With warmer temperatures, Yukoners are being encouraged to roll up their sleeves and protect the environment by doing battle with aggressive weeds.

Bruce Bennett, a wildlife viewing biologist with the Department of Environment, said he is concerned with the progression of invasive species, known to many Yukoners as weeds, in and around the territory.

Bennett said many species of plant, particularly White Sweetclover, have begun marching across the Yukon, sucking up habitat and robbing other species of space to grow.

'It may be related to global warming.

'I think what the key is ... is we've lost that -40 C,' he said.

'Maybe it's not getting warmer, but it's not cold enough in the winter to keep it down.'

Bennett said he and members of the Yukon Invasive Species Committee which includes members from Yukon government departments, federal government departments, first nations, the Yukon Conservation Society, the City of Whitehorse, and members of the public have been keeping a close eye on a number of plants, and they're noticing some problems.

Plants like sweetclover, Bennett said, are winning the battle.

'For sweetclover, it's a lost cause.

'By the time you see it's a problem, for most people, it's too late.'

Invasive plant species can affect the environment, fire management strategies and drainage patterns, he added.

Bennett said sweetclover has been lining the highways and is now starting to get into the river system, making it difficult for birds, like sandpipers, to nest, which also affects their natural predators, falcons.

Other plants, such as the Oxide Daisy, are being sold in Yukon plant nurseries and have the potential to become a very big problem, as in other jurisdictions, and need to be kept in check.

'It has a tolerance of around -30 C. It's probably been kept in check by cold temperatures, but now it's spreading.

'I think we should make it illegal to sell it, I think we should create legislation,' he said.

'We should really be thinking about what we're planting, because most invasive species come from agriculture or from gardens.'

According to the Department of Environment, there are a number of plants that are considered invasive species including: White Sweetclover, Perennial Sow-Thistle, Canada Thistle, Spotted Knapweed, Foxtail Barley, Common Tansy and Altai Wild Rye.

'Usually what happens with invasive species is they start off slowly, but once they start to explode they fill every habitat,' Bennett said.

'If you get rid of the things that are causing a problem as soon as they get here, they won't be a problem.'

Toos Omtizigt, an environmental coordinator for the Department of Highways and Public Works, said her department is also concerned with invasive species, especially sweetclover, which are lining the highways and obstructing drivers' views of the road.

She said her department has been mowing the plants down and is encouraging members of the public to pick invasive species, and is even starting to develop weed-pulling campaigns.

'Timing is key in pulling your weeds,' she said, explaining that picking the plants at the wrong time could actually spread seeds and create even more of a problem.

'I think it's a public awareness issue.'

Matthew Ball, an agrologist with Energy, Mines and Resources, said the territory's farming community also has its fair share of problems with pesky plants.

For farmers, Foxtail Barley, a perennial tufted plant with barbs on it, is an increasing problem, as the plant can get mixed in with hay and endanger the health of domestic and wild animals.

'In areas of farm land or an area where you have pets, you don't want foxtail because (the animals) will choke.'

Invasive species, including foxtail, also impact farmers bottom line, he added.

'Economics �- invasive species entering on to hay land or even into gardens causes an increase in labour or pesticide use or a reduced yield.'

Ball said he believes it's important for Yukoners to become aware of invasive species and the problems they present.