Research team
Expertise
Anthropogenic environmental change is often described in terms of its effects on biodiversity: species disappear, populations decline and ecosystems become increasingly homogenized. Understanding the underlying causal chains has been the central ambition of my research. My work therefore asks why are species or ecosystems lost, which ecological processes are set in motion following environmental degradation that causes biodiversity decline, at which organizational level do those processes operate, and how can they be modified to enable recovery and restoration. Biodiversity does not respond directly to an abstract environmental pressure such as atmospheric nitrogen deposition, soil phosphorus enrichment, soil acidification or climate change. These pressures first alter the physical and chemical conditions under which organisms live and interact. The resulting changes in resource availability, competition, mutualisms, trophic interactions and ecosystem processes then propagate through biological systems. This perspective has provided the conceptual continuity underlying a research program that includes semi-natural grasslands, heathlands, forests, peatlands and (semi-aquatic) freshwater habitats, and encompasses a wide taxonomic breadth from plants to fungi, from microorganisms to arthropods and human health. The apparent diversity of these systems reflects not a succession of unrelated research topics, but a deliberate progression towards understanding increasingly complex ecological interactions at multiple levels of biological organization because effects of environmental change is rarely confined to one level. At the level of individual organisms, I study plant fitness, resource quality and interactions with fungi and arthropods. At the population level, I investigate constraints on threatened species, including habitat quality, small population size and reproductive limitation. At the community level, I investigate interactions among plant communities and fungal and bacterial assemblages. At the ecosystem level, I examine carbon sequestration, nutrient availability, hydrological functioning and ecosystem properties that underpin human health. This highly integrated research is particularly important for understanding biodiversity conservation and restoration from local populations all the way to the landscape level. A threatened plant population may decline because its local habitat has become biogeochemically unsuitable, because regional hydrology has changed, because mycorrhizal mutualisms have been disrupted, because pollination has become unreliable, or because demographic constraints prevent recovery. Effective conservation therefore requires identifying the whole suite of actual limiting mechanism rather than assuming that generic measures for habitat protection alone will be sufficient.
Backyard beavers - Quantifying the ecological and hydrological impacts of Eurasian beaver (Castor fiber) in urban and rural landscapes.
Abstract
The comeback of the Eurasian beaver (Castor fiber) in Western Europe has sparked significant societal resistance, despite being promoted as a natural ally in biodiversity conservation and a costeffective, nature-based solution for mitigating droughts and floods. However, robust scientific evidence supporting these claims remains limited. This project aims to quantify the ecological impacts of beavers in both rural and urbanised landscapes in Flanders. Specifically, we will assess how beaver dams influence hydrology, water quality, and biodiversity by integrating existing biomonitoring datasets with newly collected field survey data. In addition, experimental artificial dams will be constructed to simulate the rewetting of various stream-associated habitats, allowing for a controlled investigation of ecosystem functioning, including nutrient cycling and greenhouse gas fluxes. Beaver-induced changes in biodiversity will be taxon-specific and the effects on key ecosystem services will be highly context-dependent. For example, factors such as nutrient load, and the presence of peat are expected to shape the impact of dams on nutrient fluxes and greenhouse gas emissions. This project aims to provide evidence-based insights for scientists and environmental managers, contributing to the development of sustainable coexistence strategies for beavers and humans in anthropogenically modified landscapes.Researcher(s)
- Promoter: Matthysen Erik
- Co-promoter: Ceulemans Tobias
Research team(s)
Project type(s)
- Research Project
CLIMAP-OAK: Climate mitigation and adaptation potential of naturally vs. artificially regenerated oak-dominated forests in Flanders.
Abstract
Restoring forests is a crucial natural climate solution that can help offset anthropogenic greenhouse gas emissions. However, little is known about the most effective and reliable forest restoration technique - artificial (planting) or natural (spontaneous succession) regeneration - to sequester carbon. These two restoration approaches can have different impacts on forest structure, soil microbial communities, and evolutionary selection pressures on trees, with significant implications for climate mitigation and adaptation potential. To address this issue, the CLIMAP-OAK project will use observational chronosequence and experimental methods to compare artificially and naturally regenerated oak-dominated forests in Flanders. The project will assess differences in stand structure, carbon stocks, and drought resistance and resilience, as well as soil microbial communities and functioning. It will also investigate climate-related selection effects on genomic and phenotypic tree traits. Moreover, the CLIMAP-OAK project will evaluate an alternative approach: seeding with local and introduced oak provenances. This approach will be assessed in terms of adaptive potential, growth, survival, drought tolerance, and root microbial diversity.Researcher(s)
- Promoter: Ceulemans Tobias
Research team(s)
Funding
- FWO
Project type(s)
- Research Project
The consequences of nitrogen-induced shifts in fungal and bacterial communities for carbon cycling in temperate forests.
Abstract
Forests constitute a large and persistent carbon stock, which has increased over the past few decades. While the exact mechanisms remain unclear, it has been suggested that increased inorganic nitrogen input resulting from human activities has contributed to the observed increase in terrestrial carbon stocks. However, this nitrogen-induced carbon sequestration appears to vary widely across geographic locations, urging for a better understanding of its underlying mechanisms. Given the importance of microorganisms in both the carbon and nitrogen cycle, we expect that they play a central role in driving nitrogen-induced carbon sequestration. This project aims to investigate the role of microbial communities in driving nitrogen-induced carbon sequestration using a combination of a large-scale field study and a mesocosm experiment. We will collect litter and soil samples from temperate forests across a large nitrogen deposition gradient in Europe and use advanced molecular and laboratory methods to determine soil organic matter composition, fungal and bacterial communities and their functioning. To elucidate the distinct contributions of direct (increased nitrogen) and indirect effects (altered soil microbiome) of nitrogen deposition on soil functioning we will conduct a mesocosm experiment. Overall, our findings are expected to enhance our understanding of the role microbes play in coupling the carbon and nitrogen cycle and how global change is affecting forest carbon stocks.Researcher(s)
- Promoter: Ceulemans Tobias
- Fellow: Boeraeve Margaux
Research team(s)
Funding
- FWO
Project type(s)
- Research Project
Effects of nitrogen pollution on host plant food quality.
