The territorial protection and resource surveillance carried out by Amazonian local communities involved in arapaima co-management has ensured the protection of vast areas of tropical forest, safeguarding the flow of multiple ecosystem services at different scales (Campos-Silva and Peres, 2016). Our results provide further strong evidence that the protection of aquatic environments within community-based fisheries arrangements ensure the protection of much larger intact aquatic and terrestrial areas compared to only the aggregate lake area alone where dry-season fishing activities are conducted. Local communities are always present and protect their harvestable aquatic environments all year-round and around the clock, although commercially valuable fish stocks become more vulnerable during the prolonged annual flood pulse, when communal protection efforts become more diffuse across the vast floodwaters. However, surveillance demands enormous dedication of time and effort, in addition to incurring a high cost to the low-income families involved, by limiting their capacity to engage in other profitable activities and subsistence food production. In this context, community-led territorial governance and protection represents a substantial opportunity cost for local households. It is therefore critical to recognize, and ideally enhance, communal surveillance activities through financial support of local communities if the long-term success of this CBC program is to be maintained (Franco et al., 2021).
Spatial extent of community-based protection
Most arapaima population assessments consider lakes as the spatial unit of fisheries management (Campos-Silva and Peres, 2016; Castello et al., 2009). However, our results show that the effective protection by resident communities, considering their routine surveillance routes on foot, are almost eight times larger than the actual aggregate lake area, and this extended protection footprint in fact becomes much larger, considering that guarding floodplain environments during the critical time of the year incidentally precludes access to adjacent upland forests that could be reached otherwise. Therefore, by avoiding illegal incursions by outside users into the floodplain and its anastomosing channels, local communities are also ensuring the added-value protection of vast areas of unflooded upland forests. In this context, beyond the strong positive impact on fisheries resources and aquatic biodiversity, as shown elsewhere (Campos-Silva and Peres, 2016; Campos-Silva et al. 2019), the effective protection of both várzea and terra firme forests during the low-water season clearly brings about strong additional benefits to terrestrial biodiversity conservation by preventing illegal exploitation by fishers, hunters, loggers and, more recently, miners.
Another key finding reported here is the spatial extent of functional protection, which is an important hidden positive impact of community-based conservation. The Juruá River experiences a flood pulse that can reach depths of up to 11 m for up to 230 days a year (Junk et al., 2011). Arapaima fish exhibit lateral migration patterns during this prolonged flood pulse, including habitual movements into flooded forests between tributary lakes and perennial streams, and the main river channel (Campos-Silva et al., 2019). Population recovery of this apex predator is closely associated with lateral migration and replenishing of depleted environments (Campos-Silva et al. 2019), which can impact the top-down trophic dynamics across an area ~ 255-fold larger than the neighbouring lake area, thereby controlling the abundance of other important prey species (Campos-Silva et al., 2021). In addition, the spatial contagion of enforcing protection ensures recolonization of previously depleted areas far away from the target lake, reinforcing the importance of co-management activities in promoting food security for Amazonian rural communities (Darimont et al., 2015; Tregidgo et al., 2020).
Cost of community-based protection in a seasonal environment
Arapaima population viability is closely linked to the hydrological cycle, including the supra-annually variable seasonal flood pulse, which markedly alters the seasonal fluvial connectivity of the floodplains along major meandering rivers of the Amazon (Junk et al., 1989). At this time of year, arapaima move between lakes, the main river channel, and the flooded forest, where they gain access to high-quality food sources. When floodwaters begin to recede, arapaima shows a high degree of site fidelity, returning to their breeding lakes, particularly when conditions are quiet including low ambient noise (Campos-Silva et al., 2019). This therefore demands a much greater community effort during this period to protect stocks against human disruptions induced by fishing gear and poaching (Fig. 3). This leads to a marked peak of labour-intensive surveillance activity that requires substantial resources, including food supplies, fuel, boats and canoes, and a larger number of volunteers because groups of arapaima can flee the lakes prematurely if they perceive a threat from outside fishers.
Lake surveillance costs increased with proximity to urban areas, particularly for those lakes containing high densities of arapaima. This is expected because lakes exposed to greater subsistence and commercial exploitation pressure — which is linked to high human population densities near urban centers, where illegal offtakes are more frequent (Silvano, 2014; Abrahams et al., 2017) — require higher territorial protection engagement and costs. In addition, considering the high-value of arapaima, productive lakes containing large stocks are often well known and more vulnerable to external exploitation, (Campos-Silva and Peres, 2016), and are therefore more intensively targeted by illegal fishers and poachers.
Comparing the costs of community-led efforts against alternative scenarios that rely on proactive participation of government agencies or NGOs, we easily reach the conclusion that local community inclusion in conservation arrangements is the cheapest and most cost-effective mechanism to ensure the protection of natural ecosystems, such as the Juruá floodplains. However, we emphasise the glaring lack of social justice behind this strategy given the heavy burden and local opportunity costs considering that the time and effort spent in territorial protection could be allocated to alternative income generation activities. In fact, the substantial asymmetry between large conservation benefits accrued at multiple scales and the local socioeconomic costs incurred locally represents one of the main bottlenecks in implementing community-based arrangements. This distortion thus needs to be addressed to strengthen the CBC model in Amazonia and beyond.
