Water level fluctuations in rich fens: an assessment of ecological benefits and drawbacks - Supplementary data

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Water level fluctuations in rich fens: an assessment of ecological benefits and

drawbacks

Mettrop, I.S.

Publication date

2015

Document Version

Final published version

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Citation for published version (APA):

Mettrop, I. S. (2015). Water level fluctuations in rich fens: an assessment of ecological

benefits and drawbacks.

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Supplementary data

Appendix A

Appendix A In both a rich fen and a Sphagnum-dominated fen in the area Stobbenribben, the redox potential (Eh) in the upper 20 cm was measured over a period of seven months in order to assess the extent to which

oxygen availability increases as a result of drought. Permanently installed redox electrodes, connected to a Hypnos data logger (MVH Consult, Leiden, the Netherlands) were used to record Eh at -1 cm, -3 cm, -5 cm,

-10 cm, -15 cm, and -20 cm, every 15 minutes (Vorenhout et al., 2011). The redox profiles indicate that periods of more than two months of drought can have major impacts on the redox potential in the upper 10 cm of the soil in both rich fens and Sphagnum-fens. The relatively dry spring of 2013 led to a significant increase of Eh, up to the time that long-term precipitation led to a significant decrease of Eh in April 2013. Especially in

Sphagnum-fens the redox potential was affected by drought, as Eh values of +600 mV were measured up to a

depth of -20 cm. These data indicate that long periods of drought do occur in intact peatlands, and therefore long-term laboratory incubation results, as reported in chapter 2, are representative and useful for assessing the effects of drought in the field.

Vorenhout, M., van der Geest, H.G., Hunting, E.R., 2011. An improved datalogger and novel probes for continuous redox measurements in wetlands. International Journal of Environmental Analytical Chemistry 91(7/8), 801-810.

-300 – -100 -100 – 0 0 – 100 100 – 200 200 – 300 300 – 400 400 – 500 500 – 600 600 – 800

Stobbenribben: Scorpidium scorpioides

Stobbenribben: Sphagnum palustre

Redox potential (mV) cm cm -1 -3 -10 -5 -15 -20 -1 -3 -10 -5 -15 -20

Nov. ‘12 Dec. ‘12 Jan. ‘13 Feb. ‘13 March ‘13 April ‘13 May ‘13 Nov. ‘12 Dec. ‘12 Jan. ‘13 Feb. ‘13 March ‘13 April ‘13 May ‘13

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Appendix B

Appendix B.1 Effects of fen site, vegetation type and their interaction on chemical variables in porewater at the start of the experiment in July 2008. F-ratios (ANOVA) are shown with their level of significance and the results of Tukey HSD post-hoc tests.

Start of the experiment in July 2008 Veg*Area Area Veg

df denom. df num. F P df num. F P KW VW WEE df num. F P Scor Call Sph Moor

Water table 43 5 1.57 0.188 2 1.83 0.172 a a a 3 13.46 0.000 b b a a pH 42 5 2.58 0.040 2 6.32 0.004 a b a 3 29.46 0.000 b b a a Alkalinity 40 5 2.61 0.039 2 2.46 0.098 a a a 3 21.50 0.000 b b a a Ca 41 5 4.32 0.003 2 10.44 0.000 b c a 3 17.50 0.000 c b a a Fe 43 5 2.19 0.073 2 2.63 0.063 a a a 3 0.83 0.486 a a a a S 40 5 2.32 0.061 2 1.64 0.207 a a a 3 1.10 0.359 a a a a Cl 41 5 1.02 0.419 2 6.72 0.003 b b a 3 10.50 0.000 b b a a o-PO4 42 5 0.62 0.689 2 0.32 0.727 a a a 3 0.95 0.427 a a a a NH4 42 5 1.95 0.106 2 0.83 0.445 a a a 3 0.94 0.428 a a a a NO3 42 5 0.62 0.689 2 2.20 0.124 a a a 3 1.42 0.253 a a a a

Appendix B.2 Effects of water level treatment on the water tables and chemical variables in porewater of different vegetation types during successive years for the five different field experiments. As response variables, the differences between the measurements right after and right before water level treatment were used. For the water levels, the differences between the measurements during and right before the increase in surface water level were also tested. F-ratios (linear mixed models) are shown with their level of significance. Differences between vegetation types were further examined by comparing their estimated marginal means in a LSD post-hoc tests. Experiment 1 = surface water level increase in a floating fen (WEE-area); experiment 2 = surface water level increase in a non-floating fen (KW-area); experiment 3 = wet periods in July, with about 50 mm of rain in two weeks (3.5–4 mm/day) in a non-floating fen (VW-area); experiment 4 = surface water level decrease in a floating fen (WEE-area); experiment 5 = surface water level decrease in a non-floating fen (KW-area). For NH4 and NO3 in experiment 3, a one-way ANOVA was used to

determine significant differences between vegetation types, since NH4 and NO3 were not measured well in

2009.

