One Ecosystem :
Research Article
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Corresponding author: Elena Mengo (elena.mengo@cefas.co.uk)
Academic editor: Alessandra La Notte
Received: 04 Apr 2022 | Accepted: 15 Nov 2022 | Published: 30 Nov 2022
© 2022 Elena Mengo, Gaetano Grilli, Tiziana Luisetti, Heather Conejo Watt, Cherry Harper Jones, Paulette Posen
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Mengo E, Grilli G, Luisetti T, Conejo Watt H, Harper Jones C, Posen P (2022) Marine and coastal accounts for Small Island Developing States: A case study and application in Grenada. One Ecosystem 7: e84865. https://doi.org/10.3897/oneeco.7.e84865
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In recent decades, a concerted effort has been made to define methodologies and frameworks to account for the contribution of the natural environment to national wealth and its role in fulfilling societal and economic needs. The linkages between natural capital and human well-being are even stronger in low-income and vulnerable countries, such as Small Island Developing States (SIDS). This is particularly true for coastal and marine ecosystems and for SIDS, considering that a large portion of their population live along the coast. Therefore, SIDS would greatly benefit from systematically assessing and recording the condition and services provided by marine and coastal habitats in ecosystem accounts. Applications of accounting frameworks to marine and coastal habitats, however, are still under development. Through a case study in the Caribbean Island of Grenada, we explore SIDS readiness to develop marine and coastal natural capital accounts, in particular framed within the guidelines of the United Nations System of Environmental-Economic Accounting Ecosystem Accounting (SEEA-EA). We find that, while data to compile accounts of ecosystems extent exist and may be suitable for accounting, data related to ecosystem condition are very limited. Data gaps significantly constrained the potential approaches to estimate the ecosystem services supply provided by the coastal and marine environment in our natural capital accounts for Grenada. Our case study investigation brings us to suggest initial steps for the development of ecosystem accounts in SIDS, including potential methodologies and approaches and discuss how developing a set of coherent accounts can play a key role in incorporating nature into decision-making.
natural capital accounting, small island developing states, ecosystem services, sustainable development, marine and coastal habitats, ocean accounting, ecosystem accounting
Natural capital (NC) is defined as the stock of natural assets (e.g. the ocean) providing a wide range of ecosystem services (e.g. wild fish) which, in combination with manufactured and human capital, enhance the well-being of humans (e.g. the food we eat) (
For these reasons, there is a recognised need to assess and monitor the status of NC, its ecosystems and the changes in ecosystem services they supply over time and space (
Whilst several applications of the SEEA framework for EA exist for terrestrial ecosystems (see, for example,
Accounting for the contribution of marine and coastal ecosystems to human well-being through consistent, coherent and integrated EA tools to systematically organise and present statistics on their ocean resources is of paramount importance for Small Island Developing States (SIDS) to mainstream the natural environment into decision-making. SIDS face a number of common challenges due to their small size, institutional weaknesses, vulnerabilities to natural disasters and economic shocks and small economies of scale which hamper effective environmental governance (
The development of ecosystem accounts, ideally in line with the approach set out in the SEEA, would facilitate international comparability of environmental and economic statistics between countries, thus giving SIDS a more effective voice in relevant international forums, as well as access to international financing resources needed to build resilience. By tracking SIDS environmental asset extent, condition, services and benefits,*
The reminder of this paper is organised as follows. Section 2 describes the SEEA EA framework and the steps for the compilation of accounting tables according to SEEA EA guidelines. Section 3 provides some background information on the case study area, Grenada and outlines the approaches used to pilot test the SEEA EA. Challenges, limitations and relevant data gaps surrounding the SEEA EA pilot test in Grenada are highlighted in Section 4, as well as opportunities for moving forward. Finally, Section 5 presents our conclusions to facilitate the development of EA in SIDS.
