Northern Belgium Research Articles

The significance of palaeoecological indicators in reconstructing estuarine environments: A multi-proxy study of increased Middle Holocene tidal influence in the lower Scheldt river, N-Belgium

Interpretation of fossil assemblages in mixed energy environments, such as estuaries, is complex due to the accumulation of material from different sources. In such environments, different proxies may result in contrasting interpretations, as is illustrated by the case of the Scheldt estuary in northern Belgium: during a phase of increased landward tidal ingression between 7000 and 5000 cal BP, mud was deposited, including microfossils that indicate increased salinity, while macrofossil records from the same deposits indicate tidal freshwater environments. By combining multiple proxies, sedimentological analysis and multivariate statistics, it is concluded that considerable landward sediment transport by tidal pumping, possibly enhanced by storms, explains how marine and brackish microfossils are massively present in freshwater tidal deposits. We propose an approach that combines the easily transported microfossils with the more local macrofossils to obtain a coherent reconstruction of the local estuarine environment, and to better understand the sedimentological processes in the wider region.

Dark Ages woodland recovery and the expansion of beech: a study of land use changes and related woodland dynamics during the Roman to Medieval transition period in northern Belgium

AbstractThe results from analyses of botanical remains (pollen, wood, charcoal, seeds) from several archaeological features excavated in Kluizen (northern Belgium) are presented. The region was largely uninhabited until the Iron Age and Roman period when a rural settlement was established, resulting in small-scale woodland clearance. The site was subsequently abandoned fromc.AD 270 till the High Middle Ages. The results of the archaeological and archaeobotanical analyses provide information on changes in land use and resulting dynamics of woodland cover and composition betweenc.600 BC and AD 1200, with a spatial and temporal resolution unrivalled in northern Belgium. Especially the long period of woodland regeneration following abandonment of the site around AD 270, covering the Late Roman and Early Medieval period, could be reconstructed in detail. Abandoned fields were first covered with pioneer woodland (Salix,CorylusandBetula), thenQuercus-dominated secondary forest and finally a late-successional forest withFagus sylvatica,Carpinus betulusandIlex aquifolium, an evolution that took over 300 years. The results also indicate that the observed increase ofFagusduring the Early Middle Ages, which was never an important element in the woodland vegetation in northern Belgium before, was related to climatic changes rather than anthropogenic factors.

Source-bordering aeolian dune formation along the Scheldt River (southern Netherlands – northern Belgium) was caused by Younger Dryas cooling, high river gradient and southwesterly summer winds

Abstract The Younger Dryas cold period caused major changes in vegetation and depositional environments. This study focuses on the aeolian river-connected dunes along the former, Weichselian Late Glacial, course of the Scheldt River in the southern Netherlands. Aeolian dunes along the Scheldt have received little attention, as they are partly covered by Holocene peat and marine deposits. The spatial distribution of the dunes is reconstructed by digital elevation model analysis and coring transects. Dunes are present on the high eastern bank of the Scheldt and in the subsurface of the polder area west of the Brabantse Wal escarpment. A reach-specific higher channel gradient probably caused a channel pattern change from meandering to braiding during the Younger Dryas. This enabled deflation from the braid plain and accumulation in source-bordering river dunes east of the incised and terraced, subsurface Late Pleistocene Scheldt valley. The age of the dune formation is established by pollen analysis and radiocarbon dating of underlying and overlying peat beds. The peat layer below the dune at Zomerbaan is attributed to the Allerød and early Younger Dryas periods. Dune formation occurred predominantly during the second part of the Younger Dryas stadial, both on and in front (west) of the Brabantse Wal escarpment. Wind direction was reconstructed by geomorphic analysis and sedimentary structures on lacquer peels. A southwesterly wind direction is demonstrated by the parabolic dune morphology. For the first time, Younger Dryas wind direction is reconstructed based on adhesion ripple cross-laminated sets on lacquer peels. Sand-transporting south-southwesterly winds were dominant during the Younger Dryas, most likely during summer.

