Trend of temporal changes of vegetation in dust center of Khuzestan province (Case study: planted area of Tovayel, Karun city)

Due to the proximity to the water supply canal (Karun to Mahshahr) called Kut-Amir Canal and the availability of suitable water for irrigating the seedlings, the cultivated area was irrigated by surface irrigation and Furrow. The purpose of this study is to evaluate the trend of vegetation changes in during four consecutive years (2018-2021) and in two seasons in seedling cultivation areas was investigated. A total of five 100-meter transects, each 50 meters apart, were systematically established in the three selected areas. Around 30 fixed plots were installed along transects. In the two growing seasons of spring and autumn, the coverage of native species was recorded. The Simpson and Shannon, dominance, uniformity, and diversity indices were estimated using the PAST software. The results of one-way analysis of variance for the spring of 2018 to 2021 showed that there is a significant difference between the mean indices of coverage percentage, dominance, uniformity, Simpson and Shannon and Ghana diversity indices in consecutive years of harvest. The results of the Wilcoxon test showed that the indexes of species number, Simpson, Shannon, Evennnes, Manhinink and Margalf increased in the second year compared to the first year. Also, due to the fact that the sig rate is less than 0.05, there is a significant difference between the dominance indices, Simpson index and Shannon during July 2020 compared to 2019, but between changes in coverage percentage in the two there was no significant difference for consecutive years. The results of Duncan test showed that there is a significant difference between vegetation percentage and dominance index, Simpson and Shannon in spring (2018 and 2019) compared to (2020 and 2021) and is in two separate categories. Take. From the above observations and results, it can be concluded that in general, Shannon and Simpson diversity indices in the last year (2021) compared to the beginning year (2018) have increased significantly and this change is the result of increasing the uniformity and species richness in the area has been. The best options for improving the desert area above are Seidlitzia rosmarinus and Tamarix passerinoides. Also, the construction of Furrow along with seedling cultivation holes causes the accumulation of rainwater and the gradual emergence of other native species.