Samaneh Sadat Mahzooni Kachapi; Pejman Tahmasebi; Ataollah Ebrahimi; Mohammad hasan Jouri; Mohsen Faal; Reza Omidipour
Abstract
Ecological processes at different scales led to heterogeneity in the landscape by changing the pattern of the landscape structure. These would result in fragmentation and disintegration of landscape structures and filtering biodiversity characteristics such as species functional diversity. We performed ...
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Ecological processes at different scales led to heterogeneity in the landscape by changing the pattern of the landscape structure. These would result in fragmentation and disintegration of landscape structures and filtering biodiversity characteristics such as species functional diversity. We performed this study to quantify the patches and classes characteristics of the landscape (metrics) and their impact on indicators of species and functional diversity. Sampling was performed in a semi-steppe rangelands of Chaharmahal and Bakhtiari, where the natural structure of the landscape creates various patches such that classified in seven different classes of plant communities. In each class, different patches were randomly selected and within them 5 to 10 macroplots of 30 * 30 m were randomly-systematically established. Afterwards, 3 plots of 2 * 2 m2 installed in macroplots in order to sample canopy cover and number of species. Taxonomic, functional diversity and functional beta diversity indices were measured using "Vegan", "FD" and "betapart" statistical packages in R software, respectively. The landscape metrics were also measured using Fragstats software. Finally, the relationships between diversity indices and landscape metrics were analyzed using linear regression. The results at the patch level showed a significant negative relationship between the shape and functional diversity indices such as leaf nitrogen weight average and leaf specific surface area weight average. The results at the class level indicate the positive effect of the functional evenness index on the edge density metric as well as the functional beta diversity of the patch richness metric.
Ali Mohammadian; Esmaeil Asadi Borujeni; Ataollah Ebrahimi; Pejman Tahmasebi; Ali Asghar Naghipour borj
Abstract
Nowadays, using satellite imagery is one of the fastest and lowest-cost methods in rangeland assessment. Also, remote sensing-based vegetation indices are among the most widely used tools to assess and monitor vegetation changes, especially in the post-fire period, and to map the burned regions in rangelands. ...
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Nowadays, using satellite imagery is one of the fastest and lowest-cost methods in rangeland assessment. Also, remote sensing-based vegetation indices are among the most widely used tools to assess and monitor vegetation changes, especially in the post-fire period, and to map the burned regions in rangelands. The present study was conducted considering the importance and extent of rangelands and the recently increased prevalence of fires in the semi-steppe rangelands of Iran, especially in Chaharmahal and Bakhtiari Province. The main objective of this study was to distinguish and identify the burned areas during 1-3 year and 3-5 year periods to adopt an appropriate post-fire management program in these areas using spectral indices. After calculating the spectral indices, the M statistical parameter was determined to designate the separation capability of the burned areas from the adjacent ones. According to the findings, using NBRT, NBR, and CSI indices is recommended to identify and distinguish the burned areas 1-3 years after the fire from the adjacent areas in semi-steppe rangeland regions of Iran. Overall, these indices are of high efficiency in separating these ranges. Moreover, T.C. Brightness and NBRT indices can efficiently identify and separate the burned areas 3-5 years after the fire. Among the studied indices for both periods of fire in the studied semi-steppe rangelands, the NBRT index showed a high potential for identifying the burned area from the adjacent areas.