Journal of Zoological and Botanical Gardens

Living collections in botanical gardens play important roles in conservation, research, and education, but their potential to generate interpretable biological information for teaching and management is often underused. This study reports a teaching experience based on dendrometric data from the arboretum of the Rio de Janeiro Botanical Garden in a graduate course on applied statistics. The course combined R programming with a problem-oriented pedagogical approach, using a census dataset of 4621 individuals with DBH ≥ 10 cm as a common object of investigation. The dataset served as a common framework for linking statistical procedures, from exploratory analysis to model-based approaches, with botanical interpretation and management-oriented questions. Analytical outputs showed that taxonomic abundance, dominated by Arecaceae and Fabaceae, did not always correspond to structural dominance measured by total basal area. In addition, height–DBH models fitted for Roystonea and Carapa highlighted interspecific and between-bed variation within the arboretum. Student submissions reproduced and adapted the analytical workflows, while instructor feedback identified difficulties in regression interpretation and model diagnostics. Overall, the experience illustrates how dendrometric data from a living collection can be incorporated into applied statistics teaching while also providing information for collection assessment and future monitoring.

Many modern urban parks have free-ranging animals. This helps with the ex situ conservation of species and raises empathy and awareness. However, these populations, which receive food and medical treatment, can exceed expected densities and require management. Estimating population size is the first step. In this study, we used the capture–marking–recapture method to estimate the population size of free-ranging Dasyprocta sp. at the Emílio Goeldi Zoobotanical Park. Captures were conducted between October 2024 and December 2025. Each individual was weighed, measured, sexed and microchipped. We estimated population size using the Rcapture package and selected the best-fitting model using the Akaike information criterion (AIC). Size structure data showed that only two young animals were captured, and medical data recorded only two deaths during the study period. Due to closure, high population density and low birth and death proportions, we used closed population models. A total of 123 captures were made, including 94 markings and 28 recaptures. The estimated population size was 201 individuals, corresponding to a density of 37.2 ind/ha. This greatly exceeds previously reported densities for agoutis, and suggests an ecological imbalance in the study area. These findings provide an important baseline for monitoring and managing this population.

Gardens provide several ecosystem services, including functioning as a habitat for diverse taxa and promoting users’ well-being. Soil biodiversity is considered an important factor in the capacity of the soil to provide ecosystem services. Nematodes are widely used as environmental indicators based on their key roles in the soil food web. Nematode and plant communities were studied across five different areas in a garden in Ireland as part of an assessment of soil health, as well as to explore their distribution patterns inside the garden. The aims of the study were to contribute to the exploration of soil biodiversity and soil health in built environments, and to study nematode communities in different plant assemblages. Using nematode morphology, a total of 33 terrestrial nematode families were identified across the garden, indicating similar levels of soil ecosystem enrichment and food web structure among different plant assemblages. A total of 25 plant families were identified in the five areas, revealing distinct plant communities inside the gardens. The study was limited to a single sampling event and the taxonomic identification of nematode and plants at the family level. However, the results highlight the use of nematodes as environmental indicators for soil health assessments in gardens, and provided baseline information that could potentially inform on soil biodiversity and plant management strategies.