Experiment 1 Veg*Year Year Veg

Period df num. df denom. F P df num. df denom. F P 2009 2010 df num. df denom. F P Call Sph Moor

Water level start during-start end-start 2 2 2 10.1 10.6 10.2 1.36 0.06 2.68 0.301 0.947 0.116 1 1 1 10.1 10.9 10.3 1.06 0.03 1.58 0.328 0.859 0.236 a a a a a a 2 2 2 10.9 9.4 10.7 2.58 10.95 0.88 0.121 0.004 0.445 a a a a a a a b a pH end-start 2 9.2 1.09 0.375 1 9.2 0.80 0.393 a a 2 10.2 0.80 0.474 a a a Alkalinity end-start 2 7.6 3.72 0.075 1 7.7 4.89 0.060 a a 2 8.9 0.46 0.674 a a a Ca end-start 2 11.0 0.57 0.584 1 11.0 0.14 0.712 a a 2 11.1 0.10 0.904 a a a Fe end-start 2 10.0 2.70 0.115 1 10.1 0.22 0.652 a a 2 10.4 0.22 0.810 a a a

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S end-start 2 8.9 0.01 0.989 1 8.9 4.97 0.053 a a 2 8.9 1.09 0.379 a a a Cl end-start 2 7.6 0.01 0.987 1 7.9 4.50 0.065 a b 2 6.9 0.40 0.683 a a a o-PO4 end-start 2 9.5 1.70 0.223 1 9.5 1.70 0.223 a a 2 10.4 2.07 0.176 a a a

NH4 end-start 2 8.0 1.72 0.239 1 8.0 2.40 0.160 a a 2 8.1 1.74 0.235 a a a

NO3 end-start 2 8.6 0.45 0.654 1 8.6 0.44 0.523 a a 2 8.5 3.27 0.088 a a a

Period df num. df denom. F P df num. df denom. F P 2008 2009 2010 2011 df num. df denom. F P Scor Call Sph Moor

Water level start during-start end-start 6 6 6 15.5 14.6 15.7 2.12 3.25 0.88 0.109 0.031 0.529 2 2 2 15.5 14.6 15.8 157.44 115.99 136.72 0.000 0.000 0.000 c a a b b b a c c 3 3 3 16.2 15.1 16.2 10.22 8.29 1.25 0.001 0.002 0.324 b c a b bc a a a a a ab a pH end-start 9 13.7 4.11 0.010 3 13.8 12.46 0.000 b b b a 3 14.7 13.99 0.000 c c b a Alkalinity end-start 9 8.4 7.80 0.003 3 8.5 28.35 0.000 a ab a b 3 14.5 3.76 0.035 b ab a a Ca end-start 9 15.0 3.54 0.015 3 15.1 13.82 0.000 b b a c 3 16.0 0.35 0.789 a a a a Fe end-start 9 11.4 1.93 0.148 3 11.5 8.22 0.003 b b a b 3 8.6 1.38 0.313 a a a a S end-start 9 11.9 2.72 0.055 3 11.4 1.27 0.332 a a a a 3 14.5 1.42 0.276 a a a a Cl end-start 9 15.7 7.18 0.000 3 15.5 70.64 0.000 ab a b c 3 16.7 1.27 0.318 a a a a o-PO4 end-start 9 13.5 1.30 0.321 3 13.1 12.79 0.000 ab a b a 3 14.1 0.88 0.474 a a a a NH4 end-start 9 7.0 2.40 0.131 3 6.9 2.39 0.156 a a a a 3 10.6 1.05 0.409 a a a a NO3 end-start 9 15.9 1.70 0.171 3 15.9 2.70 0.080 a a a a 3 16.1 1.72 0.203 a a a a

Period df num. df denom. F P df num. df denom. F P 2008 2009 df num. df denom. F P Scor Call Sph Moor

Water level start during-start end-start 3 3 3 16.0 16.0 16.0 2.21 3.13 2.70 0.126 0.055 0.080 1 1 1 16.0 16.0 16.0 289.96 1.61 0.35 0.000 0.222 0.565 b a a a a a 3 3 3 16.0 16.0 16.0 15.26 1.15 0.99 0.000 0.361 0.424 c a a b a a a a a a a a pH end-start 3 15.4 3.01 0.062 1 15.9 1.03 0.325 a a 3 16.8 2.24 0.122 a a a a Alkalinity end-start 3 10.9 4.04 0.037 1 10.9 16.87 0.002 b a 3 10.9 11.94 0.001 b b a a Ca end-start 3 12.8 3.88 0.049 1 12.8 8.48 0.012 b a 3 11.0 11.17 0.001 b bc ab a Fe end-start 3 13.7 3.86 0.034 1 13.7 25.55 0.000 b a 3 13.3 6.10 0.008 ab bc c a S end-start 3 13.5 0.36 0.784 1 13.5 0.35 0.561 a a 3 14.6 0.67 0.584 a a a a Cl end-start 3 10.8 1.13 0.380 1 10.9 21.71 0.001 a b 3 10.3 2.43 0.124 a a a a o-PO4 end-start 3 15.7 1.45 0.266 1 15.8 1.40 0.255 a a 3 13.2 1.63 0.231 a a a a NH4 end-start 3 11.0 0.43 0.739 a a a a NO3 end-start 3 11.0 1.36 0.306 a a a a

