a situational analysis of coastal mangrove sites in guyana (shell

Report

The Guyana Mangrove Restoration Project

A Situational Analysis of Coastal Mangrove Sites in Guyana (Shell Beach to Mahaica)

Owen Bovell Mangrove Specialist National Mangrove Restoration Project – Guyana

21 May, 2010

TABLE OF CONTENTS TABLE OF CONTENTS i ABSTRACTS ii INTRODUCTION 1 THE COASTAL PLAIN OF GUYANA 1 MANGROVES 1 MANGROVE SPECIES ON THE COAST OF GUYANA 2

THE HUMAN IMPACT ON THE MANGROVE FOREST 2 REASONS FOR THE MANGROVE SURVEY 3 HEALTH MANGROVE STANDS 3 IDENTIFICATION OF ACCRETION SITES 3 IDENTIFICATION OF EROSION SITES 8 IDENTIFICATION OF DEPLETED SITES 9 CONCLUSION 10 REFERENCES 11 APPENDICES 12

Summary

Mangroves are tropical forest ecosystems that normally inhabit inter-tidal sheltered coastal

sedimentary areas, where they stabilize sediment, provide coastal protection during storms, and

support fish and crab communities. In the Guianas coast three main mangrove species occur

dominated by the Avicennia species.

This report documents a survey conducted on the Atlantic coast between Skeldon, Berbice and

Shell Beach, Essequibo by a mangrove consultant attached to the Guyana Mangrove

Restoration Project. The field work was undertaken by observations on foot with GPS, Camera

and data sheet (Appendix I). It highlights coastal mangrove areas undergoing accretion and

erosion as well as areas suitable for replanting new mangrove stands and areas to be

protected. It recommends that replanting be done using the Avicennia species, the primary

species affected in the coastal shoreline.

The survey showed that the mangrove ecosystem is at various stages of development. The

natural erosion and accretion cycle is dynamic and has impacted positively and negatively on

the mangrove forests. There is an ever presence of anthropogenic impact at all sites, some

severe and some not so severe. Subsequently there is need to protect the emerging young

stands, the mature stands and areas that are threatened by the current erosion pattern.

The report identifies the Shell Beach area as a healthy mature stand of mangroves and further

stated that Hope Beach, Victoria, Greenfield, Lima, Mon Repos as accretion areas to be

replanted within the first year of the project in order of priority. In addition three hectares should

be planted at the first two sites before the end of 2010.

In particular it recommends the need for actively monitoring/studying healthy mangrove stands,

newly planted seedlings, depleted mangrove stands and areas that are considered erosion and

accretion sites to help better understand the coastal mangrove forest. Further, public awareness

activities are necessary to enhance the effectiveness of this project.

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Introduction The main areas of mangroves cannot be planted along an eroding shoreline. However certain areas are regenerating and some areas could be extended by planting mangroves seaward of existing mangrove stands. The latter development will require replanting and protection of seedlings from wave energy. The need to provide some protection for the seedlings is important, but this will necessary increase the cost of the planting exercise. Another consideration will be the choice of suitable sites. This will be dependent on whether the sites show accretion or non-eroding conditions, and whether the substrate would be suitable for planting (sandy soils are not suitable; sand/mud and clay soils are suitable). The reforesting of former mangrove areas will require considerable natural, human and financial resources. It is therefore essential that these areas be identified in advance so that proper planning will be put in place so as not to waste valuable resources. This report is presented by the National Mangrove Restoration Project mangrove specialist. The work completed is a situational analysis of the mangrove areas along the seacoast of Guyana between Shell Beach, Essequibo and Skeldon, Berbice. The Coastal plain of Guyana Guyana is situated on the north-eastern coast of South America. The country is about 215 square km, with a coastline of about 400km from the Waini River to the Corentyne River. The coast is a low-lying plain of marshes and ridges and is below sealevel in many areas (which resulted in an extensive and elaborate system of concrete sea defences). The coastal plain lies north of the Guiana shield, which is made up of residues of deeply weathered Precambrian rocks. Within the coastal plain are four principal outcrops:

