Conservation Basics: Tiny, Frustrating Tortilla Chips

Rainforest Trust’s work to protect habitats for threatened species is grounded in cutting-edge conservation science. But in this series, we explore the basics of conservation science and how they inform Rainforest Trust’s scientists.

As I was trying to think of a way to explain the concept of species distribution, I struggled to find the right analogy. Species distribution is essentially just where a species lives, but the nuances are important for conservation decision-makers. And the nuances are weird and specific — especially when it comes to habitat fragmentation, or the splitting up of species’ distributions into smaller chunks.

So I wrestled with how to properly explain how frustrating distribution can be for conservation scientists. Until I found another frustrating medium that has many of the same properties.

See, species distribution is a tortilla chip.

In this (not perfect) metaphor, let’s imagine that guacamole is the population size of a species. More guacamole = bigger population of a species.

“Wildlife and their geographic range.”

With me? Great.

What is guacamole’s natural habitat? In the brief instance in which this metaphor is useful, the moment between dipping and chewing, the natural habitat of the guacamole is the tortilla chip. The guacamole relies on the tortilla chip, without the tortilla chip, the guacamole will never make it (to you).

Before our intervention, tortilla chips are full triangles or circles, capable of sustaining a massive heap of guacamole. Pleasant amounts of lime, red onion and avocado can go from bowl to mouth in peace. But, as anyone who has opened a bag of tortilla chips can tell you, this harmony doesn’t last.

Tortilla chips, with too much human interference, break in two. When they do, these smaller fragments don’t support half of the original guacamole volume. Smaller tortilla chips bring in less guacamole proportional to their size, reducing the total guacamole volume scooped per square inch of tortilla chip surface area. As these pieces grow smaller and smaller, it becomes more difficult to support a meaningful level of guacamole. Eventually, the pieces will become useless to the guacamole.

Tortilla chips before becoming unusable, tiny pieces.

Still with me? Awesome.

We also have to account for your thumb space in picking up guacamole. The more tortilla chip surface area your thumb covers, the less guacamole you’ll scoop. This is the effective size of the tortilla chip.

The shape of the tortilla chip also matters. A circular tortilla chip has the proportional viability to hold a heap of guacamole right in the middle. But a long, skinny tortilla chip of the same size will support less guacamole than the circular chip. You could try to pick up the same volume of guacamole, but it will keep falling off the edges.

We should also take into account the structural viability of the tortilla chip. A good tortilla chip can pile on mountains of guacamole. A sub-standard tortilla chip will break with just a hint of tension.

Conservation scientists look at geographic range by taking into account the surface area of the tortilla chips and the effective size of the tortilla chips. They further evaluate these factors by the shape, structural viability and size of the tortilla chip.

I will now try to dig out of this unending metaphor.

The surface area of the tortilla chip is the “extent of occurrence.” This is complicated, so let’s use another metaphor to explain this already convoluted metaphor. Imagine a house with many unused rooms. While the entire house exists as habitat, in reality, only a few rooms are occupied. The whole house is the “extent of occurrence,” the used rooms are what’s known as the “area of occupancy.”

The “area of occupancy” is the actual space the species uses. To bring it back to the tortilla chips, some areas (covered by the thumb) aren’t home to any guacamole. Species don’t live in every corner of their “extent of occurrence,” but they do live in every corner of their “area of occupancy.” So the thumb space would be included in the “extent of occurrence” but not the “area of occupancy.”

Does the giraffe live in every part of this landscape or just part of it? The difference is the difference between “extent of occurrence” and “area of occupancy,” respectively.

Species need safeguards from random catastrophes — like a disease or a fire. If the entire species lives in one field and that field succumbs to a sinkhole, the species is no longer. If the species lives in three fields and one field succumbs to a sinkhole, two habitats remain.

So, on a basic level, the larger the extent of occurrence and area of occupancy, the more chance a species has to make it past a catastrophe.

The shape of the protected habitat (the shape of the tortilla chip) is also important. Protected areas suffer from the “edge effects,” meaning protected land right next to unprotected land will suffer from external influence more than protected land far away from unprotected land. A circle has more area away from the border than something long and skinny, meaning more habitat further from unprotected areas.

The size of the protected habitat (the size of the individual tortilla chips) is important as well. If you had one contiguous tortilla chip and broke it up into many smaller tortilla chips, we would support less guacamole. Same goes with habitat. We call this phenomenon habitat fragmentation. Small patches of habitat have more “edge” areas and less contiguous space, supporting fewer individuals. This also fragments populations, which can lead to inbreeding.

