A functional analysis reveals extremely low redundancy in global mangrove invertebrate fauna

Cannicci, Stefano; Lee, Shing Yip; Bravo, Henrique; Cantera-Kintz, Jaime Ricardo; Dahdouh-Guebas, Farid; Fratini, Sara; Fusi, Marco; Jimenez, Pedro J.; Nordhaus, Inga; Porri, Francesca; Diele, Karen

Abstract

Deforestation results in habitat fragmentation, decreasing diversity, and functional degradation. For mangroves, no data are available on the impact of deforestation on the diversity and functionality of the specialized invertebrate fauna, critical for their functioning. We compiled a global dataset of mangrove invertebrate fauna comprising 364 species from 16 locations, classified into 64 functional entities (FEs). For each location, we calculated taxonomic distinctness (Δ+), functional richness (FRi), functional redundancy (FRe), and functional vulnerability (FVu) to assess functional integrity. Δ+ and FRi were significantly related to air temperature but not to geomorphic characteristics, mirroring the global biodiversity anomaly of mangrove trees. Neither of those two indices was linked to forest area, but both sharply decreased in human-impacted mangroves. About 60% of the locations showed an average FRe < 2, indicating that most of the FEs comprised one species only. Notable exceptions were the Eastern Indian Ocean and west Pacific Ocean locations, but also in this region, 57% of the FEs had no redundancy, placing mangroves among the most vulnerable ecosystems on the planet. Our study shows that despite low redundancy, even small mangrove patches host truly multifunctional faunal assemblages, ultimately underpinning their services. However, our analyses also suggest that even a modest local loss of invertebrate diversity could have significant negative consequences for many mangroves and cascading effects for adjacent ecosystems. This pattern of faunal-mediated ecosystem functionality is crucial for assessing the vulnerability of mangrove forests to anthropogenic impact and provides an approach to planning their effective conservation and restoration.

Citation

Cannicci, S., Lee, S. Y., Bravo, H., Cantera-Kintz, J. R., Dahdouh-Guebas, F., Fratini, S., Fusi, M., Jimenez, P. J., Nordhaus, I., Porri, F., & Diele, K. (2021). A functional analysis reveals extremely low redundancy in global mangrove invertebrate fauna. Proceedings of the National Academy of Sciences, 118(32), Article e2016913118. https://doi.org/10.1073/pnas.2016913118

• Journal Article Type: Article
• Online Publication Date: Jul 26, 2021
• Publication Date: Aug 10, 2021
• Deposit Date: Aug 9, 2021
• Publicly Available Date: Aug 9, 2021
• Journal: Proceedings of the National Academy of Sciences
• Electronic ISSN: 1091-6490
• Publisher: National Academy of Sciences
• Peer Reviewed: Peer Reviewed
• Volume: 118
• Issue: 32
• Article Number: e2016913118
• DOI: https://doi.org/10.1073/pnas.2016913118
• Keywords: community ecology, functional redundancy, functional traits, biodiversity, mangrove conservation
• Public URL: http://researchrepository.napier.ac.uk/Output/2791914