Land use effects in trace element concentrations and bird biodiversity in mangrove environments within a Natural Protected Area

Abstract

Land use change is widely recognized worldwide as the main cause of mangrove forest loss. These artificial changes can modify mangrove cover, species diversity and pollutant levels, thus leading to habitat destruction. The Natural Protected Area known as The Wildlife Protection Area Laguna de Terminos, Campeche, Mexico is an area where mangrove ecosystems have faced land use changes for urban development, oil industry and agriculture. To observe the negative effects caused by these changes a study was carried out between October 2021 and January 2022. In this study we combined geochemical tools (e.g. enrichment factor (EF), adverse effect index (AEI), pollution load index), proxies such as the Integral Connectivity Index (ICI) and the relative integrated anthropization Index (RIAI) with biological data and multivariate statistical analysis to provide novel integrative knowledge to quantify environmental quality in mangrove ecosystems which can be extrapolated to other coastal ecosystems. We evaluate the potential impacts caused in mangroves by urban development, oil and agricultural activities. The geochemical data showed the highest concentrations of Zn (820 mg kg^-1), Cu (324 mg kg^-1), Ni (431 mg kg^-1), Pb (98 mg kg^-1) and Cd (0.80 mg kg^-1) in mangroves located in urban areas. The biological data highlighted that 44.5 % of bird species observed in this study could be indirectly exposed to trace elements due to their feeding habits. Mangroves influenced by oil industry activities exhibited the highest biodiversity with 24 species. Finally, the results revealed that urban development causes greater changes in mangrove cover, biodiversity, and trace element pollution in mangrove ecosystems than oil and agricultural activities, which is important information for land managers when thinking about zonation within protected urban mangrove ecosystems.

Keywords: Bioindicators; Birds; Gulf of Mexico; Laguna de Terminos; Land use; Trace elements; Wetlands.