Jirka Hodeček | CHUV - Academia.edu (original) (raw)
Papers by Jirka Hodeček
The pollination syndrome hypothesis predicts that plants pollinated by the same pollinator group ... more The pollination syndrome hypothesis predicts that plants pollinated by the same pollinator group bear convergent combinations of specific f loral functional traits. Nevertheless, some studies have shown that these combinations predict pollinators with relatively low accuracy. This discrepancy may be caused by changes in the importance of specific f loral traits for different pollinator groups and under differ-ent environmental conditions. To explore this, we studied pollination systems and f loral traits along an elevational gradient on Mount Cameroon during wet and dry seasons. Using Random Forest (Machine Learning) models, allowing the ranking of traits by their relative importance, we demonstrated that some f loral traits are more important than others for pollinators. However, the distribution and impor-tance of traits vary under different environmental conditions. Our results imply the need to improve our trait-based understanding of plant-pollinator interactions to better inform the debate surrounding the pollination syndrome hypothesis.
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Necrophagous blowflies (Diptera: Calliphoridae) are of great importance particularly during inves... more Necrophagous blowflies (Diptera: Calliphoridae) are of great importance particularly during investigations of suspicious deaths. Many studies have analyzed the distribution of blowflies based on pig experiments and baited trapping; however, data from real case scenarios are rarely used. In this article, the distribution of blowflies found during investigations of 160 real cases during 1993-2007 in Switzerland is evaluated based on habitat, altitude, and season. Ten species of blowflies were present in 145 out of the 160 cases. The most common species was Calliphora vicina, which occurs throughout the year and was present in 69 % of all cases. Lucilia sericata, Calliphora vomitoria, and L. caesar were identified among the rest of the flies as species of great forensic importance mainly due to their distributional patterns. After a comparison with a similar dataset from Frankfurt, Germany, some surprising differences were determined and discussed. The biggest discrepancies between our dataset and the German dataset were in the occurrences of L. sericata (30 % vs. 86 %, respectively), Phormia regina (5 % vs. 43 %), and L. ampullacea (1 % vs. 45 %). The life-history strategies and intraspecific behavioral variability of blowflies remain understudied, although they can be essential for an unbiased approach during a death investigation. Further research and comparison of occurrence patterns across the area of distribution of blowflies are therefore needed and recommended.
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The genus Praedora Rothschild & Jordan, 1903 is reviewed and five new subspecies are described: P... more The genus Praedora Rothschild & Jordan, 1903 is reviewed and five new subspecies are described: Praedora marshalli trevisanae ssp. nov., Praedora plagiata kitonga ssp. nov., Praedora plagiata bilineata ssp. nov., Praedora plagiata iringensis ssp. nov. and Praedora tropicalis dolnyi ssp. nov. In addition, Praedora marshalli australis Clark, 1930 stat. rev. is reinstated as a valid subspecies from synonymy with Praedora marshalli.
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Forensic Science International: Synergy
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Although ecological succession is one of the principal focuses of recent restoration ecology rese... more Although ecological succession is one of the principal focuses of recent restoration ecology research, it is still unclear which factors drive this process and positively influence species richness and functional diversity. In this study we sought to elucidate how species traits and functional diversity change during forest succession, and to identify important factors that determine the species in the observed assemblages. We analyzed species richness and functional diversity of ground beetle assemblages in relation to succession on post-industrial localities after habitat deterioration caused by spoil de-position. We selected ground beetles as they are known to be sensitive to landscape changes (with a large range of responses), and their taxonomy and ecology are generally well-known. Ground beetles were sampled on the spoil heaps during the last 30 years when spontaneous succession occurred. To calculate functional diversity, we used traits related to habitat and trophic niche, i.e. food specialization, wing morphology , trophic level, and bio-indication value. Ground beetle species were found to be distributed non-randomly in the assemblages in the late phase of succession. Ordination analyses revealed that the ground beetle assemblage was significantly associated with the proportion of forested area. Environmental heterogeneity generated assemblages that contained over-dispersed species traits. Our findings indicated that environmental conditions at late successional stages supported less mobile carnivorous species. Overall, we conclude that the decline in species richness and functional diversity in the middle of the studied succession gradient indicated that the assemblages of open habitats had been replaced by species typical of forest ecosystems.
