The IUCN Red List conservation status of Black-legged Dacnis is assessed as Near Threatened (Butchart and Stattersfield 2000, BirdLife International 2016), due to its small and restricted range of only about 245,000 km2. Previously its status was rated as Vulnerable (e.g. Collar et al. 1992), but its status of Black-legged Dacnis was revised in 2004 as the species became better known (Paglia and Fonseca 2009). The population size of Black-legged Dacnis is estimated to be ca 6700 mature individuals, with evidence of population declines due to deforestation and illegal trade (Hilty 2011, BirdLife International 2016). Black-legged Dacnis also is partially protected under conservation interest legislation in Brazil (Paglia et al. 2004, Straube and Urben-Filho 2005). Parker et al. (1996) considered this species of "high" conservation priority relative to other Neotropical birds.
Effects of human activity on populations
The greatest threats to the already low population of Black-legged Dacnis is the deforestation of the Atlantic Forest, introduced predators or competitors, and perhaps trapping/illegal trade of birds (Ridgely and Tudor 1989, Collar et al. 1992, 1997, Hilty 2011). It is at risk of being sold in the cage bird trade due to its rarity which make it valuable in captivity (Collar et al. 1992, Hilty 2011). Parker et al. (1996) considered Black-legged Dacnis to have a "medium" degree of sensitivity to human disturbance relative to other Neotropical birds.
This species is known from the following protected areas: Itatiaia National Park (Aximoff and Freitas 2009, Whittaker et al. 2010), Parque Estadual Intervales (Aleixo and Galetti 1997, Kirwan 2013), Parque Estadual Carlos Botelho (Campos 2011), Parque Estudal da Serra do Tabuleiro (de Almeida 2015), Augusto Ruschi Biological Reserve (Parker and Goerck 1997), Desengaño, Intervales, Alto do Ribeira, and Ilha do Cardoso State Parks, Serra dos Órgãos and Tijuca National Parks, Tinigua Biological Reserve, Ubatuba Experimental Station, Cananéia-Iguape-Peruibe Environmental Protection Area, and Artex and Spitzkopf Ecological Reserves (Hilty 2011). Although the range of this bird falls within many protected areas, there are hopes that with the increase of literature written on this bird, conservation efforts will increase (Whittaker et al. 2010).