The ecology of organisms that co-evolve within an ecosystem is likely to be distinct from that involving organisms recently introduced into an area. To better understand the relationship of earthworms with endophyte-infected tall fescue, earthworms in novel and toxic endophyte-infected tall fescue pastures were enumerated and identified as adults or juveniles. We hypothesized that differences in endophyte infection of the fescue would influence earthworm abundances. Earthworms in two toxic and two novel endophyte-infected tall fescue fields in Fayetteville, Ark., were sampled weekly from January through July 2007. Each type of endophyte-infected pasture was established in 1997 and 2003. Sampling was carried out utilizing a physical dig-and-sort extraction method. Although variable, sampling time was a significant factor in the number of adult and juvenile worms collected. Adult earthworm abundances showed a seasonal trend of declining numbers from winter to summer, while juvenile worms showed an increase from winter to summer. Previous studies have shown that endophyte infection of plants can impact soil organisms. In this study, type of fungal endophyte infection did not appear to impact earthworm abundances; therefore, use of novel endophyte-infected fescue in a pasture is not expected to have an impact on the ecology of earthworms
