Phytogeography of the vascular páramo flora of Ramal de Guaramacal (Andes, Venezuela) and its ties to other páramo floras

Gerardo Aymard,Antoine M. Cleef,Nidia L. Cuello

doi:10.3989/ajbm.2253

Abstract

Cuello, N.L., Cleef, A.M. & Aymard, G. 2010. Phytogeography of the vascular paramo flora of Ramal de Guaramacal (Andes, Venezuela) and its ties to other paramo floras. Anales Jard. Bot. Madrid 67(2): 177-193. Ramal de Guaramacal is an outlier and lower elevation mountain range located at the northeastern end of the Venezuelan Andes. Phytogeographical patterns and affinities of the low altitude and wet vascular paramo flora of Ramal de Guaramacal, have been studied with emphasis in to the analysis of the floristic connections of the Guaramacal paramo flora with the neighboring dry paramos of the Sierra Nevada de Merida and other paramo floras of the northern Andes and Central America. A total of 252 vascular plant taxa belonging to 150 genera and 69 families were recorded from the study area. The most species rich families are Asteraceae, Poaceae, Ericaceae and Orchidaceae, followed by the ferns families Grammitidaceae and Lycopodiacae. The most diverse genera are the ferns Elaphoglossum, Huperzia and Hymenophyllum. The analysis of generic phytogeographical composition of paramo flora showed that 52.8% of the genera are Tropical. The Temperate component is represented by 33.3% of the genera and the Cosmopolitan component is represented by 13.9% of the genera. The Neo tropical montane element (38.9%) is high in Guaramacal paramo, the Paramo endemic element (1.9%) and the Andean alpine element (0.9%) and represented by only one genus (Lachemilla) are low compared to other paramo areas. The vascular flora of Paramo de Guaramacal is largely composed of (1) a group of Neotropical widespread distributed species (32%), (2) a group of Andean distributed species (49%), part of them confined to the Northern Andes and part widespread in the Andes from Colombia to Bolivia, and (3) a group of Venezuelan endemics (19%). From an eight paramo flora comparative dataset, the closest relationships among paramos is observed between the generic paramo floras of the Colombian Cordillera Oriental of Sumapaz and Sierra Nevada del Cocuy, which are both close

Highlights

Ramal de Guaramacal is an outlier and lower elevation mountain range located at the northeastern end of the Venezuelan Andes
The vascular flora of Páramo de Guaramacal is largely composed of (1) a group of Neotropical widespread distributed species (32%), (2) a group of Andean distributed species (49%), part of them confined to the Northern Andes and part widespread in the Andes from Colombia to Bolivia, and (3) a group of Venezuelan endemics (19%)
Páramo is the open equatorial alpine vegetation located above the upper forest line (UFL) and below the permanent snow line from the northern Andes to Panamá and Costa Rica

Summary

Introduction

Páramo is the open equatorial alpine vegetation located above the upper forest line (UFL) and below the permanent snow line from the northern Andes to Panamá and Costa Rica. Through the about 400 km southwest to northeast extension of the main Venezuelan Andean mountain chain, the Cordillera de Mérida, there is a wide range of páramo hydrological conditions, from dry páramos with 650 mm/year in a single rainy season, to permanently humid páramos with over 3000 mm distributed throughout the year (Monasterio & Reyes, 1980). The latter conditions characterize the páramo areas of Ramal de Guaramacal, an outlier and comparatively low elevation (3130 m) range located at the northeastern end of the Venezuelan Andes (Fig. 1)

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