Why large numbers of reptile species face extinction and what that means for our ecosystem

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• Geoff Bennett:

  Globally, one in five reptile species is facing the threat of extinction. That's according to a recent study in the scientific journal, Nature. We take a deeper look now what's driving this extinction crisis and what it could mean for the rest of the world.

• Matt Evans, Smithsonian’s National Zoo:

  Onyx is a two year old male Komodo dragon.

• Geoff Bennett:

  On a recent day, it's Smithsonian's National Zoo in Washington, we met Onyx, a juvenile Komodo dragon. They are the world's largest lizard, often growing up to 10 feet long with some weighing more than 300 pounds. Native to a few islands in Indonesia, these incredible reptiles date back 1 million years. But because of habitat loss, Komodo dragons are now facing an uncertain future, says Matthew Evans, an assistant curator at the Smithsonian's Reptile Discovery Center.

• Matt Evans:

  Komodo dragons are endangered. And these guys are part of a species survival plan.

• Geoff Bennett:

  That plan is part of a larger effort here at the National Zoo to highlight why reptiles are vital to our entire ecosystem.

• Matt Evans:

  Komodo dragons, we call it kind of like a keystone species. So if you remove them as a top predator in the environment, the rest of that ecosystem doesn't function, right? They actually need that top predator for all the roles that are placed with creating habitat, for keeping population densities down, allows other species to breed and flourish if they disappear, is a domino effect.

• Geoff Bennett:

  The plight of the Komodo dragon is not unique, says zoologists Bruce Young, who recently co-authored the largest global reptile study of its kind.

• Bruce Young, Zoologist, Natureserve:

  Our goal was to assess every single species known at the time, we worked with over 900 scientists from around the world that that didn't know these species.

• Geoff Bennett:

  Young says the research took 17 years to complete and found that at least 21% of the world's reptiles more than 1800 species and all face extinction.

  Why are so many reptiles in danger of extinction?

• Bruce Young:

  There's a few reasons why most reptiles that are endangered are in fact endangered, loss of habitat, especially forest habitat from logging. Also, the expansion of the agricultural frontier has caused many habitats for reptiles to become destroyed.

• Geoff Bennett:

  The study also found that if all threatened reptiles were to disappear, the world would lose a combined 15 billion years of evolutionary history.

• Bruce Young:

  It'll take a big contribution by governments to kind of change the trajectory we're on.

• Geoff Bennett:

  One of the reptiles most at risk turtles, with nearly 60% of the species facing extinction, and a need of targeted conservation efforts.

• Scott Smith, Wildlife Ecologist:

  We're surveying both the land and the stream. Hopefully, we're going to find some turtles.

• Geoff Bennett:

  Scott Smith is a wildlife ecologist for the Maryland Department of Natural Resources. He's been studying these slow moving reptiles for 30 years.

• Scott Smith:

  OK, everybody ready?

• Geoff Bennett:

  We tagged along as he and a team of scientists surveyed wood turtles in Western Maryland.

• Scott Smith:

  What turtles main threats are habitat loss, roadkill, road mortality, collecting for the pet trade, climate change. And we wouldn't know that basic stuff without having come out and done the surveys.

• NO NAME GIVEN:

  71 for shell height.

• Scott Smith:

  71.0. OK.

• Geoff Bennett:

  These scientists mark and measure each turtle they find.

• Scott Smith:

  One problem we're having here is with reproduction. We have not found any youngsters at all.

• Geoff Bennett:

  And Smith says nearly all of the turtles they are finding are females.

• Scott Smith:

  What did you get?

• No Name Given:

  All female.

• Scott Smith:

  We're seeing skewed sex ratios towards females because of higher incubation temperatures due to climate change. And of course, in nature, you want a 50/50 sex ratio.

• Geoff Bennett:

  Another major issue human development in areas turtles have long called home, leading to an increase in predators like raccoons.

• Scott Smith:

  There's a lot more on the landscape now than they were historically because they can feed off our garbage, they can feed off cat food, dog food we leave out. And so we have these absurdly elevated populations of predators, which feed on turtle nests.

• Geoff Bennett:

  And while these reptiles face a host of threats, Smith says turtles around the globe are faring even worse,

• Scott Smith:

  Certain species are really on their last legs before they go extinct. So we certainly have a lot of problems. But comparatively to most of the rest of the world, our turtle populations are doing relatively well.

  Noah Greenwald, Center for Biological Diversity: Turtles actually survived the meteor that killed the dinosaurs. And so, you know, they survived a giant asteroid hitting the planet, but they might not survive us, you know.

• Geoff Bennett:

  Noah Greenwald is the Endangered Species Director at the Center for Biological Diversity.

• Noah Greenwald:

  Example, many reptiles control small mammal populations that control insects, which then has impacts elsewhere in the ecosystem, you know, those insects, then don't eat plants and don't otherwise affect things.

  One of the concerns about losing biodiversity is that, you know, nearly all of our medicines, all of our foods come from species. So as we lose the species, you know, we potentially lose a cure to cancer.

• Geoff Bennett:

  So what's the solution then to the extinction crisis?

• Noah Greenwald:

  A lot of the solution to the extinction crisis is actually also a solution to climate change that these two problems are quite interrelated and in particular we just have to protect more of the natural world so species have space to live.

• Geoff Bennett:

  While threats to reptiles have become increasingly urgent. Wildlife ecologist Scott Smith says there's still time to act.

• Scott Smith:

  It's not all bad news. We as humans can certainly change our behaviors and act to reverse this trend. But we have to do it now.