Human Land Use Places Strain on Ecosystems
In-depth studies of how human land use is having an ever greater impact on ecosystems over a period of three centuries are being carried out for the first time. This project, funded by the Austrian Science Fund FWF, investigates on a global level how the transition from an agrarian to an industrial society has affected ecosystems. Knowledge about past processes will be used to model and assess possible consequences of growing biomass demand and land use for global sustainability.
The enormous demand for land for human use is leaving our planet's ecosystems with less and less room to survive. Through their land use, humans today are already consuming over 20 percent of the Earth's natural biomass production, thereby robbing ecosystems of their most important energy source.
The intensity of land use is heavily dependent on population density, as researchers from the Institute of Social Ecology at the University of Klagenfurt have already identified in a previous project. Yet other factors complicate the picture, as shown by the example of industrialised countries. While a richer diet with a high share of meat in these countries is driving the extension of land use, technological progress is a counteracting force and reduces the spatial imprint. The researchers are now looking to resolve this conundrum in a follow-up project. Studying temporal dynamics will help them to determine both the socio-economic and natural factors that lead to human dominance over ecosystems and to identify potential consequences of this dominance.
Human Land Dominance
The intensity of human land use and its impact on the biosphere can be determined using the HANPP indicator. This measures human appropriation of net primary production. Net primary production is the biomass that primary producers, mainly plants, produce after deduction of their own cell respiration and which is therefore available as energy input for ecosystems each year. As project leader Prof. Haberl explains: "In order to determine the factors for human land dominance, we create a global HANPP timeline that extends from the 18th to the 20th centuries. This database will not only allow us to analyse how the transition from an agrarian to an industrial society has impacted on ecosystems - i.e. what proportion of the net primary production of natural ecosystems has been lost through human activity. We will also be able to examine which changes in natural and socio-economic systems have resulted in changes to HANPP. At a socio-economic level, for example, the key parameters include rising prosperity and agricultural technology. But natural limitations such as soil properties or the climate are also included in the analysis."
Beyond creating an understanding of major factors that cause changes in HANPP, an assessment of the possible consequences for global sustainability is a major goal of the project. For the first time, this project establishes a link between the production of biomaterials and the services provided by nature, as project team member Dr. Karlheinz Erb explains: "We support the hypothesis that intensive human land use changes ecosystems' productivity and their resilience and that it restricts their ability to provide other ecosystem services. It is therefore debatable whether, under changing conditions, ecosystems are still able to absorb waste and emissions to the extent they have in the past." The researchers also address changes in the availability of biomass, in global water, carbon and nitrogen flows, and in the volume of carbon that plants store worldwide as long-term consequences and are testing the hypothesis that HANPP is a relevant factor for loss in biodiversity.
This FWF project shows how important it is to consider humans' land dominance, an area that has until now been little researched, in the context of sustainable development strategies. The researchers are urging in particular that the already high pressure on ecosystems reflected in the current HANPP value should not be intensified by over-ambitious plans for replacing fossil energy with biomass energy.
Prof. Helmut Haberl
University of Klagenfurt
Institute of Social Ecology
T +43 / 1 / 522 40 00 - 406
Austrian Science Fund FWF
Mag. Stefan Bernhardt