Adaptations in the transformation of cassava (Manihot esculenta Crantz; Euphorbiaceae) for consumption in the dietary management of diabetes: the case of Palikur, or Parikwene People, from French Guiana

Introduction

In the French overseas department of French Guiana, in South America, nutrition therapy for the management of diabetes is based on French guidelines. However, this region is demographically diverse and includes several populations of Indigenous Peoples, Parikwene among others, also called Palikur. Due to socio-economical, cultural, and geographical differences, along with distinctions in the local food system, dietary recommendations, which many consider in the context of post-colonial power dynamics, are not well suited to local populations. In the absence of suitable recommendations, it is hypothesized that local populations will adapt their dietary practices considering diabetes as an emerging health problem.

Methods

Seventy-five interviews were conducted with community members and Elders, as well as healthcare professionals and administrators providing services to the Parikwene population of Macouria and Saint-Georges de l'Oyapock communes. Data regarding the representation of cassava (Manihot esculenta Crantz) consumption and diabetes were collected via semi-structured interviews and participant observation (i.e., observation and participation in community activities), namely via participating in activities related to the transformation of cassava tubers at swidden and fallow fields.

Results and Discussion

Parikwene have adapted the transformation of cassava tubers for their consumption in the management of diabetes.The importance of cassava tubers as a staple and core food to the Parikwene food system was established by identifying it as a cultural keystone species. Narratives illustrated conflicting perceptions regarding the implication of cassava consumption in the development of diabetes. Adaptations to the operational sequence involved in the transformation of cassava tubers led to the production of distinct cassava roasted semolina (i.e., couac), based on organoleptic properties (i.e., sweet, and acidic couac). Preferences for the consumption of acidic couac were grounded in the Parikwene knowledge system, as well as attention to diabetes related symptoms and glucometer readings.

Conclusion

These results provide important insights related to knowledge, attitudes, and practices in developing locally and culturally adapted approaches to providing dietary recommendations in the treatment of diabetes.

Defaunation changes leaf trait composition of recruit communities in tropical forests in French Guiana

Hunting impacts tropical vertebrate populations, causing declines of species that function as seed dispersers and predators, or that browse seedlings and saplings. Whether and how the resulting reductions in seed dispersal, seed predation, and browsing translate to changes in the tree composition is poorly understood. Here, we assess the effect of defaunation on the functional composition of communities of tree recruits in tropical rainforests in French Guiana. We selected eight sites along a gradient of defaunation, caused by differences in hunting pressure, in otherwise intact old-growth forests in French Guiana. We measured shifts in functional composition by comparing leaf and fruit traits and wood density between tree recruits (up to 5 cm diameter at breast height) and adults, and tested whether and how these compositional shifts related to defaunation. We found a positive relationship with defaunation for shifts in specific leaf area, a negative relationship for shifts of leaf toughness and wood density, and a weak relationship for shifts in fruit traits. Our results suggest that the loss of vertebrates affects ecological processes such as seed dispersal and browsing, of which browsing remains understudied. Even though these changes sometimes seem minor, together they result in major shifts in forest composition. These changes have long-term ramifications that may alter forest dynamics for generations.

Shifting cultivation and hunting across the savanna-forest mosaic in the Gran Sabana, Venezuela: facing changes

BACKGROUND

Human encroachment and overexploitation of natural resources in the Neotropics is constantly increasing. Indigenous communities all across the Amazon, are trapped between a population rise and a hot debate about the sustainability of hunting rates. The Garden Hunting hypothesis states that shifting cultivation schemes (conucos) used by Amazon indigenous communities may generate favorable conditions, increasing abundance of small and medium wildlife species close to the 'gardens' providing game for indigenous hunters.

METHODS

Here, we combined camera trap surveys and spatially explicit interview dataset on Pemón indigenous hunting scope and occurrence in a mosaic of savanna and forest in the Gran Sabana, Venezuela to evaluate to what extent the wildlife resource use corresponds to Garden Hunting hypothesis. We applied the Royle-Nichols model and binomial regression in order to: (1) assess whether abundance of small and medium wildlife species is higher close to conucos and (2) evaluate whether hunters select hunting localities based on accessibility to wildlife resources (closeness to conuco) more than wildlife abundance.

RESULTS

We find mixed evidence supporting the Garden Hunting hypothesis predictions. Abundance of small and medium species was high close to conucos but the pattern was not statistically significant for most of them. Pemón seem to hunt in locations dominated by forest, where species abundance was predicted to be higher, than in close vicinity to conucos. Hunting scope was focused on the most abundant species located close to the conuco (Cuniculus paca), but also in less abundant and unavailable species (Crax alector, Tapirus terrestris and Odocoileus virginianus).

CONCLUSIONS

Our research provided the first attempt of a systematic sampling survey in the Gran Sabana, generating a quantitative dataset that not only describes the current pattern of wildlife abundance, but sets the base-line to monitor temporal and spatial change in this region of highland Amazon. We discuss the applicability of the estimates generated as a baseline as well as, environmental challenges imposed by economic, social and cultural changes such as mining encroachment for wildlife management.

Amazonian mammal monitoring using aquatic environmental DNA

Environmental DNA (eDNA) metabarcoding has emerged as one of the most efficient methods to assess aquatic species presence. While the method can in theory be used to investigate nonaquatic fauna, its development for inventorying semi-aquatic and terrestrial fauna is still at an early stage. Here we investigated the potential of aquatic eDNA metabarcoding for inventorying mammals in Neotropical environments, be they aquatic, semi-aquatic or terrestrial. We collected aquatic eDNA in 96 sites distributed along three Guianese watersheds and compared our inventories to expected species distributions and field observations derived from line transects located throughout French Guiana. Species occurrences and emblematic mammalian fauna richness patterns were consistent with the expected distribution of fauna and our results revealed that aquatic eDNA metabarcoding brings additional data to line transect samples for diurnal nonaquatic (terrestrial and arboreal) species. Aquatic eDNA also provided data on species not detectable in line transect surveys such as semi-aquatic, aquatic and nocturnal terrestrial and arboreal species. Although the application of eDNA to inventory mammals still needs some developments to optimize sampling efficiency, it can now be used as a complement to traditional surveys.