# The importance of individuals of different sizes in the population maintenance of a palm species used by the Fulni-ô Indigenous People in northeast Brazil

## TL;DR

This study examines how leaf harvesting by the Fulni-ô Indigenous People affects the population of a palm species in Brazil, highlighting the importance of protecting younger plants and managing harvest practices.

## Contribution

The study introduces a novel approach combining demographic modeling and participatory mapping to assess sustainable harvesting practices for a culturally significant palm species.

## Key findings

- High leaf harvest frequencies led to declines in palm populations, while lower harvest rates were more influenced by growth of smaller individuals.
- Seedling recruitment was reduced, emphasizing the need to protect younger plants for population sustainability.
- Larger palm individuals had the greatest impact on population growth but showed lower survival under high harvest pressure.

## Abstract

Factors such as climate, soil characteristics, habitat type, and land management practices can influence the demography of plant populations harvested by Indigenous Peoples and local communities. Here, we assessed the demographic responses of the palm Syagrus coronata to varying leaf harvest frequencies by the Fulni-ô Indigenous People in sites with different environmental and anthropogenic conditions in Águas Belas, Pernambuco, northeast Brazil. The leaves of this species are primarily harvested for handicraft production. In collaboration with local artisans, we conducted a participatory workshop where they identified harvest locations on a regional map. Plots and subplots were established in six of these sites, and the total height of all S. coronata individuals was recorded. We monitored survival and growth over three consecutive years and counted infructescences on reproductive individuals every three months during the first two years. Newly recruited individuals were also recorded and measured. Environmental variables (light availability, air temperature, and humidity) were measured quarterly in the first year, and soil samples were collected for chemical and physical analysis. We performed a principal component analysis (PCA) to evaluate differences among sites based on environmental and anthropogenic variables. Using demographic data, we constructed integral projection models (IPMs) and conducted a life table response experiment (LTRE) analysis to estimate vital rates and deterministic population growth rates (λ) for each population and sampling interval. Our results showed that S. coronata populations under high harvest frequencies declined during the study period. In contrast, populations with lower harvest frequencies were more influenced by the growth of smaller individuals, though seedling recruitment was reduced, highlighting the need to preserve these younger plants. Higher air temperatures, nutrient availability, and soil pH likely contributed to low adult fecundity and reduced recruitment. Additionally, cattle and livestock presence may have further hindered recruitment by trampling and grazing on smaller plants. In populations subjected to intermediate and high harvest frequencies, larger individuals had the greatest impact on population growth rates. However, these individuals exhibited lower survival, suggesting that harvest pressure may negatively affect this vital rate, as the Fulni-ô harvesters preferentially target larger juveniles and adults for their more substantial leaves. Based on these findings, we recommend management strategies to support S. coronata conservation while ensuring sustainable harvesting and safeguarding Fulni-ô handicraft production.