Abstract
Classification of species in plant functional types (PFTs) according to Grime’s CSR theory has been found useful in understanding ecosystem functioning and processes and in quantifying variation along environmental gradients. The aim of this study was to assess variations in CSR strategies along stress and grazing gradients in Meyghan playa of Arak. The strategy of plant species was determined according to the Grime’s CSR strategies, based on Pierce’s method. Random- Systematic design was applied to sampling. Two-way indicator species analysis (TWINSPAN) was applied to classification of the ecological plant groups, and partial canonical correspondence analysis (pCCA) was used to identify relationship between environment factors, disturbance and the plant groups studied, using the PC-ORD4.17 and CANOCO4.5 software, respectively. Among the factors that affect plant functional types and the structure of vegetation, soil salinity as a stress factor and grazing as a kind of disturbance were studied. Results showed that stress-tolerant peaked in conditions of high salinity. Competitors with a frequency of 14.3% were mostly present in conditions of low salinity and disturbance/light grazing. Ruderals with a frequency of 7.1% were mostly present in condition of overgrazing. The presences of competitor in protected areas with low soil salinity confirmed the theory of appearance of competitive strategy in low/stress-free areas and light/graze-free. Therefore, it may be possible to use Grimes’s PFTs for assessing environmental constraints and predicting whether a species with a specific strategy is likely to be positively or negatively affected by changes in environmental stress due, for instance, to climate change.
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