Dynamic adjustment of training sets (‘moving-window’ reconstruction) by using transfer functions in paleolimnology—a new approach

Hübener, Thomas; Dreßler, Mirko; Schwarz, Anja; Langner, Kirsten; Adler, Sven

doi:10.1007/s10933-007-9145-7

Cited by 24 publications

(9 citation statements)

References 25 publications

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“…Vasko et al 2000;Toivonen et al 2001;Korhola et al 2002;Gersonde et al 2005;Haslett et al 2006;Holden et al 2008;Hübener et al 2008;Goring et al 2009;Velle et al 2011), we are probably close to the resolution of current data and methods. Decomposition of the variance in model RMSEP shows that the largest part (75% or more) is due to the fact that at a given environmental value today, there is still siteto-site variation in modern assemblages (Birks et al 1990).…”

Section: Challenges and Future Developmentssupporting

confidence: 82%

Strengths and Weaknesses of Quantitative Climate Reconstructions Based on Late-Quaternary Biological Proxies

Birks

2011

TOECOLJ

337

284

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Abstract:The importance of reconstructing past environments quantitatively in palaeoecology is reviewed by showing that many ecological questions asked of palaeoecological data commonly involve the reconstructions of past environment. Three basic approaches to reconstructing past climate from palaeoecological data are outlined and discussed in terms of their assumptions, strengths, and weaknesses. These approaches are the indicator-species approach involving bioclimateenvelope modelling; the assemblage approach involving modern analogue techniques and response surfaces; and the multivariate calibration-function approach. Topics common to all approaches are reviewed -presentation and interpretation, evaluation and validation, comparison, and general limitations of climate reconstructions. Challenges and possible future developments are presented and the potential future role of quantitative climate reconstructions in palaeoecology is summarised.

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Section: Challenges and Future Developmentssupporting

confidence: 82%

Strengths and Weaknesses of Quantitative Climate Reconstructions Based on Late-Quaternary Biological Proxies

Birks

2011

TOECOLJ

337

284

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“…DI-TP levels were reconstructed using the moving-window approach (MW). The MW approach (Hübener et al, 2008) is based on the identification of a certain number of the nearest neighbours between core-and training set diatom assemblages. For each fossil sample, the nearest neighbours were identified using Euclidean Distances derived from the sample scores of the first three DCA-axes (CANOCO 4.5, ter Braak and Smilauer 2002) of the merged MV-EDDI training set.…”

Section: Diatom-based Statistical Analysesmentioning

confidence: 99%

“…The training set and the transfer function with the best statistics were chosen for the TP reconstruction of each fossil sample from the six study lakes using an automated selection and the computer program R 2.4.1. (Hübener et al, 2008;Adler, 2008). Sample-specific training set performances were: mean R 2 = 0.651-0.817 and mean R 2 xval ¼ 0:462 À 0:491: For the TP reconstructions of Lake GUD, the MW was run without Aulacoseira subarctica (O. Müller) Haworth, owing to the special dystrophic conditions of the lake (see results Lake GUD and discussion 1.2).…”

Section: Diatom-based Statistical Analysesmentioning

confidence: 99%

A multi-proxy paleolimnological reconstruction of trophic state reference conditions for stratified carbonate-rich lakes in northern Germany

et al. 2009

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This study aims to identify reference conditions (nutrient status and diatom assemblages) as required by the European Water Framework Directive (WFD) for stratified, carbonate-rich lowland lakes with a large watershed area (watershed area to lake volume ratio (WV) [ 1.5 km 2 10 -6 m -3 ) and a retention time (RT) from 0.1 to 10 years (Central Baltic Lake-Type 1, German Lake-Type 10) in European ecoregion 14. Diatoms, pollen and geochemistry were analysed from sediment cores of six lakes from northern Germany representing different subtypes of Lake-Type 10 (varying WV and RT) and covering the past 290-1,750 years. Historic total phosphorus levels were inferred using diatom-based transfer functions selected from a merged European data set and from optimised data sets identified with the moving-window approach. Pollen and geochemical proxies were used to identify occurrence and intensity of anthropogenic catchment usage. Lake trophic state reference conditions and associated diatom assemblages were identified for three of the six study lakes. In contrast, according to fossil pollen assemblages, two lakes were already strongly impacted by intensive catchment usage when the oldest investigated sediments were laid down. Thus, reference conditions of these already eutrophic lakes could not be identified. Similarly, the lowermost samples of a core from the sixth lake showed signs of impact, and it remains unclear whether the identified dystrophic conditions occurred naturally or if they were due to the drainage of wetlands in Medieval times. Lakes with a relatively small WV (1.5-5.0 km 2 10 -6 m -3 ) and RT [ 1 year were naturally oligotrophic to low mesotrophic and a typical, representative diatom assemblage was identified. In contrast, typical reference conditions or diatom assemblages for lakes with higher WV (5-18.6 km 2 10 -6 m -3 ) and RT \ 1 year could not be identified as chemical precipitation and upstream lakes (nutrient sinks or sources) additionally influenced natural nutrient levels. Therefore, the reference situation of both trophic state and diatom assemblages in a lake may be strongly influenced by other modifying, limnological processes in addition to WV and RT. Overall, this study helps to implement the WFD by identifying reference conditions and by discussing the level of differentiation of lake types required to set reference conditions.

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“…For the downcore TP reconstructions the nine training sets were merged to increase the number of modern analogues, to increase the gradient length of interest and to allow a comparison with the results of the published TP reconstructions that used relative abundance data and combined training sets (Hübener and Dreßler, 2003;Hübener and Dörfler, 2004;Dreßler et al, 2006;Hübener et al, 2008). It is assumed that the training sets from the published literature were well chosen and, therefore, is well representative of the diatom assemblages from the corresponding sediment cores (following Overpeck et al, 1985).…”

Section: Training Setsmentioning

confidence: 99%

“…Four of the six sediment cores were from lakes in Northern Germany: Dudinghausener See (Dreßler et al, 2006;Hübener et al, 2008), Rugensee (Dreßler and Hübener, 2003;Hübener et al, 2008), Vielbecker See (Dreßler, 2006,) and Krakower Obersee (Hübener and Dörfler, 2004). All four lakes were plankton dominated during the entire period presented in the cores except for Vielbecker See, which changed from a dimictic, plankton dominated lake to a polymictic, benthic dominated lake (Dreßler, 2006).…”

Section: Tp Reconstructionmentioning

confidence: 99%

A comparison of relative abundance versus class data in diatom-based quantitative reconstructions

Adler

Hübener

Dreßler

et al. 2010

Journal of Environmental Management

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Dynamic adjustment of training sets (‘moving-window’ reconstruction) by using transfer functions in paleolimnology—a new approach

Cited by 24 publications

References 25 publications

Strengths and Weaknesses of Quantitative Climate Reconstructions Based on Late-Quaternary Biological Proxies

Strengths and Weaknesses of Quantitative Climate Reconstructions Based on Late-Quaternary Biological Proxies

A multi-proxy paleolimnological reconstruction of trophic state reference conditions for stratified carbonate-rich lakes in northern Germany

A comparison of relative abundance versus class data in diatom-based quantitative reconstructions

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