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The main objective of reclamation activities is to accelerate the restoration of post-industrial ... more The main objective of reclamation activities is to accelerate the restoration of post-industrial areas. However current ecological studies that compare reclaimed and non-reclaimed habitats evaluate these areas mainly by species richness and conservation potential. We thus tested which environmental characteristics of the spoil heap determine the structure of the beetle communities and their successional rate. During the years 1993–2007, we sampled epigeic beetles on reclaimed and non-reclaimed parts of a spoil heap in the city of Ostrava, Czech Republic. For comparison, we used multivariate methods and functional diversity indices. Our ordination models revealed that the beetle communities on the non-reclaimed part of the spoil heap were determined by forest cover and time; in contrast, the communities on the reclaimed habitat were determined by herb cover and bare ground cover. Compositional heterogeneity was significantly higher on the non-reclaimed part of the spoil heap. A comparison of the functional diversity indices showed significantly higher functional richness and evenness on the spontaneously restored part of the spoil heap. Our results provide evidence that technical reclamation is a significant disturbance that slows down the successional rate of beetle communities and negatively influences their structure. We thus recommend that at least some parts of the areas needing to be reclaimed be allowed to undergo spontaneous succession during reclamation. The areas undergoing spontaneous succession would become refuges for particular species while also supporting the heterogeneity of the habitat.
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Understanding succession is one of the main goals in ecosystem ecology, but very few studies rega... more Understanding succession is one of the main goals in ecosystem ecology, but very few studies regarding arthropods have actually examined this topic in sufficient detail. Missing are studies that examine the long-term trend of primary succession of arthropods in post-industrial habitats and also the functional consequences of primary succession on arthropods. We used epigeic beetles as a model group to investigate the process of primary succession of arthropods on spoil heaps for about 30 years of spontaneous development. For carabid beetles, we calculated indices of functional diversity (functional evenness, functional richness and functional divergence). To quantify functional diversity we used these functional traits: wing morphology, habitat preference and humidity dependence. Our results reveal that the main environmental factor determining the structure of beetle communities is spoil heap age, which is itself correlated with forest cover. The descriptive rank-abundance models that best fit our community structure were Gambin and Zipf – Mandelbrot. Abundances of brachypterous and forest species were positively correlated with successional age. Our results provide evidence that primary succession in post-industrial habitats differs from that in more natural habitats due to the rapid rate of successional changes and their attributes. In particular, abiotic factors are constitutive in comparison to interspecific competition during succession. The canonical correspondence analysis model identified that irregular disturbances are another important phenomenon of succession in post-industrial habitats. We assume that constant indices of functional evenness and richness reflect rapid colonization from surrounding habitats. Functional divergence was significantly correlated with increasing proportion of forest species. Zusammenfassung Sukzessionen zu verstehen ist eines der Hauptziele der Ökosystemökologie, aber nur wenige Untersuchungen an Arthropoden haben dieses Thema tatsächlich mit genügender Genauigkeit betrachtet. Es fehlen Untersuchungen, die den langfristigen Trend der Primärsukzession bei Arthropoden in Industriefolgehabitaten und die funktionalen Konsequenzen der Primärsukzession für Arthropoden erforschen. Wir wählten epigäische Käfer als Modellgruppe, um die Primärsukzession von Arthropoden auf
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The spoil heaps in Ostrava were created during mining of black coal in the first half of the 20th... more The spoil heaps in Ostrava were created during mining of black coal in the first half of the 20th century. Later, there were efforts to “heal” the landscape by technical reclamations, which are rather expensive. Our studies showed that spontaneous succession on non-reclaimed spoil heaps is faster then succession on their reclaimed counterparts. The communities of invertebrates on non-reclaimed spoil heaps are also more mature and contain rare species in comparison with the reclaimed ones.
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Drafts by Jirka Hodeček
The pollination syndrome hypothesis predicts that plants pollinated by the same pollinator group ... more The pollination syndrome hypothesis predicts that plants pollinated by the same pollinator group bear convergent combinations of specific floral traits. Nevertheless, some studies have shown relatively low predictive power for these floral trait combinations. This discrepancy may be caused by changes in the importance of specific floral traits for shaping interactions under different environmental conditions and for different pollinator groups. To test this, we studied pollination systems and floral traits along an elevational gradient on Mount Cameroon during wet and dry seasons. Using Random Forest models, allowing the ranking of traits by significance, we demonstrated that some floral traits are more important than others in shaping interactions and that these traits predict pollinators relatively well. However, the distribution and importance of traits varies under different environmental conditions. Our results imply the need to improve our trait-based understanding of plantpollinator interactions to better inform the debate surrounding pollination syndrome hypothesis.
