Forest fires facilitate growth of herbaceous bamboos in central Amazonia

Abstract

Severe droughts in Amazonia caused by El Niño and Atlantic dipole events are expected to become more frequent due to anthropogenic climate change. These droughts lead the tropical forests of central Amazonia to become increasingly exposed to fire. Forest-fire disturbances can create ideal scenarios for opportunistic plants, such as some bamboos. In this study, we investigate the influence of forest fires, canopy openness, and vertical distance to channel network (VDCN-a proxy for soil moisture availability) on the growth and expansion of Olyra latifolia and Taquara micrantha in the municipality of Autazes, Amazonas, Brazil. The density of these herbaceous bamboos was represented by the density of clumps (clumps ha -1 ) and of culms (culms ha -1 ), while bamboo growth was expressed as culms per clump and the average height of clumps. Forest disturbed by fire had a density of culms 116% higher than the value found in the control treatment. Plots affected by fire, which were at lower VDCN, showed evidence of higher potential for fire ignition in the low areas.The average number of culms per clump was significantly higher in post-burn forests. While canopy opening revealed a significant positive linear relationship with the abundance of herbaceous bamboo in our study area, VDCN had a negative effect on bamboo growth, suggesting that, in addition to fire, light in the understory and access to the water table are limiting factors for these two species in the upland forests of central Amazonia.

Drought-driven wildfire impacts on structure and dynamics in a wet Central Amazonian forest

“…However, this decrease in tree recruitment is likely to be accompanied by increasing seedling recruitment that may reach 10 cm DBH in the following post-fire intervals. Alternatively, the enhancement of two native herbaceous bamboo species registered in some of our fire-affected plots (electronic supplementary material, figure S2) [57] may further reduce recruitment through competitive suppression of saplings. Finally, our observations of temporal changes in mortality rates highlight the importance of multi-temporal censuses starting at the earliest time possible.…”

Characterising the vegetation-rainfall relationship in the Northeast Himalaya, India

“…Therefore, a further decrease of MAP (<1000 mm), an increase in incidence of forest fires, and deforestation can lead to shifts in vegetation (such as, forest to savanna) or change in the plant community structure. Such changes have indeed been observed in other parts tropical regions, for instance, in the savanna of Africa (Sankaran et al 2005), and in Amazonian rain forests (Ziccardi et al 2021). Therefore, further studies exploring the impact of fires, changing rainfall patterns, deforestation on the NEI forests are needed.…”

The absence of alternative stable states in vegetation cover of northeastern India

“…Therefore, a further decrease of MAP (less than 1000 mm), an increase in the incidence of forest fires, and deforestation can lead to shifts in vegetation (such as forest to savannah) or change in the plant community structure. Such changes have indeed been observed in other tropical regions, for instance, in the savannah of Africa [49], and Amazonian rain forests [65]. Therefore, further studies exploring the impact of fires, changing rainfall patterns and deforestation on the NEI forests are needed.…”