1. Introduction

Participatory management is a key strategy for natural resource conservation and management that has been adopted in many countries. It recognizes the need to address social and environmental concerns collectively, as one affects the other ^[1][2]. Theoretically, the participatory approach would lead to a “win-win” result: environmental sustainability and social development. However, its on-site implementation encounters constraints and yields unsuccessful outcomes ^[2][3][4][5]. Providing benefits and incentives for local communities is also problematic and calls for improvement ^[6][7].

Worldwide forest governance has adopted participatory approaches in the belief that this strategy would lead to environmental sustainability while also accounting for social concerns ^[4][5][7][8]. Previous studies concluded that long-standing strict and exclusionary conservation caused pressure on local communities such as displacement and restrictions on the use of resources ^[7][9][10]. Meanwhile, participatory management, a more people-centered approach, would, in theory, produce “win-win” results: a strategy for resource protection and conservation and for delivering benefits to local communities ^[1][2].

Local communities, as the cornerstone of the participatory approach, play a vital role in the success of this management strategy, hence strengthening their participation is highly important. However, local people’s participation is contingent on the incentives and benefits they will receive ^{[6][11][12][13]}. In contrast, receiving no benefits means the social objective of participatory forest management is neglected, consequently discouraging local people from participating. The studies of Cao et al. ^[14] stressed that sudden and untimely discontinuation of benefits could cause local people to revert to their former unsustainable practices in forest resource utilization. However, it is important to understand that a perpetual supply of benefits for people is irrational and inefficient. The outcome of participation should function as a means to improve people’s capabilities to achieve self-reliance and self-governance and thus, realize sustainability.

2. Social Capital in Natural Resources Management

Social capital was conceptually defined as a productive resource inherent in the relations among persons of less tangible nature than human capital ^[15]. The forms of social capital consist of trust, norms, and networks which facilitate coordinated actions ^[16]. The notion of social capital, although centers on actor’s relationships with and between actors, covers more than just social networks (Table 1). These definitions focus more on assets than social relations and highlight two main points. First, social capital is created by building social relationships. Social capital is instantiated in an actual human relationship and leads to cooperation in groups ^[17][18]. The connections and relationships are driven by interests ^[19]. Therefore, social capital formed in the relations of actors is characterized by the norm of reciprocity ^[18]. Second, social capital functions as investments in order to acquire more resources that can further people’s opportunities. Thus, social capital is a resource embedded in social networks accessed and used by actors for their actions ^[20].

Table 1. Definitions of social capital.

The concept of social capital has been applied to broad fields—in economics, sociology, political science, and anthropology, among others—that have led to the development of its diverse theoretical conceptualizations ^[22]. Social capital is used for interpreting social phenomena in the sector of natural resource management. Several studies revealed a positive correlation between social capital and people’s participation in resources management ^[22][23][24]. Social capital can contribute to developing co-management of natural resources through enhanced community member’s participation ^[25]. The results of these empirical studies follow the concept of social capital by ^[26] as a “feature of social organizations” that “facilitate[s] action and cooperation for mutual benefit” in natural resource management. Social capital, applied in natural resources management with community participation, can benefit people in two ways: (1) by having connections with people who are “prepared and obliged to provide help and support” ^[19], and (2) by having access to embedded resources owned by the people within their networks ^{[20][21][27][28]}. Through social relations, people can gain control over embedded resources that they did not own previously ^[20][21]. Lin’s ^[20] theory of social capital elucidates that each member of a group is recognized as a “custodian of the limits of the group” and each has influence in the decision-making process. Accordingly, by being a member of a group, a person can influence how the resources can be used to her or his advantage. In particular, from the perspective of poor people, the function of social capital can improve one’s status in the society, as they contribute to the person’s improved recognition and increased assets ^[29][30].

3. The social capital concept applied to a study of mangrove restoration in the Philippines

Social capital theory argues that resources are contributed and shared, and become accessible through the establishment of social relations ^[17][20][31]. Our study follows the definition of social capital by Lin ^[20] as “the capital captured through social relations… with expected returns in the marketplace” with its concept understood by its functions ^[15]. Several scholars (e.g., ^[17][19][32]) also take this view and regard social capital as a productive asset that facilitates social and economic improvement. People and communities with better networks and higher social capital have a higher possibility of achieving better outcomes ^{[19][26][33][34]}. Furthermore, the author of ^[19] emphasized that an investment in social capital must also be seen as an investment in other assets, since social capital packages other forms of capital.

