Research Proposal: Inundation as an effective water management tool to counteract the acidification in the quaking fens in the Tienhoven lakes.

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ALW Open Programme

Proposal form adapted for the Future Planet Earth Science - Bsc project

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Adapted for the BSc Project Earth Sciences at IBED UVA

The maximum length of a proposal is 12 pages, including a maximum of 4 pages for the description of the proposed research

***NOTE FOR EACH ITEM TOTAL PERCENTAGE FOR FINAL GRADE ARE ALOCATED *** 1a. Details of proposal (ITEM 1, 2 and 8: 10%)

Title: Inundation as an effective water management tool to counteract the acidification in the quaking fens in the Tienhoven lakes.

Area: X Geo and Biosphere Ο from Molecule to Organism 1b. Field(s) of research

code + field of research; please see the NWO research field list:

http://www.nwo.nl/financiering/nwo-disciplinecodes main field of research

1 code: 2 description:

3 22.40.00 Ecologie

4 If applicable: other fields of research (in order of relevance):

5 code: description:

6 15.90.00 Aardwetenschappen, overig

7 8

1c. Details of applicant Name: Axelle Stroobant

Gender: Ο Male X Female

E-mail: axelle.stroobant@student.uva.nl Date of birth: 28/11/1997

BSc study start date: 01/09/2018 Institution: University of Amsterdam

Position: Ο Professor Ο Associate professor (UHD) Ο Assistant professor (UD) X Student: Research School: University of Amsterdam – Science Park

Name and address of the responsible person at your institution (e.g. scientific director of the institute or dean of the faculty): dr. K.F. (Kenneth) Rijsdijk

Institute for Biodiversity and Ecosystem Dynamics (IBED) P.O. Box 94240

1090 GE Amsterdam The Netherlands

1f. Applying for: X BSc Project

2a. Composition of the research group

Name and title Specialization Institution Involvement Mw. Dr. A.M. Kooijman Biodiversity and

Ecosystem dynamics

University of Amsterdam

Thesis Supervisor Dhr. Dr. K.F. Rijsdijk Biodiversity and

Ecosystem dynamics

University of Amsterdam

Thesis Coordinator Dr. Renske Hoondert Ecological statistics University of

Amsterdam

Guidance Max van Soolingen Bachelor student Future

Planet Studies

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Page 2 of 10 2b. Top 5 publications related to the proposed research

1. Kooijman, A. M., Cusell, C., Mettrop, I. S., & Lamers, L. P. M. (2016). Recovery of target bryophytes in floating rich fens after 25 yr of inundation by base-rich surface water with lower nutrient contents. Applied Vegetation Science, 19(1), 53-65.

2. Lotterman, K. (2019). Flora-, vegetatie- en structuurkartering Tienhovense plassen in 2018. Vereniging Natuurmonumenten afdeling Natuur en Landschap.

3. Lamers, L. P., Vile, M. A., Grootjans, A. P., Acreman, M. C., van Diggelen, R., Evans, M. G., ... & Smolders, A. J. (2015). Ecological restoration of rich fens in Europe and North America: from trial and error to an evidence-based approach. Biological Reviews, 90(1), 182-203.

4. Aggenbach, C.J.S., D.G. Cirkel, C. Cusell, G. van Dijk, A.M. Kooijman, 2020. Onderzoek naar bevloeiing als beheermaatregel voor behoud en herstel van basenrijke trilvenen. Rapport nummer 2020/OBN241-LZ, VBNE, Driebergen.

5. Cusell, C., Mettrop, I. S., van Loon, E. E., Lamers, L. P., Vorenhout, M., & Kooijman, A. M. (2015). Impacts of short-term droughts and inundations in species-rich fens during summer and winter: large-scale field manipulation experiments. Ecological Engineering, 77, 127-138.

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3a. Scientific summary (ITEM 3a and 3b: 10%) (max. 250 words)

As quaking fens become isolated from base-rich ground or surface water, acidification can occur as stormwater and runoff water from the agricultural activities in the near surroundings becomes dominant and natural vegetation, in this case Scorpidium scorpioides, is replaced by Spaghnum-species which are found in areas with lower pH values. As the peat mosses become more dominant the fens are further acidified through the organic acids that they produce from their decomposition and by cation exchange. To counteract this process of acidification in the quaking fens in the Tienhoven Lakes it is important to assess if flooding with base rich water from surrounding crags can act as an effective water management tool to restore and preserve the rich fen vegetation types. To examine whether this is indeed an effective water management tool the pH values and EC-values at different depths and locations in the quaking fens will be measured as well as the depth of the sandy layer. When analyzing these results, a clear statement can be made about the effectiveness of inundation with water from surrounding crags as a water management tool for conservation of the rich fen vegetation types in the quaking fens in the Tienhoven Lakes.

