PPG - Ecologia e Evolução

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https://hdl.handle.net/11600/61109

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Navegando PPG - Ecologia e Evolução por Orientador(es) "Boscolo, Danilo [UNIFESP]"

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    Áreas modificadas são acessíveis aos polinizadores: uma análise do forrageio de Melipona quadrifasciata como indicador de conectividade funcional
    (Universidade Federal de São Paulo, 2014-04-25) Souza, Tatiana Machado de [UNIFESP]; Boscolo, Danilo [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Environmental changes can generate landscapes composed of a group of small, isolated patches of natural vegetation, interspersed with different types of land uses and occupation. This process interferes with plant reproduction through pollinators, what is directly linked to functional connectivity and accessibility of environments for these animals. The aim of this study was to estimate the accessibility of natural and cultivated environments of the study area for the species Melipona quadrifasciata by analysing their pollen foraging patterns in order to infer about the preferences of the species in different landscape contexts (more human modified ? over 55% of human modified spots, or less human modified ? under 55% of human modified spots), as well as inferring on the functional connectivity of these environments. For this, we allocated 15 artificial nests of M. quadrifasciata within those two different contexts. Three control colonies were allocated adjacent to the crops, while the others were placed in natural areas between 500m to 2000m away from the crops to assess in what situations the bees would forage mainly in the crops or stay in natural areas. We also made transects around the colonies to estimate available resources and acknowledge the surrounding flora, whith preparation of herbarium specimens with available pollen from natural and agricultural areas. We also collected pollen directly from the bee?s pollen basket, to know the foraging pattern of the species from the resources collected. The diversity of pollens collected by the bees was largely dependent on the distances between the crop and colonies. Collected diversity was further influenced by the association between distance and diversity of environments around each colony. Considering the data obtained and the foraging strategy of the M. quadrifasciata, it is possible to derive an indirect measure of the functional connectivity of the study area for these pollinators, what have direct influence on their movement and hence efficiency as a vector of pollen exchange in natural and farming environments. Maintaining healthy natural areas close to crop fields can be a way to keep the pollination system running in the long term, as this would ensure that natural areas around the colony are accessible enough to provide resources for nesting and food fairly constantly throughout the life of the colonies, ensuring their survival and associated environmental service.
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    Efeito da heterogeneidade da paisagem sobre redes de interações plantas-polinizadores
    (Universidade Federal de São Paulo, 2015-07-30) Tokumoto, Paola Mandetta [UNIFESP]; Boscolo, Danilo [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Most studies about the effects of anthropogenic landscape changes on biodiversity have focused on parameters such as species richness and abundance. Few are those that aim to understand the effects of these disturbances on ecological processes such as pollination, which are important for the maintenance of natural and anthropic ecosystems. Pollinating insects are sensitive to changes in the landscape, what may be one of the leading forces for the global decline of these organisms. In this context, the analysis of plant-pollinators interaction networks allows us to better understand the resistance and resilience of pollination processes against landscape changes. Recent studies show that the abundance and richness of pollinators and agricultural productivity tend to be higher in landscapes that are more heterogeneous and with greater amount of forest. However, there is a necessity to better understand how different types of environments affect plant-pollinator interaction networks with a functional approach. This study evaluated the influence of functional heterogeneity of the landscape on plant-pollinator interaction networks, on the richness and abundance of insect flower visitors, and the richness of flowers available in Atlantic Forest fragments. Our main hypothesis was that in more diverse, forested, connected and with higher quality landscapes, we should find more resistant and resilient plant-pollinator interaction networks, as well as richer flower and pollinator communities. For this, we selected 12 landscapes, within a gradient of landscape diversity and forest proportion. In each central forest fragment, we actively collected floral visitors and flowering plants to build plant-pollinator networks for each landscape. We analyzed our data using a multiple competing hypotheses model selection approach based on the Akaike Information Criterion - AIC. Pollinator communities were richer and more abundant in landscapes with higher proportion of forest; more asymmetrical in landscapes with greater functional connectivity; more modular in better quality and more diverse landscapes; and with greater diversity of interactions in landscapes with higher quality and proportion of forest. In studies that aim to understand how landscape changes affect pollination in realistic scenarios, it is important to consider, in addition to the amount of forest, how the composition and configuration of different environments in landscape affect this ecological process.
