Abstract
Understanding the factors that underlie the production of non-timber forest products (NTFPs), as well as regularly monitoring production levels, are key to allow sustainability assessments of NTFP extractive economies. Brazil nut (Bertholletia excelsa, Lecythidaceae) seed harvesting from natural forests is one of the cornerstone NTFP economies in Amazonia. In the Peruvian Amazon it is organized in a concession system. Drawing on seed production estimates of >135,000 individual Brazil nut trees from >400 concessions and ethno-ecological interviews with >80 concession holders, here we aimed to (i) assess the accuracy of seed production estimates by Brazil nut seed harvesters, and (ii) validate their traditional ecological knowledge (TEK) about the variables that influence Brazil nut production. We compared productivity estimates with actual field measurements carried out in the study area and found a positive correlation between them. Furthermore, we compared the relationships between seed production and a number of phenotypic, phytosanitary and environmental variables described in literature with those obtained for the seed production estimates and found high consistency between them, justifying the use of the dataset for validating TEK and innovative hypothesis testing. As expected, nearly all TEK on Brazil nut productivity was corroborated by our data. This is reassuring as Brazil nut concession holders, and NTFP harvesters at large, rely on their knowledge to guide the management of the trees upon which their extractive economies are based. Our findings suggest that productivity estimates of Brazil nut trees and possibly other NTFP-producing species could replace or complement actual measurements, which are very expensive and labour intensive, at least in areas where harvesters have a tradition of collecting NTFPs from the same trees over multiple years or decades. Productivity estimates might even be sourced from harvesters through registers on an annual basis, thus allowing a more cost-efficient and robust monitoring of productivity levels.
Highlights
The integration of crowdsourcing approaches in citizen science has recently become a mayor tool to collect and analyse large quantities of data efficiently and often cheaply, in the traditional areas of conservation biology [1], and increasingly in scientific domains related to plant production and improvement [2]
We assess the accuracy of seed production estimates of the Brazil nut (Bertholletia excelsa, Lecythidaceae), one of the most important non-timber forest products in Amazonia [6], by people engaging in annual seed harvesting in the Peruvian Amazon
The variables reported by concession holders were: soil type, soil drainage, precipitation, the number of branches, canopy form, closeness to conspecific neighbour, presence of companion species, health status, liana infestation, fruit predation by parrots, infestation by leaf cutter ants, strangler epiphyte infestation, imminent mortality, being a macho tree, pollinator presence, seed production history of a tree, fire and smoke produced by neighbouring land uses and gold mining
Summary
The integration of crowdsourcing approaches in citizen science has recently become a mayor tool to collect and analyse large quantities of data efficiently and often cheaply, in the traditional areas of conservation biology [1], and increasingly in scientific domains related to plant production and improvement [2]. Measurements necessarily have to run over several years to account for the high interannual variability in fruit production [7]. Due to these limitations, studies that investigated productivity of Brazil nut have considered a limited number of trees (
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