Abstract

Climate change and population pressure have an immense effect on vegetation of semi-arid regions. Long-term changes in vegetation caused by the combined effect of these two drivers are still insufficiently quantified. Moreover, the simultaneous influence of anthropogenic versus climatic drivers of vegetation change in urbanizing semi-arid landscapes is still under-explored. To fill this gap, the present study was performed in a semi-arid region, assessing long-term changes in vegetation as well as population. This study describes a 34-year (1990-2024) temporal patterns of land use/land cover (LULC) and vegetation changes in the semi-arid desert of Bahawalpur, Pakistan. Significant (P < 0.05) seasonal variations in NDVI, relative humidity, temperature, precipitation and wind speed were observed. Expansion of built-up area from 8.46 to 71.81 km² with associated vegetation loss (79.74 to 38.23 km²) was revealed by LULC from 1990 to 2024. In this duration, the range of NDVI fluctuated from -0.06 to 0.73. Precipitation showed significant negative correlations with wind (r = -0.536, P < 0.01) while a strong positive correlation with relative humidity (r = 0.82, P < 0.001). This confirms the thermodynamic association of atmospheric moisture and rainfall. Additionally, population was strongly positively correlated with relative humidity (r = 0.712, P < 0.001) and negatively correlated with wind (r = -0.526, P < 0.01), suggesting reasonable urbanization-induced microclimatic modifications. These findings suggest that vegetation in semi-arid urban landscapes may now depend more on human activities such as population shifts and irrigation than directly on natural climate patterns, prompting concerns about how these ecosystems will cope with future climate-driven water shortages. These findings also provide a foundation for global sustainable ecosystem management planning.