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    Efeito da quantidade de floresta da paisagem sobre a estrutura de redes de interação planta-visitantes florais em áreas de restauração florestal
    (Universidade Federal de São Paulo, 2016-11-10) Martins, Mauricio Nogueira [UNIFESP]; Boscolo, Danilo [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    With less than 16% of its original extent, the Atlantic Forest has been restored in order to rebuild the functional richness of biological communities. However, verification of the effectiveness of restoration actions consider only vegetation structure and species richness, while little is known about the functionality of these environments. Pollination is an ecological process and environmental service of great importance for plant reproduction and food production, and its agents are sensitive to environmental and landscape changes, so it should be considered in restoration actions. Through ecological network analysis, pollination networks between restoration areas and reference areas have been compared, focusing on the influence of local factors on restorations, neglecting the effect of the landscape structure in these areas. The objective of the present study was to evaluate the effect of the amount of forest surrounding forest restoration areas in the Atlantic Forest on the structure of the floral-plant interaction networks in these areas. Our hypothesis is that areas of forest restoration inserted in landscapes with high amount of forest have more complex and better structured networks than in areas with low amount of forest. The study was carried out in the municipalities of Antonina (Paraná) and Batatais (São Paulo), areas in different contexts of vegetation cover around forest restorations, where Antonina have greater vegetation cover than Batatais. We selected five landscapes in each region, high forest areas in Antonina, and low forest areas in Batatais, and sampled plants and their floral visitors for the construction of interaction networks, and then we analyzed the effects of the landscape on network metrics. The amount of forest in the landscape had little effect on the network metrics, which showed small and not very cohesive networks. However, in areas with high forest cover, the networks had a higher weighted connectance, indicating that the landscape factor may affect the pattern of interactions between plants and floral visitors that occur in areas of forest restoration in the early stages of succession. Our study suggests that the low effect of the amount of forest of the landscape on the structure of the studied nets can be due to other factors of the landscape and local factors of the restorations. It is also possible that restored forests in more advanced successional stages may are more attractive to floral visitors, and the amount of forest may be more relevant in this context. This project is linked to the Thematic Project approved by FAPESP Process no. 2013/50718-5, in its Module 5, related to the monitoring of fauna.
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    A quantidade de mata como principal influência em bandos mistos de aves de Mata Atlântica fragmentada
    (Universidade Federal de São Paulo, 2015-07-31) Silva, Marina Isidoro [UNIFESP]; Boscolo, Danilo [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Forest fragmentation and habitat loss are considered the major threats to biodiversity. Studies of the effects of these processes on the species should also include landscape analysis rather than just local analysis as in many studies. Among several possible landscape metrics, the landscape habitat amount has been highlighted and, in many studies, is considered as the most important for species persistence and environmental processes. Therefore, this study aimed at testing the effects of landscape forest amount on Atlantic Forest mixed-species bird flocks. Mixed flocks are associations of two or more species that interact for a time, space and direction and the survival of many species depends on this system. Changes in the forest amount could affect the mixed flocks negatively, thus the hypothesis of the study is that in landscapes with higher forest amount the flocks would be more frequent, larger and with higher species diversity. We selected seven landscapes in order to form a gradient of forest amount. In addition to this variable we also tested the effects of the size of the focal patch, the distance (isolation) of forest fragments and landscape diversity (heterogeneity) on the mixed flocks. To analyze our results we used the method of Generalized Linear Models (GLM) and subsequent selection of the most parsimonious models through the Akaike Information Criterion corrected for small samples. This study showed that forest amount is the landscape characteristic that exerts the greatest effect on the frequency, size and species richness of mixed flocks, being positive the relationship between these variables. Beyond the forest proportion, the distance of the forest patches also positively influenced the frequency of flocks. Regarding the flocks size and richness, multiple models have been selected, and the forest proportion was present in all of them. The other variables had a weak influence on these parameters. In combination with the forest proportion in multiple models, fragment size and landscape diversity influenced the flocks negatively and the distance, positively. These results are consistent with the habitat amount hypothesis and reinforce the importance of employing landscape metrics in ecological studies. The importance of forest amount for mixed flocks reflects how this variable is essential for the conservation of several bird species, for many of them depend on this system and its disappearance may lead to local extinction of these species.