Classification of VEGETATION according to their SPECIES composition is one of the most important tasks in the application of remote sensing in precision agriculture. To prepare an algorithm for such a mandate, there is a need for ground truth. Field operation is very costly and time consuming. Therefore, some other method must be developed, such as extracting information from the satellite images, which is comparatively cheaper and faster. In this study, we first introduced a simple method for Determination of the VEGETATION Specie in full cover pixels (DVS) using their laboratory measured spectral reflectance curves. Then, based on these pixels, a hybrid method for VEGETATION field classification, which we call SCANN (Spectral Characteristics and Artificial Neural Network), is introduced. In this method, different VEGETATION spectral reflectance characteristics at the three extremes of green, red, and near-infrared along with an artificial neural network method were used. Comparing the results of DVS with those of field collected data showed near 100% accuracy. Based on the results of DVS, the results of SCANN showed an overall accuracy of more than 94%. This method is suggested for unsupervised classification using Hyperspectral images.

The VEGETATION ordination and classification based on conservatism SPECIES can be better able to analyze the ecological relationships between VEGETATION and environmental factors. This study aimed to investigate changes in herb layer VEGETATION of Quercus brantii, Q infectoria, and Pyrus glabra forest types based on conservatism SPECIES, at different environmental factors. Tree and herb layer was surveyed using 24 main plots (500m2) and 3 sub-plots (4m2) randomly distributed in each main plots, respectively. Crown canopy, physiographic features, and some edaphic factors were measured in each main plot. SPECIES richness and SPECIES frequency were recorded in sub-plots as an abundance index. The relation between environmental factors and herb layer dynamic were investigated by ordination (CCA, PCA & DCA) and classification (TWINSPAN) methods after determining conservatism SPECIES. Based on the results of ordination and classification, herbaceous layer in Q. brantii type was significantly different in SPECIES composition and physiographic and edaphic factors from Q. infectoria and P. glabra types. Herbaceous layer in Q. brantii type showed a positive correlation with high levels of nutrients and the effective main components were OC, N, K, sand, altitude, and saturated humidity in top soil. The Q. infectoria and P. glabra types were observed in calcareous and heavy soils low elevation with nutrients deficiency. The herbaceous layer and soil in Q. brantii type seems to be more evolved due to climax tree layer.

The study was carried out in the Ilam Oak forest that is located in the west part of Iran. The objective of this research was to determine the plant ecological groups and site classification in this region. Data were collected from 117 sample plots using the systematic-random sampling method. The size of sampling plots was 20 m×20 m for the tree and shrub SPECIES and 1.5 m ×1.5 m for herbaceous SPECIES. Whittaker’s nested plot method was used in order to record the herbaceous SPECIES. Soil samples were collected and analyzed to study soil properties. Multivariate analysis methods were used to classify and determine the relationship between SPECIES composition and environmental factors and to recognize ecological SPECIES groups. PCORD and SPSS software were used for data analyzing. Five ecological groups were specified in the study area. Cerasus microcarpa was the indicator SPECIES in the first group, which showed high correlation with carbon and nitrogen. Quercus brantii showed the strongest correlation with CaCO3. The third group was Acer monspessulanum. Elevation and clay were the most important factors that separated this group. Amygdalus orientalis showed high correlation with elevation. These two above mentioned groups were located in higher altitude. Astragalus liyciodes was the indicator SPECIES in another distinct group in the study region with high level of stoniness percentage. Astragalus group was observed where soil stoniness was high. Results also showed that groups at higher elevation showed lower richness.

Soil seed bank is an important part of plant diversity but little is known about its structure and dynamics. Soil seed bank size and composition like standing VEGETATION cab be influenced by environmental factors and management. Knowledge of soil seed bank and its changes can be important for conservation, restoration, and management of rangelands. In this study SPECIES composition in both VEGETATION and soil seed bank were identified for two rangelands (scrubland and shrubland) in Firoz Abad in Fars province. Soil seed bank size and composition was determined by soil sampling and seed germination in glasshouse. Results of this study showed that a total of 76 SPECIES were in both VEGETATION and soil seed bank but most of them were either unique to the seed bank or VEGETATION. We found only five SPECIES common in both. SPECIES richness in standing VEGETATION was more than that in soil seed bank. Greater number of seeds germinated from upper layer of soil (5 cm). There was no similarity between VEGETATION and soil seed bank in both VEGETATION types, thus management needs to take in account both source of SPECIES.

