Research Ruurd van Diggelen

Abstract

Before restoration attempts of degraded wetlands are carried out, it is essential to first analyze the functioning of such systems and compare the present conditions to the functioning of peatlands in a less disturbed situation, preferably those under natural conditions. This not only enables an assessment of the distance-to-target (DTT), but it also helps to identify the causes of altered ecosystem functioning. An adequate analysis of disturbances, and possibilities to undo these disturbances, is essential to formulate realistic restoration scenarios and to identify potential bottlenecks therein. By the end of the 20th century, stepwise eco-hydrological landscape analyses were developed for this purpose. More recently these were formalized into a so-called Landscape Ecological System Analysis (LESA). Central to the approach is a top-down analysis where higher-order landscape components provide a framework for lower-order components: geo(morpho)logy determines hydrology, which in their turn determine soil development, and this again determines vegetation assembly, etc. Without a clear understanding of the functioning of a given ecosystem, and the bottlenecks therein, choices of management and restoration strategies often result in poor and suboptimal results. This is especially true for groundwater-fed fens which are hydrologically and biogeochemically highly complex ecosystems.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

• Geobiology

Project type(s)

• Research Project

Abstract

Before restoration attempts of degraded wetlands are carried out, it is essential to first analyze the functioning of such systems and compare the present conditions to the functioning of peatlands in a less disturbed situation, preferably those under natural conditions. This not only enables an assessment of the distance-to-target (DTT), but it also helps to identify the causes of altered ecosystem functioning. An adequate analysis of disturbances, and possibilities to undo these disturbances, is essential to formulate realistic restoration scenarios and to identify potential bottlenecks therein. By the end of the 20th century, stepwise eco-hydrological landscape analyses were developed for this purpose. More recently these were formalized into a so-called Landscape Ecological System Analysis (LESA). Central to the approach is a top-down analysis where higher-order landscape components provide a framework for lower-order components: geo(morpho)logy determines hydrology, which in their turn determine soil development, and this again determines vegetation assembly, etc. Without a clear understanding of the functioning of a given ecosystem, and the bottlenecks therein, choices of management and restoration strategies often result in poor and suboptimal results. This is especially true for groundwater-fed fens which are hydrologically and biogeochemically highly complex ecosystems.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

• Geobiology

Project type(s)

• Research Project

Abstract

Many wetland habitat types, especially also groundwater-fed peatlands ("fens"), are currently threatened across North Western Europe. Since fens provide a habitat for many endangered species of flora and fauna, they are classified as an important Natura 2000 habitat type (H7140 and H7230). EU policy is explicitly aimed at increasing the cover and quality of fens to reach a favourable conservation status in 2050. Additional to that, fens and other peatlands play a major role in the terrestrial carbon cycle: undrained peatlands act as carbon sinks due to active peat accumulation whereas drained peatlands emit huge quantities of carbon dioxide (CO2) into the atmosphere. The overall research questions are: - Are there any calcium-rich aquifers in the vicinity of the marsh and identify upwelling zones within the marsh? - How do current and historical anthropogenic hydrological changes and changes in landuse affect the ecohydrological functioning of the site? - How do the geohydrological context and the local (altered) hydrology and landuse affect the potential for alkaline fen restoration in marais de Heinsch? - What is the current biogeochemical state of the site, and how does this relate to the prerequisites for alkaline fen restoration? - What is the current vegetational state of the site, and what type of vegetation occurred there historically? - What are the main management and restoration options for alkaline fen restoration in the site? - What are alternative goals/ restoration options?

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

• Geobiology

Project type(s)

• Research Project

Abstract

The restoration and development of European protected habitat types is an important objective within the nature design of 'Landschap de Liereman' (LDL). This partly concerns poor vegetation types that require nutrient-poor conditions. However, a large proportion of these habitat types must be developed on land that is currently still in intensive agricultural use or very recently had intensive agricultural use. In concrete terms, it concerns the grounds of the Hoge Mierdse Heide (Middenblok) and along the Lieremansstaartjeloop Earlier soil research (RHDHV Haskoning and Alterra, 2013) showed that, due to the (historical) fertilization pressure, the nutrient stock in the soil is often high. The high phosphate status in particular hinders a smooth conversion to the proposed poor habitat types. Appropriate design and management measures are therefore necessary to achieve the intended objectives. The University of Antwerp has been asked to make a concise analysis of the options for developing poor nature types in this nature development project, with the aim of providing scientific support before and during the redevelopment.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

