Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Will legal international rhino horn trade save wild rhino populations?
    Eikelboom, Jasper A.J. ; Nuijten, Rascha J.M. ; Wang, Yingying X.G. ; Schroder, Bradley ; Heitkönig, Ignas M.A. ; Mooij, Wolf M. ; Langevelde, Frank van; Prins, Herbert H.T. - \ 2020
    Global Ecology and Conservation 23 (2020). - ISSN 2351-9894
    CITES - Conservation - Socioeconomics - South Africa - Traditional Chinese medicine - Wildlife crime

    Wild vertebrate populations all over the globe are in decline, with poaching being the second-most-important cause. The high poaching rate of rhinoceros may drive these species into extinction within the coming decades. Some stakeholders argue to lift the ban on international rhino horn trade to potentially benefit rhino conservation, as current interventions appear to be insufficient. We reviewed scientific and grey literature to scrutinize the validity of reasoning behind the potential benefit of legal horn trade for wild rhino populations. We identified four mechanisms through which legal trade would impact wild rhino populations, of which only the increased revenue for rhino farmers could potentially benefit rhino conservation. Conversely, the global demand for rhino horn is likely to increase to a level that cannot be met solely by legal supply. Moreover, corruption is omnipresent in countries along the trade routes, which has the potential to negatively affect rhino conservation. Finally, programmes aimed at reducing rhino horn demand will be counteracted through trade legalization by removing the stigma on consuming rhino horn. Combining these insights and comparing them with criteria for sustainable wildlife farming, we conclude that legalizing rhino horn trade will likely negatively impact the remaining wild rhino populations. To preserve rhino species, we suggest to prioritize reducing corruption within rhino horn trade, increasing the rhino population within well-protected ’safe havens’ and implementing educational programmes and law enforcement targeted at rhino horn consumers.

    Temperature effects on egg and larval development rate in European smelt, Osmerus eperlanus, experiments and a 50 year hindcast
    Keller, A.M. ; Molenaar, P. ; Leeuw, J.J. ; Mooij, W.M. ; Rijnsdorp, A.D. ; Wolfshaar, K.E. - \ 2020
    Journal of Fish Biology 96 (2020)6. - ISSN 0022-1112 - p. 1422 - 1433.
    This study investigates the effect of water temperature on the development rate of eggs and larvae, the duration of the endogenous feeding period and its consequences for recruitment of smelt (Osmerus eperlanus) in Dutch lakes IJsselmeer and Markermeer. This study measured temperature-dependent egg and larval development rates as well as mortality rates from fertilization till the moment of absorption of the yolk-sac and from yolk-sac depletion onwards in temperature-controlled indoor experiments. Using multinomial modelling the authors found significant differences in development time of egg development stages under different temperature regimes. Based on historic water temperatures, the model predicted that the larval endogenous feeding period has advanced at a rate of about 2.9 days per decade in a more than 50 year period since 1961, yet there was no change in the duration of the endogenous feeding period. As zooplankton is more responsive to daylight than water temperature cues, a mismatch between the peak of the onset of exogenous
    feeding of smelt and the peak of zooplankton blooms could lead to high mortality and therefore low recruitment of smelt. Such a mismatch might contribute to a decline in the smelt population in Lake IJsselmeer and Lake Markermeer.
    Matching scope, purpose and uses of planetary boundaries science
    Downing, Andrea S. ; Bhowmik, Avit ; Collste, David ; Cornell, Sarah E. ; Donges, Jonathan ; Fetzer, Ingo ; Häyhä, Tiina ; Hinton, Jennifer ; Lade, Steven ; Mooij, Wolf M. - \ 2019
    Environmental Research Letters 14 (2019)7. - ISSN 1748-9318
    footprints approach - global sustainability science - human dimensions - life cycle analysis - Planetary boundaries - resilience - safe operating space

