For myself, I would say that the greatest barrier is the competing interests. When we have agriculture and oil and gas activities requiring an expanded land base to carry on and to expand their businesses per se, the dollars that support those things far outweigh the dollars that we as conservationists can raise to compete with them on a dollars-and-cents basis for a site with an ecological or environmental benefit.
On April 28th, 2015. See this statement in context.