Comparative Assessment of Mangrove Biomass and Fish Assemblages in an Urban and Rural Mangrove Wetlands in Ghana

Abstract

Mangrove wetlands are one of the most important ecosystems on earth, providing habitats for both marine and terrestrial organisms as well as supporting essential human services. However, high dependence of humans on these systems is leading to significant transformation of mangrove wetlands and reduction in their ecosystem services including fisheries. The objectives of this study were to estimate the biomass of two mangrove wetlands in Ghana within urban and rural contexts and determine the fish fauna assemblages as part of baseline setting. The study used the structural parameters of mangrove species and allometry to estimate the biomass of both forest systems. Fish community structure were determined based on ecological surveys. The findings show that the standing biomass of the mangrove forests were significantly higher (p < 0.01) in the rural wetland (394.49 t/ha) compared to the urban wetland (126.29 t/ ha). Fish fauna assemblages, referring to species richness and diversity were higher in the urban wetland at 4.21 and 2.64 respectively compared to the rural wetland at 3.46 and 2.09 respectively. This paper concludes that a well-developed mangrove system with high mangrove biomass may not necessarily imply high fish species richness and diversity.

Quantifying the influence of urban land use on mangrove biology and ecology: A meta‐analysis

“…Furthermore, a subset of fish richness, that of the subsistence fisheries species, was strongly and positively related to the extent of mangrove coverage within 20 km. This contrasts with the findings of Nortey et al (), but further highlights the importance of conserving and expanding urban mangroves, which may be supporting an important subsidy to the food supply of urban and surrounding populations. Highly valuable commercial species, however, were not found to be lacking in urban sites as was reported in Tampa Bay, USA (Krebs, McIvor et al, ).…”

“…Yet one study in Australia noted an overall lack of mangrove bird species in Darwin (Noske, 1996), and another study in Brazil noted differences in the abundances of certain specialists species (Mestre, Krul, & Moraes, 2007). Similar differences in urban mangrove fish communities have also been noted, suggesting that abundance, species richness and morphology are all influenced by surrounding urban land use (Clynick & Chapman, 2002;Nortey et al, 2016;Peters, Yeager, & Layman, 2015;Viana, Lucena Fr edou, Fr edou, Torres, & Bordalo, 2010). These findings point to potential synanthropic and misanthropic tendencies of certain taxa, which may be driven by trophic level and feeding behaviour.…”

“…Mangrove loss around cities has primarily been reported for Africa, Latin America and India (Benfield, Guzman, & Mair, ; Mohamed, Neukermans, Kairo, Dahdouh‐Guebas, & Koedam, ; Nagendra, Sudhira, Katti, & Schewenius, ; Nfotabong‐Atheull, Din, & Dahdouh‐Guebas, ; Nortey, Aheto, Blay, Jonah, & Asare, ; Obiefuna, Nwilo, Atagbaza, & Okolie, ; Olagoke, Mwihaki, Bosire, & Berger, ; Vaz, ; Zamprogno et al, ). This agrees with predictions of ecological vulnerability in low‐ and lower‐middle‐income regions owing to rapid urbanization and management lags (Baird, ; McGranahan, Balk, & Anderson, ; Seto et al, ; United Nations Environment Program, ).…”

Mangrove forest structure and composition along urban gradients in Puerto Rico

“…Globally, mangrove coverage in the largest cities is decreasing faster than overall rates from corresponding countries (B. L. Branoff, 2017). In some cases, this loss results in fragmented forests consisting of novel species assemblages and size classes (Benfield, Guzman, & Mair, 2005;Mohamed, Neukermans, Kairo, Dahdouh-Guebas, & Koedam, 2009;Nortey, Aheto, Blay, Jonah, & Asare, 2016;Zamprogno et al, 2016). There are cases of expanding urban mangrove coverage (DasGupta & Shaw, 2013;Pham & Yoshino, 2016), although the young forests may contain less biomass (Friess, Richards, & Phang, 2015).…”

Monitoring of Eco-Restoration of Mangrove Wetlands through Time Series Satellite Images: A Study on Krishna-Godavari Delta Region, East Coast of India

“…Mangroves are important coastal habitats for several ecological, economical, and protective functions (Biswas et al 2009;Cavanaugh et al 2014;Nortey et al 2016) and act as barriers against storm surges, floods and tsunamis (Alongi 2008;Kulkarni 2009;Teh et al 2009;Yanagisawa et al 2009;McFadden et al 2016). They have a highly efficient nutrient retention mechanism (Alongi 2002) and serve as breeding and nursery grounds for a wide range of aquatic and terrestrial species (Kumara et al 2010).…”