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Auteur Ivana Stehlik (1971-) |
Documents disponibles écrits par cet auteur (4)
Affiner la rechercheFloral free fall in the Swiss lowlands: environmental determinants of local plant extinction in a peri-urban landscape / Ivana Stehlik in Journal of ecology, 95 (4) (July 2007)
Titre : Floral free fall in the Swiss lowlands: environmental determinants of local plant extinction in a peri-urban landscape Type de document : Imprimé Auteurs : Ivana Stehlik (1971-) ; John P. Caspersen ; Lea Wirth ; Rolf Holderegger (1965-) Année de publication : 2007 Article en page(s) : 734-744 Langues : Anglais (eng) Catégories : [CBNPMP-Thématique] Messicole
[CBNPMP-Géographique] SuisseRésumé : Local floras are being depleted by a host of human activities, including habitat destruction and fragmentation, eutrophication, and the intensification of agriculture. Species with particular ecological demands or life-history attributes are more prone to extinction than species with a broader niche. We used an old herbarium from the municipality of Küsnacht (Swiss lowlands) as a historical record for comparison with contemporary plant diversity. This comparison revealed that 17% to 28% of all vascular plants that occurred between 1839 and 1915 were extinct by 2003. Species of different habitats and life-forms had significantly different rates of extinction: wetlands, disturbed sites and meadows lost most species, whereas forests and rocky habitats were least affected; aquatics and annuals were most prone to extinction, geophytes and hemicryptophytes were intermediate, and phanerophytes and chamaephytes were least affected. Species adapted to nutrient-poor soils suffered highest extinction in all habitats, indicating that eutrophication poses an urgent threat to species diversity. Light and soil moisture requirements also had significant effects on extinction, but the direction of the effect varied by habitat. When species were grouped into IUCN categories of the red list of Switzerland, the rank order of the observed extinction matched the red list assignment. Because many of the remaining species had high estimated extinction probabilities and because extinction is often delayed (extinction debt), a substantial part of the remaining flora of Küsnacht is likely to go extinct in the near future. This will increase the dominance of the common species that already comprise 81% of the local flora. The rates and patterns of extinction in Küsnacht are probably representative of surrounding Swiss lowlands and peri-urban landscapes in most developed countries. Studies such as ours can serve as a call for action and form a basis for future monitoring of biodiversity.
Lien pérenne : DOI : 10.1111/j.1365-2745.2007.01246.x Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=148480
in Journal of ecology > 95 (4) (July 2007) . - 734-744Stehlik, Ivana (1971-), Caspersen, John P., Wirth, Lea, Holderegger, Rolf (1965-) 2007 Floral free fall in the Swiss lowlands: environmental determinants of local plant extinction in a peri-urban landscape. Journal of ecology, 95(4): 734-744.Documents numériques
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Article (2007)URL
Titre : Glacial history of the alpine herb Rumex Nivalis (Polygonaceae): a comparison of common phylogeographic methods with nested clade analysis Type de document : Imprimé Auteurs : Ivana Stehlik (1971-) Année de publication : 2002 Article en page(s) : 2007-2016 Langues : Anglais (eng) Catégories : [CBNPMP-Thématique] Phylogénie (liens existant entre espèces apparentées) Mots-clés : Rumex nivalis Résumé : The glacial history of the alpine herb Rumex nivalis was investigated using amplified fragment length polymorphisms (AFLPs) and restriction fragment length polymorphisms with polymerase chain reaction (PCR-RFLPs) of cpDNA. Both traditional statistical methods widely applied in phylogeographic research and nested clade analysis were used. The AFLPs indicated little geographic structure probably due to the wind-pollinated reproductive system of the dioecious R. nivalis. Because cpDNA haplotypes exhibited distinct distributional patterns, correlation between AFLPs and PCR-RFLPs was low. The results of common statistical methods and of nested clade analysis were largely congruent. Both supported in situ survival of one group of common haplotypes in the Central Alps. For another group of common haplotypes, classical phylogeographic analyses gave strong evidence for survival in peripheral refugia at the northern alpine border, whereas this conclusion was not as clearly supported in the nested clade analysis. Nested clade analysis provided several detailed insights on past and ongoing populational demographic processes. Thus, it is a valuable tool in the phylogeographical analysis of haplotype data, but it should preferably be combined with other statistical analyses. In situations with low genetic variation in cpDNA, classical phylogeographic analytical tools on nuclear DNA will still be the methods of choice. Lien pérenne : DOI : 10.3732/ajb.89.12.2007 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=148969
