Paleofire, Vegetation, and Climate Reconstructions of the Middle to Late Holocene From Lacustrine Sediments of the Toushe Basin, Taiwan

Abstract

We identified four climatic stages between 6.2 and 1.3 cal kyr before present (BP) based on pollen and charcoal concentrations by high-resolution Accelerated mass spectrometer (AMS) 14 C-dated sediment profile from Taiwan's Toushe Basin. From 6.2 to 4.6 cal kyr BP, the region was warm-wet with infrequent wildfires and dominant subtropical evergreen broad-leaved forests. The climate was cooler-drier from 4.6 to 3.0 cal kyr BP, with a decline in forest and increased fire frequency. From 3.0 to 2.1 cal kyr BP, climate further cooled and dried, with the development of alpine meadows and higher fire frequency. The region became warmer and wetter from 2.1 to 1.3 cal kyr BP, accompanied by forest recovery. Climatic changes were linked to changes in East Asia Summer Monsoon intensity, which is mainly controlled by solar radiation. Wildfires were likely controlled by precipitation variability that is influenced by East Asia Summer Monsoon and El Niño-Southern Oscillation. Toushe Basin experienced drought conditions and frequent wildfires during the El Niño years. Plain Language Summary The purpose of our study is to reveal the relationship between paleoclimate, vegetation, and wildfire. The study area is located in the Toushe Basin, central Taiwan. Through palynological and charcoal analysis, the vegetation, climate, and wildfire history of the past 6,000 to 1,000 years in the study area were reconstructed. The study found that after 4,600 years, the East Asian summer monsoon continued to weaken until approximately 2,000 years ago, during which time the climate was dry and cool, and wildfires were frequent. In addition, it is found that the climate in this region is mainly controlled by the changes in solar radiation. The cycle of climate change coincides with that of solar activity. In El Niño years, the Toushe Basin was dry and frequent wildfires occurred.

Abrupt Drying on the Southeast Coast of China During the Mid‐to‐Late Holocene Transition

“…It is also in line with climate inference from a compilation of peat initiation records in Fujian (Lei et al, 2017). Moreover, a shift to drier conditions during the mid-to-late Holocene transition has also been suggested by paleoclimate records in Toushe Basin and Retreat Lake from Taiwan, Southeast China (Selvaraj et al, 2007;Z. Huang et al, 2020; Figure 2).…”

“…et al, 2013); 2: Hongyuan peatland (Seki et al, 2011); 3: Shennong Cave (Zhang, Cheng, et al, 2018); 4: Dongge Cave (Dykoski et al, 2005); 5: Toushe Basin (Z. Huang et al, 2020), and 6: Shuizhuyang peat deposit (this study).…”

“…It is also in line with climate inference from a compilation of peat initiation records in Fujian (Lei et al., 2017). Moreover, a shift to drier conditions during the mid‐to‐late Holocene transition has also been suggested by paleoclimate records in Toushe Basin and Retreat Lake from Taiwan, Southeast China (Selvaraj et al., 2007; Z. Huang et al., 2020; Figure 2). The differences in the timing among the records might arise from different sensitivity of various proxies as well as differences in record resolution and dating uncertainty.…”

“… Comparisons of SZY18 records and paleoclimate records from monsoonal China. (a) Stalagmite δ 18 O records from Shennong Cave over the Holocene (left y ‐axis, Zhang, Zhang, et al., 2021) and during 5.3 and 3.5 ka (right y ‐axis, Zhang, Cheng, et al., 2021); (b) SZY18 δD C29 ; (c) SZY18 C 23 /C 29 ; (d) hopanoid flux from the Shuizhuyang peat deposit (X. Wang & Huang, 2019); and (e) arbor pollen percentage from the Toushe Basin in central Taiwan (Z. Huang et al., 2020). Age control points of the SZY18 core are shown along the x ‐axis.…”

Vertical Differences in the Long-Term Trends and Breakpoints of NDVI and Climate Factors in Taiwan

“…(2015) [87] found that during the La Niña years, southern Taiwan experienced decreased rainfall in April-June and increased rainfall in July-September, which were associated with weaker meiyu rainfall and stronger typhoons, respectively. For central Taiwan, [88] discovered that frequent drought-related wildfires, which impact vegetation in central Taiwan, were associated with the dry and cool weather during the El Niño years. Figure 8 displays the largest change in direction of the NDVI and temperature datasets, which should be interpreted carefully, considering that the largest change in direction was a snapshot of the study period and, thus, could not reveal the whole trajectory of the time series.…”