Fracture characteristics of Lower Carboniferous carbonates in northern Belgium based on FMI log analyses

AbstractRecently drilled geothermal boreholes in Mol, northern Belgium, provide new information on the Lower Carboniferous carbonates in the Campine–Brabant Basin. Because of low primary porosity, fractures in these limestones and dolostones are of major importance for reservoir permeability. The Fullbore Formation MicroImager (FMI) log of the MOL-GT-01 borehole enabled interpretation of bed boundaries and fractures in the subsurface. Relationships between the frequency of these fractures and bed thickness, lithology variations and the presence of faults were explored. The results show that thick beds contain relatively few fractures and thin beds relatively many. Except for lower values in shaly intervals, the fracture frequency (number per metre) is largely independent of lithology. Zones with substantial changes in the structural dip (called a cusp) and/or azimuth of bed boundaries were identified. The clearest cusp is present at a depth of 3284 m. Since the presence of a normal fault is most likely regarding the local and regional geology, this cusp likely resembles a fault-tip fold of a WSW-ward dipping normal fault with an inclination of at least 54°. It is uncertain whether the borehole crossed the fault itself or only a monocline on top of it. Fracture frequency is increased in the vicinity of the interpreted possible faults. Up to a vertical distance ofc.45 m from the faults, the mean fracture frequency is higher than in a non-faulted zone with similar lithology. However, frequency differences between these faulted and non-faulted zones are mostly insignificant, so no clear damage zones are present.

Wood use in early medieval weapon production

In this paper, the analyses of wood remains from weapons that were found in early medieval graves in Belgium are presented. In addition, a large number of wood identifications from other early medieval weaponry from northwestern Europe (Germany, France, Switzerland, and England) was collected, resulting in a dataset of more than 800 items. The analysis of this dataset shows that the selection of wood taxa for specific weapons was largely similar all over northwestern Europe during this period and this selection can be explained by the physical and technical properties of each of these wood species. For instance, common ash (Fraxinus excelsior) being the preferred wood for arrow and spear shafts and alder (Alnus sp.) for scabbards. However, some regional differences emerged from this extensive dataset, e.g., the use of holly (Ilex aquifolium) for the production of axe handles being restricted to northern Belgium and poplar/willow (Populus sp./Salix sp.) being the preferred wood for shields in the UK, while these were mostly made from alder (Alnus sp.) in continental Europe. The results demonstrate the added value of wood anatomical analysis of mineralized wood particles preserved in the corrosion layer of metal objects, and weapons in particular, from archeological contexts. Clearly, taxonomic identifications have the potential to shed more light on material culture, technological craftsmanship, and the burial ritual in early medieval societies.

Agricultural and landscape factors related to increasing wild boar agricultural damage in a highly anthropogenic landscape

Human–wildlife impacts (HWI) occur due to interactions between wildlife and human activities in our increasingly anthropogenic world and typically result in economic losses or increased health- and safety risks. HWI can be especially prevalent where urbanization encroaches upon natural areas, or in fragmented human-dominated landscapes. An example of such situation is the re-occurrence of wild boar in Flanders (northern Belgium). Flanders is one of the most densely populated areas of Europe and is characterized by a severely fragmented landscape. The recent return of wild boar to Flanders challenges managers to find solutions for a sustainable co-existence between humans and wild boar. As crop damage is increasing and targeting preventive measures efficient requires identifying high risk areas, we assessed the influence of the landscape around a field, as well as field-specific characteristics on the likelihood of wild boar crop damage. Because most of the reported damage in Flanders occurs in grasslands (cultivated to produce hay) and maize fields, we focused on these. We used boosted regression trees and the brglm-technique to construct distribution models explaining spatial patterns of crop damage. We found that for maize fields, landscape-level variables such as the proportion of maize, grassland, forest and urbanized areas in the surroundings of the field are key factors determining the probability of damage. In contrast, field-specific variables only played a minor role. For grasslands, both field-specific and landscape characteristics affected damage probability: a higher probability of damage was associated with decreasing distance to nearest forest, increasing distance to the nearest road, the use of inorganic fertilization and increasing age of the grassland. Our results suggest that the risk of crop damage by wild boar can potentially be mitigated by changes in agricultural practices that alter grassland characteristics, and by targeting preventive measures towards high risk maize in well-defined locations.

