Abstract Detail

Plant Research and Conservation on the Andes

Rada, Fermin [1].

Functional diversity in different plant life-forms of the tropical high Andes.

Tropical high mountain environments are characterized by strong daily temperature variations (Freezing nighttime and high daytime temperatures throughout the year), seasonal water availability and high daily evaporative demands. The “paramos” are tropical Andean ecosystems composed mainly of low strata vegetation dominated by particular life forms such as the giant rosettes, sclerophyllous shrubs and tussock grasses while at higher elevations acaulescent rosettes and cushion plants increase their presence. Paramos are bounded by the natural continuous forests or cloud forests at approximately 3000 m and permanent snow caps above 4800 m above sea level. The study of these ecosystems is essential because they present the highest floristic diversity and the largest number of endemic species of mountains worldwide. During the past three decades our objective has been to study plant adaptive strategies with the aim of understanding functional diversity in terms of low temperature resistance (LTR), water relations and leaf gas exchange characteristics in different life-forms along elevational and water availability gradients. These studies include trees (32 spp), shrubs (8 spp), giant rosettes (10 spp), acaulescent rosettes (6 spp), other forbs (18 spp), grasses including woody grasses (21 spp) and cushion plants (4 spp) along elevational gradients (2600-4500 m) and contrasting wet and dry seasons. The different life-forms may be separated according to their avoidance-tolerance ability to respond to thermal and water stresses. In general, woody life-forms tend to rely on avoidance while herbaceous on tolerance mechanisms. Very characteristic patterns have been found in terms of LTR with most woody life-forms relying on avoidance of freezing mainly through an increased supercooling capacity, while most herbaceous species depend on freezing tolerance to survive. With respect to water stress, herbaceous plants tend to be more tolerant with grasses and cushion plants as the most resistant, reaching the highest elevations in the paramo. Giant rosettes are a classic example of a life-form which has been particularly successful establishing in high mountain environments through the evolution and integration of very unique adaptations which are discussed in detail. Having a clearer picture of plant function in the Andes, our next step is to recognize possible plant responses and distribution patterns under current changing environmental conditions of high tropical mountains.

Related Links:
http://www.ciencias.ula.ve/icae

1 - Universidad de Los Andes, Instituto de Ciencias Ambientales y Ecologicas (ICAE), Facultad de Ciencias, Nucleo La Hechicera, Merida, Merida, 5101, Venezuela

Keywords:
Giant rosettes
Freezing resistance
water relations
Gas exchange
Plant life forms
Venezuelan Andes.

Presentation Type: Symposium Presentation
Session: SY06, Plant Research and Conservation on the Andes
Location: Chatham Ballroom - C/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 8:45 AM
Number: SY06003
Abstract ID:942
Candidate for Awards:None