The quality of the habitat (the structural viability of the tortilla chip) defines how many individuals a habitat can support, or carry. Some habitats can support many individuals and species, and some don’t have the same carrying capacity.

A city park, because it is smaller and prone to more disturbance will probably support a lower level of biodiversity than a vast, undisturbed landscape.

To close, I will surrender to this metaphorical quagmire.

The point of a protected area for wildlife is to support large, contiguous and sturdy tortilla chips. Rainforest Trust keeps this idea in mind with every protected area. We’ve protected both large, contiguous areas in themselves in addition to securing gaps between areas to create new vast stretches of protected land.

Because without practical chips, we have no guacamole and the consequences of breaking our bag of tortilla chips (the planet) into tiny, frustrating pieces are dire.

So let’s stop guacamole from going extinct.

From the First to the Largest Species Naming Auction: Rainforest Trust Leads the Way

Rainforest Trust is hosting the largest ever public auction of species naming rights with this fall’s Species Legacy Auction. The strategy of selling the naming rights of newly discovered species to raise funds for conservation is common, but it was Rainforest Trust CEO Paul Salaman that started the trend 25 years ago.

In the summer of 1991, Salaman led an expedition of Colombian and British students to a remote and isolated region of the Chocó rainforests in southwestern Colombia. His expedition discovered one of the world’s greatest concentrations of endemic species at a site called Río Ñambí, where Salaman discovered a never before recorded species of songbird. The distinctive new bird was a member of the Vireo family.

New member of the Vireo family discovered by Dr. Paul Salaman. Photo by Carlos Gustavo.

Colombia in the early 90s was in the grip of horrific civil strife with drug cartels controlling cities and guerrilla groups battling the government across the country. The expedition stayed at a former cocaine processing plant in the Río Ñambí forest and the area was at risk for illicit coca plantations. With the habitat of this vireo and countless other species threatened, Salaman was desperate to raise funds to buy the forests for the local indigenous population and establish a community reserve. With the new-to-science bird as yet unnamed, Salaman thought up an innovative fundraiser — to auction off the right to name the beautiful new vireo in an effort to raise the funds needed to create a reserve.

Dr. Paul Salaman posing with drawing of the bird he discovered in 1991.

Traditionally, the right to decide the second part of a scientific name of a species lies with the discoverer. “However, I broke this tradition for an exciting, if a bit crazy, new idea to underpin the conservation of the Río Ñambí,” said Salaman. “The idea of selling a bird’s name shocked some, but the general reaction was of eager anticipation and speculation as to who would win the honor of naming the bird and helping save its habitat!” The winning bid raised $75,000 that helped create the Río Ñambí and Pangan Reserves and saved countless species and buffers several indigenous communities from deforestation.

Rainforest destruction has not slowed in the past quarter century, and indigenous communities are increasingly negatively impacted. The preservation of rainforests and the people that rely on them is all the more critical. Salaman is applying the auction strategy now at Rainforest Trust, with the names of 12 new-to-science species being auctioned on December 8th. Pre-bidding is already underway. All Proceeds will be matched and will go directly towards protecting the ecologically rich homes of the flora and fauna being named, areas where there are likely other unknown species that enrich our planet and could have immense benefits to mankind.

Conservation Basics: Why Did the Chicken Cross the Road?

Rainforest Trust’s work to protect habitats for threatened species is grounded in cutting-edge conservation science. But in this series, we explore the basics of conservation science and how they inform Rainforest Trust’s scientists.

We know why the chicken crossed the road: to get to the other side. But what was on the other side?

The proverbial chicken crossed the road, motivated by its desire to get to the proverbial “other side.” We assume the chicken made this decision of its own volition and made it with purpose. Like all heroes, The Great Explorer Chicken had a choice: stay put or face the unknown. And, like all heroes, the chicken chose the unknown, battling dangers of the road to seek the dream of the other side’s brighter tomorrow. To remember this inspiring feat, we’ve etched the chicken’s infamous bravery into the annals of history.

I first reflected on the motivations of the iconic chicken after witnessing a Helmeted Guineafowl cross a road between Mto wa Mbu and Arusha in northern Tanzania. A Helmeted Guineafowl, while not a chicken, is chickenesque. I was zipping along the road in a car. The guineafowl was in the roadside brush until, like a scene out of Frogger, it ignored the oncoming hazards moving perpendicular to its trajectory and bolted.