Managing muddy floods: Balancing engineered and alternative approaches

AbstractMuddy runoff from agricultural fields is widespread across Europe causing damage to properties, transport, and freshwater systems. Clean‐up costs are high and include making water fit for drinking. Mitigation against muddy flooding (MF) includes standard soil conservation and flood protection measures. MF occurs during intense localised storms, for example, in Flanders, northern Belgium, but can also result from longer duration rainfall events, for example, in southern England. MF occurs in catchments with large areas of arable land, adjacent to property or freshwater systems. Early experience with mitigation measures favoured engineered approaches. On their own, these have frequently failed to achieve adequate protection or been ruled out on economic or safety grounds: a combination of engineered and land‐use approaches is necessary. We illustrate this with reference to the Molenbeek catchment in Flanders where monitoring shows a significant decline in erosion and damage to adjacent properties. Cost–benefit analysis of mitigation measures shows them to pay for themselves over short periods of time. Protecting freshwater systems from MF damage should focus on interrupting flow from field to streams, ditches and roads which act to convey muddy runoff to the main river channels.

Urbanisation lowers great titParus majorbreeding success at multiple spatial scales

While numerous studies have reported negative effects of urbanisation on birds, few have examined the role of urban scale in influencing breeding success. Furthermore, many studies have relied on qualitative rather than quantitative assessments of urbanisation. This study sought to address these issues by testing the effects of urbanisation, measured at two spatial scales, on the breeding success of great titsParus major. A nested study design, incorporating over 400 nestboxes, was used in study sites across northern Belgium with a priori quantified degrees of urbanisation at both local and regional scales. All measured breeding parameters were found to vary at one or both spatial scales of urbanisation; in more urbanised areas great tits displayed advanced laying dates but lower breeding success compared to rural areas, with smaller clutch sizes, lower nestling masses and fewer fledglings per egg. Importantly, urbanisation effects were not limited to big cities as birds breeding in gardens or parks in small towns also had comparatively low success. We found that both regional‐ and local‐scale urbanisation had consistent significant effects on laying date, clutch size and nestling mass, while the number of fledglings per egg was negatively influenced by local‐scale urbanisation only. Results of this study therefore highlight the importance of utilising multiple spatial scales in analysing urbanisation effects, as well as the potential negative impact of local urbanisation on breeding success. This calls for further investigation into mechanisms driving urbanisation effects and how these may vary at different scales.

Weeds and gaps on extensive green roofs: Ecological insights and recommendations for design and maintenance

While extensive green roofs (EGRs) are seeing increasing use around the world, the construction and maintenance "one size fits all" EGR solutions is under scrutiny. Apart from the search for local and adapted plant species that could complement or replace the widely used Sedum vegetation, practical problems such as weeds and gaps in the vegetation also still occur. Both weeds and gaps have been shown to impact EGR ecosystem service provisioning and preferences but have only received limited scientific attention. We therefore performed an in depth analysis of vegetation and local and regional environmental data gathered on 129 EGRs in Northern Belgium with a focus on understanding weeds and gaps. We found that gaps in the vegetation form a considerable issue on the studied EGRs, while weed cover is often relatively limited. Furthermore, we find that spontaneously colonizing plant cover is heavily impacted by substrate productivity and roof exposition, but is also influenced by planted species cover and the proximity of potential source habitats. For tree species cover, dispersal limitation plays an even more important role, while annual species are found to thrive on exposed roofs with a low planted functional diversity. Gap cover is found to decrease over age, and reduces with increasing substrate productivity. Finally, we provide design, construction and maintenance recommendations to prevent these problems based on our results and also discuss whether these issues should be considered a failure of EGRs as a system or as an opportunity for improved green roof functioning or the development of more 'natural' EGRs.