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The pollination syndrome hypothesis predicts that plants pollinated by the same pollinator group ... more The pollination syndrome hypothesis predicts that plants pollinated by the same pollinator group bear convergent combinations of specific f loral functional traits. Nevertheless, some studies have shown that these combinations predict pollinators with relatively low accuracy. This discrepancy may be caused by changes in the importance of specific f loral traits for different pollinator groups and under differ-ent environmental conditions. To explore this, we studied pollination systems and f loral traits along an elevational gradient on Mount Cameroon during wet and dry seasons. Using Random Forest (Machine Learning) models, allowing the ranking of traits by their relative importance, we demonstrated that some f loral traits are more important than others for pollinators. However, the distribution and impor-tance of traits vary under different environmental conditions. Our results imply the need to improve our trait-based understanding of plant-pollinator interactions to better inform the debate surrounding the pollination syndrome hypothesis.
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Necrophagous blowflies (Diptera: Calliphoridae) are of great importance particularly during inves... more Necrophagous blowflies (Diptera: Calliphoridae) are of great importance particularly during investigations of suspicious deaths. Many studies have analyzed the distribution of blowflies based on pig experiments and baited trapping; however, data from real case scenarios are rarely used. In this article, the distribution of blowflies found during investigations of 160 real cases during 1993-2007 in Switzerland is evaluated based on habitat, altitude, and season. Ten species of blowflies were present in 145 out of the 160 cases. The most common species was Calliphora vicina, which occurs throughout the year and was present in 69 % of all cases. Lucilia sericata, Calliphora vomitoria, and L. caesar were identified among the rest of the flies as species of great forensic importance mainly due to their distributional patterns. After a comparison with a similar dataset from Frankfurt, Germany, some surprising differences were determined and discussed. The biggest discrepancies between our dataset and the German dataset were in the occurrences of L. sericata (30 % vs. 86 %, respectively), Phormia regina (5 % vs. 43 %), and L. ampullacea (1 % vs. 45 %). The life-history strategies and intraspecific behavioral variability of blowflies remain understudied, although they can be essential for an unbiased approach during a death investigation. Further research and comparison of occurrence patterns across the area of distribution of blowflies are therefore needed and recommended.
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The genus Praedora Rothschild & Jordan, 1903 is reviewed and five new subspecies are described: P... more The genus Praedora Rothschild & Jordan, 1903 is reviewed and five new subspecies are described: Praedora marshalli trevisanae ssp. nov., Praedora plagiata kitonga ssp. nov., Praedora plagiata bilineata ssp. nov., Praedora plagiata iringensis ssp. nov. and Praedora tropicalis dolnyi ssp. nov. In addition, Praedora marshalli australis Clark, 1930 stat. rev. is reinstated as a valid subspecies from synonymy with Praedora marshalli.
Bookmarks Related papers MentionsView impact
Forensic Science International: Synergy
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Although ecological succession is one of the principal focuses of recent restoration ecology rese... more Although ecological succession is one of the principal focuses of recent restoration ecology research, it is still unclear which factors drive this process and positively influence species richness and functional diversity. In this study we sought to elucidate how species traits and functional diversity change during forest succession, and to identify important factors that determine the species in the observed assemblages. We analyzed species richness and functional diversity of ground beetle assemblages in relation to succession on post-industrial localities after habitat deterioration caused by spoil de-position. We selected ground beetles as they are known to be sensitive to landscape changes (with a large range of responses), and their taxonomy and ecology are generally well-known. Ground beetles were sampled on the spoil heaps during the last 30 years when spontaneous succession occurred. To calculate functional diversity, we used traits related to habitat and trophic niche, i.e. food specialization, wing morphology , trophic level, and bio-indication value. Ground beetle species were found to be distributed non-randomly in the assemblages in the late phase of succession. Ordination analyses revealed that the ground beetle assemblage was significantly associated with the proportion of forested area. Environmental heterogeneity generated assemblages that contained over-dispersed species traits. Our findings indicated that environmental conditions at late successional stages supported less mobile carnivorous species. Overall, we conclude that the decline in species richness and functional diversity in the middle of the studied succession gradient indicated that the assemblages of open habitats had been replaced by species typical of forest ecosystems.
