A botanical oasis rather than a biological desert: Rediscoveries, new species and new records in a tropical city

Abstract

Societal Impact StatementCities present a unique challenge for conservation. While overall native biodiversity is reduced, remnant habitats in the urban matrix can be important refugia for native and endemic species. This study reviews the rediscovery of 173 presumed nationally extinct plant taxa and discovery of 155 new native plant records, including 22 new to science and five endemics, in the botanically densely‐collected tropical city‐state of Singapore. The findings of this study indicate that plant rediscoveries and new discoveries are still possible in cities and urban areas with remaining fragments of original forest reserved for species protection, and investment in comprehensive botanical surveys and taxonomic research.Summary The conservation of native species‐dominated forest fragments and investment into botanical surveys and taxonomic research have enabled the rediscovery of presumed nationally extinct plant taxa and discovery of new native plant records in the tropical city‐state of Singapore. We compared national plant checklists of 2009, 2022, and the national Red Data Book (third edition in press) to enumerate rediscovered and newly discovered native vascular plant taxa in the last 14 years. We examined if these were from taxonomic specialist redetermination of only pre‐existing specimens or newly collected from field surveys, and if they were from particular sites and vegetation types, disproportionately represented by certain life forms and families, and predominantly threatened. We documented 173 rediscoveries and 155 new records after 2009, including 22 new to science and five endemics. Most rediscoveries were newly collected from field surveys, but most new records resulted from redetermination of pre‐existing specimens. Native species‐dominated forest fragments were the most important sites for the first collection of new records or first re‐collection of rediscoveries. Trees and climbers were well‐represented among the rediscoveries and new records. Epiphytes were significantly under‐represented compared to their proportion in the presumed nationally extinct flora. Most rediscoveries and new records are nationally Critically Endangered but regionally and globally not assessed. Our findings indicate hope for the persistence of rare native plant species and opportunities for conservation in cities.