Invasive alien acacias rapidly stock carbon, but threaten biodiversity recovery in young second-growth forests

Abstract

Under the UN-Decade of Ecosystem Restoration and Bonn Challenge, second-growth forest is promoted as a global solution to climate change, degradation and associated losses of biodiversity and ecosystem services. Second growth is often invaded by alien tree species and understanding how this impacts carbon stock and biodiversity recovery is key for restoration planning. We assessed carbon stock and tree diversity recovery in second growth invaded by two Acacia species and non-invaded second growth, with associated edge effects, in the Brazilian Atlantic Forest. Carbon stock recovery in non-invaded forests was threefold lower than in invaded forests. Increasingly isolated, fragmented and deforested areas had low carbon stocks when non-invaded, whereas the opposite was true when invaded. Non-invaded forests recovered threefold to sixfold higher taxonomic, phylogenetic and functional diversity than invaded forest. Higher species turnover and lower nestedness in non-invaded than invaded forests underpinned higher abundance of threatened and endemic species in non-invaded forest. Non-invaded forests presented positive relationships between carbon and biodiversity, whereas in the invaded forests we did not detect any relationship, indicating that more carbon does not equal more biodiversity in landscapes with high vulnerability to invasive acacias. To deliver on combined climate change and biodiversity goals, restoration planning and management must consider biological invasion risk. This article is part of the theme issue ‘Understanding forest landscape restoration: reinforcing scientific foundations for the UN Decade on Ecosystem Restoration’.

Vacant niches help predict invasion risk by birds

“…We suggest that the applicability of the vacant niche metric can be exploited to develop improved predictive models based on rigorous statistical inference. As our metric is not adequate for understanding all avian invasions, exemplified by the discrepancy of the relationship with vacant niches across regions, vacant niches should be more appropriately used as one of the explanatory variables, among others, to be included in a multi‐model inference approaches to predict the incidence of alien species; an approach rarely used with alien species (Matos et al, 2022).…”

Potential of biological invasion for carbon sequestration in a protected area: the case of the Limbe Botanic Garden (LBG) forest, Cameroon

“…28 Their invasive power alters the dominance of indicator species, thus changing the structure of communities, biomass and therefore the carbon stock. 29 The work of Hernández-Máximo et al, 30 has shown that Cedrela odorata has a very high reproductive capacity. It is a very abundant species with low production and a depressive and aggressive effect on other plants.…”

Restoration success in former Amazonian mines is driven by soil amendment and forest proximity

“…Nevertheless, in the other less-limiting substrates, we found no evidence relating the identity or origin (exotic or native) of these dominant species to the restoration success. Other studies found negative effects of planted exotics on the recovery of disturbed soils and on the establishment of native natural regeneration [ 42 – 44 ]. In this study, however, the exotic species showed low invasiveness potential, significantly decreasing in density over the years and showing low recruitment success ( table 1 ).…”