The 'how' and the 'how much' are the two big problems officials face in the war on invasive species.  The battle is a big one, difficult and expensive, as many organizations fight to keep the environment balanced, save endangered species and protect resources. 

Sparky Taber, Natural Resource Manager & Weed Manager for the local Bureau of Land Management district says the fight is "expensive." 

His work primarily concerns invasive plant species, or weeds, which he defines as "plants out of place." 

Some were introduced innocently, he says.  "Some of the most aggressive weeds we have are beautiful plants."

While others came along with the expansion of the West.  The BLM is working to control several invasive species, one of which is the Tamarisk.  Tamarisk is a small tree or shrub that was brought over from Asia for its beauty and ability to stabilize riverbanks. 

"Once established," Taber says, "They can begin to crowd out our native plant communities, reduce the plant diversity and then impact things like, say, recreation."

Native plant communities like the riparian Cottonwood groves.  Taber is working to restore those groves along area waterways. 

The fight against Tamarisk is moving along slowly, but there has been significant progress with the help of small beetles that eat the leaves or "defoliate" the rapidly growing plant. 

"Typically, combining what the beetles are doing in weakening this tree and what we do either with a chainsaw and herbicide, we have a fighting chance against this plant," Taber explained. 

The BLM is also fighting the Russian Knapweed and they aren't alone.  Mesa County has also declared war on the noxious weed. 

"It takes over a lot of acres.  It's able to out-compete the native plants here and it doesn't have any natural pests to it in the area," explained Melissa Werkmeister, Mesa County Weed & Pest Coordinator. 

Knapweed is poisonous for many grazing animals and easily takes over lands from their natural vegetation.  It's just one of the many weeds the county is spending time and resources to control.  Another big pest is the beautiful Purple Loosestrife. 

"Noxious weeds affect everything," said Werkmesiter.  "They impact everything from agriculture to recreation, wildlife.  They impact everything."

But it's not just plants, it's animals too, some large and some very, very small.  

"One of the biggest problems we have in Western Colorado is the introduction of Zebra and Quagga Mussels from other places in the United States," said Sherman Hebein, Senior Aquatic Biologist for Colorado Parks & Wildlife's Northwest Division.

These tiny creatures are spreading from the east and Colorado Parks & Wildlife has an extensive prevention campaign in place.  Hebein says it's for good reason. 

"Prevention is far better than trying to remove them after they become established and that's why we have our boat inspection program."

Since 2008, they have inspected over thirteen thousand boats in Colorado, fifty of which were heavily contaminated by the mussels. 

The mussels, almost like the weeds, tend to take over, removing nutrients from their surrounding and having a large impact on the environment. 

"They will remove most of the productivity from a water column.  They also breed very quickly.  If you start off with one pair of mussels, in two years you will have approximately ten billion, that's with a B," Hebein explained.

So far, they've held the mussels in check and say the expense of their program is justified by avoiding potentially devastating consequences down the road. 

"Prevention of infestation by these things is very much worth it because these things travel on boats.  They don't fly through the air.  The only way they're going to get to a body of water is if somebody puts it there.  So, prevention by inspecting the boats and then decontaminating when necessary avoids the extreme expense that you would see from a program where a dam or reservoir operator would have to go down and clean their intake structures," Hebein said.

Parks & Wildlife is also working on fighting Northern Pike and Smallmouth Bass, larger invasive species that crowd out local fish, some whose very existence is being threatened.

"The four big river endangered fish  are found no where else in the world.  They're only found in the Colorado, the White, the Yampa, Green River and the tributaries to those systems.  No where else in the world," said Hebein.

The fight against invasive species is not cheap.  In fact, it is estimated that hundreds of thousands, if not millions of dollars are being spent in the state annually.  But officials say the expense is worth it if you consider the possible consequences.