Effect of disturbance gradients on the structure, composition and diversity of host-parasitoid network interactions

Abstract

Changes in the landscape resulting from the association between the effects of fragmentation and habitat loss alter the physical structure and connectivity between habitats, influencing the availability and quality of resources, environmental factors and the distribution pattern of local communities. The diversity of interactions established, and the complexity of species interaction networks are determining factors for stability and ecosystem function in the landscapes. Thus, the study of trophic relationships between insects, found in natural environments, can help in the evaluation of the impact that disturbances occurring in an area cause on the biodiversity present in the landscape. Among the insects, the parasitic hymenoptera are excellent indicators of environmental impacts because they are sensitive to environmental changes and because they interference with the trophic chains where they are found. Therefore, knowledge and understanding of the composition and organization of local communities and networks of plant-herbivore-predator/parasitoid interactions can be important tools for studies that focus on the assessment, development of strategies and recovery of natural landscapes that have suffered / suffered anthropic disorders or natural disturbances. Aiming to understand the impact of landscape alteration dynamics on the structuring of communities in a landscape that undergoes different types of management and restoration processes, this work aims to estimate the abundance, the richness of species, the complexity and diversity of the networks of interactions present in the communities of hymenoptera parasitoid and lepidopteran in Capinxigui (Croton floribundus - Euphorbiaceae) in three areas with different levels of disturbance, (i) low - Semideciduous Mesophilous Forest, (ii) medium - Reforestation (Ecological Corridor) and (iii) high - Agrossilvipastoral System; at Canchim Farm, located in São Carlos - SP. For this, quantitative and qualitative metrics will be used to study the structure, diversity and organization of the host-parasitoid interaction networks present in the three study areas. The impact of the parasitoid species on the topology of the interaction networks will also be evaluated and the ecological, biological and behavioral aspects of the local guilds will be compared.