Conservationists and communities are planting thousands of agave plants to protect endangered bats, as well as the future of Mexico's tequila production.

In the dusty expanse of central Mexico's Chihuahuan Desert, chill, dark caves are hidden in the brown rocks. Inside them, during late Spring, are thousands of small, furry bats. Most of them are female and pregnant – and they've set off on a 1,000 mile (1,609km) journey from southern Mexico to the southwest of the US, where they'll give birth. They're hungry and fly for hours at night to find enough food. They flap from plant to plant, collecting nectar and spreading pollen as they go.

Among their favourites are the fluffy yellow flowers of the agave plant – flowers that appear just once in the plant's decades-long lifetime. These spiky, fleshy-leaved agave plants have a long history in Mexican culture. They're used to make syrup, rope and soap, and their juice is the main ingredient in one of Mexico's most iconic exports: tequila.

But wild agave plants are declining: in a study of 168 species, 42 are now threatened or severely endangered. This means less food for bats that depend on their flowers – and fewer bats in turn means that fewer agave plants are pollinated. To break the cycle, conservationists are working with locals to plant thousands of agave plants – helping feed the bats and protect the future of Mexico's tequila production.

One agave-dependent bat species – the lesser long-nosed bat – has seen a remarkable population recovery in recent decades, multiplying from 1,000 in 1988 to an incredible 200,000 today. But others are not doing so well. The Mexican (or greater) long-nosed bat has declined by an estimated 50% over the past two decades and is currently endangered. Another species, the Mexican long-tongued bat, has near-threatened status.

Biologist Marco Antonio Reyes Guerra is part of the Bat Friendly Project at the National Autonomous University of Mexico, which works with farmers to encourage agave farming that supports bats. He explains that many of the threats faced by bats are caused by humans. "If they have some disturbance in the caves, they are going to abandon the caves and they are going to lose their home. And people are deforesting several areas of dry forest, and in that forest there are species that bats use as a food source." These species include agaves, as well as other plants that the bats feed on.

Scientists at Bat Conservation International (BCI) are determined to turn things around for these declining species. The Agave Restoration Initiative involves planting and protecting wild agaves in the 'nectar corridor' the bats follow on their migration. "The whole thing was started because, once these migratory species leave central Mexico, they heavily depend on agaves," says Ana Ibarra, a bat biologist and regional director at BCI.

Wild agaves are facing their own threats: they're

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