Papers by Nicolas Schtickzelle
<b>Copyright information:</b>Taken from "Quantitative analysis of changes in mov... more <b>Copyright information:</b>Taken from "Quantitative analysis of changes in movement behaviour within and outside habitat in a specialist butterfly"BMC Evolutionary Biology 2007;7():4-4.Published online 22 Jan 2007PMCID:PMC1784076.turns) when flying within habitat (path 1), but flew straighter (long moves, small turns) in the matrix (paths 4, 5 and 6). Path 2 shows the tendency to return into the patch after having crossed the habitat patch boundary [14]. Path 3 resulted from a spontaneous flight (without experimental manipulation) and illustrates that experimental artefacts due to manipulation were very unlikely the cause for straighter paths in the matrix (see Methods for details). Path 4 illustrates the return to a suitable habitat patch, with the last turn at a distance of c. 25 m from the patch, well around the estimate of perceptual range. Grey: habitat patches; +: release site in the matrix.
Landscape Ecology, 2017
Context Landscape-scale population dynamics are driven in part by movement within and dispersal a... more Context Landscape-scale population dynamics are driven in part by movement within and dispersal among habitat patches. Predicting these processes requires information about how movement behavior varies among land cover types. Objectives We investigated how butterfly movement in a heterogeneous landscape varies within and between habitat and matrix land cover types, and the implications of these differences for within-patch residence times and among-patch connectivity. Methods We empirically measured movement behavior in the Baltimore checkerspot butterfly (Euphydryas phaeton) in three land cover classes that broadly constitute habitat and two classes that constitute matrix. We also measured habitat preference at boundaries. We predicted patch residence times and interpatch dispersal using movement parameters estimated separately for each habitat and matrix land cover subclass (5 categories), or for combined habitat and combined matrix land cover classes (2 categories). We evaluated the effects of including edge behavior on all metrics. Results Overall, movement was slower within habitat land cover types, and faster in matrix cover types. Butterflies at forest edges were biased to remain in Electronic supplementary material The online version of this article (
Ecological Modelling, 2016
Population viability analysis (PVA) models are used to estimate population extinction risk under ... more Population viability analysis (PVA) models are used to estimate population extinction risk under different scenarios. Both simple and complex PVA models are developed and have their specific pros and cons; the question therefore arises whether we always use the most appropriate model type. Generally, the specific purpose of a model and the availability of data are listed as determining the choice of model type, but this has not been formally tested yet. We quantified the relative importance of model purpose and nine metrics of data availability and resolution for the choice of a PVA model type, while controlling for effects of the different life histories of the modelled species. We evaluated 37 model pairs: each consisting of a generally simpler, population-based model (PBM) and a more complex, individual-based model (IBM) developed for the same species. The choice of model type was primarily affected by the availability and resolution of demographic, dispersal and spatial data. Low-resolution data resulted in the development of less complex models. Model purpose did not affect the choice of the model type. We confirm the general assumption that poor data availability is the main reason for the wide use of simpler models, which may have limited predictive power for population responses to changing environmental conditions. Conservation biology is a crisis discipline where researchers learned to work with the data at hand. However, for threatened and poorly-known species, there is no shortcut when developing either a PBM or an IBM: investments to collect appropriately detailed data are required to ensure PVA models can assess extinction risk under complex environmental conditions.
Ecological Entomology, 2017
This document is the author's final manuscript version of the journal article, incorporating any ... more This document is the author's final manuscript version of the journal article, incorporating any revisions agreed during the peer review process. There may be differences between this and the publisher's version. You are advised to consult the publisher's version if you wish to cite from this article.
PloS one, 2016
Understanding dispersal is of prime importance in conservation and population biology. Individual... more Understanding dispersal is of prime importance in conservation and population biology. Individual traits related to motion and navigation during dispersal may differ: (1) among species differing in habitat distribution, which in turn, may lead to interspecific differences in the potential for and costs of dispersal, (2) among populations of a species that experiences different levels of habitat fragmentation; (3) among individuals differing in their dispersal strategy and (4) between the sexes due to sexual differences in behaviour and dispersal tendencies. In butterflies, the visual system plays a central role in dispersal, but exactly how the visual system is related to dispersal has received far less attention than flight morphology. We studied two butterfly species to explore the relationships between flight and eye morphology, and dispersal. We predicted interspecific, intraspecific and intersexual differences for both flight and eye morphology relative to i) species-specific h...