    Background: The Planetary Boundaries concept (PBc) has emerged as a key global sustainability concept in international sustainable development arenas. Initially presented as an agenda for global sustainability research, it now shows potential for sustainability governance. We use the fact that it is widely cited in scientific literature (>3500 citations) and an extensively studied concept to analyse how it has been used and developed since its first publication. Design: From the literature that cites the PBc, we select those articles that have the terms 'planetary boundaries' or 'safe operating space' in either title, abstract or keywords. We assume that this literature substantively engages with and develops the PBc. Results: We find that 6% of the citing literature engages with the concept. Within this fraction of the literature we distinguish commentaries - that discuss the context and challenges to implementing the PBc, articles that develop the core biogeophysical concept and articles that apply the concept by translating to sub-global scales and by adding a human component to it. Applied literature adds to the concept by explicitly including society through perspectives of impacts, needs, aspirations and behaviours. Discussion: Literature applying the concept does not yet include the more complex, diverse, cultural and behavioural facet of humanity that is implied in commentary literature. We suggest there is need for a positive framing of sustainability goals - as a Safe Operating Space rather than boundaries. Key scientific challenges include distinguishing generalised from context-specific knowledge, clarifying which processes are generalizable and which are scalable, and explicitly applying complex systems' knowledge in the application and development of the PBc. We envisage that opportunities to address these challenges will arise when more human social dimensions are integrated, as we learn to feed the global sustainability vision with a plurality of bottom-up realisations of sustainability.

    A perspective on water quality in connected systems: modelling feedback between upstream and downstream transport and local ecological processes
    Teurlincx, Sven ; Wijk, Dianneke van; Mooij, Wolf M. ; Kuiper, Jan J. ; Huttunen, Inese ; Brederveld, Robert J. ; Chang, Manqi ; Janse, Jan H. ; Woodward, Ben ; Hu, Fenjuan ; Janssen, Annette B.G. - \ 2019
    Current Opinion in Environmental Sustainability 40 (2019). - ISSN 1877-3435 - p. 21 - 29.

    Food production for a growing world population relies on application of fertilisers and pesticides on agricultural lands. However, these substances threaten surface water quality and thereby endanger valued ecosystem services such as drinking water supply, food production and recreational water use. Such deleterious effects do not merely arise on the local scale, but also on the regional scale through transport of substances as well as energy and biota across the catchment. Here we argue that aquatic ecosystem models can provide a process-based understanding of how these transports by water and organisms as vectors affect – and are affected by – ecosystem state and functioning in networks of connected lakes. Such a catchment scale approach is key to setting critical limits for the release of substances by agricultural practices and other human pressures on aquatic ecosystems. Thereby, water and food production and the trade-offs between them may be managed more sustainably.

    Integrated modelling and management of water resources: the ecosystem perspective on the nexus approach
    Hülsmann, Stephan ; Sušnik, Janez ; Rinke, Karsten ; Langan, Simon ; Wijk, Dianneke van; Janssen, Annette B.G. ; Mooij, Wolf M. - \ 2019
    Current Opinion in Environmental Sustainability 40 (2019). - ISSN 1877-3435 - p. 14 - 20.

    Addressing challenges of water, energy and food security, nexus approaches towards resources management are being developed and starting to be implemented. However, the ecosystem perspective, essential for sustainable resources management, has been identified as a missing element within earlier nexus assessments. With regard to water they have mainly focused on the allocation to different sectors and users, while ecosystem services were rarely explicitly addressed. Existing aquatic ecosystem models are capable of quantifying a wide range of ecosystem services, but have thus far not been comprehensively used in a nexus context. Recent developments in aquatic ecosystem modelling approaches provide opportunities to achieve the sought integration of ecosystem services in the nexus approach. Therefore, we argue for a stronger role of aquatic ecosystem models in nexus assessments.