Period df num. df denom. F P df num. df denom. F P 2009 2010 2011 df num. df denom. F P Call Sph Moor

Water level start during-start end-start 4 4 4 9.7 10.3 10.0 1.31 0.40 0.32 0.331 0.807 0.857 2 2 2 9.5 10.3 9.9 25.03 15.01 15.89 0.000 0.001 0.001 a b a a a c b a b 2 2 2 10.9 9.4 9.7 1.91 19.20 0.18 0.194 0.000 0.842 a b a a b a a a a pH end-start 4 8.9 0.54 0.712 2 8.8 0.24 0.789 a a a 2 11.6 0.73 0.504 a a a Alkalinity end-start 4 7.7 9.10 0.005 2 7.9 10.18 0.006 b a b 2 10.2 1.96 0.190 a a a Ca end-start 4 9.7 1.20 0.371 2 9.5 3.88 0.058 a a a 2 11.1 3.04 0.088 a a a

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Fe end-start 4 4.6 0.81 0.574 2 4.6 0.26 0.781 a a a 2 10.0 0.40 0.680 a a a S end-start 4 7.1 3.08 0.091 2 7.5 5.15 0.039 ab b a 2 7.2 0.56 0.597 a a a Cl end-start 4 8.5 22.79 0.000 2 8.5 22.81 0.000 c b a 2 4.9 14.84 0.009 b a a o-PO4 end-start 4 9.9 6.40 0.008 2 9.9 4.60 0.039 b a ab 2 10.6 2.85 0.102 a a a NH4 end-start 2 8.7 2.07 0.184 1 10.7 0.11 0.742 a a 2 8.9 3.38 0.081 a a a NO3 end-start 2 10.2 0.26 0.777 1 10.5 2.73 0.128 a a 2 10.4 0.04 0.961 a a a

Period df num. df denom. F P df num. df denom. F P 2009 2010 2011 df num. df denom. F P Scor Call Sph Moor

Water level start during-start end-start 6 6 6 15.7 16.0 13.7 9.11 31.83 8.20 0.000 0.000 0.001 2 2 2 15.8 16.0 13.7 209.47 167.02 26.90 0.000 0.000 0.000 b b b a c b c a a 3 3 3 16.0 16.4 16.1 25.74 6.97 5.53 0.000 0.003 0.008 c a ab c a a b a a a b b pH end-start 5 10.5 1.09 0.419 2 11.1 2.87 0.099 a a a 3 12.2 0.60 0.624 a a a a Alkalinity end-start 5 14.4 3.10 0.042 2 17.4 8.59 0.003 b a a 3 7.8 0.63 0.614 a a a a Ca end-start 5 13.4 0.64 0.672 2 13.4 4.19 0.039 a b a 3 10.5 0.30 0.823 a a a a Fe end-start 5 9.1 1.48 0.287 2 11.1 1.61 0.244 a a a 3 10.0 1.39 0.302 a a a a S end-start 5 6.0 1.50 0.317 2 8.1 2.68 0.128 a a a 3 3.3 11.62 0.029 b b b a Cl end-start 5 15.0 1.73 0.189 2 18.8 63.01 0.000 a b a 3 16.2 2.31 0.114 a a a a o-PO4 end-start 5 10.4 1.99 0.162 2 10.6 1.61 0.244 a a a 3 9.0 1.84 0.210 a a a a NH4 end-start 2 13.4 0.14 0.669 1 14.0 0.35 0.564 a a 3 12.4 1.29 0.320 a a a a NO3 end-start 2 8.2 1.06 0.390 1 8.6 3.86 0.083 a a 3 14.6 2.76 0.080 a a a a

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Appendix C

Appendix C.1 Effect of five surface water level treatments on the pH in four vegetation types, as measured 2 days before (black lines at the left of each triplet), during (grey lines) and 2 days after the treatments (black lines at the right of each triplet). Sample means (white centres of a line) are shown with their standard deviations (n = 5). Scor = fen dominated by Scorpidium cossonii or Hamatocaulis vernicosus, Call = fen dominated by Calliergonella cuspidata, Sph = fen dominated by Sphagnum palustre, Moor with Erica tetralix and Sphagnum palustre. Experiment 1 = floating WEE-fen during raised surface water levels in winter, experiment 2 = non-floating KW-fen during raised surface water levels in winter, experiment 3 = non-floating VW-fen during raised surface water levels in summer, experiment 4 = floating WEE-fen during lowered surface water levels in summer, experiment 5 = non-floating KW-fen during lowered surface water levels in summer. Statistical information is provided in Table S2.