This study aims to test, through a pilot study, whether SIDS are prepared to develop marine and coastal ecosystem accounts, specifically considering potential alignment with the SEEA EA framework. The SEEA EA (
The development of coastal and marine ecosystem accounts in line with the SEEA EA guidance (Fig.
However, application of the SEEA EA to coastal and marine ecosystems has proved complex and a limited number of attempts exist to date. With the exception of the national-level accounts developed in the UK (
Grenada is a tri-island country of volcanic origin in the eastern Caribbean (Fig.
Following the process outlined in the SEEA EA (
Based on habitat mapping data availability and considering that there is not a single internationally agreed classification for coastal and marine habitats, we focus on the ecosystems that are most relevant for Grenada and that allow a plausible level of spatial detail. The selected ecosystems for our case study are: seagrass meadows, mangrove forests, coral reefs, sandy beaches, littoral forests, shelf sea habitats and deep-sea habitats. Table
Ecosystem Type |
Extent (Ha) |
Year |
Source |
Seagrasses |
2622 |
The dataset was compiled from six different datasets with images captured in 1999, 2007 and 2012 |
Data provided by The Nature Conservancy (TNC) via the Government of Grenada in 2017 |
Mangroves |
205 |
The dataset was compiled from four different datasets with images captured in 2007 and 2010 |
|
Coral reefs |
5460 |
The dataset was compiled from four different datasets with images captured in 1999 and 2007 |
|
Coasts and Beaches |
6 |
Unknown |
|
Littoral forests |
2730 |
Unknown |
|
Shelf sea |
270900 |
Unknown |
FAO (2018) |
Deep sea |
2342400 |
Unknown |
|
Total |
2624323 |
Data used to compile the ecosystem extent account were retrieved from various sources. The data used to map and estimate the extent of seagrass, mangroves and coral reefs, provided by The Nature Conservancy (TNC) via the Government of Grenada in 2017, were a collation of data collected over several time periods (1999, 2007 and 2012) from different sources including field surveys and aerial and satellite images. Retrieving data for habitat extent from different sources poses limitations in terms of data harmonisation in space and time. For example, regarding the data on seagrass habitat, the methodology used for digitisation of aerial images and mapping exercises is unknown, as is the quality and resolution of most of the aerial images used. Most of the aerial images used were from 1999, so are over 20 years old. From the information provided by TNC, it seems that no ground-truthing of the image digitisation was conducted. As for mangroves habitat (Figs
Data on the extent of beaches and littoral forests are based on the land-use and land-cover data layer provided by TNC via the Government of Grenada in 2017. The extent of littoral forest was estimated by assuming that the whole forest extent in coastal enumeration districts is composed of littoral forest, likely resulting in an overestimation of habitat extent. Moreover, there is no information available on what data were used to create land-use and land-cover layer, nor what date those data are from.
Extent of the shelf and deep-sea habitats were estimated from the Food and Agriculture Organisation (FAO) country report (
In relation to our case study, the only condition indicator we were able to assess in Grenada relates to seagrass bed density (Figs
No condition indicators or information were available for the other considered marine and coastal ecosystems. Building on data, as shown in Table
Selected ecosystems types extent and condition. Condition indicators only available for seagrasses.
Ecosystem type |
Extent (Ha) |
Characteristics of ecosystem condition |
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Sparse Seagrass - Low vegetation density (Ha) |
Seagrass - Medium vegetation density (Ha) |
Dense Seagrass - High vegetation density (Ha) |
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Seagrasses |
2622 |
1519.2 |
1101.3 |
2.3 |
Mangroves |
205 |
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Coral reefs |
5460 |
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Coasts and Beaches |
6 |
|||
Littoral forests |
2730 |
|||
Shelf sea |
270900 |
|||
Deep sea |
2342400 |
|||
Total |
2624323 |
Additionally, the SEEA EA guidance advises to include in the extent and condition accounts both the opening and closing variation in extent and condition of habitats during the accounting period. This was, however, not possible for this case study, based on the data available. As stated in
Exploring the potential for developing marine and coastal ecosystem accounts in SIDS required the compilation of the ecosystem services supply accounting tables in biophysical and monetary terms. We focused on the most frequently identified ecosystem services in SIDS which include: food provision (benefit of fish and shellfish provision); carbon sequestration and storage (benefit of climate regulation); natural hazard protection (benefit of erosion prevention and coastal protection); natural hazard protection (benefit of erosion prevention and coastal protection); and outdoor recreation (benefit of recreational use). Tables
Grenada marine and coastal ecosystem services, provision of selected ecosystem services in biophysical terms, 2010-2016.
