The Ants of Nantucket: Unexpectedly High Biodiversity in an Anthropogenic Landscape

Aaron M. Ellison

doi:10.1656/045.019.s604

Abstract

This first comprehensive assessment of the ant fauna of Nantucket Island, MA revealed that 43% of New England ant species and 70% of New England ant genera occur on an island occupying only 0.07% of New England's land area. Ants collected by four different research groups between 2000 and 2009 included 32, 158 individual ants (2911 incidences) from 384 spatially and temporally distinct samples representing 14 different vegetation community types. The majority of the ant species were collected from anthropogenically derived and maintained sandplain grasslands, sandplain heathlands, and Scrub Oak shrublands. These three communities are state-ranked S1 community types; the lower state-ranked communities of beaches and sand dunes, bogs, salt marshes, and forest fragments had distinct ant assemblages with much lower species richness. The large number of samples described here, from a wide range of vegetation community types, expands the known list of Nantucket ant species more than three-fold and provides a baseline for future assessment of the effects of ongoing, long-term ecosystem management on Nantucket.

Highlights

Ants are one of the “little things that run the world” (Wilson 1987)
Ant species richness may be associated positively with human population density (Schlick-Steiner et al 2008), but ant assemblage structure responds rapidly to changes in environmental conditions and usually reaches a newequilibrium on timescales ranging from years to only a few decades (Wike et al 2010, Zettler et al 2004)
On short time scales (< 10 years), ant species richness declined when forests were converted to agriculture or pasture (Dunn 2004) and in intensively grazed grasslands relative to nearby forests in Argentina and Mexico (Bestelmeyer and Wiens 1996, Quiroz-Robledo and Valanzuela-Gonzalez 1995), but in dry climates in both Australia and North America, ant species diversity was unaffected by moderate to intensive grazing (Bestelmeyer and Wiens 2001, Read and Andersen 2000)

Summary

Introduction

Ants are one of the “little things that run the world” (Wilson 1987). They account for 10-15% of the animal biomass in most terrestrial habitats (Alonso and Agosti 2000) and they perform a myriad of ecosystem services (Folgarait 1998), including, at least in New England, turning over more soil than earthworms (Lyford 1963). Ant species richness may be associated positively with human population density (Schlick-Steiner et al 2008), but ant assemblage structure responds rapidly to changes in environmental conditions and usually reaches a new (quasi-)equilibrium on timescales ranging from years to only a few decades (Wike et al 2010, Zettler et al 2004). In the southeastern U.S, ant species richness declined with increasing pesticide use and agricultural intensification (Peck et al 1998)

Methods

Results

Conclusion