3c. Summary for the general public (max. 100 words) Please provide both a title and summary for the general public, preferably in Dutch.

Title: Inundatie als een effectief instrument voor waterbeheer om de verzuring in de Tienhovense Plassen tegen te gaan.

Summary: De trilvenen die zich bevinden in de Tienhovense Plassen ondergaan door verschillende agrarische activiteiten verzuring. Hierdoor worden de vegetatietypes die normaal kenmerkend zijn voor dit soort landschappen, zoals schorpioenmossen, vervangen door soorten zoals veenmos die beter bestand zijn tegen een zure grond. Om dit fenomeen tegen te gaan moeten instrumenten voor

waterbeheer worden ingezet en in dit onderzoek zal geanalyseerd worden of het met opzet overstromen van de venen met water uit de omliggende sloten een effectief beheerinstrument kan zijn om de verzuring van de trilvenen tegen te gaan.

4. Description of the proposed research (ITEM 4 60%) Max. 8 pages (and max. 2400 words excluding literature references).

Inundation as an effective water management tool to counteract the

acidification in the quaking fens in the Tienhoven lakes.

1. Introduction

In Great Britain, Germany and The Netherlands a substantial amount of species-rich quaking fens have been drained and transformed into agricultural land, which causes the fens to become rare in Western Europe (Verhoeven et al., 1988). Because of peat excavations in The Netherlands small fens have been developing scattered in heavily fertilized landscapes over the last few centuries, causing them to be strongly affected by the agricultural activities from their surroundings and inlet of polluted river water (Verhoeven, Koerselman & Beltman, 1988). The application of excessive amounts of fertilizers that are used to increase agricultural benefit result in leaching and run-off of N, P and K in groundwater and surface water. Additionally, the use of manure increases the evaporation of ammonia that increases the nitrogen input in precipitation which both cause a change in the pH value of the water and

eutrophication, which in their turn change the dominance of species (Verhoeven et al., 1988). In Central Europe the quaking rich fens with brown-mosses, such as Scorpidium scorpioides, are a representation of a relict phenomenon from the Late Glacial and Early-Holocene periods and the disappearance of these quaking fens is strongly accelerated because of the wide-scale eutrophication and disruption of the water regime of the Central European land scale in the second half of the 20th century (Peterka et al., 2018). In combination with the conversion of quaking fens to hay meadows, forest establishment and fertilizer

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application in the surrounding landscape they can effortlessly be replaced by Spaghnum-dominated fens because of autogenic succession (Peterka et al., 2018).

Among wetlands fens contain the highest biodiversity and they provide a lot of ecosystem services like water purification and carbon sequestration (Lamers et al., 2015) and 13 of the 14 Red List species defined by Weijs & van Tooren (2014) exist almost exclusively in the quaking fens.

Therefore, it is important to treat the remaining brown-moss quaking fens as sites of priority conservation (Peterka et al., 2018; Aggenbach et al., 2020).

2. Theoretical background

A rich fen is mesotrophic and characterized with a high pH-value

but these mineral-rich fens, like the quaking fens in Tienhoven in The Netherlands, are threatened by acidification and eutrophication and the well-developed fens with Scorpidium may cover less than 10 ha in the Netherlands (Kooijman et al., 2016; van Diggelen et al., 2018).

If the peat growth exceeds the minerotrophic water layer in the fens, the supply of cations decreases which results in less effective buffering of the incoming rainwater (Lamers et al., 2015). The aerobic oxidation processes in the growing process of peat also generate acids, making the environment less suitable for minerotrophic Scorpidium species and acidphilic Spaghnum species become dominant Lamers et al., 2015). The Spaghnum species produce organic acids from its decomposition and by cation

exchange, decreasing the acid-neutralizing capacity (ANC) even further (Lamers et al., 2015). When the bicarbonate is mostly consumed, the main buffering system consists of exchanging base cations from binding sites (Lamers et al., 2015). The latter is important for rich fen species when water tables drop due to natural fluctuation or anthropogenic desiccation (Lamers et al., 2015).

