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Chiloango Mangroves

Chiloango Mangroves is a small proposed EBSA spanning the Chiloango Estuary in Cabinda and 4.5 km of coast around its mouth. It contains important coastal habitats, including sandy beaches, rocky shores, mangroves, riverine forests, and wetlands, some of which are threatened habitats. This site serves as an important area for many migratory, threatened and sensitive or slow-growing species, such as marine mammals, sea turtles and mangroves. It also supports a rich diversity of dragonflies, shellfish, fish and birds, and many endemic species. Currently, high levels of anthropogenic pressure are driving declines in ecological condition.

EBSA Description: Chiloango Mangroves

General Information

Summary

The Chiloango Estuary is in the Angolan province of Cabinda. The proposed EBSA is strongly coastal and includes the Chiloango Estuary and 6 km of coastline surrounding the estuary mouth. The mangroves and riverine forest are key features at this site; they are less noteworthy in a global context but are very significant in a local context. In fact, three of the four habitats represented in the area are threatened. Most importantly, this area supports many species whose growth and reproduction rates are slow, particularly globally threatened species such as olive ridley and leatherback turtles (that nest in the area) and manatees (that are resident in the area). The latter have been hunted throughout their range and, despite limited quantitative data, are showing extirpations in many places. Current anthropogenic pressure in the mangroves is also visible and worrying, with signs of advanced habitat degradation and destruction. The area is highly relevant in terms of the EBSA criteria: "Importance for threatened, endangered or declining species and/or habitats" and "Vulnerability, fragility, sensibility or slow recovery".

 

MARISMA updates

This is a new, proposed EBSA. 

Introduction of the area

There are two estuaries in Cabinda: the Cabinda and Chiloango Estuaries in the north and south of the provice, respectively. At the boundary with the Republic of the Congo in the north, the Cabinda River reaches the sea through the Massabi Lagoon. The proposed EBSA, however, lies at the mouth of the Chiloango River in the south, which flows into the sea through the estuary (Giresse and Kouyoumontzakis, 1985). The river is approximately 168 km long, originating from springs in the Democratic Republic of Congo (DRC), and in some places forms the boundary that separates DRC from the province of Cabinda in Angola (Sonangol, 2012). It is a coastal EBSA that is a discrete site centred around the mangroves and its associated threatened species, and is thus a Type 1 EBSA (sensu Johnson et al. 2018).

 

The Chiloango Estuary EBSA comprises four biotypes: marine, estuarine, riverine forest, and wetland areas. There are approximately 130 hectares of wetland areas encompassing small lagoons, surrounded by Endangered mangroves. The mangroves and riverine forest associated with the river were fundamental in choosing this site as a proposed EBSA; although not globally significant, these mangroves are of key local significance. Consequently, the reason this EBSA was not included in the original set of EBSAs at the South Eastern Atlantic Workshop in 2013 (UNEP/CBD/RW/EBSA/SEA/1/4) is because this local knowledge was not available at that meeting and is better than the information included in international datasets (e.g., WCMC and the World Mangrove Atlas).

 

In the EBSA, the mangroves and riverine forest are bounded by a sandy beach, surrounded by the estuary, and extend to the river and margins of the lagoon. The mangroves cover the alluvial areasof the Chiloango River mouth, corresponding to sites subjected to temporary flooding resulting from changing tides, and are populated by Rhizophora mangle (Diniz, 2006). Mangrove forest is scatteredalong the Angolan coastline and forms a transition ecosystem between land and sea of enormous biological and ecological importance, providing shelter and nurseries for crustaceans and fish that are of economic and tourism importance to the country (EPANB, 2006). The EBSA supports a rich diversity of avifauna, herpetofauna and ichthyofauna (MINAMB et al., 2015). Most importantly, it provides critical habitat for threatened species, such as African manatees that are threatened throughout their range and showing signs of local extirpations (Keith Diagne, 2015), and olive ridley and leatherback turtles that nest on the adjacent beaches.

 

Habitat loss in the proposed EBSA is largely due to infrastructure development that has fragmented forests through the construction of roads and buildings, such as the construction of a motorway linking the Town of Cabinda with Belize. It is believed that mangrove degradation in the Chiloango Estuary is also caused by fragmentation due to road construction, among other factors (Kuedikuenda & Xavier, 2009). Nevertheless, this site is still sufficiently intact to warrant conservation attention.