- Berbice sediments of terrestrial origin deposited in the Pliocene (> 10million years ago) - Coropina sediments of marine origin - Demerara sediments - Pegasse or peat sediment – a transition between the Demerara and the coropina

sediments. Mangroves The term "mangrove" is used to describe a taxonomically diverse group of tree species that grows in the upper intertidal zone of sheltered shores in the tropics. True mangrove species are those that occur exclusively in this saline wetland environment, with adaptations such as aerial roots, halophytic strategies, vivipary and water conservation (Tomlinson, 1986). These adaptations distinguish mangrove trees as a specialized minority within their families. The world mangrove area is estimated at 14,197,635 ha (Lacerda et al., 1993), not including a growing list of countries where 50-80% of mangroves have been cleared in the last 15 years (Diop, 2003). In Guyana, mangrove comprises 1% of the natural forests. The forested area of Guyana consists of 18.8 million hectares. Although 1% may seem small the mangrove forest can play an important role in protecting a vulnerable seacoast, which is only one of the many aspects of its importance. Mangroves provide the homes for many species of flora and fauna, including shrimp, crabs and many

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species of fish. A mature mangrove forest also act as a sediment trap, thereby assisting in accretion of coastal sediments thus protecting low-lying coastal areas. In recent times this forest has received additional attention for its role in carbon sequestration. It has the capacity to sequester 17 metric tonnes of carbon/hectare/year. In the Guianas of South America there are a limited number of species of mangroves. Traditionally three species - Avicennia germinans (Black mangrove) Rhizophora mangle (Red Mangrove) and Languncularia racemosa (White mangrove) were observed and were dominated by the black mangrove( Augustinus, 1978). However, there has been some uncertainty in earlier scientific literature on the exact identification of mangrove species in the Guianas. The main species of this coastal region is accepted as A. germinans (Tomlinson, 1986) and A. schauriana has also been observed. However, distinguishing the difference between the two species is easier said than done (Pastakia, 1990). Rhizophora mangle is the most common species of its genus in the Guianas although both R. harrisonii and R. racemosa have been sighted in Georgetown and the mouth of the Essequibo respectively. Another species observed but of less significance is Conocarpus erectus known as button wood. Mangrove species on the coast of Guyana In Guyana large areas of the coast have been effective mono-cultures of stands of Avicennia spp. There has been little evidence of Rizophora spp. present along the parts of the coast. This is the main pattern of mangrove development of mangrove along the Atlantic coast from Corentyne to the Essequibo River. Languncularia racemosa is also able to colonize these parts of the Guyana coast. In large developing sand banks and mudflats that dominate the coast Laguncularia and Avicennia are found pioneering these areas (Hussain, 1990). The dominance of Avicennia spp. changes along the river banks and along coastal land in close proximity to the mouths of rivers and creeks and other large waterways, with Rhizophora mangle dominating the estuary and more sheltered river banks (Hussain, 1990). Human impact on the mangrove forest The Guyana coast has historically undergone considerable human development by clearance and empouldering coastal areas for agriculture and settling in these areas of the majority of the population. With much of the coastal areas lying below the high spring tide level, the country has developed an extensive system of sea defences, by means of seawalls and groynes. The historic clearance has meant that the mangrove areas of the coast are generally thin. Only along the Waini and Pomeroon coasts are mangrove forests of any size found today (Pastakia, 1990). The result of the clearance, left scrub and grasslands only useful for grazing animals. The other next use of the thin fringe of mangrove was for fuel wood because of the close proximity of this forest to the coastal dwellers. In addition artisanal fishermen caused local damage to the mangroves by hauling their boats through the mangrove forest to hide and protect their boats and equipment. Where there is young mangrove development humans graze their animals on the succulent juvenile mangroves. This destruction is supported by the absence of sea defence rangers who should be present to ensure the protection of the foreshore areas, so the livestock is allowed to suppress or kill the next potential stand of mangroves.