When the rich fens have a reduced access to base-rich water, the fens will have a lower pH value (or become more acidic) and the rich fen mosses are replaced with Spaghnum species, which contributes even further to the acidification of the wetlands as they produce acid themselves (Kooijman et al., 2016). Currently there are some species in the Eastern Inner Polder of Tienhoven (EIP) in the Eastern

Vechtplassen which characterize rich fens like Scorpidium scorpioides but they are mostly replaced by Spaghnum populations (Lotterman, 2019). To ensure the survival or revival of rich fen species like Scorpidium it is necessary to maintain a sufficient acid neutralization capacity by the input of calcium and bicarbonate-rich water, but due to the extraction of groundwater for agriculture and drinking water, this input is reduced significantly (Kooijman et al., 2016).

The base-rich water that naturally seeps into the fens, meaning that it comes from underneath through the sand layer and originates from the water behind the Utrechtse Heuvelrug which are located at a higher point in the landscape (Weijs & van Tooren, 2014).

During dry periods of time the water tables are maintained by pumping water into the area and the hydrology of the peatlands is thus influenced by man (Koerselman, 1989). The surface water from a ditch infiltrates the fen and groundwater recharge occurs meaning that there is a reversal of flow patterns (Koerselman, 1989). The vegetation of the fens is strongly affected by the hydrologic regime and water chemistry and even small changes in the interaction between groundwater, surface water and precipitation inputs may induce substantial changes and deterioration in the rich fen species like

Scorpidium (Koerselman, 1989). A way to increase the input of base-rich water is the use of inundation which is a water management tool where the land is flooded with base-rich water (Cussel et al., 2015). In the quaking fens the pH of the soil is regulated by the base saturation of the cation adsorption complex which consists of spots on soil particles with a negative charge where cations can adsorb to (Aggenbach et al., 2020). The higher the number of basic cations (Ca, Mg, Na, K) in the amount of adsorbed cation, the higher the pH of the soil. In the Tienhoven lakes calcium is the dominant basic cation in the cation adsorption complex, thus a high pH value indicated a high calcium occupancy

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(Aggenbach et al., 2020). The surface water in fens is normally alkaline rich (Aggenbach et al., 2020). When inundation or flooding with surface water from crags is used as a water management tool in fens it allows this base rich water to penetrate the soil top layer (Aggenbach et al., 2020). Because the water of the fens is acidic this leads to an increase in the Ca2+- concentration in the pore fluid and the process of cation exchange between the pore fluid and the cation adsorption complex on the soil particles will be initiated (Aggenbach et al., 2020). This process will result in a higher pH value of the soil and an increased buffer capacity, thus it is a promising management tool to counteract acidification of the quaking fens in Tienhoven (Aggenbach et al., 2020).

3. Aims and Objectives

This proposed research aims to create a model of the different electrical conductivity (EC) values of the water at different depths in three different quaking fens in the Tienhoven lakes to give insight on whether the water originates from seepage from the groundwater of the Utrecht Ridge, rainwater, or a mixture of the two. The EC-values are an indication of the number of ions in the water, thus clarifying whether the water is base-rich or not.

When analyzing the measured EC-values in combination with the depth of the layer of sand, the pH-values and the restoration of Scorpidium scorpioides a conclusion can be made about the positive effect inundation may have on the input of base-rich water to the quaking fens and thus the restoration or preservation of the Scorpidium scorpioides species. In this research the aim Is to look at the EC-values of the water and conclude whether inundation is an effective management tool.

4. Research questions

The main question of the proposed research is the following:

‘What is the effect of inundation on the restoration and preservation of Scorpidium scorpioides species in three different quaking fens at the Eastern Inner Polder of Tienhoven?’

To be able to require enough information to answer the main question the following sub-questions will need to be answered as well:

- ‘Does inundation as a management tool counteract the effect of acidification caused by rainfall sufficiently?’

- ‘What are the EC-values of the surface water?’

- ‘What are the EC-values of the groundwater at different depths?’

- ‘Are the EC-values indicating base-rich water on locations where the sandlayer is not shallow?’ - ‘What are the types of vegetation that dominate the quaking fens?’

5. Materials and methods 5.1 Study site

The study will be conducted between April and May 2021 in three quaking bogs that are situated in the Eastern Inner Polder of Tienhoven in the province of Utrecht (fig. 1). The orange crosses represent the three quaking bogs.