    A Generically Parameterized model of Lake eutrophication (GPLake) that links field-, lab- and model-based knowledge
    Chang, Manqi ; Teurlincx, Sven ; DeAngelis, Donald L. ; Janse, Jan H. ; Troost, Tineke A. ; Wijk, Dianneke van; Mooij, Wolf M. ; Janssen, Annette B.G. - \ 2019
    Science of the Total Environment 695 (2019). - ISSN 0048-9697
    Consumer-resource interactions - Nutrient versus light limitation - PCLake - Phytoplankton - Vollenweider - Water quality management

    Worldwide, eutrophication is threatening lake ecosystems. To support lake management numerous eutrophication models have been developed. Diverse research questions in a wide range of lake ecosystems are addressed by these models. The established models are based on three key approaches: the empirical approach that employs field surveys, the theoretical approach in which models based on first principles are tested against lab experiments, and the process-based approach that uses parameters and functions representing detailed biogeochemical processes. These approaches have led to an accumulation of field-, lab- and model-based knowledge, respectively. Linking these sources of knowledge would benefit lake management by exploiting complementary information; however, the development of a simple tool that links these approaches was hampered by their large differences in scale and complexity. Here we propose a Generically Parameterized Lake eutrophication model (GPLake) that links field-, lab- and model-based knowledge and can be used to make a first diagnosis of lake water quality. We derived GPLake from consumer-resource theory by the principle that lacustrine phytoplankton is typically limited by two resources: nutrients and light. These limitations are captured in two generic parameters that shape the nutrient to chlorophyll-a relations. Next, we parameterized GPLake, using knowledge from empirical, theoretical, and process-based approaches. GPLake generic parameters were found to scale in a comparable manner across data sources. Finally, we show that GPLake can be applied as a simple tool that provides lake managers with a first diagnosis of the limiting factor and lake water quality, using only the parameters for lake depth, residence time and current nutrient loading. With this first-order assessment, lake managers can easily assess measures such as reducing nutrient load, decreasing residence time or changing depth before spending money on field-, lab- or model- experiments to support lake management.

    Success of lake restoration depends on spatial aspects of nutrient loading and hydrology
    Janssen, Annette B.G. ; Wijk, Dianneke van; Gerven, Luuk P.A. van; Bakker, Elisabeth S. ; Brederveld, Robert J. ; DeAngelis, Donald L. ; Janse, Jan H. ; Mooij, Wolf M. - \ 2019
    Science of the Total Environment 679 (2019). - ISSN 0048-9697 - p. 248 - 259.
    Alternative stable states - Diffuse source - Management - PCLake - Point source - Spatial heterogeneity

    Many aquatic ecosystems have deteriorated due to human activities and their restoration is often troublesome. It is proposed here that the restoration success of deteriorated lakes critically depends on hitherto largely neglected spatial heterogeneity in nutrient loading and hydrology. A modelling approach is used to study this hypothesis by considering four lake types with contrasting nutrient loading (point versus diffuse)and hydrology (seepage versus drainage). By comparing the longterm effect of common restoration measures (nutrient load reduction, lake flushing or biomanipulation)in these four lake types, we found that restoration through reduction of nutrient loading is effective in all cases. In contrast, biomanipulation only works in seepage lakes with diffuse nutrient inputs, while lake flushing will even be counterproductive in lakes with nutrient point sources. The main conclusion of the presented analysis is that a priori assessment of spatial heterogeneity caused by nutrient loading and hydrology is essential for successful restoration of lake ecosystems.