a: Ecosystems extent assumed to be constant in the considered period.
Type of service |
Ecosystem service |
Indicator |
2010 |
2011 |
2012 |
2013 |
2014 |
2015 |
2016 |
Provisioning |
Fish and shellfish |
Fish landings (Mt) |
2.4 |
2.3 |
2.3 |
2.7 |
2.8 |
2.7 |
2.8 |
Regulating |
Natural Hazard Protection |
Coral Reef Extent (Ha)a |
5460.7 |
5460.7 |
5460.7 |
5460.7 |
5460.7 |
5460.7 |
5460.7 |
Climate regulation |
Carbon stored (tCO2eq)a |
1551.2 |
1551.2 |
1551.2 |
1551.2 |
1551.2 |
1551.2 |
1551.2 |
|
Cultural |
Outdoor recreation |
Tourist arrivals (‘000 arrivals) |
425.1 |
357.1 |
311.8 |
370.3 |
421.9 |
462.7 |
Grenada marine and coastal ecosystem services, provision of selected ecosystem services in monetary terms, 2010-2016 (EC$ million, 2016 prices).
Type of service |
Ecosystem service |
Indicator |
2010 |
2011 |
2012 |
2013 |
2014 |
2015 |
2016 |
Provisioning |
Fish and shellfish |
Value of landings |
37.1 |
33.9 |
32.5 |
39.2 |
39.5 |
39.2 |
40.4 |
Regulating |
Natural Hazard Protection |
Reef coastal protection benefit |
1313.3 |
1313.28 |
1313.28 |
1313.28 |
1313.28 |
1313.28 |
1313.28 |
Climate regulation |
Carbon stored |
Social Cost of Carbon US EPA |
0.2 |
0.2 |
0.2 |
0.2 |
0.2 |
0.2 |
0.2 |
Cultural |
Outdoor recreation |
Recreational expenditure |
337.6 |
327.9 |
419.8 |
400.5 |
398.1 |
408.0 |
Nonetheless, our attempt to adhere to the SEEA EA to compile the ecosystem services supply tables presented a number of challenges, particularly with regard to monetary valuation approaches.
