Fifteen thousand species of animals and plants are considered threatened, according to the World Conservation Congress’s annual Red List. That’s 3,000 more than last year and biologists believe the new numbers are a conservative estimate. Host Steve Curwood talks with Conservation International biologist Michael Hoffman about the list, and the role climate change may play in species extinction.
CURWOOD: From the Jennifer and Ted Stanley Studios in Somerville, Massachusetts, this is Living on Earth. I’m Steve Curwood.
Today much of our program will focus on the diversity of life. Later on, we’ll hear why some scientists believe humans could not survive without ants, and examine some politics of endangered species protection in the United States. But first we look at the Global Species Assessment just released at the World Conservation Congress in Bangkok.
Compiled every four years, this assessment shows some progress being made in conserving biological diversity, but reports sharp declines in a number of species, ranging from quote, “the mighty shark to the humble frog.” And frogs and other amphibians received special attention this time on what is nicknamed the Red List.
Michael Hoffman is a biologist for Conservation International and co-author of an analysis of the Red List. Mr. Hoffman, hello.
HOFFMAN: Hi, how are you doing?
CURWOOD: So I’m looking at your report of the Red List here for this year, and it says that a total of about 15,000 species, including 7,000 animal types and 8,000 plant types and lichens, are now considered at risk of extinction. That’s an increase of some 3,000 more since the previous year’s Red List. Why are these numbers rising? And why do you consider these to be a conservative estimate?
HOFFMAN: Well there’s two reasons. The first major reason for the increase in the numbers of threatened species that we’re seeing on the Red List is the completion of a three year initiative called the Global Amphibian Assessment, which had never ever been done before. And in so doing, they assessed the global status of some 5,700 species. One of the key findings that has actually come out is that one-third of these amphibians are considered to be threatened with extinction.
Now the reason we expect this is an underestimate is that we estimate that there are anywhere up to in the region of 1.9 million species on the face of the earth. But we’ve described a very, very small amount of them, probably only about one percent. So the likelihood is, is that while we know a great deal about how threatened mammals are – that one in four mammals are threatened, or that one in three amphibians are threatened – we know a great deal less about the status of the world’s fish species, for example. Or the world’s plant species. For example, only four percent of the world’s plant species have actually been assessed for threat status.
CURWOOD: Now let’s talk about the amphibians. A one in three species of amphibians – that’s frogs and toads and newts, that sort of thing – are at risk. What do we know about the threats to these animals? What’s leading to this decline?
HOFFMAN: Well, the overwhelming decline for amphibians – and indeed, the overwhelming threat to all the species that we’ve assessed so far – is habitat loss and degradation. Which is being driven largely through, you know, large-scale agricultural practices, industrial development, deforestation and logging. And then an emerging threat which has developed over recent years is the threat of disease. In particular in South America and the tropical Andes, especially in high montane regions, there is a pathogenic disease called chytridia mycosis, which is affecting stream-breeding amphibians. And it has been implicated in the declines of a large number of amphibian species. And we suspect as well that it’s probably a combination of disease as well as climate change that is resulting in a large number of amphibian declines.
CURWOOD: Tell me, what is the role that climate change plays in the threat to biological diversity?
HOFFMAN: So climate change is an interesting one. In fact, a paper which was released earlier this year, and also received a lot of media attention, suggested that – I think the figures were somewhere in the region of 18 to 35 percent of species could go extinct by the year 2050. We’re already seeing how it’s changing and modifying species distributions, and we’re pretty sure it has, and can be implicated in at least some species extinctions.
CURWOOD: What’s the biology of climate change affecting species? What happens?
HOFFMAN: Well what we have is basically a shift in habitat, or a shift in biomes, if you like. And some species are able to actually shift their ranges to account for those shifting habitats. Others are less able to do that. Perhaps because they’re isolated to particular mountaintops, or they have something else which prevents them from actually shifting and moving their ranges. When that happens, extinction is very likely to occur.
But of course it’s not just the effects of long-term climate change. In the case of the frog fauna in Costa Rica it was just a short-term climatic event, a severe dry period that had been implicated as being one of the reasons whey these species just suddenly vanished.
CURWOOD: What does your assessment recommend be done?
HOFFMAN: The first step forward really is identifying where we need to be improving that protected area’s network, and then strengthening and advancing the establishment of protected areas in those places. Of course, as I’ve mentioned, protected areas often are not enough. They need to be accompanied by, in some cases, species-level action. So, this may be things such as actually controlling for invasive species, as is being done around Baja, California. We may need to mitigate the effects of bushmeat hunting in places like central Africa. We may need to look at captive breeding as a means of dealing with disease. So what we’re requiring here is a cross-spectrum of conservation responses, but built around or upon the premise that protected areas, or a protected area network, it needs to form the foundation of effective conservation.
CURWOOD: Michael Hoffman is co-author of the Global Species Assessment and a biologist with Conservation International. Thanks for taking this time with me today.
HOFFMAN: Thank you very much for having me on.
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