Urban green spaces as potential habitats for introducing a native endangered plant, Calycanthus chinensis

Abstract

Ex situ conservation in urban areas is an essential complementary approach to in situ conservation in wild areas. In this study, we combined multiple approaches, including vegetation investigations for both natural habitats and urban green spaces, eco-physiological experiments and remote sensing investigations for urban green spaces, to identify potential habitats for introducing the endangered plant species Calycanthus chinensis to urban green spaces. The results showed that (1) C. chinensis prefer living under sparse forests with canopy densities of 20–60%; (2) C. chinensis was not a shade tolerant species due to its chlorophyll a/b ratio (2.58) being higher than the threshold (2.3) for shade tolerant species; (3) the large and thin leaves of C. chinensis are easily damaged by strong wind, so this species can only live under moderate canopy cover; (4) to maintain a sparse crown for the well-being of C. chinensis, the upper layer trees in urban green spaces need to be thinned slightly; and (5) introducing this endangered species increases biodiversity and ecosystem services of urban green spaces. Finally, this study provides a framework and a case study for using urban green spaces as micro-refuges for endangered species.