Spatiotemporal variability of fire effects on soil carbon and nitrogen: A global meta‐analysis

Li, Jinquan; Pei, Jun‐Peng; Liu, Jiajia; Wu, Jihua; Li, Bo; Fang, Changming; Nie, Ming

doi:10.1111/gcb.15742

Cited by 51 publications

(29 citation statements)

References 72 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar changes could also occur following severe fires, but may be diluted or obscured by eroded material, such that the dominant processes preserved in lake sediments differ among fires. Our results thus underscore the importance of fire behaviour and the resulting severity as key controls of fire effects on the amounts and fluxes of C and other elements (Adkins et al, 2019; Li et al, 2021; Raison, 1979; Smithwick et al, 2005). Importantly, this diversity in fire effects occurred throughout the past 4800 years at Silver Lake, within multi‐millennial periods characterized by the same general climate and vegetation conditions, as well as inferred fire regime (Figure 8).…”

Section: Discussionsupporting

confidence: 55%

Section: Ecosystem Resilience To Wildfiressupporting

confidence: 54%

See 1 more Smart Citation

Fire‐regime variability and ecosystem resilience over four millennia in a Rocky Mountain subalpine watershed

Clark‐Wolf,

Higuera,

McLauchlan

et al. 2023

Journal of Ecology

View full text Add to dashboard Cite

Wildfires strongly influence forest ecosystem processes, including carbon and nutrient cycling, and vegetation dynamics. As fire activity increases under changing climate conditions, the ecological and biogeochemical resilience of many forest ecosystems remains unknown. To investigate the resilience of forest ecosystems to changing climate and wildfire activity over decades to millennia, we developed a 4800‐year high‐resolution lake‐sediment record from Silver Lake, Montana, USA (47.360° N, 115.566° W). Charcoal particles, pollen grains, element concentrations and stable isotopes of C and N serve as proxies of past changes in fire, vegetation and ecosystem processes such as nitrogen cycling and soil erosion, within a small subalpine forest watershed. A published lake‐level history from Silver Lake provides a local record of palaeohydrology. A trend towards increased effective moisture over the late Holocene coincided with a distinct shift in the pollen assemblage c. 1900 yr BP, resulting from increased subalpine conifer abundance. Fire activity, inferred from peaks in macroscopic charcoal, decreased significantly after 1900 yr BP, from one fire event every 126 yr (83–184 yr, 95% CI) from 4800 to 1900 yr BP, to one event every 223 yr (175–280 yr) from 1900 yr BP to present. Across the record, individual fire events were followed by two distinct decadal‐scale biogeochemical responses, reflecting differences in ecosystem impacts of fires on watershed processes. These distinct biogeochemical responses were interpreted as reflecting fire severity, highlighting (i) erosion, likely from large or high‐severity fires, and (ii) nutrient transfers and enhanced within‐lake productivity, likely from lower severity or patchier fires. Biogeochemical and vegetation proxies returned to pre‐fire values within decades regardless of the nature of fire effects. Synthesis. Palaeorecords of fire and ecosystem responses provide a novel view revealing past variability in fire effects, analogous to spatial variability in fire severity observed within contemporary wildfires. Overall, the palaeorecord highlights ecosystem resilience to fire across long‐term variability in climate and fire activity. Higher fire frequencies in past millennia relative to the 20th and 21st century suggest that northern Rocky Mountain subalpine ecosystems could remain resilient to future increases in fire activity, provided continued ecosystem recovery within decades.

show abstract

Section: Discussionsupporting

confidence: 55%

Section: Ecosystem Resilience To Wildfiressupporting

confidence: 54%

Fire‐regime variability and ecosystem resilience over four millennia in a Rocky Mountain subalpine watershed

Clark‐Wolf,

Higuera,

McLauchlan

et al. 2023

Journal of Ecology

View full text Add to dashboard Cite

show abstract

“…Grazing lawns further act as natural firebreaks, and the loss of rhino together with associated grazing lawns and other short grass patches, have been linked to increased fire extent and frequency at a landscape‐scale (Waldram et al 2008). Meta‐analyses on fire impacts on SOC reveal that increasing fire frequency and intensity reduce SOC stocks, the effect being mediated by rainfall seasonality, which possibly reflects the fire season (Pellegrini et al 2018, Li et al 2021). However, low intensity fires may promote SOC, likely through incorporation of partly‐burnt plant biomass into the SOC pool (Findlay et al 2022, Pellegrini et al 2022) (Fig.…”

Section: Introductionmentioning

confidence: 99%

“…They may also promote or hinder woody plant establishment (O'Connor et al 2014, Voysey et al 2021), thus influencing the quantity and quality of organic matter entering the soil through litter input and root exudation (Jackson et al 2002, Li et al 2016). In addition, grazers may reduce the intensity and frequency of fires, which may strongly affect carbon sequestration in fire‐prone systems such as savannas and grasslands (Pellegrini et al 2018, Li et al 2021). Several authors have suggested that the restoration of wild animal populations (i.e.…”

