A major review of research concerning the ubiquitous mistletoe by a Charles Sturt University ecologist has found it is not a destructive parasitic plant as believed by farmers and foresters worldwide, but is vital for maintaining ecosystems.

Dr Watson believes that mistletoes are vital to woodland animals in Australia and around the world and could offset problems in maintaining populations of native animals where few trees remain after land clearing for agriculture.
“Far from being weeds, mistletoes are important local plants that exert a powerful influence on how plants and animals are distributed across the land.”

According to Dr Watson, almost 1 500 species of mistletoe exist worldwide, living in cold coniferous forests in Canada, through temperate forests and woodlands to inhospitable deserts and steamy tropical rainforests. Nearly 90 species are native to Australia.

“Mistletoes are parasitic plants, obtaining all their water and minerals from their host plant. Therefore, they have few problems in finding water and minerals, so many species grow flowers and fruit year-round.

“They are a highly dependable food source, even during droughts. Mistletoes have high concentrations of minerals and trace elements in their leaves, making them nutritious and highly sought after by animals.”

Dr Watson identified animals from 96 families that feed on mistletoe: from porcupines, possums, baboons and bowerbirds to lemurs, lorikeets and orangutans. He even found records of an Amazonian fish that eats the fruit!

“Mistletoe also provides nesting sites for animal species from 50 families, from tiny hummingbirds to giant vultures. Some animals hibernate in mistletoe clumps during harsh winters, while koalas rest in them during hot summer days,” Dr Watson said.

The study used records in five languages and over 250 publications that date back to 79AD. This analysis has appeared in a paper published in the 2001 edition of the internationally respected Annual Review of Ecology and Systematics.

From this work, Dr Watson proposed that mistletoes should be considered keystone resources in many habitats worldwide - take them away, and the whole system collapses.

“Since many animals depend on mistletoe for food and shelter, there is a strong relationship between mistletoe density and biodiversity. In areas with more mistletoe, there appear to be more animal species. This idea is supported by research from all corners of the globe.”

Dr Watson will further test his ideas on the importance of mistletoes in the Australian landscape in large-scale experiments across NSW, due to start in September 2002.