Although the costs of community-led protection can be seen as exceedingly low compared to the typical investments on conservation interventions made by most external agencies (Silva et al., 2019), those values are extremely high for disenfranchised local communities, which accept to soldier on because this heavy burden yields many other benefits beyond a simple monetary tradeoff (Campos-Silva et al., 2021). Our study communities have legitimized their interests through co-management actions, increasingly engaging in conservation practices with intrinsic motivations that are often above economic payoffs. In addition to collective decision-making, there is a collective sense of autonomy and belonging that ensures access to natural resources for both present and future generations (Gamarra et al., 2022; Ostrom, 2009). Given little or no action enacted by toothless environmental agencies throughout the Amazon, this local community empowerment has filled the vacuum by successfully protecting their own territories against major threats by external enterprises waging predatory overexploitation (Levis et al., 2020; Lopes et al., 2021).
Strengthening recognition of hidden environmental services
Community-led biodiversity protection thorough local empowerment can ensure socio-environmental governance and maintenance of ecosystem services and opportunities for self-development both inside and outside protected areas (Campos-Silva et al. 2022), especially when confronting hostile policies in which the main environmental regulations have been dismantled (Vale et al., 2021). However, local communities cannot continue to shoulder the heavy burden of 24-by-7 environmental protection without external support. This is vital for the maintenance of community-based conservation, given that biodiversity-based value chains are not sufficiently fair to cover the intrinsic costs of environmental protection. In addition, above and beyond the financial costs associated with surveillance efforts, there are other secondary opportunity costs incurred by neglecting horticultural investments, which also provide subsistence and income (Alves-Pinto et al., 2018; Newton et al., 2012). Furthermore, a relentless state of surveillance and readiness imposes a substantial physical and psychological toll, with the ever-present possibility of violent hostilities with potential intruders, which in extreme cases can be life-threatening.
Payments for Ecosystem (or environmental) services (PES) has the potential to contribute highly positive conditional incentives for the provision of ecosystem services. Although this approach is more common in terrestrial conservation, it has recently grown in fisheries management. In sum, PES is more likely to succeed within fisheries arrangements that show (i) demand for one or a set of ecosystem services or bottlenecks in the value-chain; (ii) evidence-based approach with a clear baseline; (iii) clear boundaries and property rights; (iv) strong local governance; (v) robust monitoring, control and surveillance; and (vi) financial sustainability (Bladon et al., 2016). Arapaima co-management in the Brazilian Amazon shows a high level of community organization, in addition to the balanced participation of local institutions, NGOs, academic institutions, and government agencies. These conditions provide a solid foundation for the implementation, organization, and development of PES programs involving established CBC arrangements. This is critical because the lack of socio-political organization often makes these schemes unworkable (Salzman et al., 2018).
Our study clearly underscores an imperative moral challenge of directly compensating local communities for a wider public good generated by their environmental protection efforts (Arantes et al., 2022). A fairer return on their conservation efforts is vital to compensate for their tangible contributions and roles as protagonists of these arrangements, aligning biodiversity protection with local wellbeing. As such, strengthening and ensuring better surveillance conditions and greater economic returns to local communities can capture the long-term goals of local environmental and socioeconomic sustainability. A co-designed PES model should be conceived transparently in terms of who pays (the buyers), who benefits (the beneficiaries), and who sells (the providers) (Hallwass et al., 2013). We advocate that a PES mechanism within the arapaima CBM program in Brazil should be supported multilaterally between inter-governmental funds, non-governmental initiatives, and international cooperation, considering that the ecosystem services indirectly provided by local communities operate at a global scale (Levis ate al. 2020). The Brazilian government has the means to implement a PES program, which could become a key financial mechanism, strengthening the economic benefits of environmental protection, promoting an increased sense of ownership, and engaging new communities in arapaima management, similarly to other PES programs like the Bolsa Floresta (Cisneros et al., 2022).
Payments for Ecosystem Service programs have raised significant ethical and social concerns. If natural resources are considered a commodity, susceptible to monetary or non-monetary transactions, this could exacerbate inequalities in the distribution of benefits, potentially disadvantaging the communities involved (Kaiser et al., 2021). For initiatives to be effective, equity in the distribution of PES benefits must be part of the entire workflow of activities.
Neglecting the interconnected aspects of socio-biodiversity can undermine the effectiveness of conserving natural environments. Focusing exclusively on measurable environmental services and simplifying ecological processes can often undervalue natural resources with simplistic and direct values (Shapiro-Garza et al., 2020; Upton, 2020). One solution is a comprehensive and detailed resource assessment, avoiding the exclusion of critical operational factors for PES development and maintenance (Kaiser et al., 2021).
By benefiting from PES, communities can paradoxically become dependent and vulnerable if there are no strategies to mitigate financial and structural risks that ensure the continuity of activities (Upton, 2020). To this end, diversifying funding sources reduces the risks associated with possible interruptions or lags in payments and/or benefits (Kaiser et al., 2021). In this way, community-based surveillance systems can be ensured in the long term, as well as become established as a fair activity (Shapiro-Garza et al., 2020).
Community participation is a crucial element in the processes of designing, implementing, and monitoring the effectiveness and success of PES activities (Kaiser et al., 2021; Ostrom, 2010). In addition, this must be based on transparency among investors, beneficiaries, and providers (Shapiro-Garza et al., 2020; Upton, 2020). Thus, the active participation of community members, together with inter-institutional partnerships, can render bureaucratic and legal processes enforceable in a participatory manner (Shapiro-Garza et al., 2020). Our results showcase a highly feasible and remarkably inexpensive model in which territorial protection across vast tracts of Amazonian forests can be ensured by relatively modest financial investments that would strengthen frontline conservation.