 

Description of location

The EBSA is in the northern half of the Cabinda province of Angola, including the Chiloango Estuary and 6 km of rocky, sandy and mixed shores adjacent to the mouth. The area includes around 130 ha of wetland areas encompassing small lagoons surrounded by Endangered mangroves. The furthest extent inland is approximately 1.2 km from the coastline. The whole of the proposed area lies entirely within Angola’s national jurisdiction.

 

 

Area details

Feature description of the area

 

The Chiloango River mouth is dominated by muds from the river. Fresh-water flow out of the Chiloango River also forms a plume of low-salinity water in the adjacent coastal area that, in turn, affects the nearshore coastal processes. These features, as well as the local extent of the turtle nesting beaches, contributed to defining the alongshore extent of the EBSA. Because this is a coastal EBSA, it is described primarily for its benthic features, although the overlying water column in the estuary, surf and inner shelf is very tightly coupled to the key features and species of this site.

 

The mangrove forests of the region include species such as Rhizophora (R. mangle, R. racemosa and R. harrisonii), which tolerate high levels of salinity. The mangroves cover the whole Chiloango riverbed up to the high tide mark and extend up to the wetland area associated with the river. The Chiloango River is the southern hydrographic basin included in the Lower Guinea ichthyofaunal province, which is one of the 10 ichthyofaunal provinces as defined by Roberts (cited in Darwall et al., 2011). The Lower Guinea ichthyofaunal province extends from the Chiloango River to the Cross River in the north, and shares a boundary with the Congo River basin to the east. This region contains a rich diversity of species, and more than half of the freshwater or marine fish species seen here are endemic to the region. This region also has relatively high numbers of freshwater fish species that are threatened and have limited geographic ranges (Darwall et al., 2011). Further, a species of fresh water crab belonging to the tropical African endemic family, Potamonautidae, is found in the rivers of Cabinda (Darwall et al., 2011). Although biodiversity data are largely limited for Angola, this region is known to have the highest diversity of dragonflies and damselflies (Odonata) within the whole of Africa.

 

In terms of birds, it is important to mention the rich diversity that includes resident, visiting and seasonal migratory birds that feed and rest here. Among these, it is worth mentioning the presence of cattle egrets, white chest crows, spotted kingfishers, white chested mouse birds andblack bishops, among others. In terms of the most relevant reptiles, olive ridley and leatherback turtles can be observed nesting in the region. The beaches here thus provide critical habitat to support important life-history stages of these two threatened species. Marine mammals are also found along the coastline, such as the common whale, humpback whale, common dolphin and spotted dolphin (ACEPA, 2012). The West African Manatee (Trichechus senegalensis) is another threatened marine mammal that is important in the areas, and is classified by the IUCN as Vulnerable largely due to species declines due to hunting and habitat loss (Powell & Kouadio, 2008; Keith Diagne, 2015). Historically, its presence has been recorded in the Chiloango River, but the current distribution is unknown (MINUA, 2006; Morais, 2006), and local extirpations of this species are known across its distribution (Keith Diagne, 2015).

 

 

Feature conditions and future outlook of the proposed area

Across the system, the ecological condition of the mangrove varies a lot, i.e., from pristine areas to fully deforested areas. Current anthropogenic pressure is visible and worrying, with signs of advanced habitat degradation and destruction in some places (MINAMB et al, 2015). Further, Tati Luemba regrets the level of destruction of the mangrove as a result of stagnant water caused by the limited water mixing between river and sea (Tati Luemba press comm., 2015). It is thus important that the Chiloango Mangroves are protected to prevent the extinction or extirpation of fauna and flora that contribute to the region’s ecological integrity (press comm. Tati Luemba, 2015), especially the iconic and threatened manatee and turtle species. An assessment of ecological condition based on cumulative pressures indicates that 83 % of the area is in Fair condition and the remainder in Good condition, suggesting some degradation, but that the bulk of biodiversity and ecological processes are still intact. This means that establishing the proposed EBSA and implementing appropriate conservation and management measures in this area will contribute to protecting the existing biodiversity.

 

 

Assessment of the area against CBD EBSA criteria

 Uniqueness or rarity

 

Rank: Medium

Systems comprising the complex of river, estuary, shore, mangrove and forest are relatively rare in the area, and this particular site comprises the second largest mangrove forest in the country. Further, more than half of the freshwater or marine fish species seen here are endemic to the region. It is also a biodiversity hotspot for dragonflies and damselflies: it has the highest diversity of these insects in all of Africa.

