Hogeschool Van Hall Larenstein
Recent publications
Large-scale deforestation in the tropics, triggered by logging and subsequent agricultural monoculture has a significant adverse impact on biodiversity due to habitat degradation. Here, we measured the diversity of butterfly species in three agricultural landscapes, agroforestry orchards, oil palm, and rubber tree plantations. Butterfly species were counted at 127 sampling points over the course of a year using the point count method. We found that agroforestry orchards supported a greater number of butterfly species (74 species) compared to rubber tree (61 species) and oil palm plantations (54 species) which were dominated by generalist (73%) followed by forest specialists (27%). We found no significant difference of butterfly species composition between agroforestry orchards and rubber tree plantation, with both habitats associated with more butterfly species compared to oil palm plantations. This indicates butterflies were able to persist better in certain agricultural landscapes. GLMMs suggested that tree height, undergrowth coverage and height, and elevation determined butterfly diversity. Butterfly species richness was also influenced by season and landscape-level variables such as proximity to forest, mean NDVI, and habitat. Understanding the factors that contributed to butterfly species richness in an agroecosystem, stakeholders should consider management practices to improve biodiversity conservation such as ground vegetation management and retaining adjacent forest areas to enhance butterfly species richness. Furthermore, our findings suggest that agroforestry system should be considered to enhance biodiversity in agricultural landscapes.
Equestrianism is currently facing a range of pressing challenges. These challenges, which are largely based on evolving attitudes to ethics and equine wellbeing, have consequences for the sport’s social licence to operate. The factors that may have contributed to the current situation include overarching societal trends, specific aspects of the equestrian sector, and factors rooted in human nature. If equestrianism is to flourish, it is evident that much needs to change, not the least, human behaviour. To this end, using established behaviour change frameworks that have been scientifically validated and are rooted in practice—most notably, Michie et al.’s COM-B model and Behaviour Change Wheel—could be of practical value for developing and implementing equine welfare strategies. This review summarises the theoretical underpinnings of some behaviour change frameworks and provides a practical, step-by-step approach to designing an effective behaviour change intervention. A real-world example is provided through the retrospective analysis of an intervention strategy that aimed to increase the use of learning theory in (educational) veterinary practice. We contend that the incorporation of effective behaviour change interventions into any equine welfare improvement strategy may help to safeguard the future of equestrianism.
As digitalization increasingly gains attention in the agriculture sector, many African youths are seizing the opportunity provided by digital technologies to engage in agriculture. While prior studies have started examining the intricacies of digitalization in agriculture, they have paid less attention to its implications for fostering institutions and inter-organizational synergies that can support and sustain the businesses of youth enterprises engaging with Africa’s agriculture. Against this backdrop, we undertook a qualitative case study to shed light on the development of a community of practice comprising youth enterprises engaging in agriculture through digitalization. Thus, we studied Africa Goes Digital (AFGD), a consortium of young African enterprises that rely on digital technologies and solutions to provide services to farmers across the African continent. The results showed that: (1) the Technical Centre for Agricultural and Rural Cooperation ACP-EU (CTA) played a pioneering role as a development agency in supporting enterprises with drones and training for agriculture, which led to the formation of AFGD; (2) two prevalent themes characterized the services offered by AFGD members; (3) AFGD brings members under one platform where they leverage WhatsApp for communication and knowledge sharing and Twitter to showcase success stories and form partnerships with each other to execute certain development projects with governments and development agencies; (4) the lack of regulations or the restrictive regulations on the use of drones are still problems that some members face, and the high costs of sensors and related drones are challenges for the members. Building on the results, we discuss the implications of digitalization for supporting African governments in meeting sustainability goals and conclude by describing the theoretical contribution of our study and promising future research directions.
Fouling plays a major role in the Dairy industry. Five criteria: defined flow, no circulation, real factory product, defined product temperature and defined wall temperature, are used to review articles on this topic published between 2003 and 2020. To show the effect of those criteria in experiments, a simulation model is developed. For a good experimental design to measure fouling, the use of a dairy product in a tubular heater with a known developed flow is advised. The temperature-time history of the product and the wall temperature of the heater should be recorded. Circulation of a product will increase the fouling and decrease the flow. Although none of the reviewed articles complied to all criteria, 71% of the reviewed articles met at least two criteria. If not all criteria are met, the results are of less use for the application for process lines on industrial scale. A simulated computer model can be helpful.
