Land system science and affiliated research linked to sustainability require improved understanding and theorization of land and its change as a social-ecological system (SES). The absence of a general land-use theory, anchored in the social subsystem but with explicit links to the environmental subsystem, hampers this effort. Drawing on land-use explanations, meta-analyses, and associated frameworks, we advance a broad framework structure of eight elements – aggregations of explanatory variables – with links to the biophysical subsystem, for systematic comparisons of extant explanations. Tests and models can be employed to identify which set of variables and their configurations provide robust explanations of across land uses, identifying the potential for theory development. The framework and its application are applicable to both top-down and bottom-up explanatory approaches employed in the social sciences. Links to the environmental subsystem invite future exploration of SES explanations that reach across the different dimensions of global change and sustainability science.
The transition from command to market-oriented economies drastically affected land ownership and land management in Eastern Europe and resulted in widespread cropland abandonment. To examine these phenomena, we analysed the causes of post-socialist cropland abandonment in Argeş County in southern Romania between 1990 and 2005. Based on Landsat-derived maps of cropland use and a suite of environmental and socioeconomic variables hypothesized to drive cropland abandonment, we estimated spatially explicit logistic regression models for two periods (1990–1995 and 1995–2005) and three elevation groups. Our results showed that isolated cropland patches were more likely to become abandoned than more homogenous cropland areas. Unfavorable topography was an important determinant of abandonment in the plain and, to a lesser extent, hilly areas, but not in the mountains where locations with adverse market access and higher farm fragmentation exhibited higher likelihoods of cropland abandonment.
Global farmland biodiversity has declined rapidly in recent decades due to the homogenization of agricultural landscapes, including an increase in field sizes and decrease in woody features, such as hedgerows. Restructuring landscapes by (re)introducing woody features and decreasing field sizes can support biodiversity but at the cost of lower returns in farming. Striking a balance between biodiversity and agricultural net returns is increasingly pertinent. Here, we use spatial multi-objective optimization to allocate woody features and adapt average field sizes at the landscape scale to assess the trade-off between biodiversity, measured as the occurrence of farmland birds, and potential net returns from crop production. Our results suggest that, compared to the current landscape configuration, both agricultural net returns and biodiversity can be simultaneously increased. Restructuring only 5% of the landscape can improve bird abundance by 2% and generate about €2 million in agricultural net returns. We show that increases in farmland bird diversity are highly dependent on the location and on farmers' willingness to accept negative impacts on agricultural net returns. Our spatially explicit approach supports spatially targeted land use planning that can strike a better balance between the economic objectives of farmers and the societal desire to conserve biodiversity.
Land-use science provides critical advances for better understanding land use in light of global economic and environmental changes. The eminent importance of land-use science for global sustainabi...
Widespread cropland abandonment occurred after the collapse of socialism across the former Soviet Union, but the rates and spatial patterns of abandoned lands are not well known. As a result, the potential of this region to contribute to global food production and estimates of the carbon sink developing on currently idle lands are highly uncertain. We developed a spatial allocation model that distributes yearly and subnational sown area statistics to the most agriculturally suitable plots. This approach resulted in new, high‐resolution (1 km 2 ) annual time series of cropland and abandoned lands in European Russia, Ukraine, and Belarus from 1990 to 2009. A quantitative validation of the cropland map confirms the reliability of this data set, especially for the most important agricultural areas of the study region. Overall, we found a total of 87 Mha of cropland and 31 Mha of abandoned cropland in European Russia, Ukraine, and Belarus combined, suggesting that abandonment has been severely underestimated in the past. The abandonment rates were highest in European Russia. Feeding our new map data set into the dynamic vegetation model LPJmL revealed that cropland abandonment resulted in a net carbon sink of 470 TgC for 1990 to 2009. Carbon sequestration was generally slow in the early years after abandonment, but carbon uptake increased significantly after approximately 10 years. Recultivation of older abandoned lands would be associated with high carbon emissions and lead to substantial amounts of carbon not being sequestered in vegetation formations currently developing on idle croplands. Our spatially and temporally explicit cropland abandonment data improve the estimation of trade‐offs involved in reclaiming abandoned croplands and thus in increasing agricultural production in this globally important agricultural region.
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