Banca de QUALIFICAÇÃO: NIEGE FELIX CAETANO FRANÇA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : NIEGE FELIX CAETANO FRANÇA
DATE: 13/11/2023
TIME: 09:00
LOCAL: Google Meet
TITLE:

Evaluating the influence of diversity on the availability of flowers and fruit in restored tree communities.

KEY WORDS:

biodiversity; floral resources; phenology; flowering; fruiting; restoration; communities.

PAGES: 48
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

The first chapter tests whether the diversity of tree plants in the restored communities and their facilitation potential influence the number of reproductive individuals in the first seven years of restoration, with the aim of answering the following questions: I - How many individuals and of which plant species in the restored communities were able to reproduce by generating foraging resources for different animal species? II - Whether there is an effect of diversity and/or facilitation on the presence or absence of flowering and fruiting patterns. All planted individuals were monitored once a year during the dry season in 2017, 2018, 2019, 2022 and 2023, with no data being collected during the 2020 and 2021 pandemics. To test whether the diversity of planted species (categorical X1) and the Facilitation capacity of the planted tree community (continuous, covariant variable X2) significantly influenced the number of flowering individuals (Y1) and the number of fruiting individuals (Y2), two Analyses of Covariance were carried out. The analyses were developed in the R Studio software, using the following packages: effects, tidyverse, RColorBrewer and ggplot2. The results showed that the diversity of trees planted did not influence the number of flowering individuals. However, we did obtain a positive effect of facilitation on the number of flowering individuals between the years 2016 and 2023. However, diversity and facilitation did not significantly influence the number of fruiting individuals. The difference in production between flowering and fruiting may have occurred due to the low rainfall which can cause many flowers to abort, as well as fruit abscission, which can be produced in smaller quantities when under great water stress. During data collection, many insects were also found feeding on the flowers and buds. The main predator was Stiphra robusta, the Mané-magro, which can also reduce the number of fruits available for counting. It can therefore be concluded that facilitation is an important mechanism acting on the reproductive capacity of Caatinga species, since facilitating trees can improve climatic conditions and increase the amount of resources available for neighboring species to flower. Constant visits by various pollinators to the flowers of different species were also observed, showing that these floral resources can attract pollinators to the restored area. This work makes a substantial contribution to revealing the importance of programming restoration models with the presence of nurse or facilitator species, given their great potential to increase the reproductive capacity of neighboring species. In the second chapter, data was collected on the phenological stages of Piptadenia retusa, popularly known as Jurema-branca, in the plots with different levels of diversity in which this species was present in the BrazilDry Experiment. This monthly production was also quantified and characterized in terms of buds, flowers and mature and immature fruit. The main objective of the study was to assess whether the diversity of species that make up the restored communities would affect the phenophases of the Piptadenia retusa species, as well as the quantity of fruit and flowers produced by them. In this way, the aim is to test whether there is in fact an influence of facilitation mechanisms and an influence of the richness of species that make up the communities on the production of reproductive structures of this species. The specific objectives are I - To test whether there is seasonality and synchronization in the production of flowers and fruits by the species Piptadenia retusa, and which are the months of production of these food resources for the fauna; II - To test whether the diversity of species and the level of facilitation of the restored tree communities influence the abundance and availability of flowers and fruits of Piptadenia retusa. Under the hypotheses that: I - There is seasonality and synchronization in the production of flowers and fruits of the species Piptadenia retusa in relation to the different levels of diversity that make up the restored communities. II - More diverse plots and/or plots with more facilitators will have a greater abundance and availability of Piptadenia retusa flowers and fruits throughout the year. With this in mind, data was collected on the number of buds, flowers, mature and immature fruit, as well as the characterization of the phenophases proposed by Fournier (1974). To test whether there is seasonality in the production of food resources in the P. retusa species and which are the periods for each type of resource, Repeated Measures ANOVAs were used using monthly counts of flowers (Y1) and fruits (Y2) in communities with different levels of diversity (X1) and different levels of Facilitation (X2). By testing the months variable, it is possible to see whether there is greater durability or availability of food at different times of the year, testing whether there are communities with peaks in food supply at different times. The analyses were carried out using the R Studio software. We hypothesized that a greater diversity of tree species and a greater intensity of facilitation would result in better use of the soil and light resources available for plant growth and performance, thus increasing the quantity and length of time that flowers and fruits are provided by P. retusa. The results show that increasing diversity increased the amount of flowers and fruit produced, but facilitation did not alter this pattern. We conclude that the diversity of trees planted is a key factor in increasing the reproductive resources produced in plant communities used in restoration. These resources will be useful for the future recruitment of young plants and as a food resource for fauna.

COMMITTEE MEMBERS:
Externa ao Programa - 1813882 - ALICE DE MORAES CALVENTE VERSIEUX - nullExterna ao Programa - 1074041 - ANDREA LEME DA SILVA - nullPresidente - 1677189 - GISLENE MARIA DA SILVA GANADE