Sydney  - As all gardeners know, weeds are relentless.

In fact, they're so hardy that they'll be the big winners from climate change.

After conducting the largest study of its kind, Australian researchers warned that what we now consider weeds will be among the few plants versatile enough to cope with changes in the environment.

"As habitats change in response to climate change, the species that are most likely to survive are those with short life cycles that can adapt quickly and those that are readily dispersed - common characteristics of most weed species," Botanic Gardens Trust botanist Peter Watson said.

Watson, who led a team that looked at 11,000 plant species on six continents, predicts that most plants would be lost as their environment changed.

"When we traced the evolution of characteristics of plants from these different regions ... we were struck by the conservatism of plants - basically how rarely they were able to adapt and flourish outside of their ancestral environments," Weston said.

"Conservationists can't expect plants to dramatically change their ecological preferences and evolve to fit new habitats as the boundaries of these biomes change in response to climate change," the Sydney-based researcher said.

Most plants are stay-at-home types, whereas weeds are adventurous.

Watson said: "Plant lineages have generally remained in a similar environment, even over millions of years." (dpa)