Section: Introductionmentioning

confidence: 99%

Grazing in a megagrazer‐dominated savanna does not reduce soil carbon stocks, even at high intensities

Hyvarinen,

te Beest,

le Roux

et al. 2023

Oikos

View full text Add to dashboard Cite

Recent studies suggest that wild animals can promote ecosystem carbon sinks through their impacts on vegetation and soils. However, livestock studies show that intense levels of grazing reduce soil organic carbon (SOC), leading to concerns that rewilding with large grazers may compromise ecosystem carbon storage. Furthermore, wild grazers can both limit and promote woody plant recruitment and survival on savanna grasslands, with both positive and negative impacts on SOC, depending on the rainfall and soil texture contexts. We used grazing lawns in one of the few African protected savannas that are still dominated by megagrazers (> 1000 kg), namely white rhinoceros Ceratotherium simum, as a model to study the impact of prolonged and intense wild grazing on SOC stocks. We contrasted SOC stocks between patches of varying grazing intensity and woody plant encroachment in sites across different rhino habitat types. We found no differences in SOC stocks between the most‐ and least grazed plots in any of the habitats. Intermediately grazed plots, however, had higher SOC stocks in the top 5 cm compared to most and least grazed plots, but only in the closed‐canopy woodland habitat and not in the open habitats. Importantly, we found no evidence to support the hypothesis that wild grazing reduces SOC, even at high grazing intensities by the world's largest megagrazer. Compared to the non‐encroached reference plots, woody encroached plots had higher SOC stocks in soils with low clay content and lower SOC stocks in soils with high clay content, although only in the top 5 cm. Accordingly, our study highlights that wild grazers may influence SOC indirectly through their impact on tree‐grass ratios in grassy ecosystems. Our study thus provides important insights for future natural climate solutions that focus on wild grazer conservation and restoration.Keywords: fire, grazing impact, rewilding, soil carbon, white rhinoceros, woody encroachment

show abstract

“…The effects of fire on soil C dynamics are influenced by fire characteristics, climate zones and biomes (Dooley & Treseder, 2012; Li et al, 2021; Pressler et al, 2019; Zhou et al, 2022). Prescribed fires, which are used to minimize the severity of wildfires (Alcañiz et al, 2018), have weaker effects on soil C storage, microbial communities and enzyme activities compared with wildfires due to their lower intensity and severity (Dooley & Treseder, 2012; Li et al, 2021; Pressler et al, 2019; Zhou et al, 2022). Such ecological consequences also varied.…”

Section: Introductionmentioning

confidence: 99%

Fire decreases soil respiration and its components in terrestrial ecosystems

Zhou,

Liu,

et al. 2023

Functional Ecology

View full text Add to dashboard Cite

The impact of fire on above‐ground biomass has significant consequences on soil carbon (C) dynamics, which is essential in predicting the global C budget during the Anthropocene. However, there is considerable spatiotemporal variability in the directions and magnitudes of fire effects on soil respiration, and the drivers associated with these effects are not well understood. Here, we conducted a global meta‐analysis of 1327 individual observations from 170 studies to determine the extent to which fire influenced soil total respiration (Rs), heterotrophic respiration (Rh) and autotrophic respiration (Ra). We found fires reduced Rs, Rh and Ra, with an average effect of −11.0%, −17.5% and −40.6%, compared with unburnt sites. Specifically, wildfires significantly reduced Rs and Rh (−20.4% and −25.0%, respectively), and prescribed fire significantly decreased Ra (−74.8%). The influences of fire on Rs and its components were moderated by fire severity, season, type, climate zones and biomes. After several years from the time of the fire, the negative effects of fire on Rs diminished and then recovered to a state not significantly different from unburnt sites; Rh exhibited a similar but decayed temporal response. Similarly, the negative effects on Ra disappeared after 3 years following the latest fire. The magnitude of the effect on Rs was strongly associated with soil temperature, cation exchange capacity, total nitrogen (N) content and N‐acquiring enzyme activity. In contrast, the magnitude of the effect on Rh significantly changed with pH, bulk density, texture, soil C and nutrient contents, and C‐acquiring enzyme activity. Our findings advance the understanding of the inhibition and associated mechanisms of fire on Rs and its components, highlighting the need for new research efforts to predict the spatial‐temporal shifts in underground C‐cycling induced by fire. Read the free Plain Language Summary for this article on the Journal blog.

show abstract

Spatiotemporal variability of fire effects on soil carbon and nitrogen: A global meta‐analysis

Cited by 51 publications

References 72 publications

Fire‐regime variability and ecosystem resilience over four millennia in a Rocky Mountain subalpine watershed

Fire‐regime variability and ecosystem resilience over four millennia in a Rocky Mountain subalpine watershed

Grazing in a megagrazer‐dominated savanna does not reduce soil carbon stocks, even at high intensities

Fire decreases soil respiration and its components in terrestrial ecosystems

Contact Info

Product

Resources

About