    Modelling the spatial dynamics of Maui dolphins using individual-based models
    Jager, M. de; Hengeveld, G.M. ; Mooij, W.M. ; Slooten, E. - \ 2019
    Ecological Modelling 402 (2019). - ISSN 0304-3800 - p. 59 - 65.
    The current anthropogenic impacts on nature necessitate more research for nature conservation and restoration purposes. To answer ecological and conservation questions concerning endangered species, individual-based modelling is an obvious choice. Individual-based models can provide reliable results that may be used to predict the effects of different future conservation strategies, once calibrated correctly. Here, we calibrate an individual-based model of Maui dolphin movement, which generates Maui dolphin probability distribution maps. We used sighting data for calibration of the chosen parameter combinations; for each simulation run, collected simulated data was compared to the empirical survey data, resulting in cost (Badness-of-Fit) estimates. Using costs of four different aspects of dolphin behaviour, we estimated the most likely parameter combinations. With optimized parameter values, Maui dolphin probability distribution maps were created, resulting in distributions that fall well outside of the current protection zones where either gillnets or trawling or both are prohibited. With these results, protected areas can be properly adjusted to the estimated distribution of this critically endangered species and so aid in their conservation.
    Modelling induced bank filtration effects on freshwater ecosystems to ensure sustainable drinking water production
    Gillefalk, Mikael ; Mooij, Wolf M. ; Teurlincx, Sven ; Janssen, Annette B.G. ; Janse, Jan H. ; Chang, Manqi ; Köhler, Jan ; Hilt, Sabine - \ 2019
    Water Research 157 (2019). - ISSN 0043-1354 - p. 19 - 29.
    Macrophytes - PCLake - Phytoplankton - Regime shift - Shallow lakes - Surface water-groundwater interaction

    Induced bank filtration (IBF) is a water abstraction technology using different natural infiltration systems for groundwater recharge, such as river banks and lake shores. It is a cost-effective pre-treatment method for drinking water production used in many regions worldwide, predominantly in urban areas. Until now, research concerning IBF has almost exclusively focussed on the purification efficiency and infiltration capacity. Consequently, knowledge about the effects on source water bodies is lacking. Yet, IBF interrupts groundwater seepage and affects processes in the sediment potentially resulting in adverse effects on lake or river water quality. Securing sufficient source water quality, however, is important for a sustainable drinking water production by IBF. In this study, we analysed the effects of five predicted mechanisms of IBF on shallow lake ecosystems using the dynamic model PCLake: declining CO 2 and nutrient availability, as well as increasing summer water temperatures, sedimentation rates and oxygen penetration into sediments. Shallow lake ecosystems are abundant worldwide and characterised by the occurrence of alternative stable states with either clear water and macrophyte dominance or turbid, phytoplankton-dominated conditions. Our results show that IBF in most scenarios increased phytoplankton abundance and thus had adverse effects on shallow lake water quality. Threshold levels for critical nutrient loading inducing regime shifts from clear to turbid conditions were up to 80% lower with IBF indicating a decreased resilience to eutrophication. The effects were strongest when IBF interrupted the seepage of CO 2 rich groundwater resulting in lower macrophyte growth. IBF could also enhance water quality, but only when interrupting the seepage of groundwater with high nutrient concentrations. Higher summer water temperatures increased the share of cyanobacteria in the phytoplankton community and thus the risk of toxin production. In relative terms, the effects of changing sedimentation rates and oxygen penetration were small. Lake depth and size influenced the effect of IBF on critical nutrient loads, which was strongest in shallower and smaller lakes. Our model results stress the need of a more comprehensive ecosystem perspective including an assessment of IBF effects on threshold levels for regime shifts to prevent high phytoplankton abundance in the source water body and secure a sustainable drinking water supply.

    PCLake+ : A process-based ecological model to assess the trophic state of stratified and non-stratified freshwater lakes worldwide
    Janssen, Annette B.G. ; Teurlincx, Sven ; Beusen, Arthur H.W. ; Huijbregts, Mark A.J. ; Rost, Jasmijn ; Schipper, Aafke M. ; Seelen, Laura M.S. ; Mooij, Wolf M. ; Janse, Jan H. - \ 2019
    Ecological Modelling 396 (2019). - ISSN 0304-3800 - p. 23 - 32.
    Deep lake - Food web model - Lake ecology - Limnology - Shallow lake - Thermal stratification

