Abstract
In West African tropical estuaries, such as the Saloum Delta (Senegal), mangroves provide specific socio-economic functions including various natural food resources for local human populations. Mangrove-habitat loss is therefore of great concern, in terms of conservation and management, and highlights the need to study West African mangrove under human-induced pressures. Based on data from 2007 to 2008, this study aimed to establish a conditions report for two of the main Southern West Senegal mangroves areas: the Sine Saloum and the Petite Côte. We assessed the influence of environmental variables and human-induced pressures (i.e. shellfish harvesting and heavy metals (potentially toxic elements, PTEs)) on infaunal community structure and functions through trait-based approaches. Reflecting for example changing seasons and hypersaline events, the Saloum environmental variables and their temporal dynamics greatly impacted infaunal communities in the subtidal zone. In the intertidal area, closer to anthropogenic disturbances, pressures related to human activities took precedence over environmental variables in explaining infaunal community structure. Shellfish harvesting resulted in a significant decrease (p < 0.05) in total macrofaunal abundance (933.79 ± 626.34 ind m −2 in unexploited stations compared to 140.92 ± 71.99 ind m −2 in exploited stations; mean ± SE) in addition to a decline in biomass and taxonomic richness. Intertidal species composition was affected by both shellfish harvesting and PTEs. PTEs were also associated with a significant decrease in functional diversity and particularly with a change in macrofaunal living habits. The combination of an RLQ and fourth-corner analysis highlighted a significant association between feeding modes and sediment grain size in both tidal areas. This study provides a needed deeper understanding of the unintended effects of human activities on infaunal communities and their functioning, in a highly valuable system for humans. Pinpointed factors driving infaunal community structure and functions provide important insights for future research, as well as reference points for the implementation of management measures.
| Original language | English |
|---|---|
| Article number | 108481 |
| Journal | Estuarine, Coastal and Shelf Science |
| Volume | 293 |
| DOIs | |
| Publication status | Published - 31 Oct 2023 |
| MoE publication type | A1 Journal article-refereed |
Funding
This study was part of the project « Femmes et Coquillages » implemented by the Fondation Internationale du Banc d'Arguin (FIBA) and the ENDA-GRAF NGO. Thanks to this project, research was conducted on traditional knowledge and practices in order to contribute to the sustainability harvest of shellfish resources from Sine Saloum and the Petite Côte, while improving management capacities, women's working conditions and living environment, as well as mangrove pollution sources. The authors would like to thank the Senegalese women from Falia and Fadiouth for their valuable help in sampling. We are also grateful to Michel Le Duff (IUEM) for his help with mollusc identification and to Sébastien Hervé (LEMAR/IUEM) for drawing the map and to Simon P. Gaultier for his inputs. MPJ was further supported by the Åbo Akademi University doctoral network FunMarBio, and MCN by the Åbo Akademi University Foundation. This study was part of the project « Femmes et Coquillages » implemented by the Fondation Internationale du Banc d’Arguin (FIBA) and the ENDA-GRAF NGO. Thanks to this project, research was conducted on traditional knowledge and practices in order to contribute to the sustainability harvest of shellfish resources from Sine Saloum and the Petite Côte, while improving management capacities, women's working conditions and living environment, as well as mangrove pollution sources. The authors would like to thank the Senegalese women from Falia and Fadiouth for their valuable help in sampling. We are also grateful to Michel Le Duff (IUEM) for his help with mollusc identification and to Sébastien Hervé (LEMAR/IUEM) for drawing the map and to Simon P. Gaultier for his inputs. MPJ was further supported by the Åbo Akademi University doctoral network FunMarBio, and MCN by the Åbo Akademi University Foundation .
