Weeds Survive The Wild Better Than Natives

Eve White, from QUT's School of Natural Resource Sciences, has been investigating the effect weeds can have on native plants especially when foliage eating insects, also known as herbivores, are involved.

"While many plants need insects to reproduce there are many insects that simply feed off plants and this is having an effect on natives," she said,

"Some weed species receive all of the benefits of visiting pollinators but none of the negative consequences of herbivores."

Ms White said while pollinators - insects that carry pollen from one flower to another facilitating fertilisation - visited weeds and natives, the attack by herbivores may have an unfair advantage for the weed.

"Essentially it may give weeds the upper hand over native plants," she said.

"What I wanted to see was the herbivores eating the weeds, but this was not the case.

"Herbivores demonstrated a preference for the native plant, causing higher levels of damage to the foliage of the native both in the field and in laboratory trials."

Ms White said her study also found that while pollinators were not ignoring natives, their interest in weeds was producing a hybrid native/weed species of seed.

"In many cases when hybrids are created they are not as healthy as the original plant and this is what I have seen," she said.

"What I have found is the hybrid's seeds are not able to survive into maturity. The reproductive effort is therefore being wasted."

Ms White said the survival of many of Australia's native plants was at risk because of weed infestation.

"It is essential to understand what is occurring to our native plants so that strategies can be developed to protect them."

Ms White's field research was undertaken in Lamington National Park, Queen Mary Falls and the Bunya Mountains.