    The lake ecosystem model PCLake is a process-based model that was developed to simulate water quality based on ecological interactions in shallow, non-stratifying lakes in the temperate climate zone. Here we present PCLake+, which extends the PCLake model to cover a wide range of freshwater lakes that differ in stratification regime and climate-related processes. To this end, the model was extended with a hypolimnion layer that can be invoked and configured by forcing functions or by simple built-in empirical relationships that impose stratification. Further adjustments to the original PCLake model have been made with respect to the calculation of 1) light irradiation in the water column, 2) evaporation processes and 3) phenology of macrophytes. The simulation output of PCLake+ for different types of lakes complies well with generally accepted limnological knowledge, thus holding promise for future contributions to ecological theory and application to lakes around the globe.

    Towards a global model for wetlands ecosystem services
    Janse, Jan H. ; Dam, Anne A. van; Hes, Edwin M.A. ; Klein, Jeroen J.M. de; Finlayson, C.M. ; Janssen, Annette B.G. ; Wijk, Dianneke van; Mooij, Wolf M. ; Verhoeven, Jos T.A. - \ 2019
    Current Opinion in Environmental Sustainability 36 (2019). - ISSN 1877-3435 - p. 11 - 19.

    Wetlands play an important role in the provision of important ecosystem services like the provision of clean water to the world, adaptation to climate change, and support for biodiversity; although they are sometimes also associated with adverse climate effects. Wetlands are, however, currently grossly underrepresented in global environmental models. In this paper, we explore the required functionality of a generic model of the effects of climate and land-use changes on wetlands ecosystem services worldwide. We briefly review existing models to identify elements which can be combined to compile a generic wetland model. The proposed global wetland model should be integrated into and receive data from existing hydrology and climate models. Wetland delineation can be based on local hydrological and topographical conditions and verified with global wetland databases. We conclude that an integrated approach combining hydrology, biogeochemistry and vegetation for wetlands is not available yet, however, useful building blocks exist that can be combined.

    Towards restoring urban waters : understanding the main pressures
    Teurlincx, Sven ; Kuiper, Jan J. ; Hoevenaar, Ellen C.M. ; Lurling, Miquel ; Brederveld, Robert J. ; Veraart, Annelies J. ; Janssen, Annette B.G. ; Mooij, Wolf M. ; Senerpont Domis, Lisette N. de - \ 2019
    Current Opinion in Environmental Sustainability 36 (2019). - ISSN 1877-3435 - p. 49 - 58.

    Water bodies in the urban landscape are omnipresent, with many being small, lentic waters such as ponds and lakes. Because of high anthropogenic forcing, these systems have poor water quality, with large consequences for the provisioning of ecosystem services. Understanding of the main pressures on urban water quality is key to successful management. We identify six pressures that we hypothesize to have strong links to anthropogenic forcing including: eutrophication, aquatic invasive species, altered hydrology, altered habitat structure, climate change, and micropollutants. We discuss how these pressures may affect water quality and ecological functioning of urban waters. We describe how these pressures may interact, posing challengers for water management. We identify steps that need to be taken towards sustainable restoration, recognizing the challenges that potentially interacting pressures pose to water managers.

    How to model algal blooms in any lake on earth
    Janssen, Annette B.G. ; Janse, Jan H. ; Beusen, Arthur H.W. ; Chang, Manqi ; Harrison, John A. ; Huttunen, Inese ; Kong, Xiangzhen ; Rost, Jasmijn ; Teurlincx, Sven ; Troost, Tineke A. ; Wijk, Dianneke van; Mooij, Wolf M. - \ 2019
    Current Opinion in Environmental Sustainability 36 (2019). - ISSN 1877-3435 - p. 1 - 10.

