New native species for extensive green roofs to enrich urban ecosystem services in semiarid regions

Green roofs enhance urban ecosystem services and contributes to more resilient cities. The demand for biodiverse green roofs is increasing across various climatic regions. An optimal design includes the proper selection of vegetation to ensure functionality and sustainability. Extensive green roofs use stress-tolerant plants to maintain long-term ecosystem services. The goal of our study is to evaluate the behavior of native species from a semi-arid climate in South America. This research employs maintenance-free green roof simulators to identify the best performing species. The study evaluated 21 native plant species from the Argentine Pampas in green roof simulators. Performance indicators such as survival, coverage, self-reseeding and regrowth were monitored every 15 days for 629 days. Meteorological data were analyzed and calculate the Standardized Precipitation-Evapotranspiration Index (SPEI) to evaluate drought and wet conditions throughout the study period. We identify new native species (Hysterionica jasionoides, Margyricarpus pinnatus, and Dichondra argentea) for low-maintenance extensive green roofs and suggesting conceptual combinations to create plant palettes that promote growth in semi-arid climates. These species, characterized by slow growth and drought tolerance, enhance ecological facilitation, improving ecosystem services like temperature regulation, stormwater retention, and water efficiency. The study found marked temperature seasonality, with summer highs of 43.6 °C and winter lows of -4.5 °C. The SPEI index indicated severe drought periods mainly from October 2021 to February 2022. This study promotes the stability and sustainability of ecosystems in the face of adverse events, especially in the context of current climate variability.