Testing peatland water-table depth transfer functions using high-resolution hydrological monitoring data

Swindles, Graeme T.; Holden, Joseph; Raby, Cassandra L.; Turner, T. Edward; Blundell, Antony; Charman, Dan J.; Menberu, Meseret Walle; Kløve, Bjørn

doi:10.1016/j.quascirev.2015.04.019

Cited by 48 publications

(47 citation statements)

References 60 publications

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“…Because the transfer function is based on one‐time water‐table measurements, the reconstruction was detrended using linear regression following Swindles et al. ().…”

Section: Methodsmentioning

confidence: 99%

Ecosystem state shifts during long‐term development of an Amazonian peatland

Swindles

Morris

Whitney

et al. 2017

Global Change Biology

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The most carbon (C)-dense ecosystems of Amazonia are areas characterized by the presence of peatlands. However, Amazonian peatland ecosystems are poorly understood and are threatened by human activities. Here, we present an investigation into long-term ecohydrological controls on C accumulation in an Amazonian peat dome. This site is the oldest peatland yet discovered in Amazonia (peat initiation ca. 8.9 ka BP), and developed in three stages: (i) peat initiated in an abandoned river channel with open water and aquatic plants; (ii) inundated forest swamp; and (iii) raised peat dome (since ca. 3.9 ka BP). Local burning occurred at least three times in the past 4,500 years. Two phases of particularly rapid C accumulation (ca. 6.6-6.1 and ca. 4.9-3.9 ka BP), potentially resulting from increased net primary productivity, were seemingly driven by drier conditions associated with widespread drought events. The association of drought phases with major ecosystem state shifts (open water wetland-forest swamp-peat dome) suggests a potential climatic control on the developmental trajectory of this tropical peatland. A third drought phase centred on ca. 1.8-1.1 ka BP led to markedly reduced C accumulation and potentially a hiatus during the peat dome stage. Our results suggest that future droughts may lead to phases of rapid C accumulation in some inundated tropical peat swamps, although this can lead ultimately to a shift to ombrotrophy and a subsequent return to slower C accumulation. Conversely, in ombrotrophic peat domes, droughts may lead to reduced C accumulation or even net loss of peat. Increased surface wetness at our site in recent decades may reflect a shift towards a wetter climate in western Amazonia. Amazonian peatlands represent important carbon stores and habitats, and are important archives of past climatic and ecological information. They should form key foci for conservation efforts. Here, we present an investigation into the long-term controls on C accumulation in the oldest peatland reported in the Amazon basin.We develop a comprehensive, multiproxy palaeoecological dataset to (i) determine the developmental trajectory of the peatland and (ii) assess the peatland's response to past climate change. A hole was augered at each sampling point and water level measured at regular intervals until it equalized to determine depth to water Approximately one half of each surface litter sample was weighed, oven dried, burnt in a muffle furnace, and reweighed to determine moisture content and loss-on-ignition. The other half was used for analysis of contemporary testate amoebae (see Swindles et al., 2014). | MATERIALS AND METHODS | Study site

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“…Because the transfer function is based on one‐time water‐table measurements, the reconstruction was detrended using linear regression following Swindles et al. ().…”

Section: Methodsmentioning

confidence: 99%

Ecosystem state shifts during long‐term development of an Amazonian peatland

Swindles

Morris

Whitney

et al. 2017

Global Change Biology

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“…The use of single-shot water table measurements for testate amoeba-based hydrodrological studies has been debated previously (e.g. Bobrov et al 1999;Booth 2008;Swindles et al 2015). Whilst the method only provides a 'snapshot' of the seasonal water table variability, it has been shown to adequately represent the relative hydrological status of sample locations and is sufficient to drive a hydrological gradient for transfer function development (Swindles et al 2015).…”

Section: Methodsmentioning

confidence: 99%

“…Bobrov et al 1999;Booth 2008;Swindles et al 2015). Whilst the method only provides a 'snapshot' of the seasonal water table variability, it has been shown to adequately represent the relative hydrological status of sample locations and is sufficient to drive a hydrological gradient for transfer function development (Swindles et al 2015). Sampling should not be carried out, however, during 8 periods of extreme weather such as summer drought or after heavy rain Swindles et al 2009).…”

