Species diversity in urban green spaces in San Juan: The verdant landscape of a desert city in Argentina

DIAS RODRIGO; ANDINO NATALIA

Congreso; XLI Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2023

In extremely arid climates like the province of San Juan, creating urban green spaces with species that can survive without excessive irrigation is a challenge for forestry and landscaping. These Urban Green Spaces (UGS) play a crucial role in conserving native flora and, in many contexts, can be considered novel ecosystems as they host a mix of native and exotic species, giving rise to a unique urban biodiversity. Currently, the water requirement for maintaining UGS in San Juan poses a challenge due to the ongoing water crisis the province has been facing for about seven years. In this context, it is of great value to consider native species of arid zones in the creation and maintenance of UGS. This will ensure their sustainability by requiring little irrigation. The objective of this research was the evaluation of the diversity of urban vegetation in green spaces in the city of San Juan and the assessment of the presence of native species from arid zones. Six UGS were selected for this study: 25 de mayo, Aberastain, Bicentenario, Gertrudis Funes, Hipólito Yrigoyen, and Monseñor Severino Di Stéfano. In each of these areas, data on the plants were recorded, including their cover, species richness and abundance. Diversity indices were also used to assess their diversity: Shannon (H’), Simpson (D), and Pielou's evenness (J’). Results showed that tree cover in the studied UGS ranged from 13.14% (Bicentenario plaza) to 95.67% (Gertrudis Funes plaza).A total of 74 plant species were recorded, of which only three were native to dry areas of Argentina: Neltuma flexuosa, Parkinsonia aculeata, and Vachellia aroma. The number of individuals of these species was very low, ranging from 2 to 9 in total. In contrast, the UGS studied documented a total of 149 individuals of Morus nigra and 113 individuals of Platanus hispánica, both exotic species. These two species were found to be the most abundant of all the species observed. The Plaza Hipólito Yrigoyen had the highest diversity index values (H' = 2.90, D' = 0.08, J' = 0.85), whereas the Plaza Monseñor Severino Di Stéfano had the lowest diversity index values (H' = 1.58, D' = 0.38, J' = 0.61). Our findings indicate that native arid Argentine species are underrepresented in the urban green spaces of the city of San Juan. Conversely, exotic species are predominant. This situation demands the UGS manager’s attention, especially considering the prevailing water crisis in the region, Effective water management necessitates the implementation of diverse strategies and practices, such as choosing drought-resistant plants and employing more efficient irrigation techniques Our research emphasizes the importance of integrated planning and management involving multiple stakeholders, including government agencies, residents and sustainability experts. This collaborative approach is crucial in effectively tackling water scarcity challenges and fostering the development of sustainable and resilient urban environments.