Willingness to pay for invasive seaweed management: Understanding how high and low income households differ in Ghana
Introduction
Harmful algal blooms have been occurring in marine and freshwater systems as far back as the 1970s in North America and Europe but have been on the increase since the 1990s (Lopez et al., 2008; Smetacek and Zingone, 2013). Beginning in 2011, unprecedented tides of Sargassum, a free-floating brown alga, have been invading shorelines in West Africa and the Americas (Gower et al., 2013; Smetacek and Zingone, 2013). The proliferation of Sargassum has been attributed to nutrient pollution from the Mississippi, Amazon and Congo rivers, fertilizer run-off and effluents; iron-rich dust pollution from the Sahara; and rising sea temperatures (Smetacek and Zingone, 2013; UNEP Mission Report, 2015). The Sargassum invasions have threatened the sustainability of coastal communities as they negatively impact coastal fisheries, tourism and human health. To protect their coastal ecosystems and livelihoods, the affected countries in West Africa have adopted seaweed cleanup policies to regularly remove floating mats of Sargassum on the sea and piles of Sargassum on the beach.
Modest amounts of floating Sargassum has important ecological benefits such as serving as safe nurseries and breeding grounds, and providing food, energy and shelter to support marine life (Vos et al., 2016). However, the overwhelming influx of Sargassum since 2011 in West Africa and the Caribbean has threatened the sustainability of marine ecosystems and coastal communities. Sargassum invasions have killed fish and endangered sea turtles, and reduced sunlight and oxygen in the affected coastal ecosystems (Vos et al., 2016; van Tussenbroek et al., 2017). Due to the floating seaweeds on the sea and piles of decaying seaweeds on the beach, the operations of marine fishers have become less productive as fishers frequently catch seaweeds instead of fish and spend productive hours removing entangled seaweeds from their fishing nets (Ackah-Baidoo, 2013; Solarin et al., 2014). Coastal tourism has been threatened by beach fouling caused by heaps of rotten Sargassum on the beach that produce offensive odors, emit poisonous hydrogen sulfide that is dangerous to human health, and cause eye and skin irritation (Ackah-Baidoo, 2013; Oyesiku and Egunyomi, 2014; Louime et al., 2017).
Shortly after the 2011 invasion began, several West African countries individually adopted policies to implement periodic seaweed collection. For instance, Ghana's Environmental Protection Agency adopted a seaweed cleanup policy that directed municipal governments in the affected coastal districts to regularly remove Sargassum seaweeds from the beaches and inshore areas to protect coastal fisheries and tourism after the first wave of Sargassum beached on Ghana's shoreline in 2011. In addition to adopting country-specific policies on their own, the affected West African countries recognized the need to adopt a regional seaweed policy to clean-up floating Sargassum offshore. In November 2015, representatives from the Abidjan Convention Secretariat, Benin, Côte d’Ivoire, Ghana, Guinea, Liberia, Nigeria, Senegal, Sierra Leone, Togo, the United Nations Environment Program-Global Program of Action, and the West Africa Biodiversity and Climate Change convened in Freetown, Sierra Leone to discuss the development of a regional policy to address Sargassum invasion. The representatives proposed the “Freetown Protocol on Invasive Seaweeds/Sargassum”. After the protocol is ratified by the affected countries, it will officially become the regional seaweed cleanup policy that will require that the affected countries work together to monitor the migration of floating Sargassum and regularly collect Sargassum at sea to prevent the brown mats of seaweeds from drifting into inshore waters or beaching along the shorelines in West Africa.