Section: Methodsmentioning

confidence: 99%

“…This narrow vertical interval has been selected to ensure that a sample representing only the very recent period is obtained. A slightly modified approach was applied by Swindles et al (2015) in which the entirety of the green (living) moss fraction and 1 cm of the underlying brown Sphagnum were sampled.…”

Section: Introductionmentioning

confidence: 99%

“…Swindles et al 2015), or in place of (e.g. Booth 2002), the green fraction in calibration (training) sets, as it may provide a more representative, time-averaged signal for hydrological reconstructions than the green layer alone.…”

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confidence: 99%

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Re-assessing the vertical distribution of testate amoeba communities in surface peats: Implications for palaeohydrological studies

Roe¹,

Elliott

Patterson

2017

European Journal of Protistology

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Testate amoeba-derived transfer functions are frequently used in peatland palaeohydrological studies and involve the development of training sets from surficial peats. However, within acrotelmic peats, considerable vertical variation in assemblage composition can occur, particularly along Sphagnum stems, which may limit the representation of the associated 'contemporary' testate amoeba samples as analogues for the peatland surface. This paper presents contiguous testate amoeba assemblage data from nine monoliths collected from different peatland microforms (hummock, hollow, lawn) in three Sphagnum dominated ombrotrophic peatlands in Ontario and Quebec, eastern Canada. The aim is to: i) gain a greater understanding of the vertical distribution of xerophilous/hygrophilous taxa along Sphagnum stems; ii) determine the vertical extent of live/encysted taxa along this gradient; and iii) assess the significance of this distribution on surface sampling protocols. The results show that testate amoeba communities in the uppermost acrotelmic peat layers display considerable variability. This may reflect a complex interplay of abiotic and biotic controls, including moisture, temperature, light and other characteristics, food availability, and mineral particle availability for test construction.These findings underline the complexity of testate amoeba community structure and highlight the importance of analysing both living and dead Sphagnum stem sections when developing calibration sets.

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A Bayesian time series model for reconstructing hydroclimate from multiple proxies

et al. 2023

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We propose a Bayesian model which produces probabilistic reconstructions of hydroclimatic variability in Queensland Australia. The model provides a standardized approach to hydroclimate reconstruction using multiple palaeoclimate proxy records derived from natural archives such as speleothems, ice cores and tree rings. The method combines time‐series modeling with inverse prediction to quantify the relationships between a given hydroclimate index and relevant proxies over an instrumental period and subsequently reconstruct the hydroclimate back through time. We present case studies for Brisbane and Fitzroy catchments focusing on two hydroclimate indices, the Rainfall Index (RFI) and the Standardized Precipitation‐Evapotranspiration Index (SPEI). The probabilistic nature of the reconstructions allows us to estimate the probability that a hydroclimate index in any reconstruction year was lower (higher) than the minimum (maximum) value observed over the instrumental period. In Brisbane, the RFI is unlikely (probabilities < 5%) to have exhibited extremes beyond the minimum/maximum values observed between 1889 and 2019. However, in Fitzroy there are several years during the reconstruction period where the RFI is likely (>50% probability) to have exhibited behavior beyond the minimum/maximum of what has been observed, during the instrumental period. For SPEI, the probability of observing such extremes prior to the beginning of the instrumental period in 1889 doesn't exceed 30% in any reconstruction year in Brisbane, but exceeds 50% in multiple years in Fitzroy.

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Testing peatland water-table depth transfer functions using high-resolution hydrological monitoring data

Cited by 48 publications

References 60 publications

Ecosystem state shifts during long‐term development of an Amazonian peatland

Ecosystem state shifts during long‐term development of an Amazonian peatland

Re-assessing the vertical distribution of testate amoeba communities in surface peats: Implications for palaeohydrological studies

A Bayesian time series model for reconstructing hydroclimate from multiple proxies

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