The rapid urbanization process in recent decades has altered the carbon cycle and exacerbated the impact of climate change, prompting many cities to develop tree planting and green area preservation as mitigation and adaptation measures. While numerous studies have estimated the carbon stocks of urban trees in temperate and subtropical cities, data from tropical regions, including tropical botanic gardens, are scarce. This study aimed to quantify the aboveground biomass and carbon (AGB and AGC, respectively) stocks in trees at the Rio de Janeiro Botanical Garden arboretum, Rio de Janeiro, Brazil. Our survey included 6793 stems with a diameter at breast height (DBH) ≥ 10 cm. The total AGB was 8047 ± 402 Mg, representing 4024 ± 201 Mg of AGC. The AGB density was 207 ± 10 Mg·ha⁻¹ (AGC = 104 ± 5 Mg·ha⁻¹), which is slightly lower than the density stored in Brazil’s main forest complexes, the Atlantic and Amazon forests, but much higher than in many cities worldwide. Our results suggest that, in addition to their global importance for plant conservation, tropical botanic gardens could function as significant carbon sinks within the urban matrix.

The rapid urbanization process in recent decades has altered the carbon cycle and exacerbated the impact of climate change, prompting many cities to develop tree planting and green area preservation as mitigation and adaptation measures. While numerous studies have estimated the carbon stocks of urban trees in temperate and subtropical cities, data from tropical regions, including tropical botanic gardens, are scarce. This study aimed to quantify the aboveground biomass and carbon (AGB and AGC, respectively) stocks in trees at the Rio de Janeiro Botanical Garden arboretum, Rio de Janeiro, Brazil. Our survey included 6793 stems with a diameter at breast height (DBH) ≥ 10 cm. The total AGB was 8,047.24 Mg, representing 4,023.62 Mg of AGC. The AGB density was 207.4 Mg.ha-1 (AGC = 103.7 Mg.ha-1), which is slightly lower than the density stored in Brazil's main forest complexes: the Atlantic and Amazon forests, but much higher than in many cities worldwide. Our results suggest that, in addition to their global importance for plant conservation, tropical botanic gardens could function as significant carbon sinks within the urban matrix.

Cactaceae comprises 150 genera and 1,851 species, distributed across the tropical and subtropical Americas, with one species found outside these continents. Brazil is the third-largest center of diversity and endemism for this family, where representatives are found in all Brazilian biomes. Rhipsalis, with approximately 40 species, predominantly exhibits epiphytic habits, rupicolous and rarely terrestrial habits, occurring in almost all of Brazil except Piauí, Tocantins and Distrito Federal. This study addresses the taxonomic treatment of Rhipsalis in Minas Gerais, a state in southeastern Brazil that includes three biomes: Atlantic Forest, Cerrado, and Caatinga. Specimens deposited in herbaria in the southeastern region were analyzed, and expeditions were conducted for collection and observation. Morphological analyses enabled species descriptions and the development of a taxonomic key, while georeferenced records facilitated the creation of species occurrence maps. A total of 16 taxa were identified in the state, seven of which are endangered species, especially in the Atlantic Forest biome, including new occurrence records. The inclusion of R. neves-armondii in the Flora and Funga of Brazil for Minas Gerais is proposed, while R. burchellii, R. floccosa subsp. floccosa, and R. grandiflora are excluded due to the lack of evidence in herbaria and corrections of erroneous identifications.

Tacinga inamoena (K. Schum.) N.P. Taylor & Stuppy (Cactaceae, Opuntioideae) is a native Brazilian species found in the Caatinga phytogeographic domain. Although its flowers are adapted for bird pollination (ornithophily), few birds visit these plants in the ex situ collection at the Rio de Janeiro Botanical Garden. Despite this, fruit production occurs, prompting an investigation into the floral visitors and other animals interacting with T. inamoena flowers. This study aimed to identify floral visitors and quantify florivory damage to flowers in the Cacti and Succulents thematic collection. During the study, 79 flowers were monitored, along with their floral visitors and 26 instances of florivory, totaling 110 observation hours during the anthesis period. Despite recording only five hummingbird visits, a high fruit set was observed, with 72 fruits formed. Results indicated that bees of the genus Trigona sp. were the main floral visitors. Florivory damage, primarily caused by lizards of the species Tropidurus torquatus (Wied-Neuwied, 1820), did not negatively impact fruit formation in this cactus species under cultivation. To fully understand the reproductive success of this species, further studies are needed to assess the viability of seeds formed under these conditions, as the species may be self-compatible and autogamous.