**1. Introduction**

Coastal ecosystems are among the most productive ecosystems; offering beneficial services that enhance people's well-being and supporting local communities and national economies [1,2]. Among these services are food provision, habitat for commercially important species [3], coastal protection [4], and cultural services [5]. Another key service coastal wetlands provide that was overlooked in the past is the regulation of the global climate; currently referred to as "blue carbon" [6]. This concept recognizes the vital role of the coastal wetlands as buffers to the adverse effects of the changing, in this case, increasing, world atmospheric carbon dioxide levels [7]. This is possible through the thriving photosynthetic organisms in coastal ecosystems that extract carbon dioxide directly from the atmosphere and surface waters [8,9]. Mangroves, seagrass meadows, and tidal marshes, collectively called blue carbon ecosystems (BCEs), sequester and store carbon dioxide as

**Citation:** Quevedo, J.M.D.; Uchiyama, Y.; Muhmad Lukman, K.; Kohsaka, R. How Blue Carbon Ecosystems Are Perceived by Local Communities in the Coral Triangle: Comparative and Empirical Examinations in the Philippines and Indonesia. *Sustainability* **2021**, *13*, 127. https://dx.doi.org/10.3390/su13010127

Received: 19 October 2020 Accepted: 22 December 2020 Published: 24 December 2020

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organic carbon in their biomass (above and below ground) and soil material [10,11]. BCEs may carry out this process continuously for over thousands of years, locking away carbon that could contribute to the heating of the earth's atmosphere into a large number of carbon stocks in biomass and organic-rich soils [6].

One of the world's richest hotspots of marine biodiversity lies in the Coral Triangle Region (CTR) [12], where Indonesia and the Philippines are geographically located. In terms of BCEs in the region, Indonesia has the largest mangrove and seagrass coverage, around 2,707,572 ha [13] and 3,000,000 ha [14], respectively, whereas the Philippines has roughly 256,185 ha of mangrove forests [15] and 97,800 ha of seagrass meadows [16]. Tidal marshes are not found in these countries since they thrive in mid- to high-latitude regions [17]; ranging from arctic to subtropical regions [18]. The degradation of coastal wetlands in the Philippines and Indonesia could result in discernable loss of beneficial services such as food sources, protection against storm surges, and cultural services [19–21]. Moreover, as BCEs are in decline, their intangible and long-term service of carbon sequestration and storage are likely to be affected as well. A large number of carbon stocks sequestered over the years in Indonesia and the Philippines are threatened to be released back into the air, contributing to the further rising of global temperature, if these ecosystems continue to be degraded and lost [22,23]. Much of the deterioration of these coastal resources is mostly anthropogenic, particularly due to land-use conversion [1,24,25].

In response, researchers, policymakers, and implementers are gearing towards building a strong foundation of science, policy, and sustainable coastal management practices for the conservation and restoration of BCEs as a means of collective effort in addressing climate change [6]. Some of the recent advances on blue-carbon-related studies in the Philippines and Indonesia include carbon stock assessment and carbon sequestration potential [14,26,27], policies and finance mechanisms [28–30], and public's perceptions [31–34]. Collaborative workshops and other initiatives on blue carbon involving these two countries along with other members in the CTR are also progressing (i.e., [6,35]). There is the International Partnership for Blue Carbon (IPBC) established during the Paris Agreement, UNFCCC COP21, in 2015, which was aimed at connecting efforts of research organizations, governments, non-government and international organizations in enhancing the protection and restoration of BCEs [36]. Such partnerships can foster and strengthen the relationships of the involved countries by sharing knowledge, experiences, and expertise in understanding better the importance of BCEs in global climate regulation and adaptation, achieving sustainable development goals, growing the blue economy, and meeting national commitments to the Paris Agreement [6].

Despite the gaining momentum of the "blue carbon" discourse and collaborative actions in the international and national arenas, more work is still needed at the local level especially where local governments, implementers, and residents are the ones interacting with—benefiting from and taking advantage of resources from—these ecosystems. This work pursues how BCE initiatives permeate through the local communities in CTR, particularly in the countries of Indonesia and the Philippines using perception inquiries. Local perceptions, based on comprehensive theoretical and empirical evidence, have a critical role in supporting collective responses for the sustainable management of natural resources (i.e., [34,37]). Engaging local communities in ecosystem service assessments helps define their role in the multi-governance of environments as well as the importance of ecosystem services (ES) and the factors that influence social preferences and trade-offs related to land-use change and decision-making [38]. ES in this study is based on the definition of [38] which refers to the benefits people obtain from ecosystems. These include provisioning services (i.e., food), regulating services (i.e., climate regulation), cultural services (i.e., recreational benefits), and supporting services (i.e., habitat). Local's perception of ES is a very subjective process—it can be based on their comprehension, interpretation, and experiences. There is also a concern of how ES provides well-being and how these benefits are valued, whether as an "instrumental" value when attributed to a particular purpose or as a "relational" value when used to measure certain types of interactions, by society [39].

For instance, some locals may recognize cultural services based on their aesthetic, educational, and therapeutic values [40] while others based on the accessibility and proximity of the resources (i.e., tourism sites) [41]. There is also a shift at the conceptual level which is focusing more on "indirect drivers" in ES assessments although "direct drivers" are still largely highlighted in frameworks such as the Driver-Pressure-State-Impact-response (DPSIR) [42,43]. Indirect drivers (i.e., demographic, economic, socio-political, cultural) can heavily influence locals' perceptions and attitudes towards the environment with subsequent environmental implications (positive or negative).

In this study, people's awareness level, utilization rates, perceived threats, and management strategies were gathered and used as proxies in determining the familiarity of coastal communities to BCEs, which in turn could reflect the current management directives at a local scale in the Philippines and Indonesia in CTR. The people's awareness and utilization of ES in this work are closely associated with assessing the instrumental value of the benefits (i.e., food provision, recreation) since these benefits allow people to achieve a good quality of life [39]. "Relational" values, which are equally important, were not assessed since this involved a thorough examination of the relationship between the people and nature, like determining their specific principles or moral duties on how they can relate to nature [39]. Socio-demographic characteristics were factored in, since previous studies have shown their effect on an individual's perceptions [33,37]. Furthermore, a comparative analysis was done to determine distinctions and commonalities in perceptions as influenced by site-specific scenarios. These perceptions can be translated to become useful metrics in contextualizing and/or enhancing coastal management plans specifically in strategizing advocacy campaigns and engagement of local stakeholders. Up until recently, there has been a preference for a bottom-up approach in management and governance in the Philippines and Indonesia. How the study underscores local perceptions could also contribute to this grassroots/community-based and informed course of action for the national level to highly consider and prioritize. The availability of this information across the CTR could be a sound foundation to compare and contrast how coastal communities from different countries perceive and value their resources. This crucial learning could then be furthered into identifying common grounds that can be transferrable across or translated into a contextualized regional program within the CTR.