This editorial positions the papers of this Special Issue in a theoretical framework on green urban development. Building on different perspectives, we identify the conditions that are necessary to accelerate a successful implementation of green urban transformations, as well as several pitfalls. In short, these conditions are: the macro, meso, and micro level should be aligned; solutions in different subsystems on the meso level must coincide; and change agents on the different levels should find each other. We illustrate the effect of the (non) availability of the conditions primarily making use of Dutch examples. A major pitfall is the resilience (locked-in) of the different subsystems on the meso level (transport, housing, etc.), both internally (finances, etc.) as well as between them, with a loose or no structural integration. Based on the lessons learned, we discuss pathways to accelerate green urban transitions.
Background The parasite Toxoplasma gondii (T. gondii) is recognized worldwide as a pathogen causing a substantial human disease burden. Ingesting improperly cooked meat containing T. gondii is considered one of the major sources of human infection in Europe and North America. Consequently, control of T. gondii infections in pigs is warranted. The European Food Safety Authority (EFSA) advised to perform serological testing of pigs and farm audits for the presence of risk factors. Serological monitoring was implemented in several Dutch slaughterhouses. Blood samples from all deliveries of finishing pigs to the slaughterhouses were tested for the presence of anti-T. gondii antibodies. Using these test results, a case-control study was initiated to assess the association between the within-herd T. gondii seroprevalence and the presence of risk factors for T. gondii infections in 69 conventional finishing pig herds in the Netherlands. Results In a multivariable model twelve potential risk factors were significantly (P ≤ 0.05) associated with the level of seropositive T. gondii blood serum samples. Conclusions Serological screening of finishing pigs in the slaughterhouse for T. gondii can be used to identify presence of T. gondii risk factors on Dutch conventional finishing pig farms. The use of serological screening seems therefore a valuable tool to guide and monitor the control of T. gondii in pork production.
Calls for transformative change and participatory modes of knowledge production demand researchers to assume new roles. This paper synthesizes the literature on knowledge co-production and researcher roles to explore challenges for researchers involved in transdisciplinary environmental management projects. Our research methods combine a scoping review and reflections on personal experiences with three transdisciplinary projects. To conceptualize researcher roles in transdisciplinary knowledge co-production, we distinguish between three spaces: knowledge, formal policy, and stakeholder. Knowledge co-production requires collaboration between actors from different spaces and integration of diverse knowledge sources and types. Depending on whether researchers adopt knowledge-oriented, change-oriented or intermediating roles, they will experience different challenges. When researchers combine knowledge development with change-oriented and/or intermediating roles, they encounter new challenges, such as, maintaining independence or objectivity. To assist researchers in transdisciplinary projects, we conclude with a checklist of four elements to reflect upon: orientation, norms and values, expectations and resources.
Aim To evaluate how the spatial distribution of a heavily exploited marine gastropod (i.e. Queen conch) varies in response to a number of known biotic and abiotic variables within and between study areas that vary in environmental conditions. Location Three study areas in the north-eastern Caribbean, Anguilla, Saba Bank and St. Eustatius. Methods A novel towed video system and complemented belt transects to estimate adult queen conch densities throughout its depth range. Bayesian hierarchical spatial models (integrated nested Laplace approximations) modelled distribution patterns of adult conch. Results Our study revealed patchy distribution patterns of adult conch caused by spatial dependency. This dependency is most likely related to aggregating behaviour during spawning events. Environmental variables, such as algal cover, distance to the open ocean and depth, showed important nonlinear effects on conch abundance, although these differed among study areas. Intermediate and deep areas (ca. 17–45 m) contain most of the reproductive output of conch in the study areas and are highly important for the reproductive capacity. Main conclusions The general patchy distribution pattern and the lack of strong generic relationships between biotic and abiotic factors and adult conch abundance and distribution are likely to be at least partly due to spatial dependency and location-specific factors, which affect different phases of the conch's life history. The depth distribution of conch also indicates that surveying areas at depths beyond the practical limitation of divers is of great importance to obtain more reliable population estimates.
