From a helicopter over Arthur R. Marshall Loxahatchee National Wildlife Refuge on Wednesday, U.S. Interior Secretary Ken Salazar took in some of the daunting challenges of restoring the Everglades.

Down below, suburbs abut the refuge’s last cypress stands. Vast sugar farms loom to the north. Cattails, fueled by nutrient pollution, choke out native plants around its border. Massive man-made marshes filter dirty water flowing in, but not well enough. Giant pumps replicate a natural flow now blocked by canals and levees.

The visit to the western Palm Beach County refuge was intended to highlight Everglades restoration progress by the Obama administration, which has kick-started stalled projects with $1.5 billion in federal support over the last 3 1/2 years and struck an important pollution clean-up settlement last month with Florida.

But partisan election-year overtones buzzed almost as loudly as the cicadas. In what sounded an awful lot like Obama campaign talking points, Salazar ticked off a string of successes while also issuing a caution about the amount of work ahead and uncertain future state and federal support.

“Frankly, a great fear I have is there will be a U-turn,’’ Salazar told reporters after a chopper and airboat tour.

He questioned the long-term support of Republican Gov. Rick Scott for the deal, which will cost the state some $880 million to expand manmade marshes that reduce the flow of the damaging nutrient phosphorus.

“There has to be a continued commitment on the part of the state of Florida to get this thing done,’’ Salazar said. Scott, who had personally championed a settlement, released a statement saying his office has worked closely with federal agencies and environmentalists to secure the agreement.

“I would be shocked if Secretary Salazar said that, knowing how hard we’ve worked on our historic agreement to restore water quality and water flow to the Everglades,’’ he said. “I, along with all Floridians, care deeply about the Everglades and recognize it as an international treasure.’’

But notably absent from Salazar’s visit were representatives of the South Florida Water Management District, which is in charge of Everglades restoration for the state and headquartered a half-hour drive from the refuge. The district — which last week tentatively agreed to trim $100 million from its budget, money environmentalists argue should be put toward clean-up costs — referred questions to the governor’s office

Salazar, whose agency oversees federal parks and refuges, also warned that a budget drafted by Republicans in Congress would amount to a “death knell’’ for programs that fund conservation projects – not just Everglades restoration but nationwide.

“It’s not the kind of conservation agenda that Teddy Roosevelt or Barack Obama or I would support,’’ he said. “I will do everything I can to fight that, as will the president.’’

Salazar’s visit followed one last week to Orlando by four high-ranking administration aides to announce an $80 million purchase of “conservation easements’’ that will preserve 23,000 acres of rural wetlands in the Northern Everglades. Vice President Joe Biden and U.S. Sen. Bill Nelson, a fellow Democrat facing a tough election battle this year, made a similar Glades-as-a-backdrop stop in Miami-Dade County in April.