Assessing nucleation strategies and spatial dynamics in the restoration of neotropical terrestrial ecosystems: A comprehensive review

Neotropical ecosystems have been significantly impacted by agricultural activities and urbanization, causing biodiversity and ecosystem services losses, and requiring extensive restoration efforts. Thus, nucleation strategies appears as a cost-effective restoration method, which promotes ecological succession by establishing vegetation patches that attract fauna and facilitate natural regeneration. Here, we systematically reviewed nucleation techniques applied for Neotropical ecosystems restoration. We assessed the focus and spatial distribution of nucleation in response to stakeholder preferences and land-use types. By examining 58 studies, we identified key aspects of the use of nucleation techniques, emphasizing the need for standardized protocols to optimize nucleation strategies for ecosystem recovery. Overall, 12 nucleation techniques were used in Neotropical ecosystem restoration, with artificial perches, topsoil transfer, seedling islets and brushwood being the most frequent. Stakeholders (i.e., researchers, private sector, and governmental agencies) applied various techniques, with researchers more frequently using multiple and combined techniques. Moreover, we observed that stakeholders and land use affect the spatial patterns of nucleation, whereas their focus only responds to land-use types. Nuclei had an average size of 67.58 m² ranging from 0.16 m² to 1225 m², and techniques focused on flora and fauna showed the greatest spacing between nuclei. Fauna-related techniques were common across all land uses, and the greatest variety of techniques were used in abandoned pastures, former mining sites and protected areas. Although less frequent, using nucleation techniques in combination can contribute to restoration success by addressing multiple objectives. Research-driven innovation is advancing in this field, but single techniques dominate. Advancing the use of combined techniques and standardizing such practices is essential to scale up and optimize nucleation strategies during restoration efforts.