Oecologia

, Volume 38, Issue 1, pp 71–82

Morphological and physiological correlates of niche breadth in two species of Espeletia (Compositae) in the Venezuelan Andes

  • Zdravko Baruch
  • Alan P. Smith
Article

DOI: 10.1007/BF00347825

Cite this article as:
Baruch, Z. & Smith, A.P. Oecologia (1979) 38: 71. doi:10.1007/BF00347825

Summary

We compared adaptive strategies in two plants of Venezuelan páramos (alpine areas): the widely distributed, caulescent, and pubescent Espeletia schultzii Wedd. with the acaulescent, nearly glabrous E. atropurpurea A.C. Smith which is restricted to mesic sites just above treeline. Both species occur together at 3,450 m, near treeline.

Physiologically, E. schultzii was more drought resistant than E. atropurpurea, and was better adapted for carbon dioxide fixation under low temperatures. The densely pubescent leaves of E. schultzii are highly reflective; this increases the intensity of light needed for photosynthetic saturation and influences leaf temperature. Leaf pubescence may reduce the level of insect predation.

Measurements of leaf productivity indicate higher values for E. atropurpurea during the rainy season and higher values for E. schultzii during the dry season. However, annual values of leaf productivity are similar for both species.

Benefits of specialization in E. atropurpurea include reduced costs for stem and leaf hair production, higher growth rates during the rainy season and the ability to grow beneath canopies of some larger arborescent species. Costs of specialization include lower growth rates during the dry season, great susceptibility to insect predation and restriction to low elevation, mesic sites.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag 1979

Authors and Affiliations

  • Zdravko Baruch
    • 1
  • Alan P. Smith
    • 2
    • 3
  1. 1.Dpt. Estudios AmbientalesUniversidad Simon BolivarCaracasVenezuela
  2. 2.Smithsonian Tropical Research InstituteBalboaCanal Zone, Panama
  3. 3.Department of BiologyUniversity of PennsylvaniaPhiladelphiaUSA

Personalised recommendations