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Reasons for the Mangrove survey At present in Guyana there are concerns that the mangrove forest is under stress associated with negative environmental and anthropogenic impacts. This survey examines the thin fringe of coastal mangrove that will help to provide background information that will assist guiding the process towards mangrove restoration. The cyclic erosion processes along the coast are reflected in the status of the mangrove stands. In general it is safe to say that the mangrove forests will naturally regenerate once the natural erosion process is stopped. However, during the period of erosion the coastal species of mangroves will be severely affected, thereby reducing the efficacy of the mangrove belt as a primary sea defence mechanism (Pastakia, 1990). The human impact of reducing the mangrove is continuing. Some of the direct causes of this depletion that can be observed are: the destruction of mangrove for agricultural use; cutting mangrove for commercial fuel wood and artisanal use; using the mangrove area as dumping sites for garbage; and grazing cattle on juvenile mangroves

Unless these activities can be controlled and reduced, replanting mangroves and managing mangroves for any form socio-economic and environmental benefits will be impossible. The mangrove areas have very important environmental values, as a fisheries nursery ground, a source of primary productivity, a repository of biodiversity and a natural sea defence mechanism. This report considers areas that are proposed to be planted and protected and identifies erosion and accretion sites as well as healthy and degraded stands. Photographs of the sites of immediate concern are included in the document. Healthy coastal mangrove stands

- Shell Beach, Essequibo – This mangrove fringe appears to be a continuous healthy stand of mangroves that stretches from the Waini River mouth to the mouth of the Moruka River. (Interview with mangrove workshop participants – Essequibo 2010). This area should be monitored for the purpose of detecting positive and negative changes to the forest. Research should be conducted in this area to better understand the mangrove forest.

Identification of accretion sites

- Lima, Essequibo Coast – Evidence of regeneration of black mangroves is manifested in sparse seedling (30cm tall) growth. Mudflats are developing to the sea. Human impact seems minimal except for the dumping of garbage. This area should be among the first chosen for replanting of black mangrove.

- Hope, East Coast Demerara – Black mangrove regeneration is found in patches in a very wide expanse of mudflat (Figures 1 & 2.). There is evidence of support for bird life. Egrets (grey and White) as well as the scarlet ibis were sighted in this area (Figure 3. ). This site is in close proximity to a fishing port. There is proof human interference by the presence of garbage. This area should be given to priority for restoration activities. Studies should be conducted of the migratory waterfowl that are likely to use this area. Data may show that this area may be a possible site within the western hemisphere Shorebird Reserve network

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Figure 1. Hope - Mudflat ideal for planting

Figure 2. Hope Beach – Mudflat suitable for planting

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Figure 3. Hope - Grey and white egrets - possible area for biodiversity study

- Mon Repos, East Coast Demerara – There is a wide expanse of beach area colonizes with grass and clumps of black mangrove scrub (Figure 4). The common activity on site is boat building and fishing (Figure 5.). This area is used for dumping domestic garbage. There is an ever presence of goats grazing on juvenile mangrove plants. This area is in need of lots of public awareness work before any planting can be done. A study of the natural fishery within the area , to estimate conditions of the mangrove area in relation to the fishery resources.

Figure 4. Mon Repos - Wide mudflat with grass and black mangrove scrub

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Figure 5. Mon Repos – Boat building

- Winsdor Forest, West Coast Demerara – This site has a young mixed stand of black and White mangroves (2- 4m tall) close to to the sea wall (Figure 6.). The width of this fringe is about 3- 10m. There is mud bank development seaward. This is another area that should be a high priority for replanting. This area is also interesting for biodiversity study (Figure 7.). This area is similar to Hope Beach and should be treated in a similar manner.