4.0 5.0 6.0 7.0 4.0 5.0 6.0 7.0 4.0 5.0 6.0 7.0 4.0 5.0 6.0 7.0 4.0 5.0 6.0 7.0 pH − exp. 2 exp. 3 exp. 4 exp. 5 exp. 1 r o o M h p S ll a C Scor ’08 ’09 ’10 ’11 ’08 ’09 ’10 ’11 ’08 ’09 ’10 ’11 ’08 ’09 ’10 ’11

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Appendix C.2 Effect of five surface water level treatments on the Fe-concentrations (μmol L-1 _{) in four}

vegetation types. See the caption of Appendix C.1 for abbreviations and further information. Statistical information is provided in Table S2.

0 50 100 150 0 50 100 150 0 50 100 150 0 50 100 150 0 50 100 150 Fe µmol L −1 exp. 2 exp. 3 exp. 4 exp. 5 exp. 1 r o o M h p S ll a C Scor ’08 ’09 ’10 ’11 ’08 ’09 ’10 ’11 ’08 ’09 ’10 ’11 ’08 ’09 ’10 ’11

Appendix C.3 Effect of five surface water level treatments on the total S-concentrations (μmol L-1 _{) in four}

0 100 200 0 100 200 0 200 400 0 100 200 0 200 400 S µmol L −1 exp. 2 exp. 3 exp. 4 exp. 5 exp. 1 r o o M h p S ll a C Scor ’08 ’09 ’10 ’11 ’08 ’09 ’10 ’11 ’08 ’09 ’10 ’11 ’08 ’09 ’10 ’11

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Appendix C.4 Effect of five surface water level treatments on the 0-PO4 concentrations (μmol L-1 ) in four

0.0 1.0 2.0 3.0 0.0 1.0 2.0 3.0 0.0 1.0 2.0 3.0 0.0 1.0 2.0 3.0 0.0 1.0 2.0 3.0 o−PO₄ µmol L−1 exp. 2 exp. 3 exp. 4 exp. 5 exp. 1 r o o M h p S ll a C Scor ’08 ’09 ’10 ’11 ’08 ’09 ’10 ’11 ’08 ’09 ’10 ’11 ’08 ’09 ’10 ’11

Appendix C.5 Effect of five surface water level treatments on the NH4 concentrations (μmol L-1 ) in four

0 20 40 0 20 40 0 20 40 0 20 40 0 20 40 NH₄ µmol L−1 exp. 2 exp. 3 exp. 4 exp. 5 exp. 1 r o o M h p S ll a C Scor ’08 ’09 ’10 ’11 ’08 ’09 ’10 ’11 ’08 ’09 ’10 ’11 ’08 ’09 ’10 ’11

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Appendix C.6 Effect of five surface water level treatments on the NO3 concentrations (μmol L-1 ) in four

0 5 10 15 0 5 10 15 0 5 10 15 0 5 10 15 0 5 10 15 NO₃ µmol L−1 exp. 2 exp. 3 exp. 4 exp. 5 exp. 1 r o o M h p S ll a C Scor ’08 ’09 ’10 ’11 ’08 ’09 ’10 ’11 ’08 ’09 ’10 ’11 ’08 ’09 ’10 ’11

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Appendix D

Appendix D Redox potentials (Eh) in the upper 20 cm of the soil in the three vegetation types during summer

inundation in the KW-fen in 2013 and 2014. Scor (A) = fen dominated by Hamatocaulis vernicosus, Call (B) = fen dominated by Calliergonella cuspidata, and Sph (C) = fen dominated by Sphagnum palustre. The vertical white lines indicate the initiation and end of the treatment period. For interpolation, ordinary kriging was applied in ArcGIS (ArcMap 10.0, ESRI, Redlands, USA).

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Appendix E Fe-, S- and DOC-concentrations per vegetation type in pore water 2 days before the experiment, in inundation water during the experiment, and in pore water 2 days after the experiment. Sample means with standard deviations are indicated (n = 5). Statistical information is provided in Table 5.3. Scor = fen dominated by Scorpidium cossonii or Hamatocaulis vernicosus, Call = fen dominated by Calliergonella cuspidata, Sph = fen dominated by Sphagnum palustre. KW = Kiersche Wiede (experimental fen site), VW = Veldweg (reference fen site).