5:15 PM - 6:45 PM
[MIS03-P02] Tracing drought-induced wildfire events and vegetation evolution in the equatorial low-lying peatlands, West Kalimantan, Indonesia.
Keywords:peat deposit, organic matter, microcharcoal, pollen, wildfire
Wetlands ecosystems are immensely widespread along the Indonesia archipelago coastlines for more than 80,000 km, where an approximate 80 Mha is covered by coastal wetlands including freshwater peatlands (mires) and non-peat forming wetlands. Tropical peatlands are vulnerable to impacts from sea level rise, climate change, and anthropogenic activity, leading to fire outbreaks. Peat deposits are highly sensitive to environmental changes and well-suited for palaeobotanical investigations. In recent decades, peat fires in Indonesia have been predominantly anthropogenic in origin and exacerbated by natural origin during El Nino-Southern Oscillation (ENSO) events. Little is known about ENSO-related wildfires and their effect on vegetational changes.
This study was conducted in low-lying mires from Kapuas wetland, West Kalimantan, Indonesia with an average temperature of 26.5±0.50C, and mean annual rainfall was 3,218 ± 530 mm, without dry months (<100 mm rainfall) per year, even during the onset of the ENSO. A 500 cm peat core was obtained using a hand-operated MacCaulay peat sampler (refer to as a Russian D-corer). Here we present new palaeoecological records of equatorial peatlands using high-resolution of microcharcoal distribution, palynological, and organic petrological assessments.
Five types of peat were identified, sapric muck (Sm), sapric shorts (Ss), sapric wood (Sw), coarse hemic (Hc), and fine hemic (Hf). Four phases of peat dynamics were identified: initiation, early ombrogenous, late ombrogenous, and topogenous phases. Past vegetation shows an alternation community of mixed-riparian forest and open vegetation with free marine water inundation. High-resolution microcharcoal analysis reveals that eight fire events are preserved by the sediment core in the Kapuas wetlands. These results suggest that increased wildfire occurrence and severity significantly impacted both nutrient cycling and forest cover, resulting in altered peatland vegetation composition. While seasonal precipitation changes strongly influence aridity, the contribution of interannual monsoonal variability should not be neglected. Thus, future work will focus on further clarifying sources of regional precipitation changes.
This study was conducted in low-lying mires from Kapuas wetland, West Kalimantan, Indonesia with an average temperature of 26.5±0.50C, and mean annual rainfall was 3,218 ± 530 mm, without dry months (<100 mm rainfall) per year, even during the onset of the ENSO. A 500 cm peat core was obtained using a hand-operated MacCaulay peat sampler (refer to as a Russian D-corer). Here we present new palaeoecological records of equatorial peatlands using high-resolution of microcharcoal distribution, palynological, and organic petrological assessments.
Five types of peat were identified, sapric muck (Sm), sapric shorts (Ss), sapric wood (Sw), coarse hemic (Hc), and fine hemic (Hf). Four phases of peat dynamics were identified: initiation, early ombrogenous, late ombrogenous, and topogenous phases. Past vegetation shows an alternation community of mixed-riparian forest and open vegetation with free marine water inundation. High-resolution microcharcoal analysis reveals that eight fire events are preserved by the sediment core in the Kapuas wetlands. These results suggest that increased wildfire occurrence and severity significantly impacted both nutrient cycling and forest cover, resulting in altered peatland vegetation composition. While seasonal precipitation changes strongly influence aridity, the contribution of interannual monsoonal variability should not be neglected. Thus, future work will focus on further clarifying sources of regional precipitation changes.