In recent weeks, Thai and Philippine authorities have drawn attention to how tourism is threatening their natural paradises, reaching the decision to close the most popular tourist destinations to visitors in order to give ecosystems a period of "breathing space".

This is the case with Maya Bay in Thailand, where the government has imposed a forced pause on the visitors who have been flocking there incessantly ever since the film The Beach with Leonardo DiCaprio was shot there in 2000, while Philippine president Rodrigo Duterte announced a six-month closure of the island of Boracay, which had become, in his words, a "cesspool" — an overcrowded biological pit.

But these are not the only cases. Several European cities, including Venice and Dubrovnik, are grappling with tourist overcrowding, as is the Isle of Skye in Scotland.

Five interesting cases of tourism management:

Maya Bay in Thailand

In March, Thai authorities announced the closure of the famous Maya Bay for four months, from June to September, to allow it a brief respite. The bay — with its crystal-clear waters, white sands and limestone rocks — was made famous by the film The Beach, with Leonardo DiCaprio. Since then, 4,000–5,000 visitors every day have poured onto its beaches.

According to experts, 77 per cent of Maya Bay's corals are at serious risk, mainly due to damage caused by boat anchors, and the brief pause cannot solve the problem. But not all is lost. According to Bangkok marine researcher Thon Thamrongnawasawat, there is still a chance to recover the situation. "If we thought it was too late, we wouldn't do anything," the expert told the BBC. "We closed the island of Koh Yoong three years ago, and the corals started growing back; we will use the same approach at Maya Bay and we will also try to transplant some corals."

When Maya Beach reopens it will have a daily limit of 2,000 tourists, and boats will not be allowed to pass through, let alone anchor, in the shallow-water zone. The bay will also be closed for 4 months next year.

In 2011, Thailand closed dozens of sites that were popular diving destinations for tourists, and Koh Yoong, in the Phi Phi island chain, and Koh Tachai, in the Similan Islands National Park, were banned to visitors from mid-2016.

For a country like Thailand, which derives 22 per cent of its GDP from tourism, finding a balance between the pressure of tour operators and the need to give nature a respite is no easy task.

Cinque Terre in Liguria

The five picturesque villages of Liguria have always been a destination for tourists. The area, which has around 5,000 residents, became a national park in 1999 and welcomes over two million tourists every year.

The Cinque Terre are sought after by travellers who enjoy hiking the scenic trails that connect the villages and the terraced vineyards. Over the years, the trails have suffered the effects of wear and coastal erosion. The route between Riomaggiore and Manarola has been closed since September 2012, after a group of Australian tourists was injured in a landslide. For years there has been talk of imposing a limit on visitor numbers, but for the time being it remains just talk.

Technology, however, is a valuable aid in managing tourist flows. Park authorities are testing an app that tourists could download to see in real time the number of people on the trails. When a red warning signal appears on the app, it means the trail is overcrowded and visitors can decide whether or not to join the crowd. In the future, virtual waiting lists could be trialled.

Machu Picchu in Peru

The ancient Inca citadel of Machu Picchu, in Peru, is undoubtedly one of the places not to be missed. Its famous Inca Trail allows visitors to reach the summit through Andean landscapes and rainforests, a unique and memorable experience.

Unfortunately, unlicensed tour operators and an excess of tourists have damaged the trails, produced accumulations of rubbish and uncontrolled camping. The site is well known for exceeding the maximum recommended limit set by Unesco of 2,500 visitors per day.

In 2005, the Peruvian government placed a seasonal limit on the number of people authorised to walk the trail. In addition, every February the trail is closed to allow cleaning and maintenance operations. Tourists have adapted by booking in advance, and tour companies must comply with the regulations in order to retain their assigned permits.

Despite this, visitors continue to flood into Machu Picchu, arriving mainly by road, although last year the authorities introduced a new system requiring the purchase of a ticket with an access permit, in an attempt to control numbers.

Jeju Island in South Korea

The world's busiest flight route? In 2017 it was between Seoul, the capital of South Korea, and Jeju Island, 90 kilometres from the mainland. Jeju, also known as the "Island of the Gods", is a small corner of paradise. Tourists come to admire the volcanic landscapes, the picturesque waterfalls and the erotic amusement park "Loveland", popular with honeymooning couples but also visited by families.

In 2017, nearly 65,000 flights were recorded, with an average of 180 per day. Each year, around 15 million tourists visit the island, a disproportionate number for an area of just under 2,000 square kilometres. Today the island's environment, once pristine, is seriously damaged, and the many visitors who arrive by cruise ship stay for only a few hours and do not contribute to the local economy.

The government does not appear to be inclined to tackle the problem; on the contrary, it is considering building another airport that could triple the annual number of tourists and reach 45 million by 2035.

[vimeo url="https://vimeo.com/102001008″]Video Cano Cristales[/vimeo]

Caño Cristales in Colombia

Caño Cristales, in Colombia, is a surreal sight. A river that appears to contain an entire spectrum of colours thanks to aquatic plants and the interplay of light — ranging from red to pink, from lime green to yellow. The locals call it the liquid rainbow.

The site was at the heart of the territory occupied by the Farc guerrillas, and tourism — both foreign and domestic — was practically non-existent. In recent years, following the signing of the 2016 peace agreement, visitors have begun to venture into the country's deep interior to witness this spectacle of nature.

Today Caño Cristales, which certainly does not see tourist numbers comparable to those of other destinations, nonetheless faces the task of balancing an unprecedented influx of visitors with an extremely delicate ecosystem.

Fortunately, despite Caño Cristales being an emerging destination, the authorities have started with the right approach, defining a set of rules: no plastic bottles, no sunscreen or insect repellent in the water, no swimming in certain areas, no cigarettes, no feeding the fish. On arrival, visitors take part in a briefing to make sure all of this is absolutely