نوع مقاله : مقاله پژوهشی
نویسندگان
1 نویسنده مسئول، دانشیار پژوهش، بخش تحقیقات جنگلها و مراتع، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان خوزستان، سازمان تحقیقات، آموزش و ترویج کشاورزی، اهواز، ایران
2 دانشیار پژوهش، مؤسسه تحقیقات جنگلها و مراتع کشور، سازمان تحقیقات، آموزش و ترویج کشاورزی، تهران، ایران
3 استادیار پژوهش، بخش تحقیقات جنگلها و مراتع، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان خوزستان، سازمان تحقیقات، آموزش و ترویج کشاورزی، اهواز، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and Objective: Plants play a pivotal role in the stability of natural ecosystems. By continuously monitoring biodiversity over time, it is possible to identify the current status of vegetation and make management recommendations to preserve and improve natural habitats. This research aimed to investigate qualitative changes in vegetation cover, monitor the trend and magnitude of changes in the woodlands of the Sahara Sindi region of Iran, determine the relationships between vegetation cover indices and climatic factors, and measure diversity and species richness indices in the woodlands along the Karkheh river.
Methodology: During field visits, a homogeneous area in terms of species composition was first selected, which represented the vegetation type of the region. In the next step, sampling was carried out using a systematic random sampling method and 30 fixed plots were considered for sampling along three constructed transects. Considering the natural landscape of the Sahara Sindi region, vegetation attributes were recorded in the fixed plots during the appropriate growing season (early February to late April). In each plot, the percentage of live vegetation cover of each species was recorded by mentioning its name, the percentage of leaf litter and debris, and the percentage of bare ground. All plant species present in the study area were recorded through field surveys. The plot size for sampling was one square meter, which was determined by the minimum area method and using spiral plots and species-area curves. Then, Shannon and Simpson indices of dominance, evenness, and species diversity were measured using PAST 2.17 software. Statistical analyses were also performed in SPSS27 software. First, the normality of the data was checked using the Kolmogorov-Smirnov test, and then the paired t-test was used to compare changes in vegetation cover.
Results: The results showed that there was a significant difference between the number of species, percentage cover, dominance, Simpson and Shannon indices, evenness, and richness in the first and last years. On the other hand, there was a significant positive correlation between the rainfall in the months of January, February, March, and April and the average temperature of these four months and the diversity indices at the 1% level. A positive correlation was observed between the evenness index and rainfall, and a significant negative correlation was observed between the dominance index and rainfall at the 1% level.
Conclusion: The results of this study showed that there were significant differences between the number of species, percentage cover, dominance, Simpson, Shannon indices, evenness and richness in the first year (February 2021 to April 2022) and the final year (February 2022 to April 2023), and except for the evenness index, the differences were significant at the 1% level in other cases mentioned. On the other hand, there was a significant positive correlation at the 1% level between the rainfall in the months of January, February, March and April and the mean temperature during these four months and the diversity indices. Also, a positive correlation was observed between the evenness index and rainfall, and a significant negative correlation was observed between the dominance index and rainfall at the 1% level.
کلیدواژهها [English]
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