| Abstract | This paper aims to determine the ecological and chemical reference conditions (similar to 1800-1850 AD) and degree of floristic change at nine enriched lakes, covering a range of types across Europe, using fossil diatom assemblages in dated sediment cores and application of total phosphorus (TP) transfer functions. Additionally the study assesses the potential of analogue matching as a technique for identifying reference sites and for estimating reference TP concentrations for the study lakes using a training set of 347 European lakes and 719 diatom taxa. Oligotrophic, acidophilous to circumneutral taxa were predominant in the reference samples of several of the deep lakes, and benthic Fragilaria spp. dominated the reference samples of two high alkalinity shallow lakes. The degree of floristic change from the reference sample, assessed using the squared chord distance (SCD) dissimilarity coefficient, revealed that two sites had experienced slight change (Lago Maggiore, Felbrigg Lake), five experienced moderate change (Mjoesa, Loch Davan, Loch Leven, White Lough, Esthwaite Water), and two showed evidence of major change (Groby Pool, Piburger See). For three lakes, there were no analogues in the diatom dataset owing to the uniqueness and diversity of the diatom reference assemblages. For the remaining six sites the number of analogues ranged from 2 to 44. For two deep lakes most of the analogues seemed appropriate as they were of the same type and had low TP concentrations. However, for two other deep lakes and two shallow lakes some of the analogues differed markedly in their depth and alkalinity from the lake in question or had TP concentrations seemingly too high to represent reference conditions suggesting that the analogues may not be suitable as reference sites. For the deep lakes, similar reference TP values were calculated using the EDDI Combined TP transfer function and the analogue matching technique with concentrations typically < 20 mu g L(-1). However, for the shallow lakes, the analogue matching method produced inferred values considerably higher than those of the transfer function. The wide ecological tolerances of many of the diatom taxa found in the reference samples most likely explain the selection of inappropriate analogue sites. In summary, the study demonstrates that palaeoecological techniques can play a valuable role in determining reference conditions and indicates that the analogue matching technique has the potential to be a useful tool for identifying appropriate reference sites for lakes impacted by eutrophication |
| Authors | Bennion, H (Bennion, Helen)[ 1 ] ; Simpson, GL (Simpson, Gavin L.)[ 1 ] ; Anderson, NJ (Anderson, N. John)[ 2 ] ; Clarke, G (Clarke, Gina)[ 1 ] ; Dong, XH (Dong, Xuhui)[ 1 ] ; Hobaek, A (Hobaek, Anders)[ 3,4 ] ; Guilizzoni, P (Guilizzoni, Piero)[ 5 ] ; Marchetto, A (Marchetto, Aldo)[ 5 ] ; Sayer, CD (Sayer, Carl D.)[ 1 ] ; Thies, H (Thies, Hansjoerg)[ 6 ] ; Tolotti, M (Tolotti, Monica)[ 7 ] |
| Text | 203770 2011 10.1007/s10933 010 9418 4 ISI Web of Science WOS 000290043900003 Analogue matching Diatoms Eutrophication Reference conditions Restoration targets Defining ecological and chemical reference conditions and restoration targets for nine European lakes Bennion, H Bennion, Helen 1 ; Simpson, GL Simpson, Gavin L. 1 ; Anderson, NJ Anderson, N. John 2 ; Clarke, G Clarke, Gina 1 ; Dong, XH Dong, Xuhui 1 ; Hobaek, A Hobaek, Anders 3,4 ; Guilizzoni, P Guilizzoni, Piero 5 ; Marchetto, A Marchetto, Aldo 5 ; Sayer, CD Sayer, Carl D. 1 ; Thies, H Thies, Hansjoerg 6 ; Tolotti, M Tolotti, Monica 7 1 UCL, Environm Change Res Ctr, Dept Geog, London WC1E 6BT, England 2 Univ Loughborough, Dept Geog, Loughborough LE11 3TU, Leics, England 3 Norwegian Inst Water Res NIVA, N 5817 Bergen, Norway 4 Univ Bergen, Dept Biol, N 5020 Bergen, Norway 5 CNR, Ist Studio Ecosistemi, I 28922 Verbania, Italy 6 Univ Innsbruck, Inst Ecol, A 6020 Innsbruck, Austria 7 IASMA Res Innovat Ctr, Ist Agr S Michele AllAdige, Fdn E Mach, Environm Nat Resources Area, I 38010 San Michele All Adige, Trento, Italy This paper aims to determine the ecological and chemical reference conditions similar to 1800 1850 AD and degree of floristic change at nine enriched lakes, covering a range of types across Europe, using fossil diatom assemblages in dated sediment cores and application of total phosphorus TP transfer functions. Additionally the study assesses the potential of analogue matching as a technique for identifying reference sites and for estimating reference TP concentrations for the study lakes using a training set of 347 European lakes and 719 diatom taxa. Oligotrophic, acidophilous to circumneutral taxa were predominant in the reference samples of several of the deep lakes, and benthic Fragilaria spp. dominated the reference samples of two high alkalinity shallow lakes. The degree of floristic change from the reference sample, assessed using the squared chord distance SCD dissimilarity coefficient, revealed that two sites had experienced slight change Lago Maggiore, Felbrigg Lake , five experienced moderate change Mjoesa, Loch Davan, Loch Leven, White Lough, Esthwaite Water , and two showed evidence of major change Groby Pool, Piburger See . For three lakes, there were no analogues in the diatom dataset owing to the uniqueness and diversity of the diatom reference assemblages. For the remaining six sites the number of analogues ranged from 2 to 44. For two deep lakes most of the analogues seemed appropriate as they were of the same type and had low TP concentrations. However, for two other deep lakes and two shallow lakes some of the analogues differed markedly in their depth and alkalinity from the lake in question or had TP concentrations seemingly too high to represent reference conditions suggesting that the analogues may not be suitable as reference sites. For the deep lakes, similar reference TP values were calculated using the EDDI Combined TP transfer function and the analogue matching technique with concentrations typically < 20 mu g L 1 . However, for the shallow lakes, the analogue matching method produced inferred values considerably higher than those of the transfer function. The wide ecological tolerances of many of the diatom taxa found in the reference samples most likely explain the selection of inappropriate analogue sites. In summary, the study demonstrates that palaeoecological techniques can play a valuable role in determining reference conditions and indicates that the analogue matching technique has the potential to be a useful tool for identifying appropriate reference sites for lakes impacted by eutrophication 45 ID_PUMA cnr.ise/2011 A0 027 Defining ecological and chemical reference conditions and restoration targets for nine European lakes Defining_ecological_and_chemical_reference_conditions_and_restoration_targets_for_nine_European_lakes.pdf Articolo in rivista Kluwer Academic 0921 2728 Journal of paleolimnology Journal of paleolimnology J. paleolimnol. aldo.marchetto MARCHETTO ALDO piero.guilizzoni GUILIZZONI PIERO TA.P02.014.002 Impatto dei cambiamenti globali sugli ecosistemi acquatici |