The aim of this study was to assess the effects of forest logging on VEGETATION characteristics in forest of Shafaroud, Guilan. To do this, two regions, cultivated and control regions, with identical physiographical conditions were selected at Series 9 of Shafaroud forest. In each region, 25 main plots and in each of them, 4 sub-main plots were used in sampling to record the data on the VEGETATION. Also, soil samples were taken from center of each plot to measure tissue, bulk density, particle density, porosity, acidity of the soil and to analyze its nitrogen, phosphorus, organic matter, calcium, magnesium and sodium. After determining the plots centers, the VEGETATION sampling was done twice (one and five years after logging) in the cultivated region. The results showed that the control region had higher diversity and richness than the cultivated one. But the SPECIES dominance was lower in the control region. The Jaccard similarity index showed that the regions of control and 5-year after logging, have the most VEGETATION similarity compared with the others. Finally, the results suggest that the plant SPECIES concentration tends to be higher in the regions with high amounts of N, P, organic matter and soil porosity.

ABSTRACT Today, climate change and its obvious negative effects on ecosystems have caused concern. This research seeks to test whether VEGETATION changes are sensitive to climate shocks and also how the ecosystem recovery process is through this index. In this regard, by using the GEE platform, Java coding, GIS and statistical analysis, VEGETATION and Palmer indices were calculated and based on time series climate data, VEGETATION and climate changes were presented. The results of Palmer's drought index show that during the statistical period (1985-2020) the study area is facing drought or is moving towards drought. Also, the results indicate the longest period of drought in the region from 2013 to 2020. Totaly from 420 evaluated months, the NDVI index is below the change threshold in 70 months. Among these, 31 months of the study period is below the acceptable threshold in green and non-reservoir seasons, which is ecologically worrying. The distribution of the VEGETATION index based on hexagons in 1985 and 2005 had a normal and almost normal distribution; But in 2020, the graph deviated from the normal state and skewed towards the VEGETATION cover index under stress or even thin covers. According to the analysis of the indicators, it is predicted that the Gorgan region is on the border of such ecological developments and the historical ecosystem of the region is moving towards new ecosystems or being in a new equilibrium state with climatic conditions and human disturbances Extended Abstract Introduction Today, climate change and its obvious negative effects on terrestrial ecosystems have caused great concern to humans. These changes are effective on VEGETATION performance, plant distribution patterns, and have economic and environmental consequences. Therefore, it is important to know the behavioral pattern of VEGETATION changes against climate changes. Reviewing the studies of scientists in the world shows many researchers have used the NDVI index to study temporal and spatial changes in VEGETATION and its relationship with the climatic index of precipitation in different parts of the world. Studies have shown that NDVI follows precipitation with different time scales. Surveys showed that there are very few studies on determining the threshold of changes in the VEGETATION cover index in the face of climate shocks. Determining these thresholds can provide a suitable solution for evaluating the state of the ecosystem, the consequences of climate shocks and the reversibility or disturbance in the ecosystem. This study was conducted with the aim of improving our understanding of the dynamics of VEGETATION in the forest city of Gorgan during 1985-2020 against climatic stresses.   Methodology The current research is a comparative and monitoring research and seeks to test whether changes in VEGETATION cover are sensitive to climate shocks and also how the ecosystem recovery process is through this index. To achieve the gole, first, NDVI index was selected among the optimal VEGETATION indices and its calculation process was done as a time series in the GEE system. In parallel with those climate shocks, the main elements including temperature, precipitation and storm were calculated during the historical process of 35 years and the average and standard deviation statistical indicators were calculated for them and the trend of changes in the thresholds was determined. The results of climate plots and climate changes show that in the years before 1985, 2005 and 2020, drastic changes have occurred in climatic elements and climatic factors. Therefore, these years can be considered as the periods when the climate shock happened.. Next, the region was divided into 436 hexagons and the NDVI index for each of the hexagons was calculated and modeled for the years 1985, 2005 and 2020 as selected years affected by climate shocks. In conclusion, to analyze the trend of changes in the time series of the VEGETATION index and compare the behavior of its changes with climatic indices, the Palmer index was calculated.   