Future distribution of wild boar in a highly anthropogenic landscape: Models combining hunting bag and citizen science data

Wild boar is one of the most widespread mammals of the world and in many regions wild boar populations continue to expand. Especially in highly anthropogenic landscapes, increasing numbers of wild boar lead to a rising number of contacts with human activities causing human-wildlife impacts. In the heavily fragmented landscape of Flanders (northern Belgium) where the wild boar re-appeared in 2006 after more than half a century of absence, it is crucial to get a better understanding of the probable further distribution of wild boar in order to assess potential impacts in the near future. Wild boar occurrences have been collected by two citizen science programs: through an online observation platform and based on the reported locations of wild boar shot by hunters. This allowed us to construct a MaxEnt habitat suitability model. We constructed a new approach to define background manipulation to correct for sampling bias due to uneven sampling effort or due to areas in which hunting is not allowed based on the construction of bias files using this information. Model outcomes based on this new approach for background manipulation were compared with the known method of spatial thinning. All model outcomes were found comparable reflecting the utility of our new approach when limited data are available and spatial thinning would result in insufficient data for modelling. Our MaxEnt models show that coniferous forest, deciduous forest, maize, scrub and other low cover play a key role in increasing the habitat suitability for wild boar. Built up areas and the extent of habitat diversity only had a minor influence on habitat suitability reflecting wild boars’ behavioural flexibility to adapt to human-dominated landscapes. Unoccupied suitable habitat is mainly found in the centre of Flanders, although highly scattered. Habitat suitability in the West of Flanders was limited.

The Dutch Y-chromosomal landscape

Previous studies indicated existing, albeit limited, genetic-geographic population substructure in the Dutch population based on genome-wide data and a lack of this for mitochondrial SNP based data. Despite the aforementioned studies, Y-chromosomal SNP data from the Netherlands remain scarce and do not cover the territory of the Netherlands well enough to allow a reliable investigation of genetic-geographic population substructure. Here we provide the first substantial dataset of detailed spatial Y-chromosomal haplogroup information in 2085 males collected across the Netherlands and supplemented with previously published data from northern Belgium. We found Y-chromosomal evidence for genetic–geographic population substructure, and several Y-haplogroups demonstrating significant clinal frequency distributions in different directions. By means of prediction surface maps we could visualize (complex) distribution patterns of individual Y-haplogroups in detail. These results highlight the value of a micro-geographic approach and are of great use for forensic and epidemiological investigations and our understanding of the Dutch population history. Moreover, the previously noted absence of genetic-geographic population substructure in the Netherlands based on mitochondrial DNA in contrast to our Y-chromosome results, hints at different population histories for women and men in the Netherlands.

Characterizing carbonate reservoir fracturing from borehole data – A case study of the Viséan in northern Belgium

Abstract Fractured carbonate rocks are widely used as hydrocarbon or geothermal reservoirs. To provide a better understanding of the distribution and characteristics of such fractures, a general workflow will be presented for the characterization of fracturing from borehole data, by exploration and statistical analyses of integrated datasets. In a case study of Visean limestones in a Belgian borehole, both cores and geophysical well logs were used to investigate which factors control the characteristics of partially open veins, which contribute to permeability. Relationships between multiple variables were tested statistically. Lithology, geochemistry and geophysical well log values were taken into account, as well as quantified veins, vugs and stylolites from cores. Although natural joint frequencies appeared hard to quantify from the available data, partially open vein characteristics could be well quantified. The results show that differential compaction controlled the development of fractures. Fracturing occurred preferentially in massive reefal buildup boundstones in contrast to layered wacke- to grainstones. Layer-parallel slip along bedding surfaces could also have reduced fracture development in the latter limestones. Frequencies of cemented veins and partially open veins are positively correlated, which suggests that the partially open veins result from either re-opening by dissolution, or (re-)opening due to a later fracturation phase. In summary, this multi-source study provides a workflow for fracture characterization from boreholes, as well as insights into the factors controlling the distribution and characteristics of partially open veins, which enhance reservoir permeability.

