Harvard Forest Research

Ants, Plants, and Genes: Implications of Invasion by the Hemlock Woolly Adelgid on Dispersal of the Broad Looseflower Sedge (Carex laxiflora)

Principal Investigator: Aaron Ellison
Harvard Forest: May 01 2006 - Sep 01 2010:

Abstract:
Natural seed dispersal agents may be a key limiting component in revegetation projects. The fraction of myrmecochorous (ant dispersed) understory plant species is one-third in some northeastern forest habitats. Invasion by the hemlock woolly adelgid (Adelges tsugae) threatens eastern hemlock-dominated forests and poses a major restoration issue. A recent survey of ant diversity at sites in Massachusetts and Connecticut with varying degrees of hemlock decline showed that the overall number of ant species increased as the percent of total hemlock basal area declined. However, Aphaenogaster rudis, a major seed-dispersing ant, declined in abundance as hemlock declined. Changes in the community composition of ant assemblages associated with hemlock decline could greatly alter the recolonization potential of myrmecochorous understory plants that depend on ants for seed dispersal. This study will use chloroplast DNA microsatellites to determine how different ant assemblages associated with varying levels of hemlock decline affect dispersal and gene flow of broad looseflower sedge (Carex laxiflora). We hypothesize that both dispersal distance and gene flow of C. laxiflora will decrease as hemlock declines because of a concomitant decline in its primary disperser, A. rudis. :