Figure 6. Windsor Forest - Mixed stand of black and white mangroves (2- 4m tall)

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Figure 7. Windsor Forest - potential site for planting and biodiversity study

- Victoria, East Coast Demerara – There is a wide expanse of mudflat going seaward with tufts of black mangrove 3m tall seedlings. There seems to be very little indication of human interference with the exception of garbage. This site has similar features to the Hope area and should be among the first chosen for planting. The same recommendation should apply. A study of the accretion/erosion process in this area would be useful.

Figure 8. Greenfield -Mudflat with tufts of black mangrove trees and seedlings

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- Greenfield, East Coast Demerara – this area has a wide expanse of mudflat suited for planting (Figure 9.). This is a fishing community (Figure 10.). There seem to be negligible negative human impact. However the fresh water influence of the Greenfield main canal was non-existent for a number of years as a result of a clogged koker. The establishment of planted areas of mangrove and a comparison of these areas with naturally regenerating areas should be conducted. At the time of this survey there was evidence of the Koker outlet being desilted. This area is ideally suited for planting of black mangrove and should be planted within a year.

Figure 9. Greenfield – Mudflat as potential planting area

Figure 10. Greenfield – Mudflat as potential planting area

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- No.6 and No. 7 villages West Coast Berbice – There was a buildup of sling mud and evidence of new growth mangroves. While this is area is recommended for reforestation it is not of immediate concern. This area could be planted in the second year of the project.

Identification erosion sites

The following areas comprise predominantly mature mangrove stands. However, these areas are experiencing natural erosion together with negative human impacts such as cutting of mangroves to support agricultural and artisanal fishing activities.

- No. 63 Village to No. 50 village Corentyne, Berbice – There is a mature stand of black mangrove at this location, however there is a lot of erosion taking place with large trees topping over. This area is adjacent to economic activities- Agriculture, tourism (the No. 63 beach) and businesses. Its protection is critical to the development of Region #6. The use of local semi-hard structures should be investigated by the Guyana Sea and River Defence (SRD)

- Bounty Hall, Essequibo Coast – This site has thin fringe of mature black mangrove that has been eroding. Sea and River Defence should assist in the protection of this area.

- Better Hope to Charity – Mature stand of black mangrove eroding. There is a presence

of large dead mangrove trees uprooted. This area should be investigated by SRD

- Vreed-en-Hoop to Ruimzeight, West Coast Demerara – Mature stand of black mangrove eroding. This area should be investigated by SRD

- Abary to Profit-Foulis - Mature stand of black mangrove eroding. This area should be

investigated by SRD

- Trafalgar – Mature black mangrove being affected garbage and other pollutants. Public awareness campaign is necessary to address this problem immediately. There is also need to get to the root of the problem.

- Farm, East Bank Essequibo – The natural erosion process has removed the thin fringe

of black mangrove from this site. SRD should investigate to adapt the most suitable approach to solving this problem.

All the mentioned areas should be studied to understand the natural erosion/accretion processes. This should be a longterm study. Identification depleted mangrove areas

- Farm, East Bank Essequibo – There is evidence of many large stumps in remaining

after degradation of this former mangrove site.

- Ledestein, East Bank Essequibo – The majority of mangrove have been lost to

erosion.

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- Lancaster, Berbice - The majority of mangrove has been lost to erosion These areas

reflect large indentation in the coast line and evidence of dead wood from mature trees.

These trees have topped over and large Avicennia roots have been exposed.

These areas should be studied to understand dynamics of the mangrove vegetation/area in a

similar manner to the erosion sites.

Conclusion

The mangrove area surveyed shows that the mangrove ecosystem is at various stages of

development. The natural erosion and accretion cycle is dynamic and has impacted positively

and negatively. There is an ever presence of anthropogenic impact at all sites some severe and

some not so severe. Planting mangrove to provide soft defence structures is a necessity. The

planting should be done using the Avicennia species which is the primary species affected in

the coastal shoreline. There is need to protect the emerging young stands, the well established

mature stands and areas that may be lost to the current erosion pattern.

The following areas should be replanted with black mangroves in order of priority: Hope Beach,

Victoria, Greenfield, Lima, Mon Repos within the first year of this project. The first two sites

should be planted before the end of 2010. Three (3) hectares should be targeted for this period.

