A silk-floss tree (Ceiba speciosa) provides an oasis for floral visitors in an otherwise hostile suburban-farmland environment

Abstract

ABSTRACT Keystone components in green urban spaces can make a big difference in supporting either impoverished or rich animal communities. Trees that produce thousands of flowers at densities higher than that of herbs and produce much more nectar than the latter can be such keystone structures. However, there is a lack of specific information on trees, both native and alien, and their flower visitors in urban/suburban contexts, which blurs the conservation role that such species can perform. In 2019 and 2020, we thoroughly recorded the flower visitors to a silk-floss tree in suburban Guadalajara, Mexico. To our knowledge, this is the first comprehensive inventory of silk-floss tree flower visitors. We documented 79 species/morphospecies of insects; eight of birds, and one of mammals visiting the flowers. All, except two, are native to the region; three are endemic/quasi-endemic to Mexico. Besides direct and indirect floral resources, the silk-floss tree offered perches, resting/hiding cover, nesting substrate, and seed fibres used by several birds, and feeding substrate for gleaning insectivorous birds. Four species are on one or more conservation listings: monarch butterfly (endangered), pink-spotted swallowtail (vulnerable), sparkling-tailed hummingbird (threatened), and lesser long-nosed bat (near-threatened). Our data supports that small patches can enhance the quality of urban green spaces, and that rather than geographic origin, flower output drives visitation. Alien trees can be pollination enhancement ‘devices’ for imperilled pollination networks. Silk-floss trees are a potential option for conservation-oriented urban greening, as well as to contribute to enhancing human enjoyment of nature, and provide opportunities for public outreach.