National Heritage Areas are not allowed by law to use Federal money they receive for land purchases. Some NHA's don't even own any land. The NHA's are overseen and administered by PRIVATE organizations made up boards of directors to which any private citizen can apply for consideration to become a board member.
The only way a National Heritage Area can buy land is to raise the money itself or they can use a state program if applicable to get money (just like any municipality or non-profit can).
The whole concept of National Heritage Areas is so as not to create new National parks but instead to help related privately owned and publicly owned sites to come together and tell their story in a coherent way and to pool resources so they can spend their money and plan their interpretation etc. in a cohesive and economical way.
Every proposed National Heritage Area goes through a process of public input long before it ever gets to a vote at the Federal level. Pro and con forces have time to say their piece and contact their legislators to support or oppose any proposed area. Usually there are a series of public meetings at which time anyone can speak about what they want or don't want from a NHA. All Federal funding and designations only last for 10 years and then have to be resubmitted for approval which is a difficult and time consuming process.
The Sierry Club and other similar organizations are more than willing to buy out BLM leases in order to protect the land. I am sure those environmental groups have some fat contributors just waiting to designate someone elses land away from private ownership and control.
Ok so they just need to shuffle the shells a little more.
And because it was so difficult to obtain you KNOW that land will never NOT belong to the government again.
So, I guess everything is ok and the feds are not expanding their land holdings. Whew, I was worried for a while.