Why some species cannot colonize restored habitats? The effects of seed and microsite availability

in Journal for Nature Conservation (in press)

Restoration of calcareous grasslands was promoted as a conservation strategy to reduce the risks imposed by habitat loss and fragmentation. Restoration already provided promising results for several taxa ... [more ▼]

Restoration of calcareous grasslands was promoted as a conservation strategy to reduce the risks imposed by habitat loss and fragmentation. Restoration already provided promising results for several taxa, however some specialist species still fail at colonizing restored habitats. We aimed at explaining this lack of colonization success for three calcareous grasslands specialist species in Southern Belgium: Pulsatilla vulgaris, Trifolium montanum and Veronica prostrata. We studied: (i) Germination in control and outdoor conditions (cold, heat, smoke and litter effects); (ii) In-situ seedling emergence patterns (effects of seed addition and germination microsites availability). The three species were able to germinate in Petri dishes in the absence of treatment. Cold enhanced the germination of V. prostrata. Fire-related treatments (heat shock and smoke exposure) did not enhance germination and were deleterious to V. prostrata. Litter cover improved P. vulgaris emergence in outdoor containers, but had a negative effect on V. prostrata. In the field, V. prostrata did not emerge. T. montanum seedlings were observed in the reference grasslands when seeds were added, but not in the restored grasslands. P. vulgaris emerged in the reference grasslands, and to a lower degree in the restored grasslands. The combination of seed addition and microsites availability for seed germination resulted in enhanced seedling emergence for P. vulgaris. Our results suggest that seed and microsite availability can be limiting factors for site colonization, but the combination of both is likely much more limiting. Lower seedling emergence in restored than in reference grasslands suggests a lower habitat quality in restored grasslands. [less ▲]

Appui scientifique à la mise en oeuvre et à l’entretien des méthodes agro-environnementales bandes de parcelles aménagées (MAE 9)

Report (2013)

Wanted ! Avez-vous vu ces plantes ? La conservation des plantes messicoles dans le cadre du Programme Agroenvironnemental wallon

E-print/Working paper (2012)

Afin de mener à bien un projet de conservation des plantes messicoles menacées, la Faculté AgroBioTech de Gembloux appelle à diffuser vos observations de terrain au DEMNA

La conservation des messicoles dans le cadre du Programme Agro-environnemental Wallon

Article for general public (2012)

Evaluation du succès reproducteur de l’hélianthème jaune et de la petite pimprenelle comme indicateurs de la restauration de pelouses calcicoles

in Parcs & Réserves (2011)

Appui scientifique à la mise en oeuvre et à l’entretien des dispositifs : bandes de messicoles et bandes fleuries liés à la méthode agro-environnementale ciblée 9 : bande de parcelle aménagée

Report (2011)

Conservation of an endemic metallophyte species: effect of population history and vegetative density on the reproductive success of Viola calaminaria

in Journal for Nature Conservation (2011), 19

Demographic studies that monitor population dynamics are an essential component in establishing conservation strategies. The conventional view that human disturbance results in negative effects to species ... [more ▼]

Demographic studies that monitor population dynamics are an essential component in establishing conservation strategies. The conventional view that human disturbance results in negative effects to species and habitats is countered by the fact that some anthropogenic activities result in the origin of new habitat opportunities for species. Faced with an increase in European restoration programs, studies that assess the variability in traits conferring reproductive success among populations is particularly relevant to rare species conservation and further improves our knowledge to achieve restoration success. In the present study, we evaluated reproductive success variation (flower density, percent fructification and seed set) in Viola calaminaria, a rare endemic metallophyte, in relationship to population origins (ancestral or recent habitat), plant density and habitat structure. Results indicated that seed set varied significantly among ancestral and recently established populations, with recent populations exhibiting increased seed set (P < 0.05). Habitat structure did not influence species reproductive success. A positive significant correlation was detected between vegetative and flower density (P < 0.001). Results suggested that population origin (ancestral or recent) and local vegetative density was more important than habitat structure on reproductive success in V. calaminaria. In addition, we demonstrated that V. calaminaria populations distributed in habitats recently created by anthropogenic activity exhibited similar or higher reproductive success than populations from ancestral sites. These results are noteworthy as they show that anthropogenic activities can create new favourable habitats for some rare species. [less ▲]

