Calibrating Vegetation Cover and Grassland Pollen Assemblages in the Flint Hills of Kansas, USA

Commerford, Julie L.; McLauchlan, Kendra K.; Sugita, S.

doi:10.4236/ajps.2013.47a1001

Cited by 20 publications

(19 citation statements)

References 33 publications

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“…Although pollen records can help define the dominant vegetation cover in forests and can also be used to define temporal transitions from forested to nonforested environments, no consensus exists on the dominance of grassland vegetation cover based on pollen assemblages, or the percentage of Non‐Arboreal Pollen (NAP) types. Even in grass‐dominated landscapes, pollen productivity is higher for woody taxa than herbaceous taxa due to differences in dispersal (i.e., by wind rather than insects) (Commerford, McLauchlan, & Sugita, ). In addition, NAP in vegetation history studies is typically considered to be part of the forest understory, or as the herbaceous vegetation around the depositional environment.…”

Section: Grassland Biomes and Fire History Reconstructionsmentioning

confidence: 99%

“…Many studies designed to calibrate pollen assemblages to vegetation abundance and landscape structure (Commerford et al., ; Sugita, , ; Tauber, ) have been conducted in forests. Such studies need to be extended to grassland environments, by comparison of subsurface pollen assemblages with present‐day grassland ecosystems as defined by Dixon et al.…”

Section: Future Research Directionsmentioning

confidence: 99%

“…If we can assume that this relationship is constant through time, then we can apply the scaling from the modern day to the past, and at least reconstruct changes in forest versus grassland vegetation in the paleo record (Williams & Shuman, ). Recent studies aimed to address this challenge by calibrating the herbaceous pollen taxa from depositional environment with the surrounding vegetation (Commerford et al., ; McLauchlan, Commerford, & Morris, ) and demonstrated clear correlations between pollen taxa variations and vegetation assemblages. Another possibility is to establish the proportion of tree to nontree pollen in surface samples, and then calibrate this against satellite‐based estimates of tree cover (e.g., Tarasov et al., ).…”

Section: Future Research Directionsmentioning

confidence: 99%

See 2 more Smart Citations

Global fire history of grassland biomes

Leys

Marlon

Umbanhowar

et al. 2018

Ecology and Evolution

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Grasslands are globally extensive; they exist in many different climates, at high and low elevations, on nutrient‐rich and nutrient‐poor soils. Grassland distributions today are closely linked to human activities, herbivores, and fire, but many have been converted to urban areas, forests, or agriculture fields. Roughly 80% of fires globally occur in grasslands each year, making fire a critical process in grassland dynamics. Yet, little is known about the long‐term history of fire in grasslands. Here, we analyze sedimentary archives to reconstruct grassland fire histories during the Holocene. Given that grassland locations change over time, we compare several charcoal‐based fire reconstructions based on alternative classification schemes: (a) sites from modern grassland locations; (b) sites that were likely grasslands during the mid‐Holocene; and (c) sites based on author‐derived classifications. We also compare fire histories from grassland sites, forested sites, and all sites globally over the past 12,000 years. Forested versus grassland sites show different trends: grassland burning increased from the early to mid‐Holocene, reaching a maximum about 8000–6000 years ago, and subsequently declined, reaching a minimum around 4000 years ago. In contrast, biomass burning in forests increased during the Holocene until about 2000 years ago. Continental grassland fire history reconstructions show opposing Holocene trends in North versus South America, whereas grassland burning in Australia was highly variable in the early Holocene and much more stable after the mid‐Holocene. The sharp differences in continental as well as forest versus grassland Holocene fire history trajectories have important implications for our understanding of global biomass burning and its emissions, the global carbon cycle, biodiversity, conservation, and land management.

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Section: Grassland Biomes and Fire History Reconstructionsmentioning

confidence: 99%

Section: Future Research Directionsmentioning

confidence: 99%

Section: Future Research Directionsmentioning

confidence: 99%

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Global fire history of grassland biomes

Leys

Marlon

Umbanhowar

et al. 2018

Ecology and Evolution

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“…RPP are available in e.g. northern America for tree taxa (Calcote 1995) and some herb taxa (Commerford et al 2013), and in southern Africa for a few savanna taxa (Duffin and Bunting 2007). A relatively large number of RPP studies were conducted recently in China.…”

Section: Introductionmentioning

confidence: 99%

Relative pollen productivity estimates for major plant taxa of cultural landscapes in central eastern China

Gaillard

Sugita

et al. 2017

Veget Hist Archaeobot

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“…The AP/NAP pollen ratio is not linearly transferrable to vegetation cover because plant species vary in pollen productivity [38]. However, the ratio can be used as a relative metric of woody versus herbaceous vegetation across the sites.…”

Section: Methodsmentioning

confidence: 99%

Reconstructing grassland fire history using sedimentary charcoal: Considering count, size and shape

2017

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Fire is a key Earth system process, with 80% of annual fire activity taking place in grassland areas. However, past fire regimes in grassland systems have been difficult to quantify due to challenges in interpreting the charcoal signal in depositional environments. To improve reconstructions of grassland fire regimes, it is essential to assess two key traits: (1) charcoal count, and (2) charcoal shape. In this study, we quantified the number of charcoal pieces in 51 sediment samples of ponds in the Great Plains and tested its relevance as a proxy for the fire regime by examining 13 potential factors influencing charcoal count, including various fire regime components (e.g. the fire frequency, the area burned, and the fire season), vegetation cover and pollen assemblages, and climate variables. We also quantified the width to length (W:L) ratio of charcoal particles, to assess its utility as a proxy of fuel types in grassland environments by direct comparison with vegetation cover and pollen assemblages. Our first conclusion is that charcoal particles produced by grassland fires are smaller than those produced by forest fires. Thus, a mesh size of 120μm as used in forested environments is too large for grassland ecosystems. We recommend counting all charcoal particles over 60μm in grasslands and mixed grass-forest environments to increase the number of samples with useful data. Second, a W:L ratio of 0.5 or smaller appears to be an indicator for fuel types, when vegetation surrounding the site is before composed of at least 40% grassland vegetation. Third, the area burned within 1060m of the depositional environments explained both the count and the area of charcoal particles. Therefore, changes in charcoal count or charcoal area through time indicate a change in area burned. The fire regimes of grassland systems, including both human and climatic influences on fire behavior, can be characterized by long-term charcoal records.

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Calibrating Vegetation Cover and Grassland Pollen Assemblages in the Flint Hills of Kansas, USA

Cited by 20 publications

References 33 publications

Global fire history of grassland biomes

Global fire history of grassland biomes

Relative pollen productivity estimates for major plant taxa of cultural landscapes in central eastern China

Reconstructing grassland fire history using sedimentary charcoal: Considering count, size and shape

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