Finally there is a definite need to actively manage and monitor the planted sites, accretion and

erosion sites, mature healthy and depleted stands. There should be a robust public awareness

programme to educate the coastal dwellers about the value of the mangrove forests and to

support project activities. Studies highlighted in the report should be conducted so as to add

clarity to understanding the mangrove forest.

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REFERENCES

Augustinus P.G. E. F. 1978

The changing shoreline of Surinam

Thesis, University of Utrecht.

Diop, S. 2003. Vulnerability assessment of mangroves to environmental change. Estuarine, Coastal and Shelf Science 58, 1-2. Hussain M.Z. 1990 Restoration and expansion of the mangrove belt in Guyana Tech. Paper No. 1, TCP/GUY/8953 FAO, Rome Lacerda L.D. 1993. Utilization of Mangrove Forests in Latin America and Africa Regions, 1-42. Okinawa: International Tropical Timber Organization and International Society for Mangrove Ecosystems

Pastakia C.M.R. 1990.

APreliminary study of Mangroves in Guyana, Department of Hydraulics

Tomlinson P.B. 1986.

The Botany of mangroves,Cambridge University Press

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Appendix I

Farm – Erosion Site Mangrove Data Sheet #1

Location of Site Remarks

Name Farm, East Bank Essequibo

GPS Coordinates N 0345956 E0759958

Site Characteristics

Type of Sea Defence Earthen embankment; natural sea defence

Foreshore Condition Eroding

Freshwater Influence/Evidence of Flushing Yes

Soil Type Sand/Clay mix – dark brown

Evidence of Debris (Dumping garbage) Yes

Land Use

Agriculture Rice; sugar cane; ground provision

Housing Yes

Grazing Cows

Recreation

Other

Vegetation

Regeneration of Forest No

Mortality of trees No

Evidence of human impacts No

Evidence of degradation Dead trees – not recent but old stumps

Principal mangrove Species

Avicennia germinans X

Rhizophora mangle

Laguncularia racemosa

Crane – Erosion Site

Mangrove Data Sheet #2 Location of Site Remarks

Name Crane, West Coast Demerara

GPS Coordinates


Type of Sea Defence Earthen embankment; natural sea defence



Soil Type Sling mud

Evidence of Debris Yes – dominated by plastic bottles

Land Use

Agriculture Rice; kitchen garden

Housing Yes

Grazing Cows, sheep and goats

Recreation

Other

Vegetation

Regeneration of Forest Yes – young stand of Avicennia and Laguncularia (3 – 5 m tall)


Evidence of human impacts Yes - cutting




Rhizophora mangle

Laguncularia racemosa X

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Vreed-en-Hoop – Erosion Site Mangrove Data Sheet #3


Name Vreed-en-Hoop, West Coast Demerara

GPS Coordinates


Type of Sea Defence Earthen embankment; Concrete groyne (old); concrete wall; natural sea defence



Soil Type Sling mud

Evidence of Debris Yes, plastic bottles etc.

Land Use

Agriculture Rice, kitchen garden

Housing Yes

Grazing No

Recreation

Other

Vegetation

Regeneration of Forest Yes

Mortality of trees Yes

Evidence of human impacts Yes – cutting of trees for fuel wood and kitchen garden

Evidence of degradation Dead trees – recent as well as old stumps



Rhizophora mangle X


Waller’s Delight – Erosion Site

Mangrove Data Sheet #4


Name Wallers’ Delight, West Coast Demerara



Type of Sea Defence Earthen embankment/ Concrete wall; natural sea defence



Soil Type Sling mud

Evidence of Debris Yes – dominated by plastics

Land Use

Agriculture Rice

Housing Yes

Grazing Cows

Recreation

Other

Vegetation

Regeneration of Forest Yes

Mortality of trees Yes – Young saplings of Avicennia being uprooted. Mature trees dying