During my internship I visited and collected soil samples in two nature reserves, the first of which was Asbroek, located in the north western part of the nature reserve Pietersembos (Figure 1A). This reserve is part of the "Nationaal Park Hoge Kempen" and is a European-protected Habitat and Bird Directive area because of its high biodiversity (Natura 2000, 2022). Pietersembos is owned by "Agentschap Natuur en Bos" (ANB) and management is carried out by their department "Leefmilieu, Natuur en Energie" (LNE). The total size of the reserve is 532 ha of which 165 ha is forest reserve. The area that is now Pietersembos was bought from private owners starting in 1971 up till 2004 in order to protect the forest from land speculation (ANB, 2022; detailed management plan 2010-2029). During the mining era a large part of the reserve was used for conifer afforestation and plantation as their logs supported the mineshafts. Fauna and flora were further threatened by the fragmentation, pollution and disappearance/degradation of the heather vegetation.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

The central question in this study is whether the development of the microbial community in species-poor grasslands in nature reserve "de Liereman" can be controlled by the introduction of sod cut material collected in species-rich and well-developed reference grasslands ("soil inoculation"). We use state-of-the-art molecular techniques such as metabarcoding and qPCR.

Researcher(s)

• Promoter: van Diggelen Ruurd
• Co-promoter: Emsens Willem-Jan
• Co-promoter: Verbruggen Erik

Research team(s)

Project type(s)

• Research Project

Abstract

Fens are nutrient-poor wetlands characterized by active accumulation of organic plant matter (peat). This process requires waterlogged conditions and low microbial activity. Fens are important global sinks for atmospheric carbon dioxide (CO2), an important greenhouse gas (GHG). Unfortunately very few undisturbed fens remain, and most fens have been drained by human activity. Drainage triggers a myriad of cascading effects on fen biogeochemistry, vegetation and microbiology, and turns fens into sources of CO2. To make matters worse, fens are also increasingly threatened by nitrogen (N) enrichment. This may hamper peat formation, and could increase emissions of other potent GHGs such as methane (CH4) and nitrous oxide (N2O). The idea that degraded fens can quickly be restored by raising water levels seems naïve: recent observations suggest that rewetted fens often become nutrient-rich marshes. The effect of the drainage-rewetting cycle on GHG emissions is largely unknown, but might be dramatic. In this project, I will disentangle the interactive effects of fen hydrology and nitrogen enrichment on GHG emission. Moreover, I will investigate the influence of shifts in plant- and microbial community composition on altered GHG emissions. We hypothesize that drainage and N enrichment turn fens from sinks into sources of GHGs, and that this is partly due to shifts in plant- and microbial community composition. This change may be irreversible within human time-scales.

Researcher(s)

• Promoter: van Diggelen Ruurd
• Co-promoter: Janssens Ivan
• Fellow: Emsens Willem-Jan

Research team(s)

• Geobiology

Project type(s)

• Research Project

Abstract

The present report describes the results of soil samples taken in 2019 at monitoring points in the Elperstroom area. In this area, the extent to which hydrological modifications in and around the Natura 2000 area can contribute to strengthening and improving the current abiotic conditions is currently being investigated. Despite extensive management efforts, the main target vegetation type here, i.e. Blue Grassland (H6410), is showing signs of degradation, possibly caused by non-optimal hydrology and associated soil-chemical site conditions. At the time, the Elperstroom area was protected mainly because of the occurrence of the Parnassia subassociation of the Blue Grassland (Syntaxoncode vlg. Schaminee et al. (1996) 16AA01D). The occurrence of this variant is restricted soil-chemically to sites with low nitrogen and phosphorus availability with crop production between 1000 and 3500 kg dry matter per ha/year, a neutral to slightly acidic pH (pHH2O between 5.5 and 7.0) and good buffering against further acidification (no standards are available for this, however, see page 9) The present report describes and interprets the current soil chemical status in the context of the so-called "far" themes (desiccation, acidification, eutrophication). The chemical analyses focused on assessing (1) the acid/base balance and the likelihood of (further) acidification; (2) the stock and availability of various forms of the nutrients nitrogen (N) and phosphorus (P), as well as parameters indicative of the rate of nutrient release from the soil. In addition, a number of vegetation parameters were measured that indicate important information about the soil. These are the parameters of productivity and N/P, N/K and K/P ratios in living vegetation. The first value provides an independent estimate of soil fertility, the second parameter shows which of the nutrients N, P and/or K are limiting and therefore provides insight into the effects of changes in N/P and/or K availability.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

Groundwater discharge areas, which occur for instance in brook valleys, are fed by water that infiltrates at some distance, flows through the subsurface to lower elevations, and wells upward in the seepage area. Under natural conditions, seepage water is generally relatively poor in nutrients, with a low acidity (high pH) and increased levels of base cations (such as calcium and magnesium) and iron. Where seepage water reaches the root zone, often valuable ecosystems are found with plant species that are bound to the specific environmental conditions of seepage areas. The exact chemical composition of the seepage water is influenced by a variety of natural and anthropogenic processes (figure 1). In the past decades, recharge areas have been substantially enriched in nutrients by agricultural use. Also under the current land use, pollutants such as nitrate can leach to the groundwater and reach seepage areas. Moreover, these leached compounds can be subject to chemical reactions in the subsoil, which may for instance increase the sulphate concentration. If groundwater with high nitrate and/or sulphate concentrations reaches the seepage zone, nutrient-poor conditions and the accompanying ecosystem types may disappear.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