Barriers in the estuaries of the rivers prevent the immigration of glass eels (Anguilla anguilla) arriving on the European coast every spring. This leads to an unnatural accumulation of migrating glass eels below the barriers and this may lead to additional losses in glass eels by piscivorous fish. The proportion of predation losses can be estimated using mark-recapture techniques and abundance estimates in combination with stomach content analysis of piscivorous fish. However, whether tagging transparent glass eels increases predation risk and what the digestion rate of glass eel is in piscivorous fish are unknown. This study aimed to determine whether there is an increased predation risk for tagged glass eel; it also studies glass eel digestion status in piscivorous fish after appointed time frames. A laboratory experiment with 48 trials was conducted. Tagged (Visible Implanted Elastomer, VIE) and untagged glass eels were exposed to small (19.1-24.4cm) and large (31.9-43.5cm) sea bass (Dicentrarchus labrax) during a 2-hour trial. In 48% of the trials successful predation was present and 13% showed clear predation attempts in which bass did not capture glass eels. No significant difference was found in predation rate between tagged and untagged glass eels and between red and blue tagged glass eels. Large sea bass predated more, but all sizes consumed glass eel under laboratory conditions. Stomach content analysis showed intact glass eel bodies 4-6 hours after ending the 2-hour trial and parts of glass eel bodies up to 16-18 hours. This study showed that tagging does not increase predation in mark-recapture studies using VIE-tags in transparent glass eel. It also shows that the proportion of predation in relation to local glass eel abundance can be estimated if stomach content analysis is conducted within 4-6 hours after predation. This article is protected by copyright. All rights reserved.
Species responding differently to climate change form ‘transient communities’, communities with constantly changing species composition due to colonization and extinction events. Our goal is to disentangle the mechanisms of response to climate change for terrestrial species in these transient communities and explore the consequences for biodiversity conservation. We review spatial escape and local adaptation of species dealing with climate change from evolutionary and ecological perspectives. From these we derive species vulnerability and management options to mitigate effects of climate change. From the perspective of transient communities, conservation management should scale up static single species approaches and focus on community dynamics and species interdependency, while considering species vulnerability and their importance for the community. Spatially explicit and frequent monitoring is vital for assessing the change in communities and distribution of species. We review management options such as: increasing connectivity and landscape resilience, assisted colonization, and species protection priority in the context of transient communities.
Background: The parasite Toxoplasma gondii (T. gondii) is recognized as one of the major foodborne pathogens with a high human disease burden. To control T. gondii infections in pigs, European Food Safety Agency (EFSA) advises serological testing of pigs and audits of pig farms to identify risk factors for T. gondii infection. In line with this approach, the aim of the current study was to assess the effectiveness and costs of intervention measures implemented to reduce the T. gondii seroprevalence on finishing pig farms in the Netherlands. A crossover clinical trial was conducted at five case farms were their own control and the cross-over moment was the implementation of interventions to reduce risk factors. Each of the case farms had a farm-specific intervention strategy with one principal intervention measure (neutering of cats, professional rodent control or covering food storage). Results: All finishing pig farms (n = 5) showed a reduction in T. gondii seroprevalence within one year of implementing the intervention strategy. Cat neutering (n = 3) and feed coverage (n = 1) showed statistically significant reductions in seroprevalence. Rodent control (n = 1) did not show a statistically significant reduction. The estimated reduction in seroprevalence in response to the neutering of cats and feed coverage were 67 and 96 %, respectively. Conclusions: Our work demonstrates that it is possible to reduce the within-farm T. gondii seroprevalence within one year after interventions were implemented to reduce T. gondii risk factors. This information is essential and encouraging for policy makers, food business operators, and farmers to implement in their risk assessment and to apply to food safety control systems.
Purpose The carbon footprint for the downstream dairy value chain, milk collection and dairy processing plants was estimated through the contribution of emissions per unit of collected and processed milk, whereas that for the upstream dairy value chain, input supply and production was not considered. A survey was conducted among 28 milk collectors and four employees of processing plants. Two clusters were established: small- and large-scale milk collectors. The means of carbon dioxide equivalent per kilogramme (CO2-eq/kg) milk were compared between clusters by using independent sample t-test.The average utilisation efficiency of milk cooling refrigerators for small- and large-scale collectors was 48.5 and 9.3%, respectively. Milk collectors released carbon footprint from their collection, cooling and distribution practices. The mean kg CO2-eq/kg milk was 0.023 for large-scale collectors and 0.106 for small-scale collectors (p < 0.05). Milk processors contributed on average 0.37 kg CO2-eq/kg milk from fuel (diesel and petrol) and 0.055 from electricity. Almi fresh milk and milk products processing centre emitted the highest carbon footprint (0.212 kg CO2-eq/kg milk), mainly because of fuel use. Generally, in Ziway-Hawassa milk shed small-scale collectors released higher CO2-eq/kg milk than large-scale collectors.