This system has unique ecological characteristics as it associates different aquatic ecosystems. The estuary has riverine (Chiloango River), brackish (estuary), marine (Atlantic Ocean) and wetland areas (the Usanka Lagoon, as the largest wetland area). The interaction of different areas/ components of this system and its abiotic conditions allowed for the establishment of different fauna and flora species. This location has already been described as a coast sensitive location (MINAMB, 2015).

 Special importance for life-history stages of species

 

Rank: High

The proposed EBSA is important for as a foraging and resting site for multiple bird species, and as nesting grounds for olive ridley and leatherback turtles. The mangroves also provide key habitat as nursery areas for fish and crustaceans in the estuary.

The migratory birds use the area for resting. Furthermore, the olive ridley and leatherback turtles that are threatened species are also found here. The African Manatee (Trichechus senegalensis) is also found within this area. The Manatee features in the IUCN Red List (in Category V) and is defined as a species that is vulnerable to extinction (Annex I) by the Convention for Threatened Species International Commerce (CITES) and at the same time features in the Annex I of Hunting Law currently in force in Angola providing total protection (MINUA, 2005b).

 Importance for threatened, endangered or declining species and/or habitats

 

Rank: High

Olive ridley and leatherback turtles are both Vulnerable species that nest on the beaches in this EBSA. Given that these and green turtles nest a little further south at Malongo (monitored as part of the Cabinda Gulf Oil Company—Chevron (CABGOC) environment programme: Malongo Sea Turtle Protection Program; Fancony & Abel, 2012), it is likely that the latter species nests in Chiloango Mangroves as well. The African Manatee (Trichechus senegalensis) is also a Vulnerable species found within this area. Sites that support manatees are particularly important because this mammal has been extirpated from many sites in its distribution due to hunting and habitat fragmentation (Keith Diagne, 2015). For example, one hunter in Angola was identified in a 40-km area around the Congo River mouth, and said in an interview that he had hunted three manatees a week for the last 30 years, another fisherman from around the Bengo River noted that 77 manatees had been killed in the area in one year, and manatee meat has been seen for sale in Luanda (Keith Diagne, 2015). That this site supports both manatees and nesting turtles thus makes this EBSA particularly important for threatened species. In terms of ecosystems, the more than half the EBSA area comprises threatened ecosystem types, including Endangered rocky and sandy shores, and Vulnerable mixed shores.

 Vulnerability, fragility, sensitivity, or slow recovery

 

Rank:  High

The EBSA comprises several features that are fragile, sensitive to disturbance and that will take a long time to recover. Sensitive species with slow recovery include the turtles, manatee, and some of the birds; the mangroves are also sensitive, slow growing and take long to recover from disturbance.

 Biological productivity

 

Rank: Medium

Mangroves are among the most productive ecosystems (FAO 1994) and provide highly productive coastal lagoons and estuaries and contains essential organic nutrients. Mangroves are also an important site for reproduction and growth (nursery) of larvae and juvenile stages of important species (Shumway, 1999). This is considered the second biggest mangrove section of the country (MINAMB, 2015).

 

 Biological diversity

 

Rank: High

All habitats in this site present a set of favorable conditions for the existence of different species of plants and animals. The mangroves offer areas for feeding, reproduction, development and resting for an important component of the biodiversity. This biodiversity is noticeable through the presence of a high number of shellfish and a vast diversity of species of marine and fresh water fish. The visiting and seasonal migrating birds can also be seen. The reptiles are diverse and found along all zones, including marine reptiles (olive ridley and leatherback turtle), terrestrial reptiles (pythons) and fresh water reptiles (crocodiles). In relation to mammals, cetaceans and manatees are most relevant, but the small primates, rodents and other small herbivores in the surrounding forests are worth mentioning. This site also has the highest diversity of dragonflies and damselflies (Odonata) within the whole of Africa.

 

 Naturalness

 

Rank: Medium

Part of the area remains natural, however, a fairly large area has been negativey impacted subsistence agriculture, opening of waterways by local people, wood cutting and coal making (wood from the mangroves), and pollution from discarded waste. A systematic assessment of ecological condition based on cumulative pressures indicates that 83 % of the area is in Fair condition and the remainder in Good condition, suggesting some degradation, but that the bulk of biodiversity and ecological processes are still intact.

 

References

Angolan Association of the Oil Exploration and Production Companies (Associação das Companhias de Exploração e Produção de Angola - ACEPA) (2014) Environmental and Social Baseline to Determine the Coastal Sensitivity of the Areas Between Luanda and Namibe.

Bianchi, G., 1992. Demersal assemblages of the continental shelf and upper slope of Angola. Mar. Ecol. Prog. Ser., 81: 101-120.

