The Atlantic Forest of Brazil (Mata Atlântica) is one of the world’s 25 biodiversity conservation hotspots, home to thousands of endemic species and over half of Brazil’s threatened animal species. Around 80% of Brazil’s population live within the biome range, creating strong competition for land between nature and people. This vast rainforest, the second largest in South America, originally covered over 1.5 million km2 along the Atlantic coast. Due to historical and ongoing pressures on the natural habitat, only an estimated 11-16% of its original extent remains covered by forest. Large scale deforestation, forest degradation and habitat fragmentation severely threaten the ecosystem, and research suggests safeguarding its flora and fauna requires restoring native forest to at least 30% of its original extent. However, there is little evidence to suggest that a 30% restoration target will prevent the loss of functional diversity or reduce total species extinction rates. Although the Atlantic Forest is the focus of various restoration pacts, the success of these projects in providing ecological benefits while sustaining local livelihoods is unclear. We conducted a systematic review of habitat restoration initiatives and their impact on biodiversity, ecosystem services and local livelihoods in order to define specific biodiversity targets, and answer the question: What is the ecological threshold of forest cover required to maintain functional intactness, avoid extinction debt, and maintain total species abundance? We used specific search strings in English, Spanish and Portuguese via online bibliographical search tools such as Scopus and ISI Web of Science. Our analysis aims to answer ‘how much is enough?’ in terms of Atlantic Forest habitat restoration to achieve the desired biodiversity goals. We seek to define areas for restoration of native vegetation in the Brazilian Mata Atlântica to maximise biodiversity protection without negative consequences for agriculture and farming, commercial activity or local landowners and define a restoration plan that considers both extent (defined by ecological threshold limits) and location of habitat restoration. Furthermore, we will investigate socio-economic variables that affect the success of the desired restoration initiatives and their outcome by 2050. We will use the GLOBIOM-Brazil partial equilibrium model (IIASA) to test the influence of socio-economic drivers and targeted policies on land-use dynamics in the region. Significant effort is still needed to reach ambitious restoration targets set for the Atlantic Forest by international and national bodies, and considering the ecological outcome of reforestation plans is key to achieving the UN Sustainable Development Goals, while ensuring benefits to biodiversity and livelihoods in this region.