The combined effects of socio-economic growth as well as climate change exert increasing pressure on international river basins and require dedicated cooperative efforts to jointly manage international rivers. Cooperative strategies drawn from scientific literature, empirical research and practitioner’s handbooks are explored and clustered into six key dimensions of goals, instruments, structures, actors, leadership and resources to provide an assessment tool of actor strategies for both scientists and practitioners. The exploratory framework is applied to Dutch–German cooperation in the delta of the Rhine catchment, testing its conceptual validity and applicability in international river basin management as well as providing policy recommendations for the study area. The assessment framework can serve as an instrument to inventory, map and evaluate the importance of specific actor strategies and to facilitate dialogue and cross-border cooperation between riparian countries. Alternatively, the framework can be put to use, for example by downstream countries, to assess and coordinate their range of strategies on the national, regional and local level in order to engage and influence their counterparts.
The Steenbreek program is a private Dutch program which aims to involve citizens, municipalities and other stakeholders in replacing pavement with vegetation in private gardens. The Dutch approach is characterized by minimal governmental incentives or policy, which leaves a niche for private initiatives like Steenbreek, that mainly work on behavioural change. The aim of this paper is to build a model based on theory that can be used to improve and better evaluate depaving actions that are based on behavioural change. We tested this garden greening behaviour model in the Steenbreek program. The main result is that the model provides an understanding of the ‘how and why’ of the Steenbreek initiatives. Based on this we are able to provide recommendations for the improvement of future initiatives. Steenbreek covers a wide range of projects that together, in very different ways, take into account elements of the theoretical framework; either more on information factors, or on supporting factors, sometimes taking all elements together in a single action. This focus is sometimes understandable when just one element is needed (e.g., support), sometimes more elements could be taken into account to be more effective. If a certain element of the framework is lacking, the change of behaviour will not (or will only partly) take place. The model also gives insight into a more specific approach aimed at the people most susceptible to changing their behaviour, which would make actions more effective.
In sub-Saharan Africa crop productivity is generally low, which affects food security and livelihoods. The application of mineral fertilizers in many cases is seen as a straightforward way to improve crop productivity. In Tigray, Northern Ethiopia, agricultural extension bureaus recommend the application of considerable amounts of fertilizers. Farmers, however, hesitate to adopt these recommendations and perceive that the use of fertilizers leads to “addiction”. Different indicators are available to evaluate effectiveness of fertilizer application. We considered six different indicators: Agronomic Use Efficiency (AUE), Value-Cost-Ratio (VCR), Recovery Efficiency (RE), Capture Efficiency (CE), Soil Supply Capacity (SSC) and (partial) Nutrient Balances (NB). On-farm experiments were conducted for four years at 16 different locations. Crops involved were wheat, teff and hanfets. Experimental outcomes were evaluated using laboratory data on nitrogen, phosphorus and potassium (NPK) content of both soil and crops. Significant differences between the crops were found for CE, RE, NB and VCR. Wheat overall was found most extractive. Correlation between SSC and N-total and between RE and N-uptake was significant for all crops. For both nitrogen and phosphorus, NB correlated significantly with SSC for wheat and teff. Interaction between SSC, RE and NB demonstrated a significant trend for wheat: soils with higher SSC had lower NB and higher RE than soils with lower SSC. We concluded that achieving efficient use of mineral fertilizer goes at the cost of nutrient stock sustainability. The use of Integrated Soil Fertility Management-strategies is recommended to address these complex feedback and interaction mechanisms and to arrive at a sound balance between efficiency and sustainability of fertilizer use.
The Municipal Museum of Zierikzee houses a loose-leafed herbarium containing 360 dried plant specimens, of which the provenance, age and maker were until recently unknown. By studying the plant specimens, paper, decorations and labels, an image was conveyed of an early 18th century herbarium that matched the description of a herbarium from the legacy of Jakob Ligtvoet, who was gardener in the Leiden Hortus botanicus from 1703 till his death in 1752. This herbarium is one of the oldest garden herbaria of its kind and contains 306 unique species, of which 201 are currently native to the Netherlands. Exotic species come from the Mediterranean (82 spp.), Europe (24), South Africa (8), the Americas (9) and in tropical Asia (7). Based on our comparison of names on the oldest labels, this collection of dried plants was probably started after publication of the rst garden catalogue by the prefect of the Leiden garden and professor of botany Herman Boerhaave (1710), but before the second edition in 1719. This historic herbarium re ects the state-of-the-art of botanical science and the international network of Dutch botanical gardens in the early 18 th century.
