Banca de DEFESA: THAIS APARECIDA VITORIANO DANTAS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : THAIS APARECIDA VITORIANO DANTAS
DATE: 02/05/2025
TIME: 13:00
LOCAL: Google Meet (https://meet.google.com/weu-ywea-ipm)
TITLE:

EFFECT OF PLANT DIVERSITY AND FACILITATION ON THE DIVERSITY OF ARTHROPODS AND THEIR FUNCTIONS

KEY WORDS:

Biodiversity and ecosystem functioning; Tree richness; Plant-insect interaction; Seed dispersal; Restoration

PAGES: 200
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

Biodiversity plays an important role in the functioning of ecosystems and, consequently, in the stability of the services they provide and regulate. Changes in the diversity of a plant community can lead to alterations in biogeochemical cycles, changes in productivity, abundance and diversity of local fauna, as well as in the functions performed by these organisms. The strengthening of the relationship between biodiversity and the functioning of ecosystems can be mediated by the effect of complementarity. In these relationships, species use resources in different ways and, therefore, some ecosystem functions are improved by the effects of facilitation or niche differentiation. In plant communities, facilitation is an important structurer of the spatial distribution and relative frequency of species and is potentially important for the functioning of ecosystems. We therefore set out to investigate in this thesis how the richness, composition and facilitation potential of plant communities in a Biodiversity and Ecosystem Functioning experiment affect (I) the soil arthropod community, (II) the herbivorous insect community, (III) the configurations of plant-herbivorous insect interaction networks, and (IV) the ant community and its seed dispersal services. In the first chapter we tested the hypotheses that the abundance and diversity of soil-dwelling arthropods are positively affected by tree species richness and by a gradient of plant facilitation that can increase community productivity and resource heterogeneity, as well as improving soil conditions. Using generalised additive models (GAM), we found that tree richness, which directly affects foliage heterogeneity, positively affected total arthropod richness, as well as the richness of Hemiptera, Hymenoptera and predators. Contrary to expectations, facilitation had no detectable effect on the structure of the arthropod community. Nutrient availability and average tree height, used as an indicator of community productivity, emerged as the main drivers of arthropod abundance. In chapter two, we test the hypotheses that the abundance and richness of herbivorous insects are positively affected by tree species richness and by a gradient of facilitation between plants, which can increase community productivity and resource heterogeneity. In addition, we assessed whether these effects are mediated by the estimated average number of tree leaves, used as an indicator of plant community productivity, and by the density of trees with extrafloral nectaries, a potentially important defence trait. Using generalised additive models (GAM) to control for the effects of space and plant community composition, we found that the richness of herbivorous insects was positively influenced by tree richness, facilitation between plants and the average number of leaves, but not by the density of trees with extrafloral nectaries. Insect abundance, on the other hand, was only affected by the average number of leaves. Specifically, plant diversity influenced the richness of Coleoptera, Orthoptera and Phasmatodea, while facilitation also affected the richness of Coleoptera. In addition, the number of leaves had a positive effect on the richness and abundance of Orthoptera. In the third chapter, we examine how the tree diversity gradient affects the structure of plant-herbivore interaction networks (by controlling plant species composition) and how the structure of these networks changes over time as communities mature. We demonstrated that the number of herbivorous insect species and the number of interactions they established increased as the community matured. In addition, throughout this process, the plant-herbivore interaction networks showed less connectivity, less nesting and greater modularity. We also observed that tree diversity had a positive effect on network connectivity and nesting, but a negative effect on modularity. In the fourth chapter, we investigated the effect of tree diversity, facilitation and the density of trees with extrafloral nectaries on the abundance, richness, functional diversity and phylogenetic diversity of terrestrial ants and on the dispersal services provided by ants. The generalised linear mixed models (GLMM) showed that tree richness positively affects the abundance, richness, functional diversity and phylogenetic diversity of ants. In addition, tree richness had a strong positive effect on the proportion and distance of dispersed seeds. Contrary to our expectations, facilitation and the number of trees with extrafloral nectaries did not affect terrestrial ants and their functions. With this thesis, we have filled important gaps in how the diversity and composition of plant communities affect arthropod communities, as well as deepening our understanding of plant-herbivore interactions at different stages of community maturity. With the thesis, we contribute to filling gaps in how the diversity and composition of plant communities, together with facilitation between plants, affect arthropod communities and their trophic groups, as well as their ecosystem functions, such as seed dispersal. We also provide new insights into the processes that structure plant-herbivore-insect interaction networks.

COMMITTEE MEMBERS:
Externa à Instituição - JULIETA BENÍTEZ MALVIDO
Interno - 3060333 - ANDROS TAROUCO GIANUCA
Presidente - 1678202 - CARLOS ROBERTO SORENSEN DUTRA DA FONSECA
Externa à Instituição - FERNANDA MARIA PEREIRA DE OLIVEIRA
Externo à Instituição - GUILHERME GERHARDT MAZZOCHINI