Guidelines for collecting demographic data for population dynamics studies on vascular epiphytes

MONDRAGON, D. (Centro Interdisciplinario de Investigacion para el Desarrollo Integral Regional (CIIDIR) Unidad Oaxaca, Calle Hornos Num. 1003. Santa Cruz Xoxocotlan, Oaxaca, Mexico). Guidelines for Collecting Demographic Data for Population Dynamics Studies on Vascular Epiphytes. J. Torrey Bot. Soc. 138: 327-335. 2011.-Population dynamics studies allow us to address three of the most basic questions essential to the creation of plans for species management and conservation. Specifically: what the population status is; what the stages or demographic processes that have the greatest impact on the population growth rate (lambda) are; and what the probabilities of quasi-extinction for the species of interest are. Despite the importance of this type of research, demographic studies on vascular epiphytes are scarce. Epiphytes are key elements in the functioning of the ecosystems in which they live, as they enhance biodiversity, establish numerous interactions with other plants and animals, and are direct participants in the flow of nutrients and water. In spite of the importance of this group, population dynamics studies have only been performed on 2 of the 83 families of epiphytes. The three main challenges for field research are the difficulty of accessing epiphytes in their native environments, the combination of the vertical and horizontal distribution of these species, and the additional consideration of addressing the effects of phorophyte dynamics on epiphyte populations. This paper is designed to be the practical complement to a theoretical background in the population dynamics of epiphytes. It addresses both study design and practical issues of field work in the interest of encouraging the development of demographic studies of this form of life.