Holocene Grassland Fire Dynamics and Forcing Factors in Continental Interior of China

Abstract

Grasslands cover 41.7% of China's land surface and distribute mainly in NW China. To project future change of grassland fires, it is essential to explore paleofire dynamics. However, comparatively little is known about the patterns and driving forces of grassland fires in NW China due to the scarcity of paleorecords. Here, we present Holocene sedimentary records of grassland fire and vegetation in westerly‐dominated Xinjiang (NW China) to examine fire‐fuel‐climate interactions. We find that grassland fire regime is fuel‐limited, consistent with other grasslands worldwide. We reveal that burning increased throughout the Holocene, due to increasing moisture, grass cover, fuel load, and temperature of spring fire season. The Holocene pattern of burning coincides with several other records nearby and a global‐scale grassland fire record. Our results are different from monsoonal China where fuel load is not a constraining factor and more (less) fires occurred during colder/drier (warmer/moister) periods in the Holocene.

Variations in Holocene fire activity and its controls in the Ningshao Plain, eastern China

“…Generally, in previous studies, the Holocene fire activity in the monsoon‐dominated region of China has been regarded as drought‐driven because the aboveground fuel load was sufficiently high and thus the amount of fuel moisture (and hence flammability) was the decisive factor (Xue et al . 2018; Li & Wang 2020). Conversely, in this study, a similar tendency of fire variations – more active fire activity during the early and late Holocene and lower fire activity during the mid‐Holocene – is found in core HMD1401 and other natural fire records in eastern China, which is generally positively correlated with the moisture records in this region (Dykoski et al .…”

“…In the early Holocene, higher annual temperature and precipitation facilitated biomass growth and therefore added to the fuel load (Pei et al . 2020) and, at the same time, warmer but drier winter climates were conducive to biomass burning (Li & Wang 2020), which resulted in more frequent fire activity than in the mid‐Holocene. Certainly, studies about Holocene regional seasonal climate changes are insufficient and more Holocene fire–seasonal climate change relationship studies are needed to support this inference.…”

“…However, the exact relationship remains unclear. Some regions show a positive correlation between fire activity and climate (mainly increased precipitation and increased temperature) (Li & Wang 2020; Pei et al . 2020), whereas others show a negative correlation (Zhang et al .…”

Mid–Miocene Palaeofire and Its Complex Relationship With Vegetation Changes in the Wushan Basin, Northeastern Tibetan Plateau, China: Evidence From a High–Resolution Charcoal Record

“…To date, most studies of fire history focus on the linkages between fire and climate changes on orbital to millennial timescales and the relationship between human activities and fire regimes (Daniau et al., 2010; Finsinger et al., 2017; Inoue et al., 2018; Kappenberg et al., 2019, 2021; Li & Wang, 2020; Martínez–Abarca et al., 2021; Power et al., 2012; Shi et al., 2020; Tan et al., 2021; Thevenon et al., 2004; Verardo & Ruddiman, 1996; Walsh et al., 2008; Wang, Ding, & Peng, 2012, 2013). By contrast, very few pre–Quaternary high–resolution fire records are available to assess natural fire variability on tectonic to orbital timescales (Hoetzel et al., 2013; Hollaar et al., 2021; Zhang et al., 2020), especially in the inland of Asia (Hui et al., 2021; Miao et al., 2016, 2019).…”

“…(Daniau et al., 2010; MacDonald et al., 1991; Millspaugh & Whitlock, 1995). Among these fire proxies, sedimentary charcoal, a carbonaceous material produced by heating of biomass during incomplete combustion (Patterson et al., 1987; Whitlock & Larsen, 2002), has been widely used in paleoenvironmental studies as an indicator of fire activity across multiple timescales (e.g., Hoetzel et al., 2013; Hui et al., 2021; Li & Wang, 2020; MacDonald et al., 1991; Miao et al., 2016, 2019; Moore et al., 2022; Patterson et al., 1987; Power et al., 2006; Shi et al., 2020; Whitlock & Larsen, 2002).…”