Impacts of urban expansion on spatio-temporal patterns of carbon storage ecosystem service in Bandar Abbas Watershed using InVEST software

Urban development and land use pattern changes strongly affect the ecosystem service of carbon sequestration and storage. To integrate the concept of this climate regulation service into land use issues, we need to have information about its spatio-temporal distribution, so that with the help of mapping and quantification, protection and development sites can be selected with the continued provision of this service by the ecosystem. The current research was conducted with the aim of investigating the process of carbon sequestration and carbon storage ecosystem service changes in the process of urban growth and development and its valuation to improve the spatial planning of the land.

The study area is the coastal strip of Bandar Abbas City with a coastline length of 69 km. To comprehensively conduct the research, the smallest hydrological unit in the region where this city is located was selected which included three sub-watersheds. The total area of the region is equal to 272806 ha. At first, the land cover-land use map for the years 2000 and 2020 was prepared, and the future changes were predicted with different scenarios. Then, using the InVEST carbon storage and sequestration model, spatial distribution and changes in carbon storage and economic value were obtained.

The results showed that the largest area of the study watershed is the barren and range lands, which during the study period have decreased and man-made uses, water levels, and agriculture have increased. Modeling calculations showed the carbon sequestration capacity from 3741321.08 t in 2000 to 3763695.92 t in 2020 with an increase of 22374.82 t positive carbon sequestration. The reason for that was the growth of agricultural lands. Correspondingly, the economic value of this increase in deposition power during the study period was calculated as 874393.08 $.

It is expected that with the future usage scenarios, the positive growth of sequestration and subsequent financial benefit in terms of carbon sequestration will continue. But various factors can cause changes or disturbances in ecosystems and ultimately in ecological functions, that climate change is one of the most important factors and causes changes in the structure and functioning of ecosystems. As a result, services should be checked depending on climatic factors and land use changes, because the influence of climatic factors creates new states of the possible future situation, and uncertainty of land use scenarios and conflicts between ecosystem services can cause a change in the nature and change in the direction and size of services being provided by the ecosystem. Along with quantification, the economic value of service can provide valuable spatial principles for urban development and environmental awareness.