCIA method was tested in particular case studies and seemed to produce comparable results, with the possibility of coupling it with other LCIA methodologies, as recipe endpoint. The LCIA method proposed in this paper provides an assessment of the decrease of biomass availability due to land use (affecting the AoP resources), which is an impact category poorly considered in LCA. Nevertheless, the method has some future challenges, for instance to take into account site-specific backup technologies for the endpoint CF.

The interrelation between land-use change and socioeconomic changes is complex and highly dynamic. We here present an assessment of the human appropriation of net primary production (HANPP) in Republic of South Africa (RSA) between 1961 and 2006. HANPP is an integrated socio-ecological accounting framework that traces changes in ecosystems resulting from anthropogenic activities (harvest and land conversions) and allows to study ecological, social and economic driving forces and constraints of long-term land-use changes. We use South Africa, with its history of the rise and collapse of the Apartheid regime, as an example for an analysis of HANPP trajectories in the background of major governance shifts, and base our analysis on the best available statistical datasets, specific analyses and model results. Surprisingly, land cover as well as HANPP in the RSA remained relatively constant between 1961 and 2006, with HANPP values oscillating between 21 and 25% and of the potential NPP. However, through our analysis of the components of HANPP and their interrelations, striking turning points throughout the last five decades become evident. This allows us to discern three distinct periods, each of the phases characterized by distinct HANPP trajectories. Throughout the entire period, a trend of decoupling of HANPP from population growth could be achieved through considerable gains in land-use efficiency. The HANPP analysis reveals that this prevailing trend of increasing land-use efficiency, based on technological improvements and biomass trade, came to a halt in the ‘crisis’ phase and immediately recovered afterwards.

This article presents a comprehensive data set on Austria’s terrestrial carbon stocks from the beginnings of industrialization in the year 1830 to the present. It is based on extensive historical and recent land use and forestry data derived from primary sources (cadastral surveys) for the early nineteenth century, official statistics available for later parts of the nineteenth century as well as the twentieth century, and forest inventory data covering the second half of the twentieth century. Total carbon stocks—i.e. aboveground and belowground standing crop and soil organic carbon—are calculated for the entire period and compared to those of potential vegetation. Results suggest that carbon stocks were roughly constant from 1830 to 1880 and have grown considerably from 1880 to 2000, implying that Austria’s vegetation has acted as a carbon sink since the late nineteenth century. Carbon stocks increased by 20% from approximately 1.0 GtC in 1830 and 1880 to approximately 1.2 GtC in the year 2000, a value still much lower than the amount of carbon terrestrial ecosystems are expected to contain in the absence of land use: According to calculations presented in this article, potential vegetation would contain some 2.0 GtC or 162% of the present terrestrial carbon stock, suggesting that the recent carbon sink results from a recovery of biota from intensive use in the past. These findings are in line with the forest transition hypothesis which claims that forest areas are growing in industrialized countries. Growth in forest area and rising carbon stocks per unit area of forests both contribute to the carbon sink. We discuss the hypothesis that the carbon sink is mainly caused by the shift from area-dependent energy sources (biomass) in agrarian societies to the largely area-independent energy system of industrial societies based above all on fossil fuels.

Land-use changes considerably alter the patterns and processes of terrestrial ecosystems. In an attempt to assess the impact of the human domination of ecosystems, this study quantifies the effect of human activities on aboveground carbon stocks in vegetation, based on a comparison of potential and actual vegetation in Austria. Following an accounting approach, statistical and GIS data on vegetation, elevation, land use, biomass harvest, as well as forest inventories and real estate statistics, were entered into the assessment, which was performed at the level of municipalities (n = 2,350). The results show that aboveground carbon storage in Austria has been considerably reduced by human activities. Actual vegetation contains 64% less carbon than would be expected in potential vegetation. The conversion of forests to cropland, grasslands, and urban areas has contributed 77% to this reduction in carbon stocks, the remaining 23% is due to forest management. In Austria, aboveground carbon stocks in forests have been reduced by 30% due to reductions in stand age and changes in forest species composition. Placing the data in a historical context, this analysis suggests that the current terrestrial carbon sink is a reversal of past carbon losses.