    Algal blooms increasingly threaten lake and reservoir water quality at the global scale, caused by ongoing climate change and nutrient loading. To anticipate these algal blooms, models to project future algal blooms worldwide are required. Here we present the state-of-the-art in algal projection modelling and explore the requirements of an ideal algal projection model. Based on this, we identify current challenges and opportunities for such model development. Since most building blocks are present, we foresee that algal projection models for any lake on earth can be developed in the near future. Finally, we think that algal bloom projection models at a global scale will provide a valuable contribution to global policymaking, in particular with respect to SDG 6 (clean water and sanitation).

    Nitrogen fixation does not axiomatically lead to phosphorus limitation in aquatic ecosystems
    Gerven, Luuk P.A. van; Kuiper, Jan J. ; Mooij, Wolf M. ; Janse, Jan H. ; Paerl, Hans W. ; Klein, Jeroen J.M. de - \ 2019
    Oikos 128 (2019)4. - ISSN 0030-1299 - p. 563 - 570.
    eutrophication - nitrogen fixation - R*

    A long-standing debate in ecology deals with the role of nitrogen and phosphorus in management and restoration of aquatic ecosystems. It has been argued that nutrient reduction strategies to combat blooms of phytoplankton or floating plants should solely focus on phosphorus (P). The underlying argument is that reducing nitrogen (N) inputs is ineffective because N2-fixing species will compensate for N deficits, thus perpetuating P limitation of primary production. A mechanistic understanding of this principle is, however, incomplete. Here, we use resource competition theory, a complex dynamic ecosystem model and a 32-year field data set on eutrophic, floating-plant dominated ecosystems to show that the growth of non-N2-fixing species can become N limited under high P and low N inputs, even in the presence of N2 fixing species. N2-fixers typically require higher P concentrations than non-N2-fixers to persist. Hence, the N2 fixers cannot deplete the P concentration enough for the non-N2-fixing community to become P limited because they would be outcompeted. These findings provide a testable mechanistic basis for the need to consider the reduction of both N and P inputs to most effectively restore nutrient over-enriched aquatic ecosystems.