Dipterological surveys in Portugal unveil 200 species of long-legged flies, with over 170 new to the country (Diptera: Dolichopodidae).

A first comprehensive account on the dolichopodid fauna (Diptera: Dolichopodidae) of Portugal is presented as the result of multiple surveys by primarily Portuguese researchers between 2009 and 2016. All mainland Portuguese provinces and all districts but one (Évora) were investigated. A total of 761 dolichopodid samples were collected in 278 sampling sites distributed over 87 municipalities and 182 localities, with nearly ¾ of the samples gathered by sweep net. They contained 6,680 specimens of 200 different species, with 142 recognized (known), 40 new (undescribed) and 18 doubtful species. Medetera and Dolichopus were the most diverse among the recognized species, with 20 and 18 species respectively. Fourteen genera were represented by the new species, with Medetera as most diverse. The doubtful species included one species of Pelastoneurus, which is a first record of this genus for the Palaearctic realm. At present 208 dolichopodid species are known from Portugal. A checklist with 150 recognized species is presented, with first records of 116 species for Portugal. For nearly every species, information on its distribution, ecology and rarity in Portugal and northwestern Europe is given, as well as its seasonal activity in Portugal. Raw distribution data are available as dataset in GBIF. Seventy-five pictures of species in the field, and 15 habitat photos are also provided. Current data suggest that a higher proportion of Portuguese species are rare as compared to the Flemish fauna (northern Belgium). Both share 104 species, with 38 species only recorded from Portugal; only seven can be considered Iberian or Portuguese specialities. Though differences between the two Portuguese biomes cannot be substantiated at this moment, two very common and widespread European species, Campsicnemus scambus and Chrysotimus molliculus, seem to be restricted to the Eurosiberian biome in the northwest of the country. In terms of generic representation, the Portuguese dolichopodid fauna occupies an intermediate position between those of northwestern European and other Mediterranean countries. Despite the large amount of data gathered, the dolichopodid fauna of Portugal remains insufficiently known and a considerable number of additional known and new species can be expected with continued sampling.

Effortless or less effort? Effects of tracks on students' engagement.

It is found that assigning students to a lower track during secondary education negatively affects their academic performance. As an explanation, it is often mentioned that an anti-school culture in lower tracks undermines students' effort and involvement. This study assessed whether going to a lower track affects student engagement. For if an anti-school culture is to blame for limiting lower track students' performance, lower track assignment should reduce engagement. A sample of a longitudinal cohort study during secondary education in Flanders (northern Belgium) was used to describe development in engagement with n=5,417 students in 46 schools. Four tracks were investigated across four school years. Two main methodological challenges were present in this study, different student intake in each track and many students changing from a higher to lower track over time. Accordingly, we used inverse probability treatment weights with marginal structural mean models to account for different student intake and track changes. A comparison was made per pair of tracks that are hierarchically consecutive by matching students who were comparable across these tracks. Accordingly, there were three pairwise comparisons. It was never found that being continuously in lower track negatively affects engagement. Only for one pairwise comparison, there was evidence that students who changed from the higher to lower track had lower engagement. We rejected the hypothesis that lower tracks negatively affect student engagement. This makes the anti-school culture as an explanation for lower track assignment negatively affecting academic performance implausible.

Effects of decomposing beech (Fagus sylvatica) logs on the chemistry of acidified sand and loam soils in two forest reserves in Flanders (northern Belgium)