Provisioning Services
The fishing sector in Grenada relates to the wild seafood provisioning service and plays an important role in the Island economy, supporting the livelihoods of local communities and ensuring food security (
Regulating Services
Carbon sequestration and storage is a relevant service supplied by Grenada’s marine and coastal habitats (in particular, mangroves and seagrasses). The key function of this service is to regulate climate, thus providing local and global-scale benefits. The extent of mangrove and seagrass habitats is directly extracted from the ecosystem assets extent account in Table
Finding an appropriate method to estimate the exchange value of blue carbon in SIDS is complex and conditional to the uncertainty surrounding global and local carbon value estimates (
Information used in Table
Cultural Services
As for most SIDS, tourism is an important sector for Grenada’s economy, accounting for around 41% of the country’s GDP and 23.8% of total employment in 2019 (
The aim of this work was to test, through a case study, if and how ecosystem accounts following the SEEA EA guidance could be developed in SIDS using available data and information. To the best of our knowledge, this work is the first marine and coastal EA pilot in a SIDS context examining different ecosystem types and the related ecosystem services. Our pilot study includes the most recent data publicly available at the time of compilation. However, several challenges currently hinder the development of a full set of ecosystem accounts in SIDS and, consequently, their use for policy decisions and natural capital finance (
Some initial takeaways from this pilot study regarding the possibility to develop marine and coastal ecosystem accounts in Grenada, which can extend to SIDS, in general, include a thorough review of existing environmental and economic data that may have been generated in Grenada and may be held by the government of Grenada, as well as their suitability for a baseline assessment and subsequent use for the development of EA. Data should then be collected and recorded systematically and coherently. The resulting tables and maps should be periodically produced to track dynamics of ecosystem changes and forecast future trends. As pointed out by
The most recent data available on some of the extent of ecosystems considered were collected over 20 years ago. In addition, the collection of these data was fragmented in terms of methods, years and geographical locations. Opening and closing variation in extent and condition of habitats during the accounting period were not considered due to lack of data. Additionally, condition indicators were available only for seagrasses. The selection of condition indicators specific for marine and coastal ecosystems is challenging due to scarcity of data readily available and the scientific complexity to assess suitable condition indicators that affect ecosystem functions and related ecosystem quality (
Trends in the supply of selected ecosystem services in Grenada expressed in biophysical and monetary terms, as shown in Tables
Consideration must be given to how the values of ecosystem services and natural assets are connected to those already accounted within national accounts or outside national accounts in satellite accounts (
Recreational values for accounting purposes could be obtained using data on estimated visits, specifically to marine and coastal areas and on disaggregated expenditure types. Such information would, ideally, be obtained through a visitors’ survey and subsequent estimation of an exchange value for the ecosystem service, based on a travel cost method. Otherwise, a simulated exchange value approach (
The valuation of climate regulation services provided by marine and coastal environments, as well as the valuation method to be used to more appropriately represent the value of this service, are subject to scientific uncertainty. Extensive and more frequent habitat surveys, together with the use of new technological and analytical methods (e.g. Earth Observation, artificial intelligence), would allow a better assessment of both baseline and trends in the extent of relevant habitats. Concerning the estimation of carbon burial rates, biogeochemical research has greatly improved our knowledge in the last decades, but a degree of uncertainty still remains. Seafloor sediments may also be added to the carbon sequestration and storage estimation of a country (
The damage cost avoided approach used for estimating the natural hazard regulating service provided by coral reefs surrounding Grenada in monetary terms, despite being coherent with the SEEA EA guidance, has several limitations. For example, it is likely to result in an overestimation of the actual service in monetary terms, even though only the service provided by coral reefs is considered. The impact of storm-induced water levels is assumed to be the same for each of the reporting years. Additionally, the built capital costs are calculated using costs from different years and assuming no change in infrastructure endowment of coastal areas. Moreover, no capital depreciation is applied. Finally, estimation does not account for different flooding levels and simply calculates the total area affected by storm surge inundation. As recognised also in the SEEA EA, most regulating services vary substantially in their supply potential which depends on local contexts. More accurate valuation should be grounded on complex bio-economic and spatial modelling, coupling characteristics of marine and coastal environment with social and economic attributes. This is essential to robustly estimate the monetary value of the service, as it would allow the obtaining of a credible estimate of the economic and social damage that would occur if natural habitats did not provide protection. Data granularity is relevant to spatially link the value of land protected to different natural habitats.
