Julie G. Zaehringer

Agricultural expansion and intensification in the foothills of Mount Kenya: A landscape perspective

This study spatially assesses, quantifies, and visualizes the agricultural expansion and land use intensification in the northwestern foothills of Mount Kenya over the last 30 years: processes triggered by population growth, and, more recently, by large-scale commercial investments. We made use of Google Earth Engine to access the USGS Landsat data archive and to generate cloud-free seasonal composites. These enabled us to accurately differentiate between rainfed and irrigated cropland, which was important for assessing agricultural intensification. We developed three land cover and land use classifications using the random forest classifier, and assessed land cover and land use change by creating cross-tabulation matrices for the intervals from 1987 to 2002, 2002 to 2016, and 1987 to 2016 and calculating the net change. We then applied a landscape mosaic approach to each classification to identify landscape types categorized by land use intensity. We discuss the impacts of landscape changes on natural habitats, biodiversity, and water. Kappa accuracies for the three classifications lay between 78.3% and 82.1%. Our study confirms that rainfed and irrigated cropland expanded at the expense of natural habitats, including protected areas. Agricultural expansion took place mainly in the 1980s and 1990s, whereas agricultural intensification largely happened after 2000. Since then, not only large-scale producers, but also many smallholders have begun to practice irrigated farming. The spatial pattern of agricultural expansion and intensification in the study area is defined by water availability. Agricultural intensification and the expansion of horticulture agribusinesses increase pressure on water. Furthermore, the observed changes have heightened pressure on pasture and idle land due to the decrease in natural and agropastoral landscapes. Conflicts between pastoralists, smallholder farmers, large-scale ranches, and wildlife might further increase, particularly during the dry seasons and in years of extreme drought.

A novel participatory and remote-sensing-based approach to mapping annual land use change on forest frontiers in Laos, Myanmar, and Madagascar

ABSTRACT Tropical forests are under pressure from both commercial and smallholder agriculture. Forest frontiers are seeing dynamic land use changes that frequently lead to land system regime shifts, posing challenges for the sustainability of entire local social-ecological systems. Monitoring highly dynamic land use change and detecting land system regime shifts is methodologically challenging due to trade-offs between spatial and temporal data resolution. We propose an innovative approach that combines analysis of very-high-resolution satellite imagery with participatory mapping based on workshops and field walks. Applying it in Laos, Myanmar, and Madagascar, we were able to collect annual land use information over several decades. Unlike conventional land use change mapping approaches, which assess only few points in time, our approach provides information at a temporal resolution that enables detection of gradual and abrupt land system regime shifts.

Large-scale agricultural investments trigger direct and indirect land use change: New evidence from the Nacala corridor, Mozambique

ABSTRACT The Nacala corridor in Mozambique is one of the main host regions for large-scale agricultural investments (LAIs) in Africa. LAI companies produce crops for export, with scarcely known impacts on small-scale farmers and the environment. We conducted 101 interviews with small-scale farmers living near an LAI to elicit their perceptions of the LAI’s impacts on their own land use and the environment. Additionally, we used remote sensing to assess land use change between 2000 and 2015 in two study areas in Guruè and Monapo districts. The results show that LAIs caused deforestation both directly and indirectly. The main environmental impact perceived by farmers was that LAIs had blocked their access to rivers. Positive spillovers did occur, but could not compensate for the negative impacts experienced. A peaceful coexistence of LAIs and small-scale farmers in the Nacala corridor is only possible if existing injustices around the occupation of land are resolved.