"Among the wasps encountered on these islands, we were able to pick out the species truly dependent on the lepidopteran herbivores. As we see it, knowing not just what the species are but what they do in their lives is the key to sensible ecology", emphasizes Gergely.
Hundreds of species examined
"What is unique about our study is that we were able to look at patterns at the level of large species pools across the islands", explains Marko Nieminen, who spent three long summers boating around the islands, sampling insects by light and bait traps.
"Where other people have looked at effects of island size on restricted numbers of species or restricted levels in food chains, we did the full thing across four levels", he specifies. "Overall, we dealt with 200 species of plants, 415 species of lepidopteran herbivores, 42 species of parasitic wasps attacking herbivores and 7 species of wasps attacking parasitic wasps."
Deliberately keeping things simple
"In choosing the islands, we deliberately went for a simple system" says Marko. "Our islands were essentially smallish pieces of rocks with some forest and heathland on them. Historically, they all rose from the sea just some millennia ago, after being submerged and scraped clean of life by the last ice age. This similarity in structure and history allowed us to look at effects of island size, without having to worry about other differences among islands."
Maintaining interactions may be trickier than maintaining species
All three authors worry about the message laid plain by the study: "What this really suggests is that to save ecological interactions, we may need to conserve much larger areas than for j
|Contact: Tomas Roslin|
University of Helsinki