Biodiversity conservation in cities: Defining habitat analogs for plant species of conservation interest

Urban plant habitats have become primary drivers of species interactions. They consist of managed vegetation and spontaneous assemblages of native, naturalized, ornamental garden escapes, and invasive species. Our objective was to define urban habitat analogs for a plant species of conservation interest, Matthiola crassifolia, which has persisted in varying abundance in the Mediterranean city of Beirut. We adopted a stepwise method that integrates two vegetation assessments, floristics, and physiognomy. We placed seventy-eight quadrats (1m x 1m) in 12 study sites following a deliberate biased method to capture habitat diversity. In every quadrat, we performed taxonomic identification and recorded life form of each species. We pooled species that shared the same life form into categories and estimated area cover for each of these life forms. We performed TWINSPAN analysis on floristic data to identify species positively associated with M. crassifolia, and on life forms, to determine plant assemblages that promote optimal M. crassifolia representation. We then combined findings from both analyses to generate a description of urban habitat analogs suitable for M. crassifolia . The results revealed that urban habitat analogs favorable to M. crassifolia include green spaces dominated by palms, low-lying succulents, or by shrubs with scale-like leaves. On the other hand, spaces dominated by turf grass, canopy trees, or vegetation that produces significant litter were not favorable to M. crassifolia ’s persistence. Based on these findings, we generated a plant palette of native and non-native species to design urban habitat analogs favorable to the persistence of M. crassifolia . Synthesis and applications The application of this method can inform planting designs that yield suitable habitats for plants of conservation interest. It can also guide landscape management plans that seek to create or modify green spaces to optimize growing conditions for species of conservation interest. Depending on sites, and based on the information generated by the stepwise method, designers and managers may decide to exclude life forms of native or non-native species that do not support the growth of a species of conservation interest, or they may create an artificial habitat that is conducive to its persistence.