Heathland grasslands (Class Nardetea) are a priority habitat type within the European Habitats Directive (H6230) and are characterised in well-developed form by a high abundance of rare plant species (e.g. Heathartleaf, Tormentil, Brushgrass, Reclining Wingwort, Bell gentian, Toothed grass, Reclining wallow, Rosemary). Under natural conditions they occur frequently above the tree line, where they often occupy large areas. Under semi-natural conditions, i.e. in the anthropogenic landscape, they also occur in the lowlands in extensively managed and little or no fertilised dry to moist cultivated grasslands, especially especially on sandy, sandy loam, or sometimes slightly peaty soils.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

Belowground biodiversity is formed by fungi, bacteria, archaea, animals and plants that altogether affect soil functioning, particularly by controlling rates of production and decomposition of organic matter. Peat soils, being the most concentrated stores of soil carbon, are formed by a long-term net exceedance of production over decomposition. The REPEAT project addresses the mechanisms contributing to peat formation in fen peatlands in order to improve restoration prospects of these threatened ecosystems that provide vital ecosystem services for mitigation of climate change, regional hydrology, nutrient retention and biodiversity conservation (Bonn et al. 2016) . In Europe most fen peatlands have been severely degraded by land use. Drainage has turned the peatlands from carbon sinks into significant sources of greenhouse gases (GHG) and has made Central Europe – after Indonesia - the second largest hot-spot of peat GHG emissions worldwide (Joosten 2009). Peat formation is a precondition to re-install the vital ecosystem services provided by the fen ecosystem. However, re-establishment of high groundwater tables alone is often not sufficient to restore peat formation (Grootjans et al. 2012). In spite of decades of trials, processes that control peat accumulation (including their rates, pathways and drivers) remain unknown. Previous research on peatland carbon cycling has focused almost exclusively on rainwater-fed bogs with upward growing peatmoss (Sphagnum) as the prevailing mode of peat formation. In contrast, in groundwater-fed fens roots and rhizomes of sedges and grasses grow into the older peat matrix to form 'displacement peat'. Therefore, peat formation models developed for bogs (Clymo et al. 1998, Frolking et al. 2001) do not fully apply to fens. REPEAT aims to clarify the mechanisms of peat formation in fens by linking biogeochemical processes to soil community structure and biodiversity, as well as to plant belowground litter quality, with special focus on the prospects of restoring peat formation mechanisms. Paludiculture (biomass harvest) will receive special attention because it has recently been recognized as an key management approach that allows sustainable use of wet and rewetted peatlands.

Researcher(s)

• Promoter: van Diggelen Ruurd
• Co-promoter: Verbruggen Erik

Research team(s)

Project website

Project type(s)

• Research Project

Abstract

In this study, I aim to conduct fundamental research on a set of biogeochemical processes that, after rewetting, inhibit a shift from a drained (previously peat-accumulating) organic soil with net decomposition towards a soil with organic matter accumulation and nutrient retention. The emphasis will be on positive feedback loops on OM decomposition, with experiments to elucidate the effects of water table dynamics, iron chemistry and vegetation assembly.

Researcher(s)

• Promoter: van Diggelen Ruurd
• Fellow: Emsens Willem-Jan

Research team(s)

Project type(s)

• Research Project

Abstract

Sustainable recovery of groundwater fed fen vegetation and associated fauna requires waterlogging by restoring water management. That is why there has been a lot money invested in restoration measures in and around degraded fens. The emphasis of these measures was generally reduction of drainage within the nature reserve. An important knowledge gap is the question to what degree water management needs to be restored for the development of fen peat vegetation and the start of peat formation. A common bottleneck is that the water level dynamics in the restored fens are still too large after rewetting for the development of the desired peat-forming vegetation. The bottlenecks behind insufficient recovery of the groundwater level are not yet well known, because research into ground- and surface water flow patterns in rewetted fens has hardly been conducted. More insight into these bottlenecks is necessary in order to find the right control and management measures in the right areas, and in the right order

