Title
Branchfall as a demographic filter for epiphyte communities: Lessons from forest floor-based sampling
Date Issued
17 June 2015
Access level
open access
Resource Type
journal article
Author(s)
University of Oldenburg
Publisher(s)
Public Library of Science
Abstract
Local variation in the abundance and richness of vascular epiphytes is often attributed to environmental characteristics such as substrate and microclimate. Less is known, however, about the impacts of tree and branch turnover on epiphyte communities. To address this issue, we surveyed branches and epiphytes found on the forest floor in 96 transects in two forests (Atlantic rainforest in Brazil and Caribbean rainforest in Panama). In the Brazilian forest, we additionally distinguished between edge and core study sites. We quantified branch abundance, epiphyte abundance, richness and proportion of adults to investigate the trends of these variables over branch diameter. Branches <2 cm in diameter comprised >90% of all branches on the forest floor. Abundance and richness of fallen epiphytes per transect were highest in the Brazilian core transects and lowest in the Panamanian transects. The majority of epiphytes on the floor (c. 65%) were found attached to branches. At all three study sites, branch abundance and branch diameter were negatively correlated, whereas epiphyte abundance and richness per branch, as well as the proportion of adults were positively correlated with branch diameter. The relationship between branch diameter and absolute epiphyte abundance or richness differed between study sites, which might be explained by differences in forest structure and dynamics. In the Panamanian forest, epiphytes had been previously inventoried, allowing an evaluation of our surveying method by comparing canopy and forest floor samplings. Individuals found on the forest floor corresponded to 13% of all individuals on branches <10 cm in diameter (including crowns), with abundance, richness and composition trends on forest floor reflecting canopy trends. We argue that forest floor surveys provide useful floristic and, most notably, demographic information particularly on epiphytes occurring on the thinnest branches, which are least accessible. Here, branchfall acts as an important demographic filter structuring epiphyte communities. Copyright:
Volume
10
Issue
6
Language
English
OCDE Knowledge area
Conservación de la Biodiversidad
Ecología
Scopus EID
2-s2.0-84939226965
PubMed ID
Source
PLoS ONE
ISSN of the container
19326203
Sponsor(s)
Field work in the Brazilian study sites was supported by the Federal University of Pernambuco, which has a research agreement with the landholding that owns the forest fragments. The permit for the Panamanian study site was obtained from the Panamanian Environmental Agency (ANAM) via Smithsonian Tropical Research Institute (STRI). Field work was done for four weeks in each country: July 2012 (Brazil) and in September/October 2012 (Panama). The surveyed period coincided with the second half of the rainy season in each forest, and thus we were able to sample branches freshly broken due to heavy storms. This was important, as fallen epiphytes may die within a few months after branchfall, but can live up to a year
Sources of information:
Directorio de Producción Científica
Scopus