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The main objective of reclamation activities is to accelerate the restoration of post-industrial ... more The main objective of reclamation activities is to accelerate the restoration of post-industrial areas. However current ecological studies that compare reclaimed and non-reclaimed habitats evaluate these areas mainly by species richness and conservation potential. We thus tested which environmental characteristics of the spoil heap determine the structure of the beetle communities and their successional rate. During the years 1993–2007, we sampled epigeic beetles on reclaimed and non-reclaimed parts of a spoil heap in the city of Ostrava, Czech Republic. For comparison, we used multivariate methods and functional diversity indices. Our ordination models revealed that the beetle communities on the non-reclaimed part of the spoil heap were determined by forest cover and time; in contrast, the communities on the reclaimed habitat were determined by herb cover and bare ground cover. Compositional heterogeneity was significantly higher on the non-reclaimed part of the spoil heap. A comparison of the functional diversity indices showed significantly higher functional richness and evenness on the spontaneously restored part of the spoil heap. Our results provide evidence that technical reclamation is a significant disturbance that slows down the successional rate of beetle communities and negatively influences their structure. We thus recommend that at least some parts of the areas needing to be reclaimed be allowed to undergo spontaneous succession during reclamation. The areas undergoing spontaneous succession would become refuges for particular species while also supporting the heterogeneity of the habitat.
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Understanding succession is one of the main goals in ecosystem ecology, but very few studies rega... more Understanding succession is one of the main goals in ecosystem ecology, but very few studies regarding arthropods have actually examined this topic in sufficient detail. Missing are studies that examine the long-term trend of primary succession of arthropods in post-industrial habitats and also the functional consequences of primary succession on arthropods. We used epigeic beetles as a model group to investigate the process of primary succession of arthropods on spoil heaps for about 30 years of spontaneous development. For carabid beetles, we calculated indices of functional diversity (functional evenness, functional richness and functional divergence). To quantify functional diversity we used these functional traits: wing morphology, habitat preference and humidity dependence. Our results reveal that the main environmental factor determining the structure of beetle communities is spoil heap age, which is itself correlated with forest cover. The descriptive rank-abundance models that best fit our community structure were Gambin and Zipf – Mandelbrot. Abundances of brachypterous and forest species were positively correlated with successional age. Our results provide evidence that primary succession in post-industrial habitats differs from that in more natural habitats due to the rapid rate of successional changes and their attributes. In particular, abiotic factors are constitutive in comparison to interspecific competition during succession. The canonical correspondence analysis model identified that irregular disturbances are another important phenomenon of succession in post-industrial habitats. We assume that constant indices of functional evenness and richness reflect rapid colonization from surrounding habitats. Functional divergence was significantly correlated with increasing proportion of forest species. Zusammenfassung Sukzessionen zu verstehen ist eines der Hauptziele der Ökosystemökologie, aber nur wenige Untersuchungen an Arthropoden haben dieses Thema tatsächlich mit genügender Genauigkeit betrachtet. Es fehlen Untersuchungen, die den langfristigen Trend der Primärsukzession bei Arthropoden in Industriefolgehabitaten und die funktionalen Konsequenzen der Primärsukzession für Arthropoden erforschen. Wir wählten epigäische Käfer als Modellgruppe, um die Primärsukzession von Arthropoden auf
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The spoil heaps in Ostrava were created during mining of black coal in the first half of the 20th... more The spoil heaps in Ostrava were created during mining of black coal in the first half of the 20th century. Later, there were efforts to “heal” the landscape by technical reclamations, which are rather expensive. Our studies showed that spontaneous succession on non-reclaimed spoil heaps is faster then succession on their reclaimed counterparts. The communities of invertebrates on non-reclaimed spoil heaps are also more mature and contain rare species in comparison with the reclaimed ones.
Bookmarks Related papers MentionsView impact
The pollination syndrome hypothesis predicts that plants pollinated by the same pollinator group ... more The pollination syndrome hypothesis predicts that plants pollinated by the same pollinator group bear convergent combinations of specific floral traits. Nevertheless, some studies have shown relatively low predictive power for these floral trait combinations. This discrepancy may be caused by changes in the importance of specific floral traits for shaping interactions under different environmental conditions and for different pollinator groups. To test this, we studied pollination systems and floral traits along an elevational gradient on Mount Cameroon during wet and dry seasons. Using Random Forest models, allowing the ranking of traits by significance, we demonstrated that some floral traits are more important than others in shaping interactions and that these traits predict pollinators relatively well. However, the distribution and importance of traits varies under different environmental conditions. Our results imply the need to improve our trait-based understanding of plantpollinator interactions to better inform the debate surrounding pollination syndrome hypothesis.
Bookmarks Related papers MentionsView impact