Dalechampii oak (Quercus dalechampii Ten.), an important host plant for folivorous lepidoptera larvae

El roble de dalechampii (Quercus dalechampii Ten.), una importante planta hospedadora de las larvas de lepidópteros filófagos Llevamos a cabo un análisis estructurado de las taxocenosis de larvas de lepidópteros que viven en las copas del roble de dalechampii (Quercus dalechampii Ten.) en nueve parcelas del estudio en los Pequeños Cárpatos (Europa central). Se analizaron las diferencias entre las taxocenosis de lepidópteros de cada roble. Se hallaron 96 especies y 2.140 individuos. La abundancia de especies alcanzó su valor más elevado en mayo, mientras que el número y la diversidad de especies fueron máximos desde abril hasta mayo y desde abril hasta junio, respectivamente. La abundancia mostró dos máximos notables en las larvas que se alimentan durante la brotación y las que se alimentan al final del verano. La taxocenosis de los lepidópteros en la parcela del estudio Horný háj (un bosque aislado con una elevada densidad de hormigas) difirió significativamente de las demás taxocenosis según el índice de Sörensen para la similitud de las especies, la diversidad de las especies, el análisis de la similitud sobre la base de las pruebas de permutación y las pruebas de pares (ANOSIM), la variabilidad estacional de la composición de especies y el escalamiento multidimensional no métrico (NMDS por sus siglas en inglés)

Modèles ecologiques pour l'extrapolation des effets écotoxicologiques enregistrés lors de biotests in situ cheZ Gammarus

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCAInternational audienceEvaluating the effects of chemical contamination on populations and ecological communities still constitutes a challenging necessity in environmental management. However the toxic effects of contaminants are commonly measured by means of organism-level responses. Linking such effects measures with ecological models is a promising way to apprehend population-level impacts. In this way, population models are currently increasingly used in predictive risk assessment procedures, but their use in environmental diagnostic framework remains limited due to their lack of ecological realism. The present study with the crustacean amphipod Gammarus fossarum, a sentinel species in freshwater monitoring, combines a dual field and laboratory experimental approach with a population modelling framework. In this way, we developed an ecologically-relevant periodic matrix population model for Gammarus. This model allowed us to capture the population dynamics in the field, and to understand the particular pattern of demographic sensitivities induced by Gammarus life-history phenology. The model we developed provided a robust population-level assessment of in situ-based effects measures recorded during a biomonitoring program on a French watershed impacted by past mining activities. Thus, our study illustrates the potential of population modelling when seeking to decipher the role of environmental toxic contamination in ecological perturbations

Dalechampii oak (Quercus dalechampii Ten.), an important host plant for folivorous lepidoptera larvae

We conducted a structured analysis of lepidoptera larvae taxocenoses living in leaf bearing crowns of Dalechampii oak (Quercus dalechampii Ten.) in nine study plots in the Malé Karpaty Mountains (Central Europe). The differences between lepidoptera taxocenoses in individual oak stands were analyzed. A total of 96 species and 2,140 individuals were found. Species abundance peaked in May, while number of species and species diversity reached the highest values from April to May and from April to June, respectively. Abundance showed two notable peaks in flush feeders and in late summer feeders. Lepidoptera taxocenosis in the study plot Horný háj (isolated forest, high density of ants) differed significantly from all other taxocenoses according to Sörensen’s index of species similarity, species diversity, analysis of similarity on the basis of permutation and pairwise tests (ANOSIM), seasonal variability of species composition, and NMDS ordination