in American Journal of Botany > 89 (12) (December 2002) . - 2007-2016Stehlik, Ivana (1971-) 2002 Glacial history of the alpine herb Rumex Nivalis (Polygonaceae): a comparison of common phylogeographic methods with nested clade analysis. American Journal of Botany, 89(12): 2007-2016.Documents numériques
Article (2002)URLNunataks and peripherical refugia for alpine plants during quaternary glaciation in the middle part of the Alps / Ivana Stehlik (2000)
Titre : Nunataks and peripherical refugia for alpine plants during quaternary glaciation in the middle part of the Alps Type de document : Tiré à part de revue Auteurs : Ivana Stehlik (1971-) Année de publication : 2000 Importance : 25-30 Langues : Anglais (eng) Catégories : [CBNPMP-Thématique] Flore alpine
[CBNPMP-Thématique] Histoire de la végétation, paléoécologieLien pérenne : DOI : 10.5169/seals-73583 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=131467 Stehlik, Ivana (1971-) 2000 Nunataks and peripherical refugia for alpine plants during quaternary glaciation in the middle part of the Alps. Botanica helvetica, 110 : 25-30.Documents numériques
Article (2000)URL
Titre : Spatial genetic structure and clonal diversity of Anemone nemorosa in late successional deciduous woodlands of Central Europe Type de document : Imprimé Auteurs : Ivana Stehlik (1971-) ; Rolf Holderegger (1965-) Année de publication : 2000 Article en page(s) : 424-435 Langues : Anglais (eng) Mots-clés : Anemone sp. Note de contenu : 1 We tested whether established populations in similar environmental conditions exhibit similar or varying spatial genetic structures by comparing populations of the long-lived species Anemone nemorosa from a number of late successional deciduous woodlands in Central Europe. We discuss the ways in which genetic structure may have been shaped by clonal growth and sexual reproduction. 2 A standardized sampling strategy was used to collect 30 ramets from each of 20 populations. Genotypes of the samples were determined by allozyme electrophoresis and analysed assuming that A. nemorosa shows tetraploid-tetrasomic inheritance. 3 Genetic variation and clonal diversity were high compared with other clonal species. Most (95%) of the sampled ramets had unique multilocus genotypes with only 22 examples occurring more than once. Differences between observed and expected heterozygosities within populations were generally small to moderate. Fixation indices (mean of over 14 loci) in the populations ranged between 0.08 and 0.56 (grand mean = 0.21) confirming reports that the breeding system in A. nemorosa is predominantly outcrossing or mixed-mating. 4 Limited historic gene flow among populations (Nm = 0.62) was reflected by high population differentiation (GST = 0.29), low genetic identities among populations and a non-significant correlation between these identities and geographical distances. 5 Spatial autocorrelation (Moran’s I) showed no significant differences in genetic structures between populations under similar environmental conditions. Samples taken less than 0.5 m apart were genetically more closely related than to more distant samples, but similarity of genotypes decreased only slightly with further increase in distance. 6 The high levels of genetic variation found in populations of A. nemorosa are probably due to repeated seedling recruitment and the outcrossing or mixed-mating breeding system, whereas vegetative propagation and short-distance seed dispersal may contribute to the positive genetic autocorrelation observed at a small spatial scale.
Lien pérenne : DOI : 10.1046/j.1365-2745.2000.00458.x Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=137830
in Journal of ecology > 88 (3) (2000) . - 424-435Stehlik, Ivana (1971-), Holderegger, Rolf (1965-) 2000 Spatial genetic structure and clonal diversity of Anemone nemorosa in late successional deciduous woodlands of Central Europe. Journal of ecology, 88(3): 424-435.Documents numériques
Article (2000)URL
