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When you hear the word conservation, it may seem like a concept, and a movement, that’s only popped up in the last century or so. Like, as responsible human beings, we’ve realized what a terrible job prior generations have done managing ecosystems and the creatures that live there, and we now need some major conservation efforts to clean up the mess that we’ve made of our planet.

But organized efforts to conserve resources that directly benefit humans are actually hundreds of years older than that. In fact, the first historical attempt at conservation, as we understand it now, is believed to have been made by the Inca, way back in the 15th century… to protect poop. Specifically, seabird poop.

Let me explain. At its height, the Inca Empire was massive, spanning nearly 4000 kilometers north to south. It stretched all the way down from what is now Ecuador into Chile, and extended from the Pacific Ocean to the Andes mountains.

Most of this area was extremely dry and lacked essential nutrients for plant growth, thanks to droughts and other climate factors. But the Inca Empire is well known for its agricultural achievements, like incredible terraced gardens, and was able to support a growing population of more than 8 million people on the food it grew. And the Inca can attribute at least some of this success to seabirds specifically, their poop.

Following an example set by even earlier cultures, the Inca used seabird poop harvested from nearby offshore islands as a natural fertilizer for their crops. Not just any bird poop will work well as a fertilizer, though. Seabird poop, or guano, is packed full of nutrients essential for plant growth, thanks to their seafood-rich diet.

Most importantly, guano contains nitrogen and phosphorus, key ingredients in any fertilizer. But is also balanced with many of the other chemicals that plants need, like potassium, calcium, iron, and several others. The uninhabited islands just off the coast of Peru had huge populations of seabirds living on them.

Just three species contributed huge volumes of poop: the Peruvian pelican, the Peruvian booby, and the Guanay cormorant which actually takes its name from the word guano. In fact, these Peruvian islands have been used as a natural source of fertilizer for thousands of years. Thanks to low rainfall, the guano and its nutrients wouldn’t get washed away and the poop used to accumulate into piles 50 meters high, or more!

The Inca recognized that it was vital to protect this important source of nutrients for their crops, because it provided food stability for the empire. So they created laws that established protections for these offshore islands and the birds that called them home. A Peruvian chronicler by the name of De la Vega documented their efforts in 1609.

He wrote that each offshore island was assigned to a certain Incan province, or if it was a large island, to two or three provinces. Each village in the province had its own piece of the island, and each homeowner in the village played a part in the conservation efforts, depending on how much poop they needed. There were also laws that helped protect the birds themselves.

No one was allowed to set foot on the islands during the breeding season, so the birds wouldn’t be scared off their nests. It was also illegal to kill them during any season, on or off the islands. The punishment for either offense was death.

These accounts from De la Vega are believed by researchers to be evidence of some of the first intentional conservation efforts by humans. There are examples of earlier efforts to protect animals for spiritual and cultural reasons, which indirectly helped to protect those populations. However, this is the first example we know of where laws were set in place to protect a natural resource that was providing direct economic benefits to people -- in this case, the Inca Empire.

We use similar rationales in conservation today, like the establishment of national parks. Though the death penalty is usually off the table. The Inca’s efforts helped to keep the populations of these three bird species stable until the 19th century, when colonizers chose to ignore conservation in favor of overexploiting the islands.

This led to the eventual decline of these seabirds, and while some have stabilized, others are still in trouble. Seabird poop is not quite as widely used today for crops, thanks to synthetic fertilizers, but it is still a vital source of fertilizer for marine ecosystems. The nitrogen and phosphorus in seabird poop gives phytoplankton populations a boost, and is important for corals.

Healthy corals means healthy reef fish and commercial reef fishing is a 6 billion dollar a year industry. In fact, the benefit provided by pooping seabirds has been estimated by conservationists to be worth at least 1 billion dollars a year! Unfortunately, seabird populations around the globe are declining, thanks to a number of threats including ingesting marine debris or being caught as bycatch in fishing nets.

But thanks to the Inca, we’ve known their value for hundreds of years so hopefully we can take a leaf out of their book. Thanks for watching this episode of SciShow, and thanks to our patrons for supporting our channels. Before you ask, no, we don’t accept fertilizer.

But we do have neat perks to thank you guys like monthly bloopers, fancy facts, and our After Hours podcast, which covers everything even weirder and grosser than seabird poop that we can’t talk about in our regular episodes. If you’d like to get involved, check out patreon.com/scishow. [♩OUTRO].