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Fig. 1: Topographical location of the Tienhoven lakes (Lotterman, 2019, p.7) 5.2 Experimental design

The three quaking bogs in the Tienhoven lakes are chosen as experimental sites and compared with each other.

The EC-values will be measured in the three quaking fens at different depths with intervals of 10 cm until the sand layer is reached. Each quaking bog will be divided into grid cells of 5 by 5 meters and the measurements will always be conducted 5 meters apart from the edge of the quaking fen. Reference points of the different locations will be indicated with a GPS and later used to map out the results using ArcGIS or Google Earth Pro. The measured EC-values will be noted in an Excel sheet and a model will be created using Matlab to visualize the different values at different depths making it clear for further analyzation.

The pH values of the located cells will also be measured and added to the margin of the models created in Matlab.

6. Expected results

It is expected that de EC-values will increase with depth as they are an indicator of the amount of calcium and bicarbonate concentrations in water and the water that originates from behind the Utrechtse Heuvelrug is provided in the fens through seepage from the sand layer underneath (Weijs & van Tooren, 2014).

The acid-neutralizing capacity (ANC) of divides the fens into rich fens and poor fens, the rich fens have a higher ANC than the poor fens. The pH in floating fens is determined by the bicarbonate-carbon dioxide buffering system and usually this value is around 6-6.5, the rich fens also have higher decomposition rates in comparison with acidic peatlands (Lamers et al., 2015). Therefore, it is expected that the pH level of the three quaking fens that are being examined in this research will approximately have the same values because of the increasing buffering capacity that is caused by flooding with base rich water from surrounding crags.

Since the base rich water originates from beneath through seepage from the sand layer it is expected that this base rich water has an easier access to the fens when the sandy layer is shallower (Cussel et

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al., 2013). It is thus expected that the EC-values will be higher when there is a shallow sandy layer causing an increase in the buffer capacity to counteract acidification in the fens and a higher pH value. When inundation is a productive water management tool to restore and preserve the rich fen vegetation like Scorpidium scorpioides the EC-Values and pH should also be higher when the sandy layer is less shallow.

7. Final Pitch

Since the rich fens account for high biodiversity andecosystem services like carbon sequestration and water purification in Europe the quaking fen sites, like the one in Tienhoven, should be treated as sites of priority conservation. To ensure the conservation of these quaking fens it should be studied which water management tools can provide this. In this research the effect and effectiveness of inundation with water from surrounding crags will be researched as a water management tool for conservation of these fens.

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Page 8 of 10 References

Aggenbach, C.J.S., D.G. Cirkel, C. Cusell, G. van Dijk, A.M. Kooijman, 2020. Onderzoek naar bevloeiing als beheermaatregel voor behoud en herstel van basenrijke trilvenen. Rapport nummer 2020/OBN241-LZ, VBNE, Driebergen.

Cusell, C., Mettrop, I. S., van Loon, E. E., Lamers, L. P., Vorenhout, M., & Kooijman, A. M. (2015). Impacts of short-term droughts and inundations in species-rich fens during summer and winter: large-scale field manipulation experiments. Ecological Engineering, 77, 127-138.

Koerselman, W. (1989). Groundwater and surface water hydrology of a small groundwater-fed fen. Wetlands Ecology and Management, 1(1), 31-43.

Kooijman, A. M., Cusell, C., Mettrop, I. S., & Lamers, L. P. M. (2016). Recovery of target bryophytes in floating rich fens after 25 yr of inundation by base-rich surface water with lower nutrient contents. Applied Vegetation Science, 19(1), 53-65.

Lamers, L. P., Vile, M. A., Grootjans, A. P., Acreman, M. C., van Diggelen, R., Evans, M. G., ... & Smolders, A. J. (2015). Ecological restoration of rich fens in Europe and North America: from trial and error to an evidence-based approach. Biological Reviews, 90(1), 182-203.

Lotterman, K. (2019). Flora-, vegetatie- en structuurkartering Tienhovense plassen in 2018. Vereniging Natuurmonumenten afdeling Natuur en Landschap.

Peterka, T., Hájek, M., Dítě, D., Hájková, P., Palpurina, S., Goia, I., ... & Štechová, T. (2018). Relict occurrences of boreal brown-moss quaking rich fens in the Carpathians and adjacent territories. Folia Geobotanica, 53(3), 265-276.

van Diggelen, J. M. H., van Dijk, G., Cusell, C., van Belle, J., Kooijman, A., van den Broek, T., ... & Smolders, A. J. P. (2018). Onderzoek naar de effecten van stikstof in overgangs-en trilvenen: ten behoeve van het behoud en herstel van habitattype H7140 (Natura 2000).

