GENEVA (AP) — Switzerland, known for natural beauty like pristine lakes and majestic Alpine peaks, ranks among the world's richest countries whose plant and animal life is under the greatest threat. Environmentalists are seeking better protections for the country's biodiversity in a nationwide vote that culminates Sunday.

The latest polls suggest that initial enthusiasm has waned for the proposal that would boost public funding to encourage farmers and others to set aside lands and waterways to let the wild develop more, and increase the total area allocated for green spaces that must remain untouched by human development.

The contest, which is mostly decided by mail-in ballots followed by a morning of in-person voting Sunday, still looks tight: A poll by the respected agency gfs.bern for the Swiss public broadcaster published Sept. 11 showed support falling to 46% in early September from 51% survey in an earlier poll in mid-August.

The federal government — parliament and the executive branch — opposes the plan, as do many rural voters and the country's main right-wing party, according to polls. They call it too costly, say 600 million Swiss francs (over $700 million) is already spent on biodiversity protection each year, and fear economic development will suffer.

Passage would cost at least another 400 million francs for national and local governments, the Federal Council estimates. The initiative would also, for example, prohibit construction of new railway lines through a protected dry meadows — even if such meadow is set aside and developed elsewhere, it says.

“Passage of the biodiversity initiative would severely limit (sustainable) energy and food production, restrict the use of forests and rural areas for tourism, and make construction more expensive,” argues the campaign for a “no” vote on its web site. “YES to biodiversity, but NO to the extreme biodiversity initiative.”

Proponents, meanwhile, point to dwindling natural resources in Switzerland and threats to bees, frogs, birds, mosses and other wildlife. They argue that protected green spaces are “the main capital for tourism” and more of them would support local economies.

“Diversified nature guarantees air purity, drinkable water, pollination, fertility of the soil, and our food supply,” said a committee that backs the idea. “But in Switzerland, biodiversity is suffering. One-third of all our plant and animal species are threatened or have already disappeared.”

The Organization for Economic Cooperation and Development, a think tank that counts 38 mostly rich countries as members, has produced a comparative look at threats to plan and animal life. Switzerland ranks among the top four countries with the highest rates of threatened species in all eight categories of wildlife.

The voting is part of the latest Swiss referendums, which take place four times a year to give voters a direct say in policymaking in the country of some 9 million people. The only other nationwide issue up for consideration this time is a pension reform plan backed by the government that also shows weakening support, the poll showed.