Invertebrate Terrestrial Diversity Along a Gravel Road on Barrie Island, Ontario, Canada

Although roads have been a part of our landscape for hundreds of years, their impact on the plant and animal populations has only recently been studied. We examined the effect a gravel road had on terrestrial arthropod diversity in the Barrie Islands, Canada. Over a ten-week period during the summer of 1999 we systematically sampled ground and aerial terrestrial arthropods at 5, 10 and 15 m from a 250 m stretch of road. We collected nearly 5,000 insects the majority of which were Coleoptera, Diptera and Hymenoptera. We collected over 2,000 non-insect invertebrates that included representatives from the classes Gastropoda, Annelida, Arachnida, Crustacea, and Diplopoda. There were significantly more individuals at 5 m from the road than at 10 or 15 m. Our results show that invertebrate diversity indices were similar at 5, 10 and 15 m distances from the road. The similar diversity indices may reflect the level to which we keyed out invertebrates (Order) and had we keyed specimens to Family might have found greater differences. Another possibility is that over time invertebrate populations return to pre-disturbance levels along roads that experience limited vehicular traffic