The Helmeted Guineafowl: A Chickenesque Species

But why?

On the north side of the road were buildings, homes and a sufficiency of cows: a human-dominated landscape. On the south side was a private ranch, managed for both wildlife and cattle. Cattle grazing occurred on the outskirts of the property and wildlife abounded in the center, including guineafowl.

As the guineafowl crossed from protected area to unprotected area, it passed from one habitat to another habitat. It did not cross from habitat to “not habitat.” Habitat is the space where living things live, so everywhere is habitat because living things live everywhere. Just as the Serengeti is habitat, the tracks of the New York City subway are habitat. In fact, subway tracks are suitable habitat for the Brown Rat.


But the Brown Rat did not evolve on subway tracks. Nevertheless, it still finds those rails a reliable place to settle down after a long day of pizza-nabbing. Each species relies on a unique combination of habitat factors to live, with some species more discerning than others. The Brown Rat, we might conclude, is not a picky creature. Some species of tropical montane hummingbirds, who only live on a few isolated mountaintops in Central America, are perhaps more choosy.

Habitat types differ in geology, climate (including temperature and precipitation), geographic location, water chemistry and soil properties. Different communities of plants and animals can also create different habitats; some species may rely on another species to survive. Some wasps only lay eggs in fig trees, some ants rely on Acacia trees to colonize and some people just, like, can’t live without their dogs. There is no fixed number of habitat types, only a lengthy list of factors to describe habitat. Each combination (cold, wet and mountainous; warm, dry and mountainous; temperate, marine and sea-level; etc.) is a unique habitat. If you add another factor to the list, the differentiation grows.

The species-habitat relationship is a major tenet of Rainforest Trust’s work to help protect the specific habitats endangered species rely on to survive. Take, for example, Rainforest Trust’s project with the Critically Endangered Palawan Forest Turtle. The entire species relies on lowland swamp forest habitat in one corner of the Philippines. Without this habitat in this location, the entire species will go extinct. If you want to protect gorillas, you need to understand where gorillas thrive. If you want to protect Leafcutter ants, you need to understand where Leafcutter ants thrive. Same goes for pythons, tuna, sugar maples and every other species on the planet.

The Palawan Forest Turtle. Photo courtesty of N. Cegalerba and J. Szwemberg.

As Jeff Goldblum said in my favorite movie: “Life, uh, finds a way.” While terse, Michael Crichton’s punchy take is a decent one-line description of the entire field of biology. Life is everywhere and, uh, finds a way. There are microbes that rely on the salty water of the Dead Sea and spiders that only live on top of Mt. Kilimanjaro. Anywhere on Earth, we should ask, “What lives here?” not, “Can anything live here?”

So why, dare I ask, did the Helmeted Guineafowl cross the road?

Guineafowl rely on habitat traits to survive, and we can assume that both sides of the road, being adjacent, contained the necessities of guineafowl life. The south side was managed for wildlife, ensuring food availability and nesting space, while the north side was not. On the south side of the road, the guineafowl would compete with other guineafowl for resources; on the north side of the road, the guineafowl might compete with domestic chickens. Due to differences in anthropogenic influence, the plant communities, insect communities and soil properties might be different on either side. Two places on Earth, the south side and the north side of one road, vary only in minutiae, but important minutiae.

But the guineafowl and I had different knowledge of the situation. I knew which side might be empirically better for the guineafowl. The guineafowl understood the situation on the ground. Maybe there wasn’t enough food in its immediate vicinity. Maybe another guineafowl scared it. Maybe a Bat-eared Fox was trying to eat it. Maybe it was venturing off to live somewhere new. Maybe it was training for the Guineafowl Olympics. The guineafowl didn’t know the other side held, statistically, fewer opportunities for success. The guineafowl only knew what it knew in that definitive moment and, unlike me, knows what happened in the seconds, hours, days, months and years afterwards.

Our hero must make a decision.

So why did the guineafowl cross the road? After putting the pieces together, we can determine that the scientific, definitive answer is: Who knows? As much as we try to understand the species-habitat relationship, we’ll never be able to predict everything. For conservation, we do the best we can to understand every detail of each side of the equation (species and habitat) and plan for what we know, hoping the wildlife go along with the plan. I don’t know why a guineafowl runs across a road, risking its life.

Maybe the guineafowl just wanted to get to the other side.