Root biomass and production by two cushion plant species of tropical high-elevation peatlands in the Andean páramo

Abstract

High-elevation peatlands in the Andes are receiving increasing attention for their biodiversity and their high rates of carbon accumulation. However, the ecology of these peatlands and the environmental factors that control their carbon dynamics remain under-studied. Here we report on the patterns of root biomass productivity and turnover rates for two cushion plant species (Distichia muscoides, Plantago rigida) that commonly dominate high-elevation peatlands (> 4200 m a.s.l.) in the Andean paramo landscape of Northern Ecuador. Root biomass for P. rigida ranged from 680 to 864 g m-2 and was approximately 40 % higher than for D. muscoides (507–620 g m-2). In contrast, root production was almost twice as high for D. muscoides (2000–2800 g m-2 yr-1) than for P. rigida (1030–1080 g m-2 yr-1). These patterns resulted in high root turnover rates, especially for D. muscoides (0.98–1.90 yr-1). Below-ground productivity (as C) at our sites conservatively ranged from 0.55 to 1.5 kg m–2 yr–1, representing approximately 30 % of the estimated total productivity for these species, which only accounts for root production down to 50 cm depth. These high productivity rates are in accordance with the extremely high rates of carbon accumulation that have been reported for high-elevation peatlands of the Andes.