Geographical Inequalities in Land Degradation Research: Evidence from Spatio-Temporal Analysis in Nepal

Land degradation is a major challenge to sustainable development in Nepal’s fragile mountain and lowland environments. This study synthesizes five decades (1970s–2024) of research, analyzing 764 peer-reviewed articles with explicit spatial coverage. Literature was categorized thematically (ecological, climate/hydrological, geomorphological, socio-economic, political, and development oritend), geographically (physiography, river basins, provinces), and temporally (pre-1993, 1993–2015, post-2015). GIS-based spatial digitization enabled intersection analysis, zonal statistics, and frequency mapping to quantify research density and variation. Statistical tests, including Welch’s ANOVA, Games–Howell post-hoc, and Kruskal-Wallis multiple comparisons, evaluated differences across regions and periods, revealing the evolution, spatial biases, and thematic trends in Nepal’s land degradation research. Results reveal a pronounced increase in research output over time, with exponential growth after 2015, alongside significant spatial and thematic unevenness. Research is strongly clustered in the Chure/Siwalik and Tarai landscapes, the Bagmati and Koshi basins, and densely populated central regions, while the Middle and High Mountain regions, Karnali and Mahakali basins, and western Nepal remain under-studied. Ecological and geomorphic perspectives dominate the literature, whereas socio-cultural and development-focused studies receive comparatively limited attention. Despite increasing alignment with global sustainability frameworks, notable geographic and thematic gaps persist. Using a spatial–temporal and thematic lens, it identifies key research biases and gaps, and outlines priorities for more balanced, policy-relevant, and climate-resilient land management scholarship.