NTFP harvesters as citizen scientists: Validating traditional and crowdsourced knowledge on seed production of Brazil nut trees in the Peruvian Amazon

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.

Strategies to optimize modeling habitat suitability of Bertholletia excelsa in the Pan‐Amazonia

“…With respect to the most important predictors that control its spatial distribution, our results are similar to those found in other studies. In Peru, seed production was found to be positively correlated with clay content and negatively with sand content (Thomas et al, ). In Brazil, Guerreiro et al () found that the species has a preference soils with a clayey to very clayey texture.…”

“…In addition, our model indicates that many lowland areas were suitable in contrast to the prevailing notion that this species prefers upland areas (Scoles et al, ). Indeed, species seed production has been shown to be lower when trees were close to rivers (Thomas et al, ). The unexpected inclusion of lowland areas as suitable Amazon‐nut habitat was discussed with experts.…”

Combining species distribution modelling and environmental perceptions to support sustainable strategies for Amazon-nut (<i>Bertholletia excelsa</i> Bonpl.) planting and conservation

“…8), our results are similar to those found in other studies. In Peru, seed production was found to be positively correlated with clay content and negatively with sand content (Thomas et al 2017).…”

“…excelsa has been shown to be lower when trees were close to rivers (Thomas, et al 2017). The unexpected inclusion of lowland areas as suitable Amazon-nut habitat was discussed with experts.…”

“…Another reason is that its seeds are one the most important non-timber forest product traded in the region (Thomas et al, 2017). Fruit's success is recently attributed to health benefits offered by the seeds rich in selenium and other micronutrients .…”