Journal for Nature Conservation 73 (2023) 126383 Available online 16 March 2023 1617-1381/© 2023 Elsevier GmbH. All rights reserved. Human impacts, habitat quantity and quality affect the dimensions of diversity and carbon stocks in subtropical forests: A landscape-based approach Júlio R. Bastos a, * , Elivane S. Capellesso a , Alexander C. Vibrans b , M´ arcia C.M. Marques a a Laborat´ orio de Ecologia Vegetal, Departamento de Botˆ anica, Setor de Ciˆ encias Biol´ ogicas, Universidade Federal do Paran´ a, Caixa Postal 19031, 81531-980, Curitiba, PR, Brazil b Departamento de Engenharia Florestal, Universidade Regional de Blumenau e FURB, Rua S˜ ao Paulo, 3250, 89030-000, Blumenau, SC, Brazil A R T I C L E INFO Keywords: Atlantic forest Edge effect Fragmentation Conservation ecosystem Ecosystem service ABSTRACT Fragmentation is recognized as one of the main factors affecting species and functionality losses in tropical landscapes. In this study, we assess how landscape quality and quantity affect taxonomic and functional di- versities and carbon stocks in the Atlantic Forest. We used a large dataset, which comprises 92,754 adult trees of 668 species, distributed over an area of 95,733 km2 in the state of Santa Catarina, southern Brazil. In each plot, we quantifed the taxonomic diversity (species richness), the functional diversity (functional richness), and the aboveground carbon stock and related it to different landscape metrics (fragment area and total area, number of fragments, total edge area, index of the largest fragment, effective network size and aggregation index) and anthropogenic impacts in three surrounding landscape buffers (radius 1000, 3000 and 5000 m). We built mul- tiple regression models, selecting the best models (Akaike’s criterion), to assess the infuence of the landscape and anthropogenic index on diversities and carbon stocks. Our study shows that the landscape quantity and quality, and the anthropogenic effects are factors that negatively affect the carbon stock, reinforcing that small- scale exploration, within the fragment itself, is an important factor in reducing diversity and carbon stock. The importance of considering local exploitation has important implications for conservation, and these results bring important insights for conservation, especially for forest fragments in anthropized landscapes, where exploration within the fragments are factors that interfere in the conservation and maintenance of biodiversity and ecosystem functioning. 1. Introduction Tropical forests are considered the largest repository of terrestrial biodiversity and ecosystem services in the world (Myers et al., 2000; Pan et al., 2011). Urban, industrial and agricultural expansions have led to the disorderly occupation and use of lands, causing loss of biodiversity and degeneration of ecosystem services in these forests (Chiang et al., 2016; Jones-Walters, 2008). In terms of the carbon fxation service, the loss of tropical forests has considerably reduced aboveground biomass (Laurance et al., 2011; Pütz et al., 2011), which contributes to 7 to 17% of global carbon emissions (Achard et al., 2014). In this scenario, biomass accumulation and carbon storage in tropical forests are considered essential for mitigating global climate change (Agreement, 2015), as it is estimated that approximately 45% of terrestrial carbon is stored in tropical forests (Pan et al., 2011; Poorter et al., 2017). There- fore, understanding the range of anthropogenic impacts on tree species diversity and carbon stocks is crucial for forest management plans and climate change mitigation at the global level. The fragmentation of natural habitats, that is, the landscape-scale process derived from the loss of ecosystems and their spatial separa- tion (Fahrig, 2003) is considered one of the main causes of biodiversity loss (Travers et al., 2021), generating chain effects that affect pop- ulations, communities, and ecosystem services (Fahrig, 2003; Li et al., 2023; Pütz et al., 2011, 2014). In tropical forests, the effects of frag- mentation on species diversity are well documented (Fahrig, 2003; Laurance et al., 2000; Lˆ obo et al., 2011). They include habitat loss, forest edge creation, disruption of biological connectivity, isolation of pop- ulations, invasion by alien species, and local extinctions, which together * Corresponding author. E-mail address: julioricardobastos@gmail.com (J.R. Bastos). Contents lists available at ScienceDirect Journal for Nature Conservation journal homepage: www.elsevier.com/locate/jnc https://doi.org/10.1016/j.jnc.2023.126383 Received 17 November 2022; Received in revised form 21 February 2023; Accepted 6 March 2023