Banca de DEFESA: ANDERSON DANTAS LEAL

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : ANDERSON DANTAS LEAL
DATE: 23/02/2024
TIME: 09:00
LOCAL: https://www.youtube.com/watch?v=_GGKeHe1MGY]
TITLE:

Ant diversity patterns at local, regional and global scales

KEY WORDS:

Biogeography; Communities; Tree richness; Disturbance; Habitat loss

PAGES: 132
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

Biodiversity patterns are affected by factors such as climate, human disturbances and  biotic interactions, which operate at different spatial scales. Understanding diversity  patterns and their determinants is essential for effective conservation efforts. However,  many regions and taxonomic groups are often overlooked due to a lack of adequate data.  In particular, invertebrates and arid/semiarid regions receive less attention. For example,  ants play a fundamental role in ecosystem functioning, but there are knowledge gaps  regarding their global biodiversity patterns, their response to anthropogenic disturbances  and their relationship with plant composition and diversity. Similarly, the Caatinga, a  species-rich dry forest, lacks clear knowledge about its animal diversity patterns.  Therefore, in this thesis we set out to investigate the determinants of ant diversity at three  different scales: (i) global, testing the effect of climate and topography, (ii) regional,  testing the effect of anthropogenic disturbances and (iii) local, testing the effect of tree  species richness and their facilitation capacities. In addition, (iv) we examined the  determinants of animal diversity in the Caatinga and the correlation of diversity  distribution between different animal taxa. In the first chapter we tested the relative  strength of abiotic gradients in determining spatial patterns of ant diversity around the  world and between biogeographic realms. We used multiple regressions to relate global  ant diversity data to climatic and topographic data. Our findings suggest that ant diversity  is higher in tropical regions, especially in areas with higher annual rainfall and higher  average temperature. However, the abiotic determinants between biogeographic realms  varied greatly, which challenges the generality of the global pattern. This highlights the importance of considering regional historical and ecological contexts when investigating  biodiversity patterns. In the second chapter we tested the influence of chronic  anthropogenic disturbances (e.g. logging and grazing) and habitat loss on ant species  richness (total, specialist and generalist species). We then used multiple regressions to  examine the impact of disturbance vectors on ant diversity patterns. We found that habitat  loss reduces species richness at all levels, including specialist and generalist species,  while chronic disturbance has a particularly strong impact on species overall and on  specialist species. Our findings highlight that it is necessary to include the drivers of  chronic disturbance in order to measure our real impact on biodiversity. The third chapter  examines the impact of tree richness, tree facilitation and the presence of plants with  extrafloral nectaries on ant diversity patterns, including species richness, phylogenetic  diversity and abundance. We collected ants in all 155 plots of the BrazilDry project, a  biodiversity experiment established in the Açu National Forest. The plots contain one,  two, four, eight and 16 plant species with varying compositions and a gradient of  facilitation. Our results suggest that plant diversity is the main mechanism responsible for  the richness and phylogenetic diversity of ants in the BrazilDry experiment. Possibly the  result comes from a bottom-up effect in the trophic chain, in which plants provide  essential resources for the ants, increasing their diversity. In chapter four, we examine  the correlation between the distribution of animal diversity in the Caatinga among five  taxonomic groups: birds, reptiles, amphibians, mammals and ants. We also tested the  influence of abiotic factors on the distribution of diversity within these groups. To do this,  we retrieved species distribution maps and climate variables from online databases.  Pearson's correlations were used to test the overlap of diversity between the groups, and  multiple linear models were used to test the relative importance of abiotic factors in  organizing the diversity of these groups. Our findings indicate that animal biodiversity in  the Caatinga largely overlaps, but the response to abiotic conditions varies according to  the taxonomic group analyzed. With this thesis, we have filled important gaps in ant  diversity, distribution, abiotic determinants and responses to tree richness. In addition, we  describe the abiotic determinants and the degree of overlap of animal diversity in the  Caatinga.

COMMITTEE MEMBERS:
Externo à Instituição - MÁRIO RIBIRO DE MOURA
Externo à Instituição - JOUDELLYS ANDRADE SILVA
Interno - 3060333 - ANDROS TAROUCO GIANUCA
Presidente - 1678202 - CARLOS ROBERTO SORENSEN DUTRA DA FONSECA
Interno - 1718346 - EDUARDO MARTINS VENTICINQUE