Iranian Journal of Applied Ecology

Knowledge about plant communities and their relationships with ecological factors is one of the most important issues in conservation ecology particularly in the recent decades. The current investigation aimed to study the vegetation ecology of Palangan habitat in Aghdagh Protected area, Ardabil province. In order to collect species and environmental data, a total of 45 plots along a 1500 m elevational gradient and an interval of 100 m were surveyed. Braun-Blanquet scales were used to evaluate vegetion cover of each plot. Floristic and ecological characteristics of the area were studied along elevational gradient using DCA ordination and TWINSPAN classification methods. Four vegetation groups detremined in TWINSPAN were also identified in the DCA diagram and their species and environmnetal characters have been evalyated by one-way ANOVA. Based on these anlayses, altitude and slope were the most important ecological factors affecting the vegetation of the area. Endemicity values are not significatly changed among different altitudinal belts, but in stead, the number of therophytes and plants with wide distributional ranges are significam,ty different along elevation. The relatiohsip between altitude and species richness, like to other mountainus systems, show almost unimodal pattern which peaks at 1800 m.

The knowledge of rangeland vegetation types and factors influencing on their establishment and stability is essential for sustainable management and regeneration of rangeland areas. With this aim, Gonbad watershed, due to different vegetation types, environmental conditions and grazing managements was studied. The watershed was stratified to homogenous units based on morphology of vegetation types and environmental factors. Land properties, total canopy and canopy of the main five vegetation forms (annual grasses, perennial grasses, annual forbs, perennial forbs, and shrubs) were determined in 3 to 4 plots (1 x 1 m²) in each unit; plant and surface soil were sampled. Using TWINSPAN method, Silen sp., Centaura virgate, Astragalus verus and Cousinia bijarensis were identified as indicator species. DCA analysis subdivided the watershed into six ecological groups based on indicator plant species, production of perennial grasses and environmental factors, such as percent of sand and clay, and slope aspect. Based on the analysis of indicator species Asteragalus gossypinus (p= 0.001), Taeniatherum crinitum (p= 0.002) and Heteranthelium piliferum (p= 0.007) classified the vegetation cover into three main groups. Silen sp., Astragalus gossypinus, Centaurea virgat, Artemisa siberi, and Festuca ovina represent mountainous steppe and semi-steppe ecological environments. These deep rooting species are resistant to dry conditions. Therefore, ecological