ST.-DENIS, Réunion — Ever since Johnny Begue and his friend stumbled on a barnacle-encrusted airplane wing flap last week – one that appears to be from the same kind of plane as Malaysia Airlines Flight 370 that disappeared without a trace more than a year ago – just about every piece of flotsam kicked up along the shores of this island in the Indian Ocean has attracted scrutiny.
A plastic water bottle with Chinese writing on it? Call the police and send it off for examination.
A scrap of metal that looks like it could be from a plane? Alert the authorities. It might be one more clue.
“It is madness, really insane,” said Florent Spiesser, 32, who moved to Réunion from mainland France a decade ago after taking a vacation here and falling in love with the place. “No one has ever heard of this place, and now the whole world knows Réunion.”
Roughly 4,000 miles from Europe and lying off the southeastern coast of Africa, between the islands of Madagascar and Mauritius, Réunion is an overseas department of France.
With its lush jungles, towering mountains, dazzling waterfalls and sweeping expanses of sugar cane fields, more than 40 percent of the island has been declared a World Heritage site by Unesco.
The cities and towns that ring the island are named after Christian saints. On the island’s west coast, soft white-sand beaches offer a playground for tourists, most of them European. The east coast, where the airplane wing was found Wednesday, is littered with stones and pebbles, trapping trash that has washed ashore over the years.
“If anyone had heard of Réunion before, perhaps they heard about shark attacks or people falling down mountains or the vicious mosquitoes that came to the island in 2006,” said Mr. Spiesser, who works for the island’s tourism department.
“But now, the world can see what an amazing place this is,” he said. “It really is Jurassic Park.”
Rising nearly 10,000 feet into the clouds, Piton des Neiges on Réunion is the highest mountain in the Indian Ocean.
While the island is a botanist’s dream, with a stunning variety of plant life, there are curiously few animals. “There are no snakes, no scorpions, no monkeys, no spiders,” Mr. Spiesser said.
But there is one of the most active volcanoes in the world: Piton de la Fournaise, on the island’s southern side.
Just as scores of reporters descended on the island, the volcano was putting on a show, kicking up earth and lava and adding to the otherworldly landscape on the southern end of the island.
The eruption posed no danger to the island’s 850,000 residents and did not interfere with the plane investigation, but officials here were quick to capitalize on the global attention and arranged helicopter rides over the volcano and along the coast.
Rudy Clain, 50, a pilot for Corail Helicopters who participated in the search, took several reporters on an aerial tour.
“Look at that shoreline,” he said as he zipped along the coast. Although Réunion is only a speck in the sea, the currents routinely bring debris from thousands of miles away, he said. “There is a lot of area to search.”
On Sunday, metallic debris was found on the shore near the capital, St.-Denis, and was taken by the Réunion air transport police, according to law enforcement officials. The Associated Press later quoted Azharuddin Abdul Rahman, Malaysia’s director general of civil aviation, as saying that the fragment was from a “domestic ladder” and not a fragment from a plane.
For the past year, search efforts for Flight 370 have been mainly focused on an area 3,000 miles away, off the west coast of Australia.
However, the authorities have said that it is entirely possible that any debris caught up in the swirling currents of the Indian Ocean could migrate to this island or to Madagascar and southern Africa.
Malaysia’s Transportation Ministry released a statement on Sunday saying that the airplane part found here was a part of the wing known as the flaperon and was part of a Boeing 777 aircraft, the same model as Flight 370.
Martin Dolan, the head of the Australian agency coordinating the underwater search for the plane, told reporters that “the only 777 aircraft that we’re aware of in the Indian Ocean that could have led to this part floating is MH370.”
Mr. Dolan, reached by telephone on Sunday night, urged caution regarding reports of additional debris being found on Réunion.
“I would treat these reports with some skepticism at this point,” Mr. Dolan said.
On Saturday night, the wing flap was flown to Toulouse, France, and investigators from Malaysia, France, China and the United States, as well as Boeing, are expected to begin the process of formal verification on Wednesday.
If it is confirmed to be from Flight 370, at least one part of the mystery will be solved, erasing any lingering doubt that the airplane did indeed crash, as investigators believe, and offering some closure for the relatives of the 239 people on board.
But there will remain a host of other questions.
Specifically, why did Flight 370 go sharply off its route from Kuala Lumpur, Malaysia, to Beijing on the night of March 8, 2014, and what could have led to its catastrophic end?
Pope Francis called the head of the Roman Catholic Church on Réunion when it became clear that the wing part was likely from Flight 370. And on Saturday night a prayer vigil was held in St.-André, near where the wing part washed ashore.
Sophie Ingra, 18, was one of hundreds who attended the service.
“What is important for us is to share both in the bad and in the hope for the future,” she said.
Mr. Begue, who found the wing flap and has been overwhelmed by the media frenzy, told reporters that he was on the beach looking for a stone to grind chilies when he saw the debris and called a local radio station to report his discovery.
“I did not know what it was at first,” he said. But the discovery’s significance soon became clear, making Mr. Begue an overnight celebrity, interviewed by news organizations from Perth, Australia, to Beijing.
He said that his sympathies were with the passengers’ families and that he would be happy if his discovery helped them in their grief. “I am proud that this big event happened on Réunion and of any role I could play in solving this mystery,” Mr. Begue said.
A previous version of this article misstated the distance from Réunion to Europe. It is roughly 4,000 miles, not 1,000.
Reporting was contributed by Michelle Innis in Sydney, Australia, Nicola Clark in Paris and Christopher Buckley in Hong Kong.