The Polylepis forests in Ecuador

P. reticulata. Pichincha-Ecuador (2007)

The tree genus Polylepis is endemic of the Andean páramos (Fjeldsa and Kessler, 1996). Even now, Polylepis forests continue to disappear at an alarming rate, partly because people follow cultural traditions of cutting down, burning and shepherding and partly due to ever-increasing population growth and its increasing demands on the landscape. According to the scientific community, Polylepis forests need a careful systematic study and conservation biological investigation.

Páramo El Angel. Carchi-Ecuador

Trunk of Polylepis.

Classification

Phylogeny Rosaceae (Potter et al, 2006)

trnL/F Phylogeny Sanguisorbeae (Kerr, 2004)

Phylogeny of Polylepis based on morphological characters (Schmidt-Lebuhn A.N. Kessler, M and M. Kumar. 2006)

Distribution

The genus belongs to Family Rosaceae, subfamily Rosoidea, tribe Sanguisorbeae (Simpson, 1979, 1985). The genus Polylepis has 28 species distributed in South America, from northern of Venezuela to northern of Chile and Argentina (Kessler , 2006). According to Simpson (1985) and Romoleroux (1996) the highest number of species occurs in Ecuador, Peru and Bolivia, but these groups of plants are not related to one another based on morphological characters. However, hybridization is very common among species of this genus and therefore their morphological recognition is very difficult sometimes (Romoleroux, 1996; Schmidt-Lebuhn et al, 2006). In the case of Ecuador, Romoleroux (1996) identified 7 species of Polylepis, 1 of them endemic (P. lanuginosa). In Ecuador, there are three areas of diversification of Polylepis: Mojanda (1), Papallacta(2) and El Cajas(3).

Polylepis and its adaptation to the high Andean environment

P.reticulata. El Cajas. Azuay

Polylepis is an exclusively arborescent genus that occurs naturally at higher elevations than any other arborescent angiosperm (Simpson 1978, 1984; Romoleroux 1992). Polylepis sericea shows supercooling of all its tissues (Rada et al, 1996; Goldstein et al, 1994). Polylepis forests grow near to massive rock outcroppings and talud slopes. Some studies found a lack of correlation between air temperature and elevation in Polylepis forest (Cabrera et al, 1998). These data suggest the presence of special microclimatic conditions (thermal refuge) which moderate freezing temperatures in relation to the surrounding páramos. In addition, warm air present in these thermal refuges extends through rocks and slopes providing better soil conditions than surroundings areas. Consequently, warmer soils improve establishment and growth of tree seedlings.

Illinizas- Ecuador

Polylepis' research in Ecuador

At this moment, some people are working in many aspects of Ecology, Reproductive Biology, Systematic and Conservation of the Ecuadorian Polylepis Forests. These studies are been carried out at Escuela Politecnica del Ejercito, Biotech Labs (Population Genetics, Physiology, Soil Ecology, Tissue Culture), Universidad del Azuay (Ecology and Physiology), and Pontificia Universidad Católica del Ecuador (Systematics, Distribution, Ecology and Invertebrates), University of Florida ( Systematics and Evolution). If you are interested to know more about these studies, we created a discussion group about Ecuadorian Polylepis Forests (ecuadorpolylepis@yahoogroups.com).

Laguna Verde. El Angel-Ecuador

Useful links

Mojanda-Pichincha Ecuador

Some bibliography

Cabrera, H. M. Rada, F. and Caviedes L,. 1998. Effects of temperatura on photosynthesis of two morphological contrasting plant species along an altitudinal gradient in the tropical high Andes. Oecologia 114:145-152.

Fjeldsa, J. and M. Kessler. 1996. Conserving the biological diversity of Polylepis woodlands of the highland of Peru and Bolivia. A Contribution to Sustainable Natural Resource Management in the Andes. NORDECO

Goldstein, G. Meinzer, F. C. and Rada F. 1994. Environmental biology of a tropical treeline species Polylepis sericea. In Tropical Alpine Environrments: Plant form and function, ed. P. W. Rundel, A. P. Smith and F. C. Meinzer. Cambridge: University Press.

