The páramo vegetation of Ramal de Guaramacal, Venezuela. 2. Azonal vegetation - Cuello & Cleef 2009

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Phytocoenologia, 39 (4), 389–409 Berlin – Stuttgart, December 30, 2009

The páramo vegetation of Ramal de Guaramacal, Trujillo State, Venezuela. 2. Azonal vegetation. by Nidia L. CUELLO A., Guanare, Venezuela and Antoine M. CLEEF, Amsterdam, The Netherlands with 8 figures, 4 photographs and 5 tables Abstract. The azonal páramo vegetation present at the top of Ramal de Guaramacal in the Venezuelan Andes was studied by means of observations, plant collections and surveys consisting of a total of 71 small plots of between 0.25 to 6 m2. Azonal vegetation is represented in the study area by habitats experiencing water stress (peat bogs and aquatic vegetation). The azonal vegetation present in two peat bogs areas of Páramo El Pumar (Laguna El Pumar y Laguna Seca), and in a small valley where water collects in Páramo de Guaramacal, near the ‘Las Antenas’ area between ~2900 and ~3000 m were analyzed. A total of 53 morphospecies, belonging to 30 species of vascular plants, 20 species of cryptogams and 3 undetermined species of algae have been documented for the azonal vegetation. The interpretation of a TWINSPAN clustering, based on affinities of floristic composition and species cover, allowed the recognition of six azonal vegetation communities grouped into three alliances and one order. The new alliance Sphagno recurvi–Paepalanthion pil o si groups the new bunchgrass páramo association P a e p a l a n t h o pilo si–Ag rostietum basalis and the both new Sphagnum bog associations: S p h a g n o re c u rv i – C a ri c e t u m bo n plandii and Sphagno sparsi–Caricet u m b o n p l a n d i i . The new alliance C a ri c i b o n p l a n d i i – C h u sq u e io n angustifolia contains a bamboo páramo (‘chuscal’) association C a ri c i b o n p l a n d i i – C h u sq u e e t u m a ng u s tifoliae growing close to the lake shores, in periodically flooded areas, and characterized almost exclusively by Chusquea angustifolia. The alliance Dist ri c h o su b m e rsi – Iso ë t i o n Cleef 1981 is represented by the submerged aquatic community of Sphagnum cuspidatum and the Iso ë t e t u m k a rst e n i i Cleef 1981. Keywords: floristic composition, phytosociology, azonal páramo vegetation, Sphagnum, peat bog, Isoëtes, bamboo páramo, Chusquea, Andes, Venezuela. eschweizerbartxxx ingenta

Introduction The azonal páramo vegetation in Guaramacal was studied between 2870 and 3050 m, mainly in two peat bog areas of the Sector Páramo El Pumar (Laguna El Pumar and Laguna Seca). Azonal patches are also present in the small valleys or depressions where water collects in Páramo de Guaramacal, near the ‘Las Antenas’ area. Peat bogs associated with glacial and seasonal lakes or fluvio-glacial valleys are common features in Andean and Costa Rican páramos. A great variety of azonal bog vegetation communities associated with glacial lakes and terrain depressions have been described and named from the Colombian (Cleef 1981, Sanchez & Rangel 1990, Cleef et al. 2005, 2008, Rangel et al. 2006 among others) and Costa Rican páramos (Brak et al. 2005). A low number of diverse aquatic and peat bog vegetation communities have been reported for Venezuelan páramos (Vareschi 1955, 1980; Monasterio 1980, Bono 1996, Berg 1998, Berg & Suchi 2001) with only a few of them treated in a syntaxonomic context of the upper páramo vegetation of Sierra Nevada de Mérida (Berg, 1998). Vareschi (1955) described an association (‘S p h ag ne tum m a g he l l a n i c i ’) from Naiguatá between 2500–2700 m. DOI: 10.1127/0340 – 269X/2009/0039– 0389

As mentioned before Sphagnum bogs are present in the equatorial Andes and the Central American Talamancas; up to date, they are not classified at the level of order and class. Other bogs and mires which have been described for the northern Andes concern vascular cushion bogs (P lantagini rigidaeDistich ietea muscoides Rivas Martínez & Tovar 1982) and cyperaceous reedswamps (Galio canescen tis-Gratio lio n bo gotensis Cleef 1981), grass mires (Calamagrostion ligulatae Cleef 1981), both belonging to the order M archantio plicataeEp ilo b ietalia d enticu latae Cleef 1981. Other azonal aquatic vegetation includes flush communities (Xen o p h y llion crassae-Wern erio n pygmaeae Cleef 1981), the vegetatation of glacial lake bottoms (Ditricho su b mersi-Isoëtio n k arst enii Cleef 1981) and ponds (Limo selletea australis Cleef 1981). Sphagnum bogs have not been classified in the absence of comprehensive synthetic presence tables thus far. They are found in valleys in the uppermost forests and the lower páramo, where conditions allow for Sphagnum growth. Eutrophic to mesotrophic conditions allow for mires, which are characterized by active mineroptrophic input from surrounding zonal vegetation on slopes. The highest bogs in páramos are the vascular cushion bogs consisting of Plantago rigida. Distichia muscoides, Oreobolus cleefii and the flat cushions of Xyris subu0340 – 269X/09/0039 – 0389 $ 9.45 © 2009 Gebrüder Borntraeger, D-14129 Berlin · D-70176 Stuttgart


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