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1.
Tobias Plieninger Christian SchleyerMartin Mantel Patrick Hostert 《Land use policy》2012,29(1):233-243
Most industrial countries have experienced a transformation of land use: from decreasing to expanding forest areas, the so-called forest transition. Outside closed forests, European rural landscapes exhibit a diversity of tree-based agricultural systems, but the question of whether this forest transition has also affected ‘trees outside forests’ has rarely been studied. The aim of this study is to analyze the spatial-temporal dynamics of farm trees and woodlands in an agricultural landscape in Eastern Germany from 1964 to 2008, based on aerial photographs and digital orthophotos. Taking a landscape ecological perspective, we quantify farm tree dynamics, disentangle processes of gain and loss in the socialist and post-socialist periods of Eastern Germany, and assess differences in ecosystem services provided by farm trees. A substantial increase of overall tree cover by 24.8% was observed for the selected time period, but trajectories have been disparate across different farm tree classes. The increase in tree cover was stronger in steep valleys than on hills and plateaus, indicating a significant interdependence between topography and trajectories of change. Patch numbers of farm trees did not increase, which suggests that the expansion of tree cover is mostly due to a spatial expansion of previously existing tree patches. Overall net gains in tree cover were rather similar during the socialist and post-socialist eras. The general increase in tree cover was accompanied by increase in agriculture-related ecosystem service provision, but the increase in pollination and pest control services was much lower than that in water purification services. These findings present the first empirical evidence from an industrialized country that there is also an ongoing ‘forest transition’ outside closed forests. Potential, partially counteracting drivers of change during the socialist and post-socialist periods have mainly been related to farm policies and the environmental consciousness of land users and society as a whole. 相似文献
2.
To assess the attainable greenhouse gas (GHG) mitigation potential from crop production in China's most important grain production region, the North China Plain (NCP), single farm environmental and economic performances of 65 winter wheat–summer maize (WW–SM) producing households were determined. The results revealed a huge heterogeneity among farms, with up to five times higher environmental impact of worst compared to best performing farms. Astonishingly no trade-off between productivity and sustainability could be identified in the region, with high-yield farms emitting no different amounts of GHGs per hectare compared to low-yield farms. Building on cluster analysis, with farms grouped according to their economic and environmental performance into ‘poor’, ‘fair' and ‘good’ producers, the regional GHG mitigation potential was estimated. Under the scenario assumption that all grain in the NCP is produced under ‘good’ production conditions, 21% and 7% of GHG could be mitigated in wheat and maize production, respectively. The study shows that in the NCP, exemplary for China's rapidly developing agricultural sector, the crop management skills of a substantial share of farmers could obviously not keep pace with the massive input intensification. Among others, farmer–farmer trainings are recommended to close the gap in crop production performance among producers. 相似文献
3.
In September 2012, the Niger Delta (Nigeria) experienced a severe flood. By conducting a differences-in-differences estimation (as well as qualitative interviews), this paper studies the effects of the flood and of relief aid provided by an oil company on relational capability, a concept which covers bonding, bridging, and linking aspects of social capital (SC). We find that the flood increased bonding SC, measured as trust in the community, but reduced bridging SC, measured as participation together with unknown people in common-interest projects. The aid distributed to some people, on the other hand, was associated with higher bridging SC. The aid was not distributed according to flood damages but mostly according to social status. Our findings emphasize how a disaster can affect the repartition of bonding and bridging SC in the short term. They also highlight the need to build social cohesion in vulnerable communities from a longer-term and institutional perspective. 相似文献