Authors: Chamberlain, Dan; Reynolds, Chevonne;Amar, Arjun;Henry, Dominic;Caprio, Enrico;Stofberg, Miqkayla;Batáry, Péter;

Urban biodiversity, and its associated ecosystem services, is an important component of the quality of life of urban residents. The Luxury Effect posits a positive association between biodiversity and socioeconomic status in urban areas, and is thus reflective of environmental injustice, as the benefits associated with biodiversity are not equitably shared across society. Our meta-analysis showed there was a positive association between terrestrial biodiversity measures and socioeconomic status. Furthermore, the strength of the Luxury Effect was greater in arid areas. Many key and emerging climate impacts are concentrated in urban areas, thus the degree of environmental injustice represented by the Luxury Effect may be amplified in the future, especially in arid regions. However, there were biases in geographic coverage (more studies in the developed world) and taxonomic groups (most studies were on plants and birds) in the publications considered. Furthermore, some studies have revealed complex interactions between urban land cover and socioeconomic status. Here, we suggest the research priorities that are needed to fully understand mechanisms driving the Luxury Effect. This is necessary to develop strategies for sustainable development of cities and thus to promote environmental justice, enhancing the quality of life of urban residents across all sectors of society.