Padrões espaciais e diversidade de abelhas em paisagens antropizadas na Mata Atlântica

Abstract

The decline in pollinators, particularly bees, is not just a concern, but a pressing global issue. These insects play a pivotal role in pollination, and their dwindling numbers over the past three decades have sparked numerous studies. These studies, while informative, have been scattered and employed diverse metrics and approaches, making it challenging to arrive at consistent conclusions. This thesis, therefore, is a timely and unique effort to synthesize and chronologically organize this wealth of knowledge, pinpointing gaps through a systematic review in Chapter 1. By doing so, it provides a comprehensive overview of the current state of research on bee diversity and its impact on pollination services, and identifies areas where further research is needed, contributing to the conservation of bee communities. The journey of research on bee diversity within landscape ecology, initially rooted in the Island Biogeography Theory, has been a testament to adaptability and progress. The Island Biogeography Theory, proposed by MacArthur and Wilson in 1967, initially suggested that the size and isolation of habitat patches are the key factors influencing pollinator diversity. However, as time progressed, it became clear that the landscape matrix is not necessarily hostile, allowing species to move between habitat patches. This realization led to a shift in research focus towards the landscape context and multiscale assessments, determining effect scales for populations and species groups, which are crucial for the conservation of bee communities. Recent studies in agricultural and urban landscapes have evaluated the functional responses of bee communities at different scales, considering landscape heterogeneity. Floral and nesting resources in adjacent habitats can promote species coexistence. In agricultural areas, the impact of bee diversity on seed and fruit production has also been assessed, underscoring the importance of conserving these pollinators in natural and semi-natural areas. However, studies on the effects of human-induced changes on bees' dietary specialization, particularly in tropical regions, need more records and specialists. The empirical study in Chapter 2 assessed the functional diversity responses of neotropical bees, including dietary specialization, sociality levels, flight distances, and nesting patterns, across 12 heterogeneous agricultural landscapes in the Atlantic Forest in Sergipe. A total of 498 specimens, representing 61 species from 16 tribes and four families, were captured. Of these, 421 individuals were collected by net during 192 hours of active searching (16 hours per sampling point), while 77 bees were collected using pan traps over 864 hours (3 days per sampling point). The pan trap method complemented the research data by capturing bee species not collected by a net. The analyzed models reveal a significant correlation between the proportion of forest and the diversity of habitats, and the taxonomic and functional richness of bee species. This pattern is particularly pronounced in landscapes with intermediate levels of forest habitat and greater diversity of land use and cover classes. These findings underscore the importance of habitat heterogeneity and equitable distribution for conserving bee species and maintaining pollination services, emphasizing the relevance of your work in this field. Additionally, to enhance the results of Chapter 2, we included the Chapter 3 as a short communication estimating the maximum flight distance for Neotropical bees based on the centroid measurement of bee wings used in our methodology. This estimation is crucial for understanding the potential for bee movement and dispersal, which in turn can inform landscape planning and conservation strategies.