Relict Species, 2009
... 1 c = 1.43 , p= 0.23 for P. euno-mia, 2 1 c = 0, p= 1 for L. helle) (Fig. 1). Whatever the ti... more ... 1 c = 1.43 , p= 0.23 for P. euno-mia, 2 1 c = 0, p= 1 for L. helle) (Fig. 1). Whatever the timing of mowing, summer or autumn, the probability of emergence was higher in the control strips than in the corresponding mown strips ...
Dispersal Ecology and Evolution, 2012
Methods in Ecology and Evolution, 2014
1. Laboratory microcosm experiments using protists as model organisms have a long tradition and a... more 1. Laboratory microcosm experiments using protists as model organisms have a long tradition and are widely used to investigate general concepts in population biology, community ecology and evolutionary biology. Many variables of interest are measured in order to study processes and patterns at different spatiotemporal scales and across all levels of biological organization. This includes measurements of body size, mobility or abundance, in order to understand population dynamics, dispersal behaviour and ecosystem processes. Also, a variety of manipulations are employed, such as temperature changes or varying connectivity in spatial microcosm networks. 2. Past studies, however, have used varying methods for maintenance, measurement, and manipulation, which hinders across-study comparisons and meta-analyses, and the added value they bring. Furthermore, application of techniques such as flow cytometry, image and video analyses, and in situ environmental probes provide novel and improved opportunities to quantify variables of interest at unprecedented precision and temporal resolution. 3. Here, we take the first step towards a standardization of well-established and novel methods and techniques within the field of protist microcosm experiments. We provide a comprehensive overview of maintenance, measurement and manipulation methods. An extensive supplement contains detailed protocols of all methods, and these protocols also exist in a community updateable online repository. 4. We envision that such a synthesis and standardization of methods will overcome shortcomings and challenges faced by past studies and also promote activities such as meta-analyses and distributed experiments conducted simultaneously across many different laboratories at a global scale.
BMC evolutionary biology, Jan 22, 2007
Dispersal between habitat patches is a key process in the functioning of (meta)populations. As di... more Dispersal between habitat patches is a key process in the functioning of (meta)populations. As distance between suitable habitats increases, the ongoing process of habitat fragmentation is expected to generate strong selection pressures on movement behaviour. This leads to an increase or decrease of dispersal according to its cost relative to landscape structure. To limit the cost of dispersal in an increasingly hostile matrix, we predict that organisms would adopt special dispersal behaviour between habitats, which are different from movements associated with resource searching in suitable habitats. Here we quantified the movement behaviour of the bog fritillary butterfly (Proclossiana eunomia) by (1) assessing perceptual range, the distance to which the habitat can be perceived, and (2) tracking and parameterizing movement behaviour within and outside habitat (parameters were move length and turning angles distributions). Results are three-fold. (1) Perceptual range was < 30 m....
Oikos, 2004
... Nicolas Schtickzelle,; Michel Baguette. ... We examined the viability of the bog fritillary b... more ... Nicolas Schtickzelle,; Michel Baguette. ... We examined the viability of the bog fritillary butterfly Proclossiana eunomia Esper, a specialist glacial relict species, in a highly fragmented landscape (<1% of suitable habitat in 10 km 2 ), by way of population viability analysis. ...
Oikos, 2005
Using surrogate data in population viability analysis: the case of the critically endangered cran... more Using surrogate data in population viability analysis: the case of the critically endangered cranberry fritillary butterfly. Á/ Oikos 109: 89 Á/100. Population viability analyses (PVA) are central tools for the management of threatened populations. However, the parameterisation of effective PVA models is very demanding in high quality data, which are often impossible to collect on endangered populations. Here we propose the use of a generalisation strategy to bypass this limitation: management measures for an endangered metapopulation of the cranberry fritillary butterfly in the Netherlands are evaluated with RAMAS/GIS by using parameters estimated from a healthier metapopulation in Belgium. The Belgian metapopulation seems viable, with stable abundance and number of local populations, despite their erratic dynamics, whereas the Dutch metapopulation shows a continuous decline in the course of time, with many vacant habitat patches. Simulations of various scenarios indicated that (1) large scale restoration of habitat patches would be necessary to ensure long-term survival of the species in the Netherlands as not enough suitable habitats are currently remaining; and that (2) global warming is expected to put a major threat on both metapopulations by reducing the growth rate of this glacial relict species, and/or increasing environmental stochasticity (amplified climatic variations).
