Folia Geobotanica

, Volume 48, Issue 1, pp 7–22

Species Diversity and Life-Form Patterns in Steppe Vegetation along a 3000 m Altitudinal Gradient in the Alborz Mountains, Iran

  • Parastoo Mahdavi
  • Hossein Akhani
  • Eddy Van der Maarel
Article

DOI: 10.1007/s12224-012-9133-1

Cite this article as:
Mahdavi, P., Akhani, H. & Van der Maarel, E. Folia Geobot (2013) 48: 7. doi:10.1007/s12224-012-9133-1

Abstract

Biodiversity pattern and life-form spectra were studied along a 3,000 m altitudinal gradient from a semi-desert area to the alpine peak of Tochal Mountain. The gradient is located on the southern slopes of Central Alborz with a Mediterranean continental climate. DCA ordination was applied to 1,069 relevés and 7 quantitative variables to discover the relation of diversity and altitude. A biodiversity pattern was obtained by relating values for species richness and Shannon-Wiener’s index to 100-m altitudinal sections. Altitude was determined as the major ecological gradient. Both diversity indices are negatively correlated with altitude and show a decreasing trend beyond a peak in species richness at 1,800–1,900 m a.s.l. towards a very low diversity in the high alpine zone. The biodiversity peak does not match with the potential tree line in the area (2,500–3,000 m a.s.l.). The high diversity in foothills can be related to habitat heterogeneity, longer suitable climatic conditions, and diverse disturbance factors, while unfavorable conditions at high-altitude alpine and low-altitude desert areas reduce the number of species at both extremes. Life-form patterns clearly change along altitudinal gradient. Annuals with decreasing trend, and hemicryptophytes and chamaephytes with increasing trend along the altitudinal gradient are notable patterns of life form in the area. Temperature, soil moisture and nutrients are the main factors that explain the ecological influence of altitude on species diversity and life-form patterns in the semi-arid steppe vegetation of the area.

Keywords

Altitudinal gradientBiodiversity patternCentral AlborzDCA ordinationLife formSteppe vegetation

Supplementary material

12224_2012_9133_MOESM1_ESM.pdf (43 kb)
ESM 1(PDF 43 kb)

Copyright information

© Institute of Botany, Academy of Sciences of the Czech Republic 2012

Authors and Affiliations

  • Parastoo Mahdavi
    • 1
  • Hossein Akhani
    • 1
  • Eddy Van der Maarel
    • 2
  1. 1.Department of Plant Sciences, School of BiologyUniversity of TehranTehranIran
  2. 2.Community and Conservation Ecology GroupUniversity of GroningenGroningenThe Netherlands