With great ecosystem services comes great responsibility: carbon sequestration and climate modelling in Brazilian urban forests

Abstract

Urban forests are unique ecosystems that are frequently characterized by harsh conditions and face numerous pressures and threats. They contribute to the well-being and sustainability of cities by delivering a wide range of ecosystem services. Here, we analyze different aspects of urban forests an its ecosystem services. In chapter one, we observe several trends in the scientific production in the themes of ecosystem services and urban forests between 1996 and 2022. In chapter two, we analyze the ecosystem services provided by the urban areas of 25 cities of the Atlantic Forest in Brazil through the i-Tree Canopy software. Finally, in chapter three, we examine how climate change might affect Brazilian urban forests. Our results show that between 1996 and 2022, a total of 813 documents were published in 208 different journals, with 20.62% of annual growth. Our results show that scientific production in the area has grown notably over the years. Scientific production has shown a consistent growth trend from 2011 onwards. The results suggests that the importance of urban forests and ecosystem services has gained greater recognition and attention in recent years. Our data reveal that together, the cities studied sequester a significant total of 235.3 kilotonnes of carbon and substantial 864.82 kilotonnes of CO2 Equivalent (CO2 Equiv.) annually. Furthermore, together they also store, through their vegetation, a total of 4861.19 kilotonnes of carbon and 17824.32 kilotonnes of CO2 Equiv. We found out that the average monetary estimate of annual carbon sequestration was $3.57 million, while the average stored estimate was $73.76 million. Pearson’s correlogram showed a strong positive correlation between density of inhabitants and the percentage of impervious areas in urban areas (p < 0.001). Our findings show that climate change, even in more optimistic scenarios, may severely impact the environmental suitability of urban forests in all phytogeographic domains, that is, the climate will not be suitable anymore for the urban forest types that are now present in the areas studied. The impacts in the environmental suitability are expected especially in the Atlantic Forest and Cerrado, two biodiversity hotspots. The two most affected phytogeographic domains house most of the Brazilian human population, one of which tends to suffer substantial impacts. We also warn that Brazilian urban forests can be drastically affected, having their composition extremely modified and their biodiversity may diminish and even face homogenization. Therefore, urgent mitigation and adaptation actions are needed to tackle climate change and the maintenance of ecosystem services.