    Modeling water quality in the Anthropocene: directions for the next-generation aquatic ecosystem models
    Mooij, W.M. ; Wijk, Dianneke van; Beusen, A.H.W. ; Brederveld, R.J. ; Chang, M. ; Cobben, Marleen M.P. ; DeAngelis, D.L. ; Downing, A.S. ; Janssen, A.B.G. ; Hengeveld, G.M. - \ 2019
    Current Opinion in Environmental Sustainability 36 (2019). - ISSN 1877-3435 - p. 85 - 95.
    Everything changes and nothing stands still” (Heraclitus). Here we review three major improvements to freshwater aquatic ecosystem models — and ecological models in general — as water quality scenario analysis tools towards a sustainable future. To tackle the rapid and deeply connected dynamics characteristic of the Anthropocene, we argue for the inclusion of eco-evolutionary, novel ecosystem and social-ecological dynamics. These dynamics arise from adaptive responses in organisms and ecosystems to global environmental change and act at different integration levels and different time scales. We provide reasons and means to incorporate each improvement into aquatic ecosystem models. Throughout this study we refer to Lake Victoria as a microcosm of the evolving novel social-ecological systems of the Anthropocene. The Lake Victoria case clearly shows how interlinked eco-evolutionary, novel ecosystem and social-ecological dynamics are, and demonstrates the need for transdisciplinary research approaches towards global sustainability.
    Nutrient pollution and critical thresholds for Chinese lakes: a case of Lake Taihu
    Janssen, A.B.G. ; Yang, Jing ; Li, Xiaolin ; Strokal, M. ; Kroeze, C. ; Mooij, W.M. - \ 2018
    In: International Society of Limnology XXXIV Congress Book of abstracts. - - p. 281 - 281.
    China has gone through a vast development of economy, human population and society. Whilst this vast development has strengthened China’s international position, it has also resulted in environmental issues including eutrophication of lakes. As a result many Chinese lakes experience turbid waters with toxic cyanobacteria blooms including Lake Taihu. These cyanobacterial blooms are detrimental to ecosystem services such as the provisioning of water for drinking and irrigation, and to food supply and tourism. To prevent eutrophication to impede China’s future sustainable development, it is important to understand the possible consequences of eutrophication of freshwater lakes. In this respect, two important aspects need to be addressed.The first aspect is to determine current nutrient loads to lakes from all sources. Nutrient loads to lakes can be based on measurement data or estimated by models such as MARINA. The second aspect is to determine the critical nutrient load of the specific lake that marks the threshold between clear and turbid water. Critical nutrient loads can be determined by ecosystem models like PCLake. By combining knowledge on the current load with the critical nutrient load, managers can define goals to reduce the nutrient load beyond the critical nutrient loadHere we focus on the assessment of the current and critical nutrient loads of Lake Taihu, a large shallow lake (area: 2250km², average depth: 2 m) that is located in southeast China. This lake became hypereutrophic during last decades. Depending on the maximum allowable chlorophyll-a concentrations, our results show that 50-90% of the current nutrient load to Taihu has to be reduced to reach sufficient water quality. We compare this output with findings for other Chinese lakes. This knowledge is valuable for sustainable development in China.
    Taking advantage of model diversity: benefits of ensemble modelling for managing algal blooms in polluted lakes
    Janssen, A.B.G. ; Troost, Tineke A. ; Mooij, W.M. - \ 2018
    In: International Society of Limnology XXXIV Congress Book of abstracts. - - p. 134 - 134.
    Climate change and increasing anthropogenic stress have intensified the occurrence of nuisance algal blooms worldwide. Toxic and highly adaptive blooms of cyanobacteria can threaten drinking water safety and break down ecosystem functions by suppressing aquatic macrophytes. To prevent the deterioration of aquatic ecosystems, ecological models play an important role to simulate possible scenarios and provide options for environmental management. However, the complexity of ecosystems makes it difficult to simulate all the physical, chemical and biological processes in one model. Instead of looking for a panacea, the urgent demand for such management tools has accelerated the development of a large and diverse number of ecological models for different contexts. Ensemble modelling is an approach inspired by weather forecasting. Model diversity is exploited to improve the robustness of algal bloom prediction. Ensemble modelling might also result in important insights how the differences in model structure contribute to the fit of the models to data. In this study, we selected two ecological models to examine their underlying causality. One widely applied model is PCLake, which is a dynamic model and includes food web interactions. PCLake is often used for so-called bifurcation analysis to define the critical loading that define lake regime shifts. Another widely applied model is BLOOM, whose phytoplankton module is built with linear programming and supported by an empirical database. To see how the models’ conceptual differences reflect on the simulated outcomes, we analyze their differences in model structure and thereafter run them for theoretical scenarios that vary in temperature, nutrient loading and light intensity,respectively. As a final step, we plan to apply both models in real-world scenarios and validate them with observed data, to see and explain how ensemble modelling works in practice. Our results show that ensemble modelling can be beneficial for managing algal blooms in polluted lakes
    Conserving Biocultural Diversity through Community–Government Interaction : A Practice-Based Approach in a Brazilian Extractive Reserve
    Mooij, Marjolein ; Dessartre Mendonça, Sabine ; Arts, K.A.J. - \ 2018
    Sustainability 11 (2018)1. - ISSN 2071-1050
    We examined how community–government interaction may promote or hinder the conservation of biocultural diversity. Research was done with the extractive community of the Reserva Extrativista Riozinho da Liberdade, located in the state of Acre, Brazil. The reserve is governed by ICMBio, a Brazilian governmental organisation overseeing reserve policy implementation. This paper describes the interaction between ICMBio and the inhabitants of Riozinho da Liberdade. A Practice-Based Approach was used as a theoretical scope to look at the interaction on a practical level. It was found that ICMBio tried to develop the living standards of community members in various ways, for example, by offering suggestions for the improvement of livelihoods, and by proposing alternatives for consumptive behaviour. Although the relationship between ICMBio and the community was generally valued by community members, this did not always equal compliance with ICMBio’s rules, or responsiveness to ICBMIO’s suggestions for development. Our results show that although compliance was often suboptimal from a government perspective, biocultural diversity may still be reproduced through close interaction between community and government, and thus conserved. As such, our investigation provides counterweight to the abundant empirical evidence on the harmful social consequences of government interference in local nature governance. A main methodological insight of our work is that a Practice-Based Approach enabled us to detect (non-)compliant behaviour that would have otherwise likely gone unnoticed.
    Model studies on the dynamics of hydrophobic organic compounds in shallow lake ecosystems
    Kong, Xiangzhen - \ 2018
    Wageningen University. Promotor(en): W.M. Mooij; A.A. Koelmans. - Wageningen : Wageningen University - ISBN 9789463433471 - 253

