Human appropriation of net primary production in South Africa, 1961 - 2006

Die Republik Südafrika unterlag fundamentalem sozial-politischen Wandel im 20.Jahrhundert. Das Apartheidregime intensivierte die ernsten sozial-politischen Probleme die Südafrika auch heute noch spürt und weite Teile des Landes wurden durch Kultivierung von natürlichen Ökosystemen transformiert. Im 19. Jh. verdreifachte sich und die Fläche des Ackerlandes und die Fläche von Holzplantagen wuchs um das 10-fache. Die vorliegende Studie analysiert anthropogen verursachte Änderungen in Kohlenstoffflüssen indem sie den sozial-ökologischen Indikator HANPP (Human Appropriation of Net Primary Production) anwendet. HANPP wird einerseits durch menschliche Ernte verursacht und andererseits durch menschliche Änderungen von ökologischer Biomasseproduktion (NPP), beispielsweise durch Landtransformation, Landnutzungsänderungen oder Bodendegradation. HANPP dient als integrierter Indikator für die Intensität von Landnutzung, da er nicht nur Änderungen in Biomasseflüssen durch menschliche Aktivitäten aufzeigt, sondern auch in Beziehung zu Faktoren wie sozialem Wohlstand, Biodiversität, nachhaltiger Nutzung von natürlichen Ressourcen und zukünftiger Entwicklung von Landnutzungssystemen gesetzt werden kann. Diese Studie quantifiziert HANPP in Südafrika von 1961 bis 2006. Der Trend in HANPP blieb relativ konstant in diesem Zeitraum und bewegte auf einem jährlichen Level von etwa 24% der potenziell verfügbaren Biomasse (NPP0). Erst unter genauerer Betrachtung der unterschiedlichen Ströme von HANPP werden Auffälligkeiten deutlich. HANPP auf Ackerland verkleinerte sich zusehends nach 1986 und gleichzeitig stieg HANPP verursacht durch Weidewirtschaft und Feuerholzentnahme an. Diese Ergebnisse können einerseits in Bezug zur grünen Revolution, welche bis in die 1970ger eine Steigerung agrarischer Produktivität bewirkte, gestellt werden und andererseits zur finanziellen Krise ab den 1980ern bis zum Ende der Apartheid (1994), welche eine Stagnation landwirtschaftlicher Modernisierung mit sich brachte. Die wachsenden Bevölkerungszahlen und die schwache agrarische Produktivität bewirkten ein Sinken der HANPP pro Kopf über den gesamten Zeitraum hinweg. Da aber der Bedarf an Biomasse pro Kopf nicht zurückging, wurde Südafrika zu einem immer größeren Nettoimportland von Biomasse, was bedeutet, dass sich HANPP auch auf andere Länder verlagert und die Aneignung von Biomasse nicht mehr auf die Landesfläche von Südafrika beschränkt ist.During the 20th century the Republic of South Africa experienced fundamental social, political and ecological transitions. The Apartheid regime intensified the severe socio-economical problems with which South Africa is still struggling today and humans transformed natural ecosystems to a wide extent. From 1900 until today, the area under crop production more than tripled and the area under forest plantations grew more than 10-fold. This thesis applies the socio-ecological indicator Human Appropriation of Net Primary Production (HANPP) that aims at measuring human-induced changes in biomass flows resulting from two processes: Anthropogenic harvest and human-induced land conversion (such as land cover change, land use change and human induced soil degradation). HANPP is useful as an integrated indicator of land-use intensity, because it does not only measure changes of biomass flows in ecosystems from land use, but can also be related to the main social and economical driving forces for long-term changes in land cover and land use. HANPP data allow for drawing conclusions on the degree of transformation of natural ecosystems and its implications for factors such as social wealth, biodiversity, sustainable use of natural resources and prospects for a future development of land use. This study quantifies HANPP in South Africa over the period from 1961 to 2006. Despite the rapid changes that South Africa underwent in the observed period, HANPP remained approximately constant, suggesting that over the whole period under investigation humans appropriated around 24% of the total biomass potentially available in each year. However, shifts in patterns of biomass appropriation can be discerned when analyzing pathways of aHANPP separately. HANPP on cropland steadily declined after 1986 and simultaneously aHANPP caused by grazing, harvest of roundwood and fuelwood increased. These results can be interpreted either in context of the green revolution, which initially brought a rise in productivity on agricultural land, or in the background of the economic and political crisis in the 1980ies, which triggered a stagnation in agricultural modernization until 1994, when the country finally had its democratic opening. Rising population numbers and weak agricultural productivity in the past decades resulted in a decreasing aHANPP per head. However, per person demand for agricultural biomass did not decline. As a consequence South Africa became a net-import country of biomass, which means that South African aHANPP is distributed among other countries as well

