Biodiversity on Broadway - Enigmatic Diversity of the Societies of Ants (Formicidae) on the Streets of New York City

Marko Pećarević,James Danoff-Burg,Robert R Dunn,Anna Dornhaus

doi:10.1371/journal.pone.0013222

Marko Pećarević, James Danoff-Burg + Show 2 more

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https://doi.org/10.1371/journal.pone.0013222

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Abstract

Each year, a larger proportion of the Earth's surface is urbanized, and a larger proportion of the people on Earth lives in those urban areas. The everyday nature, however, that humans encounter in cities remains poorly understood. Here, we consider perhaps the most urban green habitat, street medians. We sampled ants from forty-four medians along three boulevards in New York City and examined how median properties affect the abundance and species richness of native and introduced ants found on them. Ant species richness varied among streets and increased with area but was independent of the other median attributes measured. Ant assemblages were highly nested, with three numerically dominant species present at all medians and additional species present at a subset of medians. The most common ant species were the introduced Pavement ant (Tetramorium caespitum) and the native Thief ant (Solenopsis molesta) and Cornfield ant (Lasius neoniger). The common introduced species on the medians responded differently to natural and disturbed elements of medians. Tetramorium caespitum was most abundant in small medians, with the greatest edge/area ratio, particularly if those medians had few trees, whereas Nylanderia flavipes was most abundant in the largest medians, particularly if they had more trees. Many of the species encountered in Manhattan were similar to those found in other large North American cities, such that a relatively small subset of ant species probably represent most of the encounters humans have with ants in North America.

Highlights

Urban and suburban areas are increasing in number and population density globally [1,2]
Of the four most common species, two (L. neoniger and S. molesta) are native, and two (T. caespitum and N. flavipes) are introduced (Table 1). Both native and introduced ant species coexist in Manhattan in relatively large numbers
The most diverse and least diverse medians sampled represented a large range, most medians were similar in their ant species richness

Summary

Introduction

Urban and suburban areas are increasing in number and population density globally [1,2]. 2003 was the first year that more people lived in urban areas than in rural ones [3]. With these shifts, the recognition of the role of urban ecological health and conservation is increasing [3,4,5]. Barring apocalyptic catastrophes [e.g., 6], urban and suburban habitats will be among the most common habitats on Earth for many generations to come and the most common setting for human interactions with wild species [5]. Urban environments vary (and have long varied) in their diversity and ecological health from complex urban gardens to habitats superficially devoid of life such as the glass walls of skyscrapers [7]. A central question for urban ecology is to understand which species persist in urban environments and what governs their diversity and composition

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