The lushly forested nation of Guyana on Thursday joined a regional pact to protect jaguars, the elusive spotted cat that is the biggest land predator in the Americas but has become vulnerable as expanded agriculture and mining carves away at their fragmented habitat.

Leaders of the government's environment ministry were signing an agreement with the New York-based conservation group Panthera, which is trying to establish a "jaguar corridor", a network of pathways that would link core jaguar populations from northern Argentina to Mexico. Guyana is pledging to ensure the protection of jaguars, the national animal that is a near-threatened species.

The South American nation, with some of the region's least spoiled wilderness, joins Colombia and nations in central America in recognising the corridor and agreeing to work towards the long-term conservation of jaguars, according to Esteban Payan, regional director for Panthera's northern South America jaguar program.

A network of cameras equipped with motion sensors and fixed to tree trunks has revealed tantalising glimpses of sleek, solitary jaguars slinking through Guyana's dense rainforests and vast grasslands stretching to the country's border with Brazil.

Scientists reported finding a relatively healthy jaguar density of three to four animals per 161 miles in Guyana's southern Rupununi savannah. That means that preserving grasslands are as important to conservation of jaguars as protecting the dense rainforests, they say.

Evi Paemelaere, a Belgian jaguar scientist with Panthera, said villagers in remote spots in Guyana have helped her set up cameras along the roads and hunting trails that the big cats like to travel on.

"Amerindians are very keen on being part of the project," she said from the capital of Georgetown.

Jaguars once roamed widely from the south-western United States to Argentina, but have lost nearly half of their natural territory and have disappeared altogether from some countries. Heavy hunting for their spotted coats decimated their numbers in the 1960s and early 1970s until the pelt trade was largely halted. No one has any reliable estimates of how many jaguars are left in the wild, where they prey on peccaries, tapirs and, as they are powerful swimmers, river turtles.

Guyana, a country roughly the size of the US state of Idaho where most of the 756,000 inhabitants live along its Atlantic coastline, has been widely recognised for balancing progress with preservation. In 2009, it began a low-carbon push aimed at maintaining very low rates of deforestation and combating climate change, while also promoting economic development. It could receive up to $250m from Norway by 2015 as an incentive to protect its forests through sustainable mining, timber harvesting and other projects.

Alan Rabinowitz, Panthera's CEO and a zoologist whose research in Belize in the 1980s led to the creation of the world's first jaguar preserve, said Guyana's signing of the jaguar agreement "demonstrates the government's continued commitment to its legacy of conservation alongside economic progress and diversification".