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Abstract Detail


Ecological Section

Diazgranados, Mauricio [1].

Climate change and predicted geographic distribution of frailejones species (subtribe Espeletiinae, Asteraceae) in the neotropical Andes.

The páramo of the South American Andes, characterized by grasslands and the dominance of plants with stemmed rosettes (known as frailejones species), is the most diverse ecosystem of the high elevations worldwide. There are 145 species of frailejones, classified within the endemic monophyletic subtribe Espeletiinae Cuatrec. (family Asteraceae). I wanted to know if climate change will affect significantly the species geographic distributions (SGDs) of frailejones? Some authors have predicted for 2050 that the rise of temperatures (2-3ºC) and increased rainfall will cause a considerable shift of the inferior limit of the páramos, which will be 400 meters higher than the present, with complete loss of some localities and a substantial reduction in the total area of this ecosystem. Hence, I tested the hypothesis that there are statistical differences between SGDs under current (1960-1990) and future (year 2050) conditions. To model the frailejones SGDs I built an exhaustive database of herbarium specimens and field collections (~7500 entries), including all extant species. Most of the collection localities were geo-referenced and mapped with ArcGIS 9.2. Environmental data from WorldClim (19 bioclimatic variables and elevation, 30 arc-seconds of resolution, years 1960-1990 and 2xCO2-CCM3 scenario for 2050) were analyzed, excluding redundant and co-linear variables. For all the species with more than 15 collections geo-referenced I modeled SGDs with the Maxent algorithm. The extent of the SGDs was determined based on the minimum training value given by the algorithm. I tested statistically if there were significant differences in total area, number of fragments, fractal dimension and overlapping areas of SGDs between both scenarios. The results showed significant differences between current and future SGDs, suggesting that climate change will have a significant impact on the geographic distribution and conservation of these species, probably driving several taxa to extinction.


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1 - Saint Louis University, Department of Biology, 3507 Laclede Ave., Macelwane Lab 231, St. Louis, Missouri, 63103-2010, United States of America

Keywords:
bioclimatic niche analysis
climate change
Espeletia
frailejones
northern Andes
subtribe Espeletiinae.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM
Number: PEC017
Abstract ID:305


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