The plight of Amazonia's oldest peatland

摘要

> Peatlands are globally important ecosystems in terms of biodiversity, hydrology, and for the role they play in the carbon cycle. They store approximately one‐third of the carbon contained in the terrestrial biosphere, whilst covering only approximately 3% of the land and freshwater surface. Tropical peatlands represent an important component of this carbon store and can be found in Asia, Africa, South and Central America. However, tropical peatlands are also under severe threat of destruction from human activities including deforestation, agricultural expansion and resource exploitation. In South America, the Pastaza–Mara?on foreland basin (PMFB) in NW Peru represents the most carbon dense landscape in Amazonia due to an abundance of peatlands, including nutrient‐poor ombrotrophic peat domes and river‐influenced minerotrophic swamps. The Aucayacu peatland in the PMFB is a nutrient‐poor peat dome and represents the oldest peatland yet reported in Amazonia. It is a relatively large peatland—it is estimated that Aucayacu has maximum dimensions of 33 km (NW‐SE) by 15 km (NE‐SW) (Fig.

Location of Aucayacu in Peruvian Amazonia. The yellow dots outline the edges of the peatland. The location of the study site is shown on a Landsat TM RGB false colour image (NASA Landsat Program, Orthorectified, WRS‐2, Path 007, Row 063, downloaded from http://earthexplorer.usgs.gov/ ). Band 4 was assigned to red, band 5 was assigned to green and band 7 was assigned to blue.

). The flora of the site is characterized by stunted vegetation due to low nutrient status, known as ‘pole’ and ‘dwarf’ forest, which at Aucayacu grows above a patchy understory of grasses and ferns (Fig.

a. Pole forest vegetation in Aucayacu. b. Ground surface and pool in Aucayacu.

). Recent research has shown that Aucayacu has laid down peat up to 7.5 m deep in ～ 8900 years.