Darwall, W.R.T., Smith, K.G., Allen, D.J., Holland, R.A, Harrison, I.J., and Brooks, E.G.E. (eds.). (2011) The Diversity of Life in African Freshwaters: Under Water, Under Threat. An analysis of the status and distribution of freshwater species throughout mainland Africa. Cambridge, United Kingdom and Gland, Switzerland: IUCN. xiii+347pp+4pp cover.

Diniz, A. C. 2006. Características Mesológicas de Angola. Instituto Português de Apoio ao Desenvolvimento. Lisboa, 2006.

Fancony, P., Abel, A. 2012. Effective Management Of Endangered Species In Oil and Gas Operations. International Conference on Health, Safety and Environment in Oil and Gas Exploration and Production, 11-13 September, Perth, Australia, https://doi.org/10.2118/156766-MS.

FAO (1994) Mangrove forest management guidelines (English) In: Food and Agricultural Organisation (FAO) Forestry Paper, no. 117 / FAO, Rome (Italy). Forest Resources Division, 339 p.http://archive.org/stream/mangroveforestma034845mbp/mangroveforestma034845mbp_djvu.txt (accessed 17 April 2013).

Giresse, P. and Kouyoumontzakis, G., 1985. Gabon, Congo, Cabinda and Zaire, pp 625-638. In: Bird, EC and Schwartz, ML (Eds.). The World's Coastline. New York, Van Nostrand Reinhold Co. 1071 pp.

Johnson, D.E., Barrio Froján, C., Turner, P.J., Weaver, P., Gunn, V., Dunn, D.C., Halpin, P., Bax, N.J., Dunstan, P.K., 2018. Reviewing the EBSA process: Improving on success. Marine Policy 88, 75-85.

Keith Diagne, L., 2015. Trichechus senegalensis (errata version published in 2016). The IUCN Red List of Threatened Species 2015: e.T22104A97168578. http://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T22104A81904980.en. Downloaded on 28 August 2018.

Kuedikuenda, S., Xavier, M. (2009). Framework Report on Angola’s Biodiversity. Ministério do Ambiente. Luanda, 2009.

Holness, S., Kirkman, S., Samaai, T., Wolf, T., Sink, K., Majiedt, P., Nsiangango, S., Kainge, P., Kilongo, K., Kathena, J., Harris, L., Lagabrielle, E., Kirchner, C., Chalmers, R., Lombard, M. 2014. Spatial Biodiversity Assessment and Spatial Management, including Marine Protected Areas. Final report for the Benguela Current Commission project BEH 09-01.

Ministério do Urbanismo e Ambiente (MINUA), 2006. Programa de Investimento Ambiental. Relatório do Estado Geral do Ambiente em Angola. Angola.

Ministério do Ambiente (MINAMB), Holísticos, C4 EcoSolutions (2015). “Approaching the urgent adaptation needs and reinforcement of the Angolan abilities in regards to climate change” – Description of selected sites: Chiloango.

Powell, J. & Kouadio, A. (2008) Trichechus senegalensis. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.1. http://www.iucnredlist.org. Acedido a 19 de Setembro de 2012.

Shumway, C.A. 1999. Forgotten Waters: Freshwater and Marine Ecosystems in Africa. Strategies for Biodiversity Conservation and Sustainable Development.

http://pdf.usaid.gov/pdf_docs/PNACF449.pdf (accessed 17 April 2013).

Sonangol (2012), Bodiversidade em Cabinda. Luanda, 2012.

Legislation:

Resolução n.º 42/06, de 26 de Julho: Aprova a Estratégia e o Plano de Acção Nacionais para a Biodiversidade. [Citação: EPANB, 2006].

Press Articles:

Luemba, Tati (2015). Secretaria Provincial de Urbanismo e Ambiente de Cabinda.

http://jornaldeangola.sapo.ao/reportagem/mangal_da_foz_do_chiloango_em_risco_de_desaparecer

 

Select the icon in the top right corner of the map to view the EBSA delineation in full-screen mode.

 

 Chiloango Estuary3

EBSA criteria met at a high (red), medium (orange) or low (yellow) rank. 

 

Download the proposed EBSA description:

 icon Chiloango Mangroves 2018 (522.49 kB)

 

Download the proposed EBSA boundary:

 icon Chiloango Mangroves KMZ 2018 (10.9 kB)

Download a map of the revised EBSA:

icon Chiloango Mangroves 2018 (363.76 kB)