The aim of this study is to determine the contribution of student interventions to urban greening processes. In two Dutch cities action research was conducted, including reflexive interviews a year after the first intervention, to assess factors causing change in the socio-ecological system. Results show that students and network actors were mutually learning, causing the empowerment of actors in that network by adding contextualized knowledge, enlarging the social network, expanding the amount of interactions in the socio-ecological system and speeding up the process. Students brought unique qualities to the process: time, access to stakeholders who tend to distrust the municipality and a certain open-mindedness. Their mere presence made a difference and started a process of change. However, university staff needed to keep the focus on long-term effects and empowerment, because students did not oversee that. After a year, many new green elements had been developed or were in the planning phase. In Enschede, the municipality district managers were part of the learning network, which made it easier to cause changes in the main ecological network. In Haarlem however, no change took place in the main ecological network managed by the municipality, because no political empowerment of the civil society group had developed yet.
The sensitivity of tropical forest carbon to climate is a key uncertainty in predicting global climate change. Although short-term drying and warming are known to affect forests, it is unknown if such effects translate into long-term responses. Here, we analyze 590 permanent plots measured across the tropics to derive the equilibrium climate controls on forest carbon. Maximum temperature is the most important predictor of aboveground biomass (−9.1 megagrams of carbon per hectare per degree Celsius), primarily by reducing woody productivity, and has a greater impact per °C in the hottest forests (>32.2°C). Our results nevertheless reveal greater thermal resilience than observations of short-term variation imply. To realize the long-term climate adaptation potential of tropical forests requires both protecting them and stabilizing Earth’s climate.
Rats in urban areas pose health risks as they can transmit various zoonotic pathogens. Monitoring rat populations in urban areas is therefore a key determinant in risk assessments for taking adequate control and preventive measures. However, large-scale and long-term monitoring of rat populations is labor-intensive and time consuming. The aim of this study was to develop a low-cost and low-time- consuming method to gain insight into the trends of rat populations in urban and non-urban environments in the Netherlands, and to identify potential drivers of these trends. From 2014 to 2018, local municipalities or their pest control organizations voluntarily submitted quarterly overviews of rat nuisance reports in urban areas. For non-urban areas, a nationwide record of reported bycatch species from the muskrat control was used to assess a potential trend. To identify potential drivers of observed trends, employees of nine municipalities were interviewed. Rat nuisance reports from 25 municipalities were analyzed. An increasing trend in rat nuisance reports was observed in 12, a decreasing trend in 3 and no trend in 10 municipalities. In non-urban areas, no trend in the bycatch of rats was detected. The increase in rat nuisance reports was associated with a large municipality resident size. No consistent drivers could be identified, but potential drivers were discussed in the interviews. Although it was not possible to quantify their influence on the rat population trends seen, they provide direction for future studies on drivers of rat populations.
Background noise can have strong negative consequences for animals, reducing individual fitness by masking communication signals, impeding prey detection and increasing predation risk. While the negative impacts of noise across taxa have been well documented, the use of noise as an informational cue, providing animals with reliable information on environmental conditions, has been less well studied. In the tropical rainforest, downpours can be intense and frequent. Strong rainfall may impede efficient orientation and foraging for bats that need echolocation to both navigate and detect prey, and can result in higher flight costs due to increased metabolic rates. Using playback experiments at natural roosts, we tested whether two bat species, differing in their hunting strategies and foraging habitats, use rain noise as a cue to delay emergence from their roosts. We found that both species significantly delayed their emergence time during rain noise playbacks versus silence and ambient noise controls. We conclude that bats can use background noise, here the acoustic component of rainfall, as a reliable informational cue to make informed decisions, in this case about whether to initiate foraging trips or remain in the shelter of their roosts. Our findings suggest that environmental background noise can sometimes be beneficial to animals, in particular in situations where other sensory cues may be absent.
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1,695 members
Mart Vlam
  • Delta Areas and Resources
Rik Eweg
  • Applied Research Centre Animals and Business
S. Nederlof
  • Wageningen, Masters Management of Development
Peter van der Meer
  • Department of Forestry
Velp, Netherlands