London, June 5 (IANS): Parasitic "vampire" plants that attach onto and derive nutrients from another living plant may benefit the abundance and diversity of surrounding vegetation and animal life, reveals a new study.

By altering the densities of the hemi-parasite (a parasitic plant that also photosynthesises) Rhinanthus minor, ecologists assessed the impact of the "vampire" plant on the biodiversity of a species-rich, semi-natural grassland.

Photosynthesis is a process used by plants to convert light energy from the Sun into chemical energy that can be later released to fuel the organisms' activities.

They compared the plant and invertebrate communities in areas where Rhinanthus minor was removed, left at natural densities, or increased in abundance.

"Although hemi-parasites are known to increase the diversity of other plants in the community by suppressing the dominant species they parasitise, none of us predicted there would be such dramatic and positive impacts on other components of the grassland community," said lead author and professor Sue Hartley at the department of biology at York University.

"R. minor increased the abundance of all sorts of animals including snails, woodlice, butterflies, wasps and spiders," Hartley added.

"Our study provides a clear demonstration of the importance of indirect interactions as major structuring forces in ecology and the strong cascading effects of these interactions across trophic levels," said co-researcher Libby John from the University of Lincoln.

The manipulation of a single sub-dominant plant species causes substantial changes in the abundance and diversity of organisms across four trophic levels, the authors said.

"This is an important finding for the conservation and management of these chalk grassland communities, which are exceptionally species rich but also rare and threatened," Hartley said.

The results were published in the journal Ecology.