Outcomes of a native bamboo on biomass and carbon stocks of a neotropical biodiversity hotspot

Old-growth tropical forests provide an essential climate regulation service to humans, functioning as carbon (C) sink due to the high productivity, species diversity, and variety of life forms, such as bamboos. Bamboos growth fast and display plastic functional traits, which favor the occupation of environments under different conditions, making them efficient C stockers in addition to providing raw material for local human populations. Asian bamboos are known to sequester considerable amounts of C in a short time, and although is likely that New World bamboo species have the same capacity, this perspective is rarely addressed. To evaluate the impact of a native bamboo on biomass and carbon stocks of an Atlantic Forest Protected Area, we first developed an allometric equation to estimate its live aboveground biomass (AGB) based on the destructive sampling method. We then compare our results to the AGB of forest components previously estimated for the same area, as well as to Asian and other Neotropical bamboo species to place our case study in a global scenario. In four 1-ha permanent plots in São Paulo State, Brazil, we made a census of all live culms and collected 20 healthy ones for equations purposes. The Merostachys neesii Rupr. (Poaceae) studied species has 343 clumps ha⁻¹, 3663 culms ha⁻¹, and 12.1 Mg ha⁻¹ of biomass (5.2 Mg C ha⁻¹) or 4% of total AGB and C stocks of the studied area. M. neesii's contributes as much as palms solely, but more than lianas and tree ferns together for the total AGB in the old-growth Montane Atlantic Forest we studied. These results show that the non-inclusion of bamboos may underestimate the role of terrestrial ecosystems in buffering anthropogenic CO₂. The comprehension of bamboo ecology is crucial for conservation and management purposes, and it is relevant since, with global warming, the C stored may be released turning these ecosystems into source instead of a sink of C.