Oikos, 2009
... As a consequence, and according to species mobility and requirements, these definitions may u... more ... As a consequence, and according to species mobility and requirements, these definitions may underestimate or overestimate both the area and the amount of habitat (Dennis et al. 2003, 2006, Vanreusel and Van Dyck 2007). ...
Molecular Ecology, 2010
Genetic variability, kin structure and demography of a population are mutually dependent. Populat... more Genetic variability, kin structure and demography of a population are mutually dependent. Population genetic theory predicts that under demographically stable conditions, neutral genetic variability reaches equilibrium between gene flow and drift. However, density fluctuations and non-random mating, resulting e.g. from kin clustering, may lead to changes in genetic composition over time. Theoretical models also predict that changes in kin structure may affect aggression level and recruitment, leading to density fluctuations. These predictions have been rarely tested in natural populations. The aim of this study was to analyse changes in genetic variability and kin structure in a local population of the root vole (Microtus oeconomus) that underwent a fourfold change in mean density over a 6-year period. Intensive live-trapping resulted in sampling 88% of individuals present in the study area, as estimated from mark-recapture data. Based on 642 individual genotypes at 20 microsatellite loci, we compared genetic variability and kin structure of this population between consecutive years. We found that immigration was negatively correlated with density, while the number of kin groups was positively correlated with density. This is consistent with theoretical predictions that changes in kin structure play an important role in population fluctuations. Despite the changes in density and kin structure, there was no genetic differentiation between years. Population-level genetic diversity measures did not significantly vary in time and remained relatively high (H E range: 0.72-0.78). These results show that a population that undergoes significant demographic and social changes may maintain high genetic variability and stable genetic composition.
Landscape Ecology, 2005
Despite the importance assigned to inter-patch movements in fragmented systems, the structure of ... more Despite the importance assigned to inter-patch movements in fragmented systems, the structure of landscape between suitable habitat patches, the matrix, is often considered as to be of minor interest, or totally ignored. Consequently, models predicting metapopulation dynamics typically assume that dispersal and movement abilities are independent of the composition of the matrix. The predictions of such models should be invalided if that crucial assumption is unverified. In order to test the hypothesis of a patch-specific resistance, we led an experimental study to assess the matrix effects on the movement ability of juvenile Natterjack toads ͑Bufo calamita͒. The movement behaviour of first year toadlets, the dispersal stage in this species, was investigated in an arena experiment. Toadlet mobility was assessed in five landscape components that were mimicked in the lab: sandy soil, road, forest, agricultural field, and pasture. We analysed several movement components including move length, speed, efficiency and turning angle distribution. Our results showed that movement ability was strongly affected by the land cover, even if body size modulated the behavioural responses of toadlets. Performances were the best in the arenas mimicking sand and roads, and the worst in the forest arena, toadlet moves being three to five times less effective in the latter. The mobility was intermediate in the two other arenas. We propose here a new method to quantify functional connectivity, based on quantitative estimates of relative values for resistance of landscape components. This method offers a reliable alternative for resistance value estimates to subjective 'expert advice' or inference from genetic population structure.
Landscape Ecology, 2009
... Research Centre, Université catholique de Louvain, Place Croix du Sud, 4, 1348 Louvain-la-Neu... more ... Research Centre, Université catholique de Louvain, Place Croix du Sud, 4, 1348 Louvain-la-Neuve, Belgium e-mail: [email protected]; camille.turlure@uclouvain ... Spectrum of plant species used as nectar resources by B. aquilon-aris was composed of nine ...