Our pilot study focused on biophysical and monetary ecosystem services supply. Ecosystem services use and possible approaches to compile biophysical and monetary use tables have not been included since they are beyond the scope of our research and given the paucity of required data. The role of the use tables in environmental accounting is to make the contribution of ecosystem services to economic and human activities explicit, including household, businesses and government. The use tables should be harmonised with national accounting frameworks and, in the case of SIDS, could be further divided into policy-relevant sub-categories (e.g. commercial fisheries vs. small-scale fisheries). This would enable policy plans to be tailored around specific sectoral needs. The compilation of an ecosystem services use table was not possible under existing data limitation. Previous applications of EA accounting in marine and coastal ecosystems also show that the compilation of a use table is particularly difficult (see
The fundamental role of the oceans for the planet and humankind is emphasised in the 2030 Agenda for Sustainable Development (
By using Grenada as a case study to test SIDS readiness for the development of ecosystem accounts, we showed that, overall, it is currently difficult to compile a full set of marine and coastal accounts for SIDS with readily available data. Appropriate data to compile natural capital accounts, both biophysical and monetary (e.g. spatial, environmental or economic), may be already available to governmental departments, agencies and local and Non-Governmental Organisations (NGOs), but it is necessary to pragmatically consider how to regularly collect, organise and use that information, as well as ensure coherence and consistency across information sources over time. Regular collection of biophysical data and indicators in SIDS is usually hampered by limited resources across governmental and non-governmental organisations. Furthermore, considerable work is also required to adapt and test approaches, particularly for monetary valuation, that can be applied consistently with international accounting frameworks, such as the SEEA and allow the full integration of ecosystem values (
It is necessary to strengthen national and international cross-government and cross-departmental collaboration and communication. At the SIDS national level, engagement with diverse stakeholders, including local communities, private sector and NGOs, is key in EA development. It is also required to build national capacity and technical expertise and knowledge through closer collaboration between SIDS and the wider international NC accounting community, for example, by expanding the pilot applications already undertaken under the GOAP and UN supervision. The need for cooperation, increased synergies through collaboration and capacity building development emerged also during a consultation held in June 2019 with relevant Grenadian stakeholders, undertaken within the Commonwealth Marine Economies Programme (CME). Despite limited familiarity with natural capital accounting concepts, stakeholders widely recognised that incorporating natural capital into national accounts would be beneficial for the sustainable development of Grenada. Therefore, the construction of a full set of accounts in SIDS necessitates enhanced awareness and understanding of natural capital and ecosystem services concepts and, most importantly, greater cooperation to promote synergies between institutions and key actors involved in natural capital management. A pragmatic way forward, based on closer collaboration between SIDS national organisations and continued mobilisation or access to international funding and knowledge exchange opportunities*
The authors would like to thank the Grenadian Ministry of Climate Resilience, Environment, Forestry, Fisheries and Disaster Management for supporting the wider work carried out over the years under the CME programme. The authors would like to thank particularly Mrs Aria St. Louis, (Head of the Environment Division) who has greatly assisted the Cefas socio-economic team during the visit in country in June 2019 and for the continuous engagement and support of this study. The authors would also like to thank the anonymous reviewers for their valuable comments.
Funding for this project was through the Commonwealth Marine Economies (CME) Programme managed by the FCDO. Commonwealth Marine Economies Programme - GOV.UK (www.gov.uk). Research and fieldwork activities took place over the years 2018 and 2019.
The UN Statistical Commission adopted the SEEA-EA (
The authors refer to the most frequently cited definition of Sustainable Development that is “development that meets the needs of the present without compromising the ability of future generations to meet their own needs” (
There has been an active debate over the definition, interpretation and classification of ecosystem services and the need to distinguish between ecosystem services and benefits for economic valuation and for accounting purposes (see, for example,
Monetary values are normalised in 2016 prices using Grenada’s Consumer Price Index.
While we recognise that keeping the extent of some ecosystem types constant is a strong working assumption, for the purpose of this work, it is considered appropriate to illustratively display endowment of ecosystems that are important to SIDS and it is also supported by other applications in the marine realm (e.g.
While social cost of carbon is listed in the SEEA EA (
Examples include: the Official Development Assistance (ODA) grants and funds, direct research investments and science support, such as the UK FCDO funded CME Programme, the German Gesellschaft für Internationale Zusammenarbeit (GIZ) projects and programmes in the Caribbean, including Grenada and the EU funded Caribbean Investment Facility (CIF).