Biomass turnover time in terrestrial ecosystems halved by land use

The terrestrial carbon cycle is not well quantified1. Biomass turnover time is a crucial parameter in the global carbon cycle2–4, and contributes to the feedback between the terrestrial carbon cycle and climate2–7. 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 uncertain5,10–13. 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 aect 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 aects all biomes roughly equally, but with large dierences between land-use types. Land conversion, for example fromforests to agricultural fields, is responsible for59%of the acceleration; the use of forestsand 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 aects the fundamental trade-off between carbon turnover and carbon stocks

Spatial variability in sustainable development trajectories in South Africa:provincial level safe and just operating spaces

The Sustainable Development Goals (SDGs) represents the first globally agreed framework to address human development and environmental stewardship in an integrated way. One approach to summarising national SDG status is our “barometer for inclusive sustainable development in South Africa”. The barometer downscales global social and planetary boundaries to provide status and trends for 20 critical indicators of environmental stress and social deprivation. In this paper, we explore the sub-national heterogeneity in sustainable development indicators by creating barometers defining the ‘safe and just operating space’ for South Africa’s nine provinces. Our results show that environmental stress varies significantly and provinces need to focus on quite different issues. Although generally environmental stress is increasing, there are areas where it is decreasing, most notably, marine harvesting. Social deprivation results show more of a pattern with high levels of deprivation in employment, income and safety across the provinces, and historically disadvantaged provinces showing the most deprivation overall. Although deprivation is generally decreasing, there are notable exceptions such as food security in six provinces. Our provincial barometers and trend plots are novel in that they present comparable environmental and social data on key indicators over time for all South Africa’s provinces. They are visual tools that communicate the range of key challenges and risks that provincial governments face, and are non-specialist and accessible to a range of audiences. In addition, the paper provides a critical case study of spatial disaggregation of national data that is required for the SDGs implementation

Analyse der Entwicklung von Investitionen in Kraftwerke und Netze in Österreich, Deutschland, Norwegen und Großbritannien

Zsfassung in engl. Sprache16

From the past to the present, from census to the grid : a socio-ecological analysis of land-use intensity across multiple spatial and temporal scales

Supplying sufficient amounts of biomass to a growing and prospering world population, while avoiding natural depletion, is a key challenge of the 21st century. From a production side perspective this will likely entail the intensification of current agricultural lands. However, many uncertainties relate to potentials of harvest increases and associated environmental trade-offs, particularly at the global scale. In this thesis I apply a consistent socio-ecological perspective on land systems that allows addressing three interrelated and virulent knowledge gaps: (a) Detecting current global patterns of land-use intensity through integrating socio-economic costs and benefits with changes at the land system level; (b) identifying regions with the highest (sustainable) intensification potentials and (c) tracing past land system trajectories in order to identify socio-economic and natural framework conditions under which changes in land-use intensity occur. Results on long term land system trends in Europe reveal surprising similarities between the most heterogeneous political and biophysical regions over the past 150 years. Land-use intensification was a somewhat universal trajectory on croplands in Europe, whereas trends on grasslands and forests were highly diverse, owing to economic and natural particularities. However, in a global perspective, cropland use intensity around 2000 differed substantially in terms of associated costs and benefits across biophysical regions. Improving global input efficiency could substantially reduce environmental burdens in high-input regions, such as many European countries and Eastern Asia, and raise biomass outputs by ca. 30% in the one quarter of croplands that are under low land-use intensity. This thesis contributes to land-use intensity research, both in a conceptual and empirical way. The holistic perspective on land use across various spatial and temporal dimensions allowed for insights into archetypical patterns of intensification, including related costs, benefits and future potentials, both, for societies and ecosystems.Keine Zusammenfassung vorhandenMag.a Maria NiedertscheiderAlpen Adria Universität Klagenfurt, Dissertation, 2016OeBB(VLID)241351