Mountain Biking in the Parks

Little by little, more details are surfacing about plans the International Mountain Bicycling Association has for making inroads in the national park system. On first blush, the IMBA announced that it simply wanted to gain more access to dirt roads in national parks for its membership.
Then, as I noted in a post back in January, the group admitted that, oh, by the way, we really do want to see some gnarly single-track trails cut in the parks.
Now more details are surfacing as officials at Big Bend National Park go through the process of developing an environmental assessment to create some of those trails for the cyclists. And those details are a tad bit discouraging.

Why are they discouraging?
Well, the IMBA has gone from claiming it was just interested in accessing more dirt roads in national parks to laying down guidelines for how it wants single-track trails built. According to Public Employees for Environmental Responsibility, IMBA wants Big Bend crews to either upgrade existing trails or build new trails specific for mountain biking.
PEER says IMBA has said it wants trails without water bars that might force riders to dismount, and it wants trails 4-feet wide and that zigzag through the woods. Plus, IMBA doesn't want bike trails near dirt roads that might generate dust from passing vehicles.
There are other concerns specific to Big Bend. For instance, Big Bend officials already are struggling to maintain 200 miles of hiking trails but they lack adequate funding and personnel to get the job done. With that in mind, where will the park come up with the additional money not just to build mountain bike trails, but to maintain them?
PEER officials also point out that there are plenty of mountain biking options nearby to Big Bend. For instance, there are 100 miles of mostly single-track trails in the Terlingua/Lajitas area, and more than 900 miles of old ranch roads and trails open to bikes in Big Bend Ranch State Park. And, the national park itself already has 180 miles of dirt roads and 125 miles of paved roads that are available to mountain bikers.
So I guess the bottom-line question is do we really need to cut single-track mountain bike trails in Big Bend or other national parks that face many of the same logistical and financial dilemmas?
The backcountry of parks long has been where one could go to escape the mechanized world. How long will it be before hikers and horseback riders will have to dodge mountain bikers?