Desert urban ecology: urban forest, climate, and ecosystem services

Accelerated urbanization in the desert environments leads to changes in land cover, local climate, and ecosystem services. This study aims to answer the question of how land cover changes in vegetation structure due to the urbanization process affect regional temperature and ecosystem services in hot arid regions. The study evaluated the impact of 21-year (2002-2022) changes in tree canopy cover and vegetation structure on land surface temperature and ecosystem services in the Phoenix-Mesa-Scottsdale Metropolitan Statistical Area in Arizona, US, located in the northern Sonoran desert. The i-tree canopy software was used to evaluate the change in tree cover and to calculate the changes in ecosystem services and benefits derived from trees. The Normalized Difference Vegetation Index (NDVI), Surface Urban Heat Island Intensity (SUHII), Urban Thermal Field Variation Index (UTVFI) indices, as well as Ecological Evaluation Index (EEI) were used to evaluate the climatic and ecological structure of the region. Then, the relationship between the indices was evaluated by pearson correlation analysis. The results demonstrated that decreased tree canopy cover resulted in decreased ecosystem services and adversely affected the urban economy. Moreover, the large amount of bare land cover is susceptible to diurnal exposure to unobstructed solar radiation, which heats up the land surface rapidly due to its low specific heat capacity, compared to impervious surfaces in urban areas. The outcomes of the study, which provides evidence-based assessment, contribute to decision-makers and planners in improving ecosystem services, urban resilience and sustainability in the region and elsewhere with similar ecological characteristics.