Results and discussion The results of climate change monitoring based on the Palmer index showed that during the statistical period the study area is facing drought in most years. The most severe climatic fluctuations and drought in the region were recorded in 2018 and in the months of October to December. The longest period of drought has also prevailed in the region from 2013 to 2020. During this period, rainfall, temperature and storm fluctuations have the most changes. The results of drought monitoring show that in 270 months, the region is facing climatic drought stress, 57 months of the study period, the region is facing severe and very severe drought stress. The results of the time series of the NDVI VEGETATION index showed that, out of the 420 evaluated months, 70 months of the year the NDVI index is below the change threshold, 31 of which are in the green and non-accumulating seasons, the seasons when the VEGETATION is expected to be at its maximum. Placing below the acceptable range means crossing the ecological thresholds and challenges the recovery and restoration of the ecosystem, also the ecological performance will be affected at this point. Based on the assessment of the Palmer index, from 2014 to 2019, the situation of the Palmer index is in the extreme drought range. Also, since 2015, i.e. with a one-year time delay, NDVI index has experienced the lower limit of the equilibrium threshold of VEGETATION cover. These conditions are also valid for the years 2008, 2009, 2002 and 1997. In general, it can be said that the VEGETATION cover index is dependent on climatic changes and fluctuations and shows high sensitivity to changes. The important point in this section is that in the years when the NDVI index changes are at the lower limit of the threshold, we witness the most climate shocks and temperature changes, the occurrence of severe storms and precipitation fluctuations. The distribution of the VEGETATION index based on hexagons in 1985 and 2005 have a normal distribution; but in 2020, the graph has deviated from the normal state and skewed towards the VEGETATION cover index under stress or even thin covers. The visual interpretation done on the VEGETATION cover index in 1985 confirms the condition of the VEGETATION cover in the southern and western limits of the region in a state with suitable dense and pasture VEGETATION and forest cover on the edges. However, in 2005 and 2020, this cover has been changed and mainly turned into agricultural land and poor rangeland. In such a way that in 2020, the situation of the region has revealed the critical state of VEGETATION. The VEGETATION cover index in the central areas of the city has also reached from a relatively favorable situation in 1985 to a critical situation with almost no dense and stress-free VEGETATION cover in 2020. The results of the present studies are consistent with the studies of Visentr Serrano et al. in 2013 and confirm the relationship between NDVI VEGETATION and climate change. In addition, the results of the studies are consistent with the studies of Alwesabi 2012, Xiai & Moody, 2005 and Yan et al. 2001. In such a way that the present study and the aforementioned studies all confirm the influence of the VEGETATION index on climate fluctuations and precipitation with a one-year time difference.       Conclusion In general, the threshold is defined as a border with different conditions. After crossing the thresholds, the stability and positioning of the NDVI in the equilibrium range is often difficult, and the ecosystem is constantly spending energy to restore itself or to position itself in a new stability state. The result of the mentioned disorders is the reduction of resilience and resistance in the region, which leads the ecosystem to alternative states or crossing the threshold or being in a new equilibrium state. The results showed that the areas where green VEGETATION is concentrated and denser are less affected by climatic stresses and show more resilience. However, the areas that have become spots and islands due to destruction in the urban areas are more affected by climatic stress and destruction and show less tolerance against the destruction factors. The results help managers to focus their management plans for the preservation and maintenance of urban green spaces as well as forest and pasture ecotones on the edge of the city by knowing the thresholds.   Funding There is no funding support.   Authors’ Contribution Authors contributed equally to the conceptualization and writing of the article. All of the authors approved thecontent of the manuscript and agreed on all aspects of the work declaration of competing interest none.   Conflict of Interest Authors declared no conflict of interest.   Acknowledgments  We are grateful to all the scientific consultants of this paper.

Mansourieh and Sharifieh are two recently dried wetlands in Khuzestan province, that have become important dust sources. This study was carried out in Sharifieh and Mansourieh wetlands to assess the VEGETATION condition and trend, following the implementation of water spreading and artificial recharge in recent years. To evaluate changes in VEGETATION, five transects of 100 meters, 50 meters apart, were established in the water spreading site in a random systematic manner, and data was collected from 30 permanent plots for six times between 2017-2019. SPECIES richness and diversity indices were measured using the coverage percentage factor. The results obtained in Mansourieh showed a significant difference between the water spreading site and the non-irrigated site. Simpson and Shannon indices showed a gradual increase in SPECIES diversity following the implementation of flood spreading by means of Shahid Poursharifi Channel. Likewise, in Sharifieh wetland, Shannon and Simpson diversity indices improved in response to the enhancement of SPECIES richness and decreasing dominance (from two dominant SPECIES to over 20 SPECIES). In Sharifieh, we obtained a significant difference between the years 2017 and 2018 in terms of diversity indices. In general, the flood spreading areas will experience an improvement in native VEGETATION, which will be translated into reduced dusts storm frequency and severity.