Historical landscape repeat photography as a tool for land use change research

Abstract

This study applies repeat photography – the comparison of historical and recent landscape photographs from the same camera point – to the case of highland Madagascar. First, it evaluates whether repeat photography is an efficient, effective, and useful method to identify region-wide trends in land use change. To do so, it proposes and applies a systematic methodology that addresses the significant obstacles of spatial bias and temporal inconsistency. When compared with the analysis of air photos and satellite images, the technique is found to provide useful high-resolution data and a deeper historical reach. If pursued opportunistically alongside other fieldwork, the method is efficient in time and cost; it can be a useful way to identify environmental trajectories worthy of further investigation, to corroborate other studies, and to illustrate changes. Second, the overall trends of 20th century land-use change in highland Madagascar are investigated. Results suggest that many parts of the central highlands – dominated 100 years ago by open grasslands – are now characterized by expanded and intensified agriculture, an increased presence of trees (fruit trees and exotic reforestation species), and general stability in soil erosion. These results complicate the view of Madagascar as an island suffering problematic environmental degradation, such as deforestation and erosion.