Unfortunately, the implementation of seaweed cleanup policies in some of the affected countries has not succeeded due to funding challenges. For example, Ghana's seaweed cleanup policy has no mechanism to provide funding to implement periodic seaweed collection. What is more interesting is the fact that even at the regional level, funding for the implementation of the proposed regional seaweed cleanup policy in West Africa is uncertain. However, the affected West African countries would need to find innovative ways to fund seaweed cleanup since the negative impacts of Sargassum invasion on their coastal ecosystems and traditional fishing economies cannot be overlooked. Therefore, we need a comprehensive knowledge of the non-market values (the monetary value stakeholders place on environmental goods and services not traded in markets) associated with seaweed cleanup or coastal conservation to address the funding challenges impeding the implementation of seaweed cleanup policies in West Africa. Non-market values associated with coastal conservation can serve as inputs to conduct cost-benefit analysis of seaweed cleanup policies to assess the economic value of implementing such policies and ensure the prudent use of scarce financial resources in the affected developing countries. Such cost-benefit analyses would be required by development partners or international organizations that may support the affected countries with loans or grants to implement seaweed cleanup. Non-market values associated with coastal conservation can also serve as indication of public support for the funding of seaweed cleanup (see Wan et al., 2017). Knowledge of citizens' support for seaweed cleanup is pivotal as evidence of strong public support can enable governments in the affected countries make difficult financial decisions to reallocate scarce resources to fund seaweed cleanup. It can also help the affected governments assess the feasibility of taxing their citizens or acquiring loans to implement periodic seaweed collection.
It is very important that non-market valuation studies are conducted in a way that generate useful inputs for policy analysis and policymaking in developing countries struggling with funding for environmental conservation. One of the ways in which scholars can make this important contribution is to implement non-market valuations with the goal of supporting benefits transfer (BT) studies. Non-market valuation studies usually involve the use of surveys to collect willingness to pay (WTP) data. Oftentimes, researchers conducting non-market valuations have to rely on existing studies to infer benefits or WTP due to budgetary and time constraints that make it impractical to conduct original WTP studies. Benefits transfer (BT) methods are used to transfer WTP from a study site where an existing WTP study was conducted () to a policy site where an original WTP study is not feasible (). To illustrate BT methods, let the WTP of a study site be a function of income: . Expert opinions and inflation rates can be used to adjust to estimate in a unit-value BT method (Johnston et al., 2015). Another unit-value BT method involves the formula, where is the income elasticity of WTP (Pearce et al., 2006). For the function transfer method, the WTP function, , from the study site and variables, , from the policy site are used to predict (Pearce et al., 2006). For the meta-analysis approach, and descriptive data such as population demographics from multiple studies are used to develop a meta-analysis model, then descriptive data for the policy site is used to predict using the meta-analysis model (Pearce et al., 2006).
One way scholars can support BT research is to address the differences in the WTP of heterogeneous groups in their original non-market valuation studies. Since the demographics of a policy site and a study site are not exactly the same, studies that address differences in the WTP of heterogeneous groups support the BT literature by providing useful WTP estimates that allow BT scholars to account for demographic differences between a study site and a policy site. The importance of addressing heterogeneity to support BT studies or non-market valuation in general cannot be overemphasized since BT studies serve as the backbone of policy analyses and cost-benefit analyses (Smith et al., 2002; Pearce et al., 2006; Johnston et al., 2015) and can save developing countries facing funding challenges scarce resources that would otherwise be used to implement original WTP studies.
To address heterogeneity in non-market valuation, researchers have increasingly applied statistical techniques such as latent class analysis to classify survey data into unobservable groups or subsamples (Breffle et al., 2011). Membership for such statistically-generated groups are not unique and such groups do not constitute any easily-identifiable group in the real world. As such, WTP studies using statistically-generated subsamples provide researchers with little to no policy insight on how distinct, easily-identifiable socio-economic groups systematically value environmental resources differently. On the contrary, classifying survey data into distinct, easily-identifiable groups such as income-based groups produces more reliable, policy-relevant WTP estimates that are more useful to the BT literature.