Verhoeven, J. T. A., Koerselman, W., & Beltman, B. (1988). The vegetation of fens in relation to their hydrology and nutrient dynamics: a case study. In Vegetation of inland waters (pp. 249-282). Springer, Dordrecht.

Weijs, W. A., & van Tooren, B. F. (2014). Verlanding in nieuwe petgaten van de Oostelijke Vechtstreek. De Levende Natuur, 115(002), 42-4

5a. Timetable of the project (ITEM 5: 10%)

Week 1: 5/04/’21 – 11/04/’21 - Meeting supervisors

- Framework of subject of the bachelor project

Week 2: 12/04/’21 – 18/04/’21 - Meeting supervisors - Finalize research question

Week 3: 19/04/’21 – 25/04/’21 - Getting acquainted with the study site - Fieldwork

Week 4: 26/04/’21 – 02/05/’21 - Write introduction - Write methodology Week 5: 03/05/’21 – 09/05/’21 - Finish writing introduction

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Week 6: 10/05/’21 – 16/05/’21 - Fieldwork

- Write research proposal Week 7: 17/05/’21 – 23/05/’21 - Fieldwork

- Finish writing research proposal Week 8: 24/05/’21 – 30/05/’21 - Fieldwork

- Conceptualize found data Week 9: 31/05/’21 – 06/06/’21 - Create models with the data Week 10: 07/06/’21 – 13/06/’21 - Analyse the results found from data

- Start writing bachelor thesis Week 11: 14/06/’21 – 20/06/’21 - Write bachelor thesis

Week 12: 21/06/’21 – 27/06/’21 - Finish writing bachelor thesis Week 13: 28/06/’21 – 04/07/’21 - Present bachelor thesis

5b. Budget

Please provide 100 words of explanation for the various items requested. Estimate for lab instruments and measurements are allowed!

Equipment:

- Electrical conductivity prod - pH gauge

- Measuring tape - Flagpoles - Thermometer

- Canisters for water samples Consumables:

- Car and fuel to drive to the Tienhoven Lakes Fieldwork:

- GPS

Personnel (in research months) Month 1 Month 2 Month 3

Bsc student 2 2 2

Research costs (in k€)

Equipment 2000

Consumables** 320 320

Fieldwork** 500

6. Scientific embedding of the proposed research (ITEM 6 + 7: 10%) - University of Nijmegen

- University of Amsterdam - Natuurmonumenten

7. Knowledge utilisation - 7A: Beneficiaries identified: - University of Amsterdam - University of Nijmegen - Natuurmonumenten - 7B: Stakeholder feedback: No - 7C: Beneficiaries confirmed: - University of Amsterdam - University of Nijmegen - Natuurmonumenten

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Page 10 of 10 - 7D: Education:

The researcher who applied for this project is a third year bachelor student of Future Planet Studies with a major in Earth Sciences at the University of Amsterdam. This research is identified as a bachelor thesis and is the final course of the three year bachelor’s program.

- 7E: Data management:

The raw data is collected from the field work at the study site and the qualitative data will be collected using literature that is available on Google Scholar and University libraries.

- 7F: Data distribution or integration:

The data will be available when the bachelor thesis is finished. - 7G: Outreach method identified:

The final results will be presented in June when the bachelor thesis is finished. 8. Statements by the applicant

YES/NO I endorse and follow the Code Openness Animal Experiments (if applicable). YES/NO I endorse and follow the Code Biosecurity (if applicable).

YES/NO By submitting this document I declare that I satisfy the nationally and internationally accepted standards for scientific conduct as stated in the

Netherlands Code of Conduct for Scientific Practice 2012 (Association of Universities in the Netherlands (VSNU)).

YES/NO I have completed this form truthfully.

YOUR DETAILS:

Name: Axelle Stroobant

Place: Amerikalei 181, 2018 Antwerpen, België Date: 18/05/2021

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Please submit the application to NWO in electronic form (pdf format is required) using NWO’s electronic application system, which can be accessed via the NWO website. The application must be submitted from the account of the main applicant. For any technical questions regarding submission, please contact the helpdesk (iris@nwo.nl).

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