Evaluation of Mangrove Connectivity Using Biological Models With Different Larval Dispersal

• Autor(a) principal: Sanches, Paola Franzan
• Data de Publicação: 2019
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: http://www.teses.usp.br/teses/disponiveis/21/21134/tde-06032020-144944/
• topic: Clibanarius vittatus; Clibanarius vittatus; Monokalliapseudes schubarti; Monokalliapseudes schubarti; Aichi Targets; AMP; Conectividade; Connectivity; Conservação; Conservation; Desenvolvimento Larval; Fluxo Gênico; Gene Flow; Larval Development; Mangroves; Manguezais; Metas de Aichi; MPA; SNP; SNP

Networks of Marine Protected Areas are a key strategy to conserve marine biodiversity against anthropogenic pressures, due to the maintenance of connectivity among areas. Connectivity guarantees gene flow and resilience. It is affected by oceanographic processes, especially in mangroves, where spatial discontinuity configures an island aspect and tide variation influences the persistence and recruitment of juveniles. Considering mangrove vulnerability due to its suppression that can affect gene flow, the understanding of mangrove connectivity is essential to its conservation and management. Thus, the main goals of this thesis were: 1) to investigate the current state of knowledge about connectivity along the Brazilian coast as well as evidences of the use of connectivity in the design and management of MPAs; 2) to assess gene flow and networks of connectivity in the Brazilian EEZ, in order to verify extremes of distance in which connectivity still occurs for the Brazilian coast; and 3) to investigate connectivity among Brazilian mangroves based on a comparative analysis of SNP marker of two species with different life histories: the indirect larval development of Clibanarius vittatus contrasted with the direct development of Monokalliapseudes schubarti, with the hypothesis that there are differences in the genetic populational structure of both, with higher structured populations for M. schubarti due to its direct development. We intend to assess the extent of mangroves acting as stepping-stones, discussing its protection under Brazilian laws. Among results, we found that: 1) fish (52.2%) and genetic tools (69.3%) were, respectively, the most common taxa and method used in the studies, which were carried mostly at regional-scale (55.8%), but in combination covered all Brazilian coastline. From all references, 31% mentioned species or taxonomic groups and, although almost 20% considered \"area conservation\", only four studies (4.5%) explicitly mentioned MPA, as it major focus. From the 67 Brazilian MPA, only 7 mention marine connectivity in documentation. We identified two key aspects that are important steps towards operationalizing connectivity in marine conservation: the need for collaborative and integrative research at different spatio-temporal scales; 2) the highest distance with significant connectivity is 3,800 km. Higher distances have only 1% of chance to have connectivity strength 3, and are predominantly strength 1. There was a low-level of connectivity among areas in SE and S Brazil and high levels of connectivity among areas in the NE and N Brazil. Islands had mostly low and intermediate levels of connectivity with coastal areas, but knowledge on the connectivity of oceanic islands is nearly nonexistent.3) C. vittatus presented higher connectivity than M. schubarti and consequently population structure is higher for M. schubarti, elevating the vulnerability of M. schubarti in scenarios of mangrove suppression. There is no significant correlation between gene flow and population distance for both species. All mangroves have proved to be important to other mangroves, but no steping-stones have been identified among mangrove sites. Our results show that connectivity exist among preserved and non-preserved mangroves. However, mangrove suppression can, compromise gene flow and a study focusing on mangroves as stepping-stones has to be undertaken. There is still time to recover impacted mangroves, as long as policies change their focus to mangroves\' importance concerning also gene flow. We conclude there is a need of establishing new MPAs to act as stepping-stones in a network, as well as the necessary increase in marine connectivity studies, including connectivity assessments among MPAs and mangroves.