Abstract

Background and purpose
Monitoring the trend of long-term Land Use (LU) changes in Protected Areas (PAs) and ecological risk assessment is one of the appropriate management methods for prevention of habitat destruction and threats in these areas. The Hara Protected Area (PA) is known as the largest natural habitat in the Persian Gulf and in terms of diversity in habitat form, there are three types of deltaic, island and coastal types with dense, low and thin covers. This area is also rich in flora and fauna and pristine natural landscapes. Therefore, it is necessary to control the process of changes caused by various human activities development and also to assess the ecological risk level caused by these activities. In this regard, the main research questions are: 1) What is the trend of LU changes in the studied area? 2) What is the ecological risk in this area? 3) Considering land use changes trend and ecological risk in the area, what is the status of the landscape pattern indicators?
 
Materials and Methods
In this study, from the topographic map of the studied area (on a scale of 1:25000) and satellite images of Landsat TM in 1989 and 1999, Landsat ETM+ in 2009 and OLI_TIRS in 2021 to evaluate LU changes and habitat integrity was used. In order to classify the images, the random forest algorithm was used and the accuracy of the classification was also evaluated using the overall accuracy obtained from the confusion matrix.
To obtain the ecological risk index, distance sampling method was used in time scale. The studied area was divided into ecological risk assessment units with an area of 10 * 10 km. Then, based on the number of lost (damaged) landscape indicators in each year, ecological risk level was calculated and the obtained results were assigned to evaluation areas as the central pixel. In addition to measuring ecological risk level, from the landscape ‎Separation index (Si) to show the degree of dispersion of patches, from the landscape Fragmentation index (Fi) to check the integrity of the habitat, the Fractal Dimension index (FDi) ‎and Vulnerability (Vi) were also used to measure the geometric order and complexity of the ‎patches. ‎
 
Findings and discussion
Human activities development has caused significant changes in the structure and ‎function of the natural ecosystems of the land. Therefore, it is necessary to continuously ‎monitor and understand the spatial-temporal dynamics of LU changes and the resulting ‎ecological risk. Among the LU classes in the area, tidal zones ‎have the most increasing trend, and water areas show a decreasing trend. The results of the ‎ecological risk assessment also indicate that due to population growth, economic development, ‎and human activities, especially tourism, ecological risk level has increased in very high ‎and high levels classes. Fi, Si, Di, FDi, and Vi indices evaluation, also indicated that most ‎changes are related to mangrove forests and the distance between small forest patches has ‎increased.
 
Conclusion
According to the results, the mangrove forests of the Hara PA have experienced many changes in terms of size and quality over time, and despite their high importance, their distribution and expansion are decreasing due to human activities. In line with these changes, the landscape pattern of the Hara PA has also been affected and its quality has decreased. Accordingly, continuous control and monitoring of human activities to prevent the increase of ecological risk and the reduction of habitat quality in the PAs is essential, and according to the protection approaches, any ‎indiscriminate and unplanned exploitation is prohibited in these areas. ‎