Evidence of human impacts Yes cutting

Evidence of degradation Dead trees – young and mature



Rhizophora mangle


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Metenmeeerzorg – Accretion Site



Name Metenmeerzorg, West Coast Demerara

GPS Coordinates N 343536 E 0761280


Type of Sea Defence Concrete wall; natural sea defence

Foreshore Condition Accretion

Freshwater Influence/Evidence of Flushing Yes - Adjacent canal and koker

Soil Type Sling mud

Evidence of Debris Yes

Land Use

Agriculture Sugar cane

Housing Yes

Grazing Sheep, cows, donkeys

Recreation No

Other Fishing

Vegetation

Regeneration of Forest Yes – sparse growth of black mangrove






Rhizophora mangle


Windsor Forest – Accretion Site



Name Windsor Forest/Ruimzeigth West Coast Demerara





Freshwater Influence/Evidence of Flushing Yes – canal and Koker

Soil Type Sling mud

Evidence of Debris Yes – dominated by plastic bottles

Land Use

Agriculture Rice

Housing Yes

Grazing No

Recreation Yes – relaxation and exercise

Other Fishing

Vegetation

Regeneration of Forest Yes – dense stand of Avicennia and Laguncularia ( 3m tall)



Evidence of degradation No



Rhizophora mangle


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Mon Repos – Accretion Site Mangrove Data Sheet #7


Name Mon Repos, East Coast Demerara



Type of Sea Defence Earthen embankment; concrete wall; natural sea defence



Soil Type Sand/Clay mix ; sling mud

Evidence of Debris Yes – plastic bottles, old wood etc.

Land Use

Agriculture Fishing, cattle, ground provision, green vegetables

Housing Yes

Grazing Cows, goats and sheep

Recreation Relaxation

Other

Vegetation







Rhizophora mangle


Hope Beach – Accretion Site

Mangrove Data Sheet #8 Location of Site Remarks

Name Hope, East Coast Demerara





Freshwater Influence/Evidence of Flushing Yes – Hope canal and Pump

Soil Type Sling mud

Evidence of Debris Yes

Land Use

Agriculture Coconut estate; Kitchen garden

Housing Yes

Grazing Cows

Recreation Yes – bird watching (white and grey egrets and scarlet ibis); relaxation

Other Fishing

Vegetation

Regeneration of Forest Yes- juvenile black mangroves (2m tall)


Evidence of human impacts yes




Rhizophora mangle


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Victoria – Accretion Site Mangrove Data Sheet #9


Name Victoria, East Coast Demerara





Freshwater Influence/Evidence of Flushing Yes – Victoria main canal/ Koker/pump

Soil Type Sling mud

Evidence of Debris Yes – plastic bottles, old metal etc.

Land Use

Agriculture Rice; sugar cane; ground provision

Housing Yes

Grazing Cows

Recreation No

Other

Vegetation



Evidence of human impacts Yes - cutting




Rhizophora mangle


Ann’s Grove – Accretion Site Mangrove Data Sheet #10


Name Ann’s Grove, East Coast Demerara



Type of Sea Defence Rip rap; concrete wall; natural sea defence


Freshwater Influence/Evidence of Flushing Yes - canal

Soil Type Sling mud

Evidence of Debris Yes – Plastic bottles etc.

Land Use

Agriculture Coconuts; fruits; ground provision etc.

Housing Yes


Recreation

Other

Vegetation

Regeneration of Forest Yes – young stands of Avicennia and Laguncularia ( 20cm to 3m tall)






Rhizophora mangle


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Greenfield – Accretion Site



Name Greenfield, East Coast Demerara





Freshwater Influence/Evidence of Flushing Yes - canal

Soil Type Sling mud

Evidence of Debris Yes – Plastic bottles ect

Land Use

Agriculture Fishing; Coconuts; fruits; .

Housing Yes


Recreation

Other

Vegetation

Regeneration of Forest Yes – young stand of Avicennia ( 2m tall)






Rhizophora mangle


a situational analysis of coastal mangrove sites in guyana (shell

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