Social capital is the resource captured from social relations ^[21][31]. In this regard, the number of ties and networks a person has is a major factor that determines his social capital. However, increased social relations may not always increase one’s social capital, as several factors may affect the number of resources a person can access through his social relations. This study focused on three factors that can affect social capital: (a) diversity of social relations, (b) resource accessibility and social capacity, and (c) trust.

3.1. Social Relations and Diversity

Theoretically, having more social relations corresponds to having higher social capital, as these relations function as sources of embedded resources ^[19][28][34]. However, Teilmann ^[28] elaborated that “not all ties are similar.” Each tie has different amounts of resources and information. The nature and type of the social relations a person is associated with also affect the quantity and diversity of resources he can access. Two of the most common dichotomies of social relations were described by Granovetter ^[35] and Putnam ^[36]. Granovetter ^[35] differentiated strong ties from weak ties. Strong ties are relations that are readily available and can be easily established ^[35] and require little maintenance ^[28] while weak ties are the more distanced connections ^[35][37]. Putnam ^[36], on the other hand, differentiated social relations between bonding and bridging. Bonding social relationships are those with homogeneous groups, while bridging relations are the connections with other social classes ^[27][38][39]. Despite the stronger relationships with strong ties and bonding social capital, it may not be enough to produce sufficient benefits, opportunities, and impacts to improve one’s condition; for this purpose, establishing weak ties and bridging social capital are necessary. The work of Woolcock and Narayan ^[34] also explained that for the poor, bridging social capital is more important since it allows them to “get ahead” by accumulating more resources and better opportunities. Although bonding social capital is also relevant, it can only help the poor to “get by”.

3.2. Resource Accessibility and Social Capacity

Social relations are sources of information and resources, and having social relations benefits people as it increases their assets ^[17][20]. However, social relationships alone may not be sufficient to advance a person’s condition and status. Utilization of social relations is required for them to be impactful. Everyone has their own capacity to utilize their social relations and the attached embedded resources, or social capacity. It is the “ability of rural people to organize and use their social capital and other assets through various social structures and processes to achieve valued economic objectives” ^[32]. Lin ^[20] elaborated this in his theory of social capital, that access to and use of social resources are dependent on the ability of the individual. Those people who can use their social relations more effectively are expected to have higher incomes ^[32].

3.3. Trust

Trust is “a basic element of the relational dimension” ^[40] and the most essential element of social capital ^[35]. It is requisite to build and maintain social relations ^[26] and functions as a lubricant for interactions and cooperation between actors ^[28]. Groups exhibiting trust in their members can accomplish more compared to those without trust ^[15][41][42]. Furthermore, utilizing social relations requires trust; in contrast, having no trust depletes the purpose of social capital and undermines the contribution and sharing of embedded resources ^[21][39].

Table 3. Descriptive statistics of social capital variables of the sampled households.

* Statistical differences (Kruskal–Wallis) Significance level: *** p < 0.001. ^a Variables used for computation of social capital value. ^b Variables used for computation of ties value. ^c Variables used for computation of embedded resources value. ^d Variables used for computation of trust value.

The most perceivable impact of local participation can be observed in the difference in the amount of external social relationships, presented by number of the ties, between the members of the People’ Organization (PO) and nonmembers which is an important determinant of social capital. Members of POs have established connections and partnered with different government organizations. The networks with external organization have also improved the PO members’ access to diverse and more resources, mainly provided through government programs, that made more embedded resources available to the PO members compared to the nonmembers. Dasgupta et al. ^[37] described this as the utilization of indirect links, in which people can establish networks by means of their existing ties.

It was also determined, through the interviews and consultation, that nonmembers respect those who are members of the PO and recognize their accomplishments. Nonmember residents, as well as the village councils and the local government, have acknowledged both POs for their role in the protection and conservation of the environment. Residents of the two barangays generally trust the POs not only as environmental stewards but also as conflict managers and credible sources of information.