95
3.3.2 Fauna
Mangrove forests play a crucial role in providing suitable habitats for fauna, safe
breeding and chick rearing grounds, nurseries for a diversity of fishes and shellfishes, as well as ideal foraging grounds for animals such as fishes, birds and aquatic
invertebrates and refuge from predators (Macintosh et al. 2002). Faunal assemblages of mangroves are significantly less studied and documented than the forests
they inhabit (Lee 2008). Animals found within mangrove environments include a
variety of taxa, many of which are vulnerable or threatened as a result of human
activities in the coastal zone (Nagelkerken et al. 2008). Some of the animals depend
on mangrove areas their whole lives while others utilize them only during specific
periods such foraging, shelter and breeding (Nyanti et al. 2012).
3.3.2.1 Invertebrates
Invertebrates break down leaf litter that act as fertilizer (Smith 1987), increase surface area of mud through burrowing (Kristensen 2008; Penha-Lopes et al. 2009) and
increasing the diffusion rate of gases (Lee 1998) that ultimately affect the growth
and productivity of the mangrove vegetation (Nielsen et al. 2003; Kristensen and
Alongi 2006). In the Wouri river estuary mangroves as worldwide, the well-known
invertebrates are crabs and molluscs. They are the predominant taxa in mangrove
forests and are thought to play a significant ecological role in the structure and function of this ecosystem (Cannicci et al. 2008; Ngo-Massou et al. 2012). They form an
important link between the primary detritus at the base of the food web and consumers of higher trophic levels (Sousa and Dagremond 2011).
Crabs
Many researchers were interested by mangrove crabs in Cameroon (Boyé et al.
1975; Guiral et al. 1999; Longonje 2008; Longonje and Raffaelli 2013; Ngo-Massou
et al. 2012, 2014, 2016). Din et al. (2014) have presented a review of mangrove
crabs evolution in Cameroon. The data have shown 33 species recorded grouped
into 19 genera and 10 families (Table 3.1). Ongoing surveys (unpublished data)
have improved these results with more species and new families of crabs in the
coastal Atlantic mangroves of the country (Fig. 3.6).
Molluscs
Abundance and biomass of molluscs in mangrove habitats can be equally impressive than brachyuran crabs (Nagelkerken et al. 2008), although the number of comparative studies on mollusc diversity and structure in Cameroon mangroves is
limited (Plaziat 1974; Boyé et al. 1975; Bandel and Kowalke 1999; Guiral et al.
3 Impact of Urbanization on the Evolution of Mangrove Ecosystems…
3.3.2 Fauna
Mangrove forests play a crucial role in providing suitable habitats for fauna, safe
breeding and chick rearing grounds, nurseries for a diversity of fishes and shellfishes, as well as ideal foraging grounds for animals such as fishes, birds and aquatic
invertebrates and refuge from predators (Macintosh et al. 2002). Faunal assemblages of mangroves are significantly less studied and documented than the forests
they inhabit (Lee 2008). Animals found within mangrove environments include a
variety of taxa, many of which are vulnerable or threatened as a result of human
activities in the coastal zone (Nagelkerken et al. 2008). Some of the animals depend
on mangrove areas their whole lives while others utilize them only during specific
periods such foraging, shelter and breeding (Nyanti et al. 2012).
3.3.2.1 Invertebrates
Invertebrates break down leaf litter that act as fertilizer (Smith 1987), increase surface area of mud through burrowing (Kristensen 2008; Penha-Lopes et al. 2009) and
increasing the diffusion rate of gases (Lee 1998) that ultimately affect the growth
and productivity of the mangrove vegetation (Nielsen et al. 2003; Kristensen and
Alongi 2006). In the Wouri river estuary mangroves as worldwide, the well-known
invertebrates are crabs and molluscs. They are the predominant taxa in mangrove
forests and are thought to play a significant ecological role in the structure and function of this ecosystem (Cannicci et al. 2008; Ngo-Massou et al. 2012). They form an
important link between the primary detritus at the base of the food web and consumers of higher trophic levels (Sousa and Dagremond 2011).
Crabs
Many researchers were interested by mangrove crabs in Cameroon (Boyé et al.
1975; Guiral et al. 1999; Longonje 2008; Longonje and Raffaelli 2013; Ngo-Massou
et al. 2012, 2014, 2016). Din et al. (2014) have presented a review of mangrove
crabs evolution in Cameroon. The data have shown 33 species recorded grouped
into 19 genera and 10 families (Table 3.1). Ongoing surveys (unpublished data)
have improved these results with more species and new families of crabs in the
coastal Atlantic mangroves of the country (Fig. 3.6).
Molluscs
Abundance and biomass of molluscs in mangrove habitats can be equally impressive than brachyuran crabs (Nagelkerken et al. 2008), although the number of comparative studies on mollusc diversity and structure in Cameroon mangroves is
limited (Plaziat 1974; Boyé et al. 1975; Bandel and Kowalke 1999; Guiral et al.
3 Impact of Urbanization on the Evolution of Mangrove Ecosystems…