Rada, F. Azocar, A. Briceno, B. Gonzalez, J. and García-Nuñez C. 1996. carbon and water balance in Polylepis sericea, a tropical treeline species. Tree 10 (4): 218-222.

Romoleroux, K. 1992. Rosaceae in the páramos of Ecuador. Pp. 85-94 in Páramo:An Andean Ecosysytem under Human Influence, eds. H. Balslev and J. L. Luteyn. Academic Press, San Diego.

Romoleroux, K. 1996. Rosaceae. Pp. 50-95 In Flora of Ecuador, eds. Gunna Herling and L. Andersson. Council for Nordic Publications in Botany.

Simpson, B. 1979. A revision of the genus Polylepis (Rosaceae: Sanguisorbeae). Smithsonian Contributions to Botany 43: 1-62.

Simpson, B. 1986. Speciation and Specialization of Polylepis in the Andes. Pp. 304-316. in High Altitude Tropical Biogeography. Oxford University Press. Oxford.

·         Dickson EA, K. Kresovich, S. and J.J. Doyle. 1992. Nuclear DNA content variation within Rosaceae. American Journal of Botany 79: 1081-1086.

·         Eriksson TH, Hibbs, M. Yoder, A. Delwiche, C. and M. Donaghue. 2003. The phylogeny of Rosoideae (Rosaceae) based on sequences of the Internal Transcribed spacers (ITS) of nuclear ribosomal DNA and the trnL/F region of chloroplast DNA. International Journal of Plant Sciences 164: 197-211.

·         Kerr MS. 2003. A Phylogenetic and Biogeographic Analysis of Sanguisorbeae (Rosaceae) with Emphasis of the pleistocene radiation of the high andean genus Polylepis. PhD Dissertation. University of Maryland

·         Fjeldsa J. & Kessler M., 1996. Conserving the biological diversity of Polylepis woodlands of the highland of Peru and Bolivia. A Contribution to Sustainable Natural Resource Management in the Andes (NORDECO,1996).

·         Kessler, M. 1995. The genus Polylepis (Rosaceae) in Bolivia . Candollea 50:131-171.

·         Kessler M. and A. N. Schmidt-Lebuhn. 2006. Taxonomical and distributional notes on Polylepis (Rosaceae). Organisms, Diversity and Evolution: 67-69.

·         Latif H. 2004. A contribution of the Taxonomy of four taxa of Sanguisorba (Rosoidea-Rosaceae). Pakistan Journal of Biological Sciences 7: 1540-1545.

·         Morgan D. Soltis, D.and K. Robertson. 1994. Systematic and Evolutionary Implications of rbcL Sequence Variation in Rosaceae. American Journal of Botany 81: 890-903.

·         Potter De, T. Evans, R. Oh, S. Smedmark, E. Morgan, R. Kerr. M. Robertson, R. Arsenault, M. Dickinson, T. and C. Campbell. 2007. Phylogeny and Classification of Rosaceae. Plant Systematics and Evolution 266: 5-43.

·         Schmidt-Lebuhn A.N. Kessler, M and M. Kumar. 2006. Promiscuity in the Andes: Species Relationships in Polylepis (Rosaceaea, Sanguisorbeae) based on AFLP and Morphology. Systematic Botany 3: 547-559.

·         Schmidt-Lebuhn A. N, Seltmann, P. and M. Kessler. 2007. Consequences of the pollination system on genetic structure and pattern of species distribution in the Andean genus Polylepis (Rosaceae): a comparative study. Plant Systemtics and Evolution: 91-103.

·         Tantawy M and M. Naseri. 2003. A contribution to the Achene Knowledge of Rosideae (Rosaceae) LM and SEM. International Journal of Agriculture & Biology 5: 105-112.



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Last update 05/07/2008

Photos courtesy of Galo Zapata Rios
If you have comments or suggestions, email me at maclaudiasegovia@yahoo.com