    The twentieth century witnesses the widespread eutrophication and intensive organic contaminations in earth surface water systems located in highly populated areas, resulting in severe deterioration of water quality in freshwater ecosystems around the globe. This is particularly the case for many freshwater shallow lakes in China. The interaction between excess nutrient loading and enormous organic contaminants discharge has raised increasing attention from both scientists and lake managers, whereas accurate prediction for both substances cannot be properly predicted based on knowledge from either field alone. However, efforts in the related scientific research, particularly the development of relevant modeling tools, remains scarce. To this end, the aim of this thesis is to develop an integrated ecological and chemical modeling tool, which is composed of contaminant fate module (CF), food web accumulation module (FW) and ecological module (EM), in the hope to fulfill the research gap above. We collected three groups of HOCs, namely hexachlorocyclohexanes (HCHs), polycyclic aromatic hydrocarbons (PAHs) and Per- and polyfluoroalkyl substances (PFASs), in multiple compartments from two Chinese shallow lakes that are currently in distinct ecological states, i.e., Lake Small Baiyangdian (in clear state) and Lake Chaohu (in turbid state). In particular, paleo-records of PAHs residual levels in Lake Chaohu in two sediment cores covering the time span of over 60 years were obtained. We elaborated to explicitly investigate the fate, transport and transformation of these contaminants in these two shallow lakes using the developed modeling tool, with either steady state or dynamic simulations (in time scales of both short-term intra-annual (1-2 years) and long-term inter-annual (60 years)). The following issues were addressed: 1) fate of the chemicals in lake environment and the dominant processes; 2) seasonal patterns of chemicals in lakes and the driving factors; 3) long-term dynamics of chemicals in lakes and the driving factors; and 4) impact of abrupt changes in ecosystems on the distribution of contaminations in shallow lakes. For modeling techniques, we implemented uncertainty analysis on the model using both classic Monde Carlo and more advanced Bayesian Markov Chain Monte Carlo (MCMC) algorithm. We recommend to apply MCMC to contaminant modeling approach to make calibration possible and to remove the overestimated uncertainty in predictions. Furthermore, we compared the advantages and disadvantages of our model to other models with similar objectives, and we further proposed a more comprehensive modeling framework that incorporates hydrodynamic models to address spatial variations of contamination, which embraces the fruitful outcomes in aquatic ecosystem modeling. Finally, we advocate to add modeling approach as the third dimension for the ‘contemporary & paleo-observations’ strategy, which together contribute to the ‘golden triangle’ framework. New insights and discoveries may emerge for the evaluation on the organic contaminants in shallow lake systems, which may contribute to ecological and human health risk assessment. This ‘golden triangle’ may serve as the multidiscipline framework for limnologic research in the future.

    Spatial heterogeneity in critical nutrient loads of large shallow lakes : implications for Lake Taihu (China)
    Janssen, A.B.G. ; Jager, Victor de; Kong, X. ; Mooij, W.M. - \ 2018
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