PARENT SESSION
Oral Session #77: Biodiversity and Ecosystem Function II.
Presiding: G. Chong
Thursday, August 8. 9:00 AM to 11:30 AM. Coconino Meeting Room, TCC.

Floristic diversity and composition of riparian forests in Yanachaga, Departamento de Pasco, Peru (2500 mosl).

Gomez, Daniel^*,1, Reynel, Carlos^*,1, ¹ Universidad Nacional Agraria La Molina, Lima, Peru

ABSTRACT- Floristic diversity and composition of plants above 10 cm dbh was studied in a 1 Ha plot (100x100) centered in a riparian area in the San Alberto cachtment, Cloud montane forests at 25000 mosl . The area is located in the limits of the Yanachaga National Park. Species richness is extremely high (156 spp/ha), the highest ever reported at this altitudinal belt, and comparable to the species richness of many lowland forest sites below 500 mosl (e.g Pucallpa, Jenaro Herrera, Camisea, etc, in Peru). Thirty-three dicotiledoneous and 1 monocot. families were reported in the plot. The most speciose families are Lauraceae(24 spp.), Melastomataceae (15 spp.), Myrtaceae (12 spp.), Euphorbiaceae (10 spp.), and Rubiaceae (8spp.); between Lauraceae and Melastomataceae 25% of the species are contained. The most frecuent species belong to Cyathea Pteridophita), Miconia (Melastomataceae), Hedyosmun (Chloranthaceae), Clusia (Clusiaceae), and Weinmmannia (Cunnoniaceae). In terms of composition, the plot is fairly consistent with others reported for the same altitude. Average diameter is 17.9 cm; average height 12 m. The most dominant species are Topobea multiflora (Melastomataceae)and Guettarda hirta (Rubiaceae). Microtopography area is very broken, and the comparison between the riparian against the slope and summit areas within the plot shows the riparian to be the most diverse.

KEY WORDS: Yanachaga, Floristics, Composition, Diversity