Knowledge of how real-world heterogeneous groups value environmental resources differently does not only improve the quality of BT estimates (Barbier et al., 2017), it also produces a more reliable understanding of how the drivers of WTP vary across socio-economic groups (see Breffle et al., 2011). For instance, Breffle et al. (2015) studied the WTP for lake conservation in Wisconsin, USA and found that income is a significant driver of WTP for low-income households but not significant for high-income households. Also, they found that environmental attitudes impact the WTP for high-income households more than the WTP for low-income households. Their findings imply that, in valuing environmental resources, low-income households pay attention to income, while richer households pay more attention to environmental attitudes than poorer households do. Nastis and Mattas (2018) also studied WTP for the reduction of greenhouse gas emissions in Greece. They revealed that income elasticity for emission reductions is 0.96 for all households, but much higher, 1.40, for high-income households and lower, 0.48, for low-income households. Similarly, Barbier et al. (2017) studied the WTP for the reduction of eutrophication in the Baltic Sea in nine European countries. They also revealed that the income elasticity of WTP (0.6–0.7) for high-income households is significantly larger than that of their low-income counterparts (0.1–0.2). These findings prove that high-income and low-income households differ in their non-market values for environmental protection; knowledge of the systematic differences in the drivers of WTP are beneficial to our understanding of public support for environmental protection; and such knowledge can be beneficial to the estimation of reliable benefit transfers.
The environmental policy literature is replete with WTP studies on marine and coastal conservation, and invasive species policies (O'Garra, 2009; Garcıa-Llorente et al., 2011; Halkos and Matsiori, 2012; Breffle et al., 2015; Risen et al., 2017; Ison et al., 2018; Needham and Hanley, 2019; Rodella et al., 2019). However, none of the existing studies provide knowledge about WTP for invasive seaweed management or the differential influence of the drivers of WTP for income-based groups in any developing country. As a result, our goal is to address the lack of funding for seaweed cleanup by studying the drivers of public support or WTP for seaweed cleanup in West Africa. We conducted a contingent valuation study to understand how WTP and drivers of WTP to support seaweed cleanup vary systematically across high-income and low-income households in Ghana. Our study supports efforts to address the funding challenge impeding the implementation of seaweed cleanup in developing countries by providing useful policy insights on how high-income and low-income households differ in their WTP for seaweed cleanup. Our work also adds to the growing literature on the heterogeneity of consumers' non-market values for environmental resources and supports the benefit transfer and cost-benefit analysis literatures on environmental protection in developing countries.
Section snippets
Study site
We conducted a contingent valuation (CV) survey in Elmina, one of the affected coastal towns in Ghana. Elmina is a vibrant town of 64 km square (Arthur and Mensah, 2006) and 25,560 residents (World Population Review) located in the Central region of Ghana. Elmina is among the largest fishing towns in the Central region with fishing activities dating back to the 1400's (Odotei, 2002). The town has the largest landing site in the region, and the third largest landing site in the country (Aheto et
Contingent valuation method
We applied the contingent valuation method (CVM) in our study to elicit both use values (i.e. the direct or indirect benefits derived from a resource) and non-use values (i.e. the satisfaction of knowing that a resource exists for the benefit of others, future generations, or for the sake of existence) residents will derive from coastal conservation in Elmina, Ghana. Although Choice Experiments (CE) can also be used to elicit both use and non-use values, CVM has several advantages over CE. CVM
Survey results
A total of 502 households participated in the survey, representing 91% of the 550 households targeted for the survey in Elmina. Out of the 502, 480 provided answers to the WTP question but 22 did not. Out of the 480 households that provide WTP data, 312 (65%) selected WTP values greater than zero, 145 (30.21%) selected zeroes and 23 (4.79%) selected “don't know”. Among the 312 WTP answers (WTP>0), we detected and deleted one outlier. For the zero WTP answers, we treated 13 out of the 145 as
Discussion
We conducted this research to understand the drivers of public support or WTP for the clean-up of invasive Sargassum seaweeds in developing countries, and how the drivers of WTP vary across high-income and low-income households. We also aimed at estimating the mean WTP for high-income and low-income households, as well as the mean WTP for the general public to support the periodic collection of invasive Sargassum seaweeds in Elmina, Ghana. We carried out this study to provide insights on the
Conclusion
We studied the influence of socio-demographic factors on public support or willingness to pay (WTP) for seaweed cleanup in Elmina, Ghana. We conducted this research to understand how the drivers of WTP vary across high-income and low-income households as well as the general public in developing countries. As we have revealed, household income, education of household head, years of residence, distance to the beach and attitudes about invasive seaweeds significantly influence the WTP of all
Funding
This research was partly funded by the Ecosystems Science Center and the Great Lakes Research Center at Michigan Technological University.
Declaration of competing interest
The authors declare no conflict of interest.
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