Le statut du brome épais (Bromus grossus) en Région Wallonne

in Adoxa (2011), 69-70

Le brome épais (Bromus grossus Desf. ex DC.) est une graminée commensale des moissons bien qu'on la trouve occasionnellement en bordure de champs ou dans des terrains en friche. C'est une espèce menacée ... [more ▼]

Le brome épais (Bromus grossus Desf. ex DC.) est une graminée commensale des moissons bien qu'on la trouve occasionnellement en bordure de champs ou dans des terrains en friche. C'est une espèce menacée de disparition dans toute son aire de répartition, raison qui a justifié son inscription à l'annexe II de la Directive 92/43/CEE du Conseil du 21 mai 1992 concernant la conservation des habitats naturels ainsi que de la faune et de la flore sauvages (aussi connue comme la "Directive Habitats"). Cette protection est assurée au niveau wallon par l'inscription de l'espèce à l'annexe VIa du décret du Gouvernement Wallon du 6/12/2001 ; en raison de sa très grande rareté, la Région Wallonne a une responsabilité importante pour sa conservation. [less ▲]

Plant species extinction debt in a temperate biodiversity hotspot: community, species and functional traits approaches

in Biological Conservation (2011), 144

Destruction and fragmentation of (semi-) natural habitats are considered the main causes of biodiversity loss worldwide. Plant species may exhibit a slow response to fragmentation, resulting in the ... [more ▼]

Destruction and fragmentation of (semi-) natural habitats are considered the main causes of biodiversity loss worldwide. Plant species may exhibit a slow response to fragmentation, resulting in the development of an extinction debt in fragmented plant communities. The detection of extinction debt is of primary importance in habitat conservation strategies. We applied two different approaches proposed in the literature to identify extinction debt in Southeast Belgium calcareous grasslands. The first method compared species richness between stable and fragmented habitat patches. The second explored correlations between current species richness and current and past landscape configurations using multiple regression analyses. We subsequently examined results generated by both methods. In addition, we proposed techniques to identify species that are more likely to support extinction debt and associated functional traits. We estimated a respective extinction debt of approximately 28% and 35% of the total and specialist species richness. Similar results were obtained from both methods. We identified 15 threatened specialist species under the current landscape configuration. It is likely the landscape configuration no longer supports the species habitat requirements. We demonstrated that non-clonal species are most threatened, as well as taxa that cannot persist in degraded habitats and form only sparsely distributed populations. We discussed our results in light of other studies in similar habitats, and the overall implications for habitat conservation. [less ▲]

Perception and understanding of invasive alien species issues by nature conservation and horticulture professionals in Belgium

in Environmental Management (2011), 47

We conducted a survey to determine how two professional sectors in Belgium, horticulture professionals and nature reserve managers (those directly involved in conservation), view the issues associated ... [more ▼]

We conducted a survey to determine how two professional sectors in Belgium, horticulture professionals and nature reserve managers (those directly involved in conservation), view the issues associated with invasive plant species. We developed and utilized a questionnaire that addressed the themes of awareness, concept and use of language, availability of information, impacts and, finally, control and available solutions. Using co-inertia analyses, we tested to what extent the perception of invasive alien species (IAS) was dependent upon the perception of Nature in general. Only forty-two percent of respondent horticulture professionals and eighty-two percent of nature reserve managers had a general knowledge of IAS. Many individuals in both target groups nonetheless had an accurate understanding of the scientific issues. Our results therefore suggest that the manner in which individuals within the two groups view, or perceive, the IAS issue was more the result of lack of information than simply biased perceptions of target groups. Though IAS perceptions by the two groups diverged, they were on par with how they viewed Nature in general. The descriptions of IAS by participants converged with the ideas and concepts frequently found in the scientific literature. Both managers and horticulture professionals expressed a strong willingness to participate in programs designed to prevent the spread of, and damage caused by, IAS. Despite this, the continued commercial availability of many invasive species highlighted the necessity to use both mandatory and voluntary approaches to reduce their re-introduction and spread. The results of this study provide stakeholders and conservation managers with practical information on which communication and management strategies can be based. [less ▲]