For protected areas in the Brazilian Amazon, one basic question is often overlooked: is there enough money to manage what lies inside the boundary?

A reserve may exist in law. It may appear on maps and in official counts of how much of Brazil is under protection. On the ground, management depends on staff, fuel, boats, radios, fire brigades, monitoring, community work and the ability to respond when illegal miners, loggers, poachers or land-grabbers arrive. Without those things, protection can remain largely administrative.

A new paper in Environmental Conservation puts numbers to the gap. Helenilza Ferreira Albuquerque Cunha and colleagues examined 300 federal protected areas in Brazil between 2014 and 2023. Together, they cover nearly 750,000 square kilometers. The researchers compared actual spending with evidence-based estimates of the minimum cost of managing each site. In 2023, 72% of the areas studied were underfunded. The combined shortfall was about $958 million in purchasing-power terms.

The deficit was sharpest in the Amazon. Protected areas there had an average funding gap of 79.2% in 2023, meaning they received roughly one-fifth of what they needed. Of the 122 Amazon protected areas in the study, 120 fell below minimum cost thresholds.

This is not simply a story of neglect. Over the decade studied, investment rose by about 30%. Brazil also has one of the world’s largest protected-area systems. The problem is that protection has expanded faster than the financing needed to manage it. Remote and ecologically important areas often have the weakest political constituency.

That matters because these areas are expensive to run. Many are vast and difficult to reach. Enforcement may require long patrols across forests, rivers and informal roads. A single manager may be responsible for an area larger than some countries. Costs rise quickly.

Tourism, concessions and private investment can help, especially in well-visited parks. They are less likely to cover the basic costs of large Amazon reserves whose value lies mainly in keeping forests standing, protecting biodiversity, supporting traditional communities, and reducing degradation.

Brazil has already built a protected-area system of global importance. The new study shows that much of it still rests on a thin financial base. If protected areas are to do the work expected of them, they need more than lines on a map. They need the steady funding that turns protection into management.

The story: Brazil has protected much of the Amazon. It now has to pay for it.