Journal of Thermal Biology, 2011
Temperature profoundly impacts on distribution and habitat-use of organisms. The development of e... more Temperature profoundly impacts on distribution and habitat-use of organisms. The development of ectothermous caterpillars does not depend on host plant quality only, but also on the availability of suitable thermal conditions. Selection for thermally favorable microclimates (i.e. behavioral thermoregulation) is a primary mechanism of temperature control, and caterpillars can be either (or alternately) temperature conformers (i.e. passively adopting ambient temperature conditions) or thermoregulators (i.e. able to some extent to elevate or decrease their body temperature relative to ambient temperature). Here, we addressed the functional significance of different structural vegetation elements for the behavioral thermoregulation by caterpillars of two butterfly species. Results: Weather conditions influenced the caterpillar detection probability within host plant patches, indicating that caterpillars can hide and use suitable microclimates provided by vegetation structures to cope with weather variations. This is why we (1) evaluated the heterogeneity in temperature conditions provided by these structures, (2) quantified the influence of ambient temperature and light intensity on caterpillar body temperature, and (3) tested how position on structure, substrate color and exposition influenced caterpillar body temperature. As expected, vegetation structures provided heterogeneous temperature and sun exposition conditions, while caterpillar body temperature was dependent on ambient temperature and light intensity. But body temperature was additionally influenced by the position on vegetation structures, substrate color and exposition. Conclusions: These results suggest that there is no unique and fixed structure in the vegetation subsuming the best thermal conditions for caterpillars. We argue that a better understanding of the thermal properties of vegetation structures is essential for correctly understanding caterpillar habitatuse and the behavioral mechanisms driving their body thermoregulation. Conceptually this means that thermal conditions should be included in the definition of a species' functional habitat. Practically this may influence the choice of appropriate habitat management for species of conservation concern.
Journal of Insect Conservation, 2010
... Camille Turlure Julie Choutt Hans Van Dyck Michel Baguette Nicolas Schtickzelle ... s... more ... Camille Turlure Julie Choutt Hans Van Dyck Michel Baguette Nicolas Schtickzelle ... size and its reliability has recently been criticized, mainly because non-random sampling, imperfect species detection and adult longevity had not been taken into account (eg, Zonneveld et al ...
Journal of Applied Ecology, 2003
1. Population viability analyses (PVA) are extremely useful tools for the management of endangere... more 1. Population viability analyses (PVA) are extremely useful tools for the management of endangered species at the landscape scale. Two main families of spatially explicit models are available to perform PVA: (i) presence-absence models, in which local populations are either existing or extinct at each generation, and (ii) structured population models, in which the dynamics of each local population are modelled. In this study we compared the usefulness of both approaches for the prediction of the persistence of a species living in a highly fragmented landscape. 2. The cranberry fritillary Boloria aquilonaris is an arctic-alpine relict species in western Europe. It lives in landscapes where altitude or the proximity of oceans provide the high humidity conditions required for the formation of peat bogs, the only habitat of the butterfly. In such landscapes, the distribution of the butterfly is fragmented, following the natural distribution of peat bogs; this fragmentation is increased by human-induced peat bog destruction. 3. The study of the dynamics of a highly fragmented metapopulation of the cranberry fritillary in a network of 14 habitat patches totalling 26•23 ha revealed that: (i) the density at the equilibrium was c. 700 butterflies ha − 1 ; (ii) local population dynamics in small populations were negative; and (iii) six estimates of the growth rate R t showed large variations even in a large population. Both local extinctions and recolonization events are likely to occur, and two sites (one of 7 ha) unoccupied during two generations were recolonized in the third year. 4. We conclude that the future of this metapopulation is not guaranteed, given its large spatial scale and unbalanced, erratic local population dynamics. We hypothesize that global warming could explain the instability of local population dynamics detected here in addition to the decline of this arctic-alpine relict species, which is currently reported in all its refuge localities in the Netherlands. 5. Presence-absence models based on metapopulation structure and habitat characteristics should provide relatively safe predictions, as the population network (14 patches) is just below the minimum amount of suitable habitat (MASH) for the longterm persistence of a viable metapopulation. However, careful investigation of local population dynamics showed a high instability in the network, which is confirmed by population extinction at a large site. 6. Synthesis and applications. We urge conservation biologists to consider the local population dynamics of endangered species for the management of metapopulations in fragmented landscapes. In the case of the cranberry fritillary, continuing site protection is essential.
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Papers by Nicolas Schtickzelle