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Gembloux, Belgium

Sebek P.,IRSTEA | Sebek P.,Masaryk University | Barnouin T.,Reseau Naturaliste Entomologie | Brin A.,Purpan Engineering School | And 10 more authors.
Ecological Indicators | Year: 2012

In European forests, large scale biodiversity monitoring networks need to be implemented - networks which include components such as taxonomical groups that are at risk and that depend directly on forest stand structure. In this context, monitoring the species-rich group of saproxylic beetles is challenging. In the absence of sufficient resources to comprehensively survey a particular group, surrogates of species richness can be meaningful tools in biodiversity evaluations. In search of restricted subsets of species to use as surrogates of saproxylic beetle richness, we led a case study in Western Europe. Beetle data were compiled from 67 biodiversity surveys and ecological studies carried out from 1999 to 2010 with standardised trapping methods in France and Belgium. This large-scale dataset contains 642 forest plots, 1521 traps and 856 species. Twenty-two simplified species subsets were identified as potential surrogates, as well as the number of genera, a higher taxonomic level, taking into account, for each surrogate, the effort required for species identification, the practical monitoring experience necessary, the species conservation potential or the frequency of species occurrence. The performance of each surrogate was analyzed based on the following parameters: overall surrogacy (correlation between subset richness and total species richness), surrogacy vs. identification cost balance, surrogacy variation over a wide range of ecological conditions (forest type, altitude, latitude and bio-geographical area) and consistency with spatial scale. Ecological representativeness and ability to monitor rare species were supplementary criteria used to assess surrogate performance. The subsets consisting of the identifiable (or only easy-to-identify species) could easily be applied in practice and appear to be the best performing subsets, from a global point of view. The number of genera showed good prediction at the trap level and its surrogacy did not vary across wide environmental gradients. However, the subset of easy-to-identify species and the genus number were highly sensitive to spatial scale, which limits their use in large-scale studies. The number of rare species or the species richness of single beetle families (even the best single-family subset, the Cerambycidae) was very weak surrogates for total species richness. Conversely, the German list of monitoring species had high surrogacy, low identification costs and was not strongly influenced by the main geographical parameters, even with our French and Belgian data. In European-wide monitoring networks, such internationally validated subsets could be very useful with regard to the timing and cost-efficiency of field inventories. © 2012 Elsevier Ltd.

Ligot G.,University of Liege | Gheysen T.,University of Liege | Lehaire F.,University of Liege | Hebert J.,University of Liege | And 3 more authors.
Annals of Forest Science | Year: 2013

Context: Over the past few decades, the impact of large herbivorous ungulates on forest vegetation has been clearly highlighted. Among those impacts, bark stripping of coniferous trees is one of the most damaging. Bark stripping leads to rot development, inducing serious loss of timber value. Aims: The present study aimed firstly at evidencing the factors explaining the variations observed in fresh bark peeling rate for spruce and Douglas-fir in southern Belgium and secondly at identifying the key factors to consider when setting up a deer management plan. Method: Fresh bark peeling rate was recorded with a systematic sampling survey from 2004 to 2007. The covered territory was then divided into 63 distinct hunting zones of area ranging from 1,000 to 25,000 ha. About 5,000 plots were monitored annually. Each zone was characterized with a large number of explanatory variables. The explanatory variables were integrated firstly into fixed linear models using a stepwise procedure, and then into a mixed model. Results: The significant variables included in the model (R 2 = 44 %) are (by decreasing order of importance) red deer densities, proportion of coniferous stands and agricultural areas, snow cover, distance to urban habitats, and species diversity in the understory. Conclusion: The models revealed the impacts of several factors on bark peeling: deer density, deer-carrying capacity of the territory, landscape structure, and severity of winter conditions. The adjusted model allowed subtracting the impact of winter conditions in order to produce a relevant indicator for hunting management. In addition, the model was used to assess the sensitivity of a forested area to bark peeling based on its environmental characteristics. © 2012 INRA and Springer-Verlag France.

Prevot C.,Avenue Marechal Juin | Licoppe A.,Avenue Marechal Juin
European Journal of Wildlife Research | Year: 2013

This study analyses the natal dispersal of red deer and wild boar in order to compare their dispersal capabilities in southern Belgium and to evaluate the relevance of management unit areas (MUA) designed for their monitoring. Dispersal was studied thanks to a mark-recovery method based on 111 red deer fawns and 1,613 piglets. The recovery rate of ear-tagged animals was 68 and 40 %, respectively. In both species, sub-adult males moved on longer distances (x̄ red deer=4.82+/-4.17 km and x̄ will boar=4.90+/-5.65km) than females and juveniles x̄ (red deer=1.84+/-1.46 km and x̄ will boar=2.49+/-3.74 km). Taking into account the age and sex categories, we found no difference between species in dispersal mean distance. But we observed higher maximal dispersal distances in wild boar compared to red deer. The natal home range mean sizes were 5.29 km2 (+/-4.87) for red deer and 6.23 km2 (+/-4.60) for wild boar. Red deer and wild boar showed similar dispersal rates according to age and sex category: 53 and 42 % in sub-adult males and 14 and 16 % in females and juveniles. Our results confirmed the higher proportion of philopatry in females and juveniles of both species compared to sub-adult males more likely to disperse. Wild boar of any sex or age seemed to be less sensitive than red deer to infrastructure (road, rail, river) network on which the management unit area limits are currently based. © 2013 Springer-Verlag Berlin Heidelberg.

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