We studied the effect of coarse woody debris (CWD) on the soil nutrient status in two beech (Fagus sylvatica) dominated forest reserves in Flanders, Belgium: Wijnendale Forest, on a sandy soil and Kersselaerspleyn in Sonian Forest, on a loamy soil. More specifically, we looked at the chemical composition of beech logs of different stages of decay. In addition, we examined the chemical composition of the organic and the mineral soil at five distances from the decomposing logs. We considered the concentrations of the following elements: C, N, P, S, Ca, K, Mg, Mn, Fe, and Al.The results indicate a difference in wood and soil chemical composition between the two forest sites. The soil and the aboveground biomass of Wijnendale had the highest total N concentration and the lowest concentrations of P and base elements (Ca, K, Mg, and Mn). There is an increase in element concentrations in CWD of both forests during the decomposition, except for K and C. The higher N concentration in Wijnendale, explained by high atmospheric nitrogen deposition in this forest, persisted during decomposition. By contrast, the concentrations of P, Ca, K, and Mg in dead wood of both forests became similar when decomposition proceeded. The effect of CWD was more pronounced in the organic soil layer than in the mineral soil. The organic soil in the proximity of CWD had a higher pH and higher concentrations of C, N, P, Ca, Mg, and Mn (in Sonian forest) and a lower Al concentration (in Wijnendale forest) and this is highly significant for Ca, a limiting nutrient in moderate to highly acidic forests. The percentage of the soil surface impacted by the logs is 0.92% and 0.36% for Sonian and Wijnendale respectively, which is expected to increase with time, considering the fact that both reserves are only recently left unmanaged. The results of this study highlight the contribution of CWD in sustaining the nutrient status and buffering capacity of forest sites, in particular on soils sensitive to acidification and exposed to high nitrogen deposition.

Intermittent reproduction, mortality patterns and lifetime breeding frequency of females in a population of the adder (Vipera berus).

Female adders (Vipera berus) are “capital breeders” that exhibit delayed maturity and intermittent reproductive frequency. We studied the attainment of sexual maturity, the initiation of annual breeding in mature females, the energy and mortality costs associated with breeding, the length of the reproductive cycle and female lifetime reproductive frequency. We use longitudinal data obtained during an 18-year (2000–2017) mark–recapture study in a large population of adders in northern Belgium. A minority (15%) of the females gave birth to their first litter when they attained the actual age of 3 years, upon surpassing a minimum snout-vent-length of 38 cm. However, most females reproduced for the first time when they were 4 years or older. In mature females, breeding in a given year depends to a large extent on their body condition at the onset of the active season, indicating that a threshold level of energy reserves is necessary to start a reproductive cycle. During breeding years females stop growing, lose about one-third of their initial body mass and are very emaciated after parturition. The decrease in relative body mass was most notable initially in the largest and fattiest females. During the non-breeding years, females forage intensely to rebuild their fat reserves; their abilities to do so will strongly affect whether and when they engage in subsequent reproductive bouts. We used a multistate mark–recapture analytical method to simultaneously estimate the capture and survival rates of breeding and non-breeding females, a necessary procedure to obtain accurate estimates of survival probabilities. The analysis indicated much higher capture rates during the breeding years, but did not reveal a substantial effect of reproductive state on annual survival rates. Although some females were observed to breed in successive years, the reproductive cycle was most often biennial or triennial. However, most females (ca. 70%) that attained sexual maturity reproduced only once during their lifetime, while a minority of the females (ca. 5%) were observed to breed on 3–5 annual occasions. On average, females produced only ca. 1.3 litters during their reproductive lifetime. The short reproductive lifetime is a consequence not only of mortality directly related to the reproductive activities, but also of mortality associated with recovering from the weakened post-parturient body condition during the long intervals (1–2 years) between reproductive bouts.

Ecosystem Services as (Co-)performative Practice: Experiences from Integrated Water Management in Flanders

Environmental concepts are performative in that they help create the environment they describe. This paper explores the performativity of the ecosystem services concept in the field of integrated water management in Flanders (northern Belgium). The data was collected from 23 in-depth interviews with professionals in the field, conducted in two rounds with a five-year interval and complemented with on-site observations of practices applying the concept. Results indicate that ecosystem services was only marginally performative on its own, and rather was seen as a ‘co-performative concept’ that – in conjunction with existing concepts – could accelerate the envisioned integration process through promoting initiatives, mobilising stakeholders, shaping orientation, creating win-win situations, and more. Yet, despite these aspirations, the concept has in general failed to perform as expected. Many perceived ecosystem services as an academic concept, too complex for practical application. Common strategies were either to adapt the concept to fit one’s professional context or to create a new practical context (a stakeholder workshop, for example) where the concept could function. The paper goes on to discuss the more general implications of the (pseudo-)malleability and context-dependence of the ecosystem services concept.

