Introduction:
Rare, Threatened, and Endangered Species
The International Union for the Conservation of Nature (IUCN) is a global organization that assesses the conservation status of biodiversity around the world. This results in the production of the Red List of Threatened Species, which is a catalog of the relative risk of extinction for species spanning the globe. The information can be used to understand the current state of biodiversity, the human impact on species, and the needs and opportunities for conservation. The IUCN data and reports are made public online and can be accessed by visiting http://www.iucnredlist.org/.
DATA SET:
The IUCN catalogs three categories of species that are facing challenges to their continued existence: Critically Endangered, Endangered, and Vulnerable. Critically Endangered species are those that face an extremely high risk of extinction, Endangered are those with a high risk of extinction, and Vulnerable are those that are at risk of becoming Endangered. Together, these categories can be grouped under the term “Threatened.” View the graphs of Threatened species from the years 2000 and 2015. To do this, and to answer questions 1-3, you will need to use the drop down menu to switch from Critically Endangered, Endangered and Vulnerable for the years in question.
1. Does the number of bird species in all of the categories (Critically Endangered, Endangered, and Vulnerable) increase from 2000 to 2015? Which category shows the greatest percent increase? By what percentage is that category increasing? (Hint: to find percent increase, first find the difference between the two numbers and then divide by the original number. Multiply this value by 100 for percent).
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2. Are there any categories for which the number of Threatened mammal species surpasses that of birds?
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3. Of mammals, birds, and amphibians, which taxonomic group has seen the greatest increase in all categories from 2000 to 2015?
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4. The IUCN cautions that these data should not be interpreted as a clear indication of the increase in numbers of species that are threatened. What is another plausible explanation for this trend?
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5. To understand this concept better, we can also make a graph of the total number of species in each taxonomic group compared with the number that have been assessed by the IUCN Red List. From the Data Set Menu, select “Number of Species, Number Assessed and Number Threatened”. Of mammals, birds, reptiles, and fishes (disregard plants for the time being), which of these taxonomic groups has been most thoroughly assessed? Which has the greatest knowledge gap (the greatest difference between the number of species and the number that have been assessed)?
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6. Now, using the same graph, look at plants. What percentage of described flowering plants has been assessed? (Hint: to find the percent of species that has been assessed, divide the number assessed by the total number of species from the graph).
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7. What percentage of the plant species that have been assessed is threatened? (Hint: to find the percent of assessed species that is threatened, divide the number threatened by the number assessed).
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8. Endemic species are those that are found in a limited geographic area and nowhere else. Select “Number of Endemic and Number Threatened” from the Data Set Menu. Which country has the greatest number of endemic animals? Which country has the greatest number of threatened endemics?
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9. Which country has the highest percentage of its endemics threatened? What is that percentage? (Hint: to find the percent of endemics that are threatened, divide the number of threatened endemics by the number of endemics).
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10. What general conclusion can you draw from this overall analysis of the IUCN data?
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