Flora and vegetation of rocky outcrops/cliffs near the Hyrcanian forest timberline in the Mazandaran mountains, northern Iran

Abstract

Due to their numerous endemic/sub‐endemic and rare plant species, rocky outcrops and cliffs, particularly those occurring at the timberline and forest/steppe ecotones of the Hyrcanian area, are considered as among the most important and fragile ecosystems in Iran. As a representative of such ecosystems, one of the last remnants of relatively undisturbed timberline and ecotone areas of the central Hyrcanian region was selected for phytogeographical, floristic and vegetation analyses. The flora and vegetation of rocky outcrops and crevices at altitudes of 2500–3000 m a.s.l. was surveyed by 40 relevés of 25 m2 surface area. A total of 215 vascular plants belonging to 55 families and 150 genera were identified in the different vegetation types. Hemicrytophytes (55.8%) were the dominant life form and Euro–Siberian/Irano–Turanian biregional plants (28.2%) were the most common chorotype at the study sites. A phytogeographical analysis indicated that Euro–Siberian elements (including Hyrcanian endemics) precede other uniregional chorotypes in the timberline and upper‐mountain parts of the central Hyrcanian area. The Caucasus, an important biodiversity hotspot close to Iran, has a considerable number of taxa in common with the Irano–Turanian floristic regions. Five vegetation types were identified using a modified TWINSPAN procedure and subsequently analysed by indirect gradient analysis applying both species‐related (species richness, life form and phytogeographical elements) and topographic/bedrocks features of the studied relevés. The analysis revealed that the vegetation of the area is mainly affected by altitude, heat index, northness, slope inclination and bedrock features.

Sensitivity of Vegetation on Alpine and Subalpine Timberline in Qinling Mountains to Temperature Change

“…In ordinary circumstances, the temperature warming up in alpine timberline areas is reflected by the timberline rising to higher altitudes [28][29][30]. Johnston et al also highlighted climate warming in high-altitude mountains in his findings [31].…”

Comparative study of floristic diversity along altitude in the northern slope of the central Alborz Mountains, Iran

“…The locality of the Alborz between Hindu Kush-Himalaya Mountains in the east, and Anatolia and Caucasus Mountains in the west makes it so important and strategic in terms of historical, evolutionary, phytogeographical and biogeographical aspects (Noroozi et al 2008;Naqinezhad et al 2017). The Caucasus and Central Anatolian Mountains have been identified as the areas with a strong biogeographic connection with the Alborz (Noroozi 2008).…”

“…Although, the ecotones and alpine areas of the Alborz are naturally more protected comparing to the forests, but they supply a large amount of food capacity for cattle, so is highly under the pressure of sheep grazing mainly in last decades. Human and agricultural activities, livestock grazing, severe harvesting of endangered species for economic and ornamental purposes as well as the collection of medical plants are the main threats in the Hyrcanian forest (Naqinezhad et al 2017). On the other hand, overgrazing of the vegetation in the delicate sub-alpine and alpine areas caused destruction in vegetation, habitat and biodiversity loss and intensive reduction in space for endemic and narrow distributed species (Noroozi et al 2008).…”

Floristic Diversity and Distribution Patterns Along an Elevational Gradient in the Northern Part of the Ardabil Province Rangelands, Iran

“…The Moghan Plain-Sabalan Mountain rangelands (MPSMRs) in Ardabil province, Iran, supply livestock forage and play an essential role in food provision, groundwater enrichment, clean water production, wildlife, tourism, recreation, medicinal plant provision, beekeeping, and climate change mitigation (Ghorbani et al 2014(Ghorbani et al , 2017(Ghorbani et al , 2018Nazari Anbaran et al 2016;Ghafari et al 2017Ghafari et al , 2018. According to the literature, 396 plant taxa have been identified in the area.…”