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

Voor natuurherstel en -ontwikkeling in Nederland is de omvorming van landbouwgrond naar natuur een grote en moeilijke opgave. Deze omvorming van landbouwgronden is van belang voor behoud en herstel van natuurgebieden en de ontwikkeling van een samenhangend netwerk van natuurgebieden. Door een intensief landbouwverleden is de nutriëntenvoorraad en -beschikbaarheid groot, waardoor het herstel van natuurtypen die gebonden zijn aan een relatief lage nutriëntenbeschikbaarheid een zeer lastige opgave is. In Nederland zijn de afgelopen twee decennia een aantal strategieën regelmatig toegepast: plaggen c.q. ontgronden van de nutriëntenrijke toplaag, uitmijnen van P, verschralen door middel van maaien en afvoeren of begrazen, bevorderen van het vastleggen van P, en het laten zitten van de nutriëntenrijke toplaag en overschakelen op andere, meer productieve doelen. Zowel in Nederland als daarbuiten is onderzoek verricht naar de effectiviteit en de werking van de deze strategieën, maar de resultaten daarvan en de gevolgtrekkingen daaruit lijken elkaar deels tegen te spreken. Zulke ogenschijnlijke tegenstrijdigheden hebben daarnaast geleid tot controverses in het debat over de omvorming van voedselrijke landbouwgronden. Deze gaan over het wel of niet ontgronden, de omgang met bodemfauna, de vraag of met andere strategieën voedselarme natuurtypen kunnen worden gerealiseerd en over hoe de beschikbaarheid van fosfaat het beste kan worden gemeten.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project website

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand the Flemish Public Service. UA provides the Flemish Public Service research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand the client. UA provides the client research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand Province of Drenthe. UA provides Province of Drenthe research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

In this study, I aim to conduct fundamental research on a set of biogeochemical processes that, after rewetting, inhibit a shift from a drained (previously peat-accumulating) organic soil with net decomposition towards a soil with organic matter accumulation and nutrient retention. The emphasis will be on positive feedback loops on OM decomposition, with experiments to elucidate the effects of water table dynamics, iron chemistry and vegetation assembly.

Researcher(s)

• Promoter: van Diggelen Ruurd
• Fellow: Emsens Willem-Jan

Research team(s)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand INBO. UA provides INBO research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand Prov. Drenthe. UA provides Prov. Drenthe research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

In this study, I aim to conduct fundamental research on a set of biogeochemical processes that, after rewetting, inhibit a shift from a drained (previously peat-accumulating) organic soil with net decomposition towards a soil with organic matter accumulation and nutrient retention. The emphasis will be on positive feedback loops on OM decomposition, with experiments to elucidate the effects of water table dynamics, iron chemistry and vegetation assembly.

Researcher(s)

• Promoter: van Diggelen Ruurd
• Fellow: Emsens Willem-Jan

Research team(s)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand the Province Drenthe. UA provides the Province Drenthe research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand the Bosschap. UA provides the Bosschap research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand the Flemish Public Service. UA provides the Flemish Public Service research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand the Flemish Public Service. UA provides the Flemish Public Service research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand KMDA. UA provides KMDA research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand the Flemish Public Service. UA provides the Flemish Public Service research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand Province of Drenthe. UA provides Province of Drenthe research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand the Flemish Public Service. UA provides the Flemish Public Service research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand a private institution. UA provides the private institution research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: van Diggelen Ruurd
• Co-promoter: Meire Patrick

Research team(s)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand KWR. UA provides KWR research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand Province of Drenthe. UA provides Province of Drenthe research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

The Agency for Nature and Forest of the Flemish Government manages several areas with extensive grassland surfaces in the Antwerp Campines. To optimise the management and plan restoration works it is necessary to study the potentials of these grasslands. The objective of this study is to figure out the maximum potentials based on the current biotic qualities, the main abiotic parameters and specific local settings (e.g. management objectives). Secondly measures to reach these objectives will be defined. An essential part of the study will be the current constraints and possible solutions.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

This project addresses the impact of changed hydrochemical conditions on plant-plant interactions in peat producing ecosystems. We will compare the response of typical species on different hydrolochemical constraints to those of general wetland species. Three possible bottle-necks will be investigated: germination, seedling establishment and competiton between adult plants.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

The city of Antwerp has the ambition to turn its eastern outskirt, Rugeveld-Boterlaar-Silsburg, into a landscape park. This park will be part of the green finger of the Schijn valley that enters the urbanised area of Antwerp. Because of the presence of important nature values and the major aim of nature development, this research project was set up to produce a vegetation and landscape map of the area. The main aim is to map the vegetation and landscape and produce a set of directives for planning and management. The conclusions of this study must be directly applicable in the development plans of the area. The Ecosystem Management Research Group is proceeding with extensive field work, combined with the wide local knowledge, to localise all the ecological valuable sites and describe the available opportunities. For the different ecotopes points of interest are described to help to reach an optimal symbiosis between the ecological values and the established development plan.

Researcher(s)

• Promoter: van Diggelen Ruurd
• Co-promoter: Van Ballaer Bram

Research team(s)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand KMDA. UA provides KMDA research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: van Diggelen Ruurd

Research team(s)

Project type(s)

• Research Project