WARSAW -- Poland's path to energy independence through shale gas is being delayed by skylarks, red kites and local farmers hesitant to grant access to their land.The nation is sitting on the European Union's biggest reserves of the fuel, enough to last at least 50 years and free it from dependence on Russia, according to the Polish Geological Institute. Exploiting the deposits will require the government to allay the concerns of the Kashubian ethnic minority, farmers, environmentalists and tourism officials. They worry that hydraulic fracturing, the drilling method that made the U.S. the world's biggest producer, will pollute their water.Explorers from ConocoPhillips to Chevron Corp. and Polskie Gornictwo Naftowe i Gazownictwo S.A. may spend $4.5 billion this decade sinking wells to tap into natural gas more than 3 miles below the nature reserves and winding roads that link rural villages in the north. Last year, about 25 percent fewer wells were completed than forecast by the Environment Ministry as some projects were delayed."People in the region have emotional ties to their land, which they've owned for generations," said Malgorzata Klawiter, a Pomeranian regional official tasked with promoting the gas development. "For them, the value of an old home with a shack and surrounding land is much higher than any market estimate."The ministry expects companies to drill 39 wells this year, more than double the annual average over the previous 30 months, as the government moves to simplify environmental rules.Poland's technically recoverable reserves are put at trillion cubic feet, 33 percent more than those of America's Marcellus Shale, the U.S. Energy Information Administration said.