Another Reason National Parks are Vital for Endangered Species

It's all about functional diversity, which is vital for ecosystems.

A jaguar photographed in Braulio Carrillo National Park, Costa Rica, by a Tropical Ecology Assessment and Monitoring (TEAM) Network camera trap.
A jaguar photographed in Braulio Carrillo National Park, Costa Rica, by a Tropical Ecology Assessment and Monitoring (TEAM) Network camera trap.

 TEAM Network

With animal habitat constantly shrinking due to development by humans and the environmental losses due to climate change, national parks offer a safe refuge for endangered and threatened species.

But a new study finds that these protected areas preserve more than just species. They save what’s known as functional diversity, the critical variation of traits within species.

For the study, researchers at Rice University analyzed more than 4,200 photos from camera traps in the protected rainforest at Braulio Carrillo National Park in Costa Rica. Researchers assessed the species diversity of what they saw.

Species diversity is the number of species found in an ecosystem.

“Functional diversity on the other hand is a measure of the variety of traits (physical or ecological characteristics) that species in an ecosystem possess,” study co-author Rice PhD student Daniel Gorczynski explains to Treehugger. “For example, body size and diet are examples of traits. If you have a group of species that has a lot of different body sizes and a lot of different diets, it will have large functional diversity, regardless of how many species there are.”

However, he points out, if you have many species but they are about the same size with similar diets, then the functional diversity will be low.

“Ecosystems often require a wide variety of traits in order to continue working properly. This is why functional diversity is so critical, because it more directly measures the ecological consequences of diversity, not just the number of species,” he says.

No Decline Despite Deforestation

An agouti photographed in Braulio Carrillo National Park, Costa Rica, by a Tropical Ecology Assessment and Monitoring (TEAM) Network camera trap.
An agouti photographed in Braulio Carrillo National Park, Costa Rica, by a Tropical Ecology Assessment and Monitoring (TEAM) Network camera trap.  TEAM Network

The images that Gorczynski and Rice assistant professor of biosciences Lydia Beaudrot examined were taken between 2007 and 2014. They found that the diversity of traits in mammals in the park didn’t decline, despite deforestation that fragmented forests on more than half of private lands surrounding the park. No mammals went extinct during that time either.

“We were pleasantly surprised by the results. In other studies, researchers have found that some species are declining in their population sizes in this particular Costa Rican protected area, so we were expecting that we might also see some declines in functional diversity as well. However, we didn't end up seeing evidence of that,” Gorczynski says.

“Our measurement of functional diversity stayed the same over time, and we also found some functional redundancy among the mammals. This indicates that many species also share functional traits, and the functional diversity of the community may be maintained, even if some species do go extinct in the future.”

The results of the study were published in the journal Biotropica. The species analyzed in the study included jaguar, ocelot, tapir, tayra, coati, raccoon, javelina, deer, opossum, and several rodents.

“This gives us a better idea as to how tropical ecosystems and diversity may be changing (or not) under pressure caused by human development,” Gorczynski says. “This is the first time, to our knowledge, this type of study has been conducted for large mammals in a tropical rainforest protected area.”

Although the results are promising, the researchers say that it's hard to say if other parks are showing similar resilience and preservation of species.

“This protected area in Costa Rica is fairly close to large human settlements and has experienced a good amount of forest loss in surrounding private lands, so the fact that we don't see obvious changes in functional diversity is a good sign,” Gorczynski says.

“But at the same time many protected areas around the world have been shown to be losing species despite their conservation status, so we might expect loss of functional diversity to be more severe in those locations as well. Basically, we need more of this type of monitoring in protected areas around the world to know for certain how mammal functional diversity is changing.”