Abstract
Insects are keystone species as they provide vital pollination services. Among the most cited drivers of insect decline worldwide are landscape homogenization, spread of introduced pathogens, use of pesticides, ongoing climate change and, most importantly, the loss of floral resources. Therefore, current environmental strategies to mitigate insect loss mainly advocate enhancing the floral resource abundance. However, whereas the primary focus now lays on increasing the quantity of food provisioning, maintaining sufficient food quality may be equally, or perhaps even more important for conservation. The quality of floral resources is primarily contingent upon the composition and relative abundance of nutrients such as nitrogen, phosphorus and base cations, sugars (mainly sucrose, fructose and glucose) and proteins and amino acids in both plant tissue and nectar and pollen. One of the primary environmental factors that can affect the nutritional quality of floral resources is plant nutrient availability, as it strongly affects plant physiological processes. However, nutrient pollution of natural and semi-natural ecosystems currently constitutes one of the most important components of global change worldwide, which is reflected by an approximate respective 100% and 400% increase of reactive nitrogen and phosphorus fluxes in global nutrient cycles. In an era of ever increasing nutrient pollution, this research proposal will focus on the specific contribution of different types of nitrogen pollution on the current biodiversity crisis. This research proposal is original in its focus on the link between nitrogen pollution and host plant quality, studying the underexplored hypothesis that degradation of plant resource quality may contribute to the widely observed insect decline. Further unique novelties include experimentally disentangling direct and indirect effects of nitrogen pollution and its common mitigation strategies in nature restoration and disentangling effects of pollution with reduced (mainly originating from agriculture) versus oxidized (mainly originating from combustion processes) nitrogen compounds via experiments and large-scale observational evidence across Europe (>25 000 standardized observations in >10 countries). We also aim to identify, for the first time, species-specific critical thresholds of pollution with oxidized and reduced nitrogen across taxonomic groups. This novel evidence may have far reaching ramifications for environmental policy regarding nitrogen that currently does not discriminate among reduced versus oxidized compounds for biodiversity conservation. To obtain these goals, we will use host plants and butterflies as model species as they have been proven to be very sensitive to environmental changes and relatively easy to use in experimental designs. The general objectives of this research proposal are to quantify the effects of nitrogen pollution on plant resource quality on the one hand, and to evaluate the subsequent effects on the behavior and fitness of phytophagous butterflies, on the other. Furthermore this proposal aims to disentangle the primary effects of nitrogen pollution from secondary, potentially confounding effects of nature restoration methods to mitigate nitrogen pollution. The general expectation is that the nutritional quality of plant resources is affected by nitrogen pollution and, in turn, negatively affects butterfly fitness and behavior. We also expect that current nitrogen pollution mitigation strategies also negatively affect butterflies, potentially compounding the general decline of insects. Finally, we expect that the experimentally determined relative contribution of both drivers will be reflected in large-scale observations of species decline and that these insights will lead to novel environmental policies and nature restoration strategies to mitigate biodiversity loss.Researcher(s)
- Promoter: Ceulemans Tobias
- Fellow: Wiegmans Dymphna
Research team(s)
Funding
- BOF
Project type(s)
- Research Project
HAbitat Restoration in the WINgevalley: ecological restoration and endangered species recovery in a fragmented landscape (HARWIN).
Abstract
LIFE HARWIN is part of the LIFE sub-programme "Nature and Biodiversity". The project region suffers from several threats like habitat fragmentation and too small populations of key species. In this project we aim for the ecological restoration and quality improvement of 350 ha qualifying habitats along the entire gradient of the Winge Valley: aquatic habitats 3130 (annex species Luronium natans), 3140, 3150; heathland habitats 6230*, 4030, 4010; grassland habitats 6410, 6510; fen habitats 7140, 7230 and forest habitats 9120, 91E0*, 9160. Target locations for the restoration of habitats are consistently chosen adjacent to restore habitat connectivity and attain a favorable habitat size. This is crucial because remaining habitats are mostly small and isolated, characterized by a lot of species loss and not part of a sustainable natural ecosystem anymore. This restoration will also benefit the expansion or (re)colonization of several Annex I species of the Birds Directive and Annex II species of the Habitat Directive. For achieving this goal, Natuurpunt and ANB, two professional nature conservation managers and the main landowners of the project area will implement the restoration actions. This cooperation is reinforced by the academic input of APM and Antwerp University , both with experience within the project area, who will bring in their expertise in studying populations confronted with environmental pollution and habitat fragmentation and with restoration of remnant populations through ex-situ cultivation and reintroduction . The partnership thus ensures the valorization in practical applications of environmental science, in defiance of any gap that can exist between academic scientists and professionals and volunteers. Therefore, the expertise of the Dutch umbrella foundation LA, that was founded precisely to bridge the gap between academic institutions and professionals and volunteers, will be indispensable for the goals of this project.Researcher(s)
- Promoter: Ceulemans Tobias
Research team(s)
Funding
- EU-NT. KAD
Project website
Project type(s)
- Research Project