Alison Ravenscraft
Orthopteran Song on the Boston Harbor Islands
My project focuses on the singing Orthoptera (crickets, grasshoppers and katydids) of the Boston Harbor Islands national park area and will contribute to the ongoing All Taxa Biodiversity Inventory (ATBI). I am creating an electronic database which will hopefully include a photograph, description, and song recording of every Orthopteran species on the islands. Ideally, this database will be formatted for a video iPod, making it useful as a portable guide for on-site species identification by sight or sound.
During July and August 2007, I visited the harbor islands on a weekly basis to collect specimens and take audible-frequency recordings of the species in their natural habitats. Back in the lab, I photographed the specimens and attempted to record them individually. I am now analyzing my recordings using the Raven sound analysis software. This analysis will help to assess the bioacoustic diversity of the islands and hopefully will aid the identification of some potentially cryptic cricket species. I will also search for shifts in singing patterns related to the periodic overflights of aircraft from nearby Logan Airport. Such song adjustments in response to anthropogenic noise have been reported for birds and frogs, but not yet for insects.
The bioacoustic diversity of an environment is a valuable indicator both of the total number of species present and of the habitat quality of the area.1 Consequently, of the innumerable dimensions of the environment that species share as limiting resources, none comes close to that of bandwidth in being a single measurable axis of relevance to a wide spectrum of animals, both invertebrate and vertebrate, in a local community. My project will therefore facilitate the monitoring of habitat quality and species richness on the Boston Harbor Islands, furthering conservation efforts on the islands.
1 Klaus Riede, "Acoustic monitoring of Orthoptera and its potential for conservation." Journal of Insect Conservation, 2, 217–223 (1998). |