Forest fragmentation and tree species composition jointly shape breeding performance of two avian insectivores

Habitat fragmentation and forestry practices affect forest structure and composition, and hence, their intrinsic value for biodiversity conservation. While higher tree species diversity is commonly proposed to result in habitat of higher quality for forest species, how these tree diversity and tree composition effects interact with forest fragmentation in terms of critical resources and demographic effects on forest birds remains poorly understood. We investigated here possible synergistic effects of forest fragmentation and tree species composition on the breeding performance of two common, insectivorous forest birds in a human-dominated landscape in northern Belgium. We monitored the breeding performance of Great Tits and Blue Tits in 53 plots across independent gradients of tree species composition and forest fragmentation. In addition, data on the biomass of the main food source of these two species (i.e. caterpillars) was collected during the breeding season. Both tree composition and habitat fragmentation impacted the breeding performance of Great and Blue Tits. Effects of tree species composition were mainly driven by tree species identity, rather than by tree species diversity, and the highest breeding performance was obtained in monocultures of Pedunculate Oaks. Fragmentation effects were only observed in resource-poor Beech monocultures with breeding performance declining with reduction in forest area. Structural Equation Modelling revealed diverse and species-specific pathways: for Great Tits tree composition effects on breeding performance were driven by resource availability while for Blue Tits these effects were driven by variation in clutch size. Thus, forestry practices aiming at promoting forest-dependent birds could benefit from including tree species that support high arthropod numbers and by maintaining forest patches of larger sizes.

Using an online survey to assess the spatial distribution of wild boar (Sus scrofa L.) crop damage and factors influencing this distribution and severity in Limburg province, Belgium

Wild boar (Sus scrofa L.) reappeared in Flanders (northern Belgium) in 2006 after almost half a century of absence. Interactions between wild boar and human activities are frequent due to extensive fragmentation of the landscape in Flanders. Complaints about agricultural damage are increasing but the actual extent of crop damage remains unknown. The goal of this study was to assess the current risk and the spatial distribution of crop damage, as well as factors influencing damage distribution in the province of Limburg (eastern Flanders). An online survey was sent to farmers by email. Moreover, as we expected potential respondent bias towards farmers that already experienced damage, we also conducted a follow-up non-respondent check by telephone. Our study showed that the current crop damage probability on a farm lies between 42% (likely an overestimation due to respondent bias in the online survey) and 22% (an underestimation based on the non-respondent check). There is considerable geographical variation in the proportion of farms that report boar damage; probability for crop damage due to wild boar is relatively high for farmers in Limburg but shows a geographically heterogeneous spread. Factors explaining the crop damage probability differed strongly between the online survey and the non-respondent check and no consistent results could be found. Our results show that using the online survey, it was possible to get an initial insight in the geographical distribution of crop damage. However, as we found differences between the results of the online survey and the non-respondent check, taking management decisions based solely on online survey results without conducting a non-respondent check could lead to misguided actions.

Reporting on young people, sexuality, and social media: a discourse theoretical analysis

ABSTRACTThe amount of public interest in and media panic over youth, sexuality, and social media has grown in recent years. In this paper, we explore the discursive practices that are disciplining the digital intimacies of young people through print media discourses. Therefore, we use a Foucauldian feminist approach and conduct a discourse theoretical analysis of 183 news articles published in Northern Belgium between 1 January 2009 and 31 December 2016. Our findings show that the discourse in newspapers reporting on youth, sexuality, and social media consists of three recurring discursive practices. First, there is the problematization of social media. Second, this problematization is legitimized by the use of authoritative voices, such as those of academics or other experts. Third, this results in a gendered categorization where young girls are extensively included in the debate and young boys and their digital experiences are most often excluded. This gendered discourse not only perpetuates sexual double standards throughout society but also implicitly disciplines young people to adhere to hetero-patriarchal ideals of femininity and masculinity.