Biology Question

in this exercise, you will obtain a list of threatened species for the U.S., a developing (tropical) country of your choice, and then contrast the causes of species imperilment in the U.S. and your other selected country with those in the world at large.

From this assessment, you will develop an understanding of the primary threats to biodiversity and their magnitude both locally and globally.

This activity aligns with Module Outcome 3.

For this assignment, you will return to the IUCN database using different search criteria for each country and individual threat to biodiversity. Thus, each search will enable you to determine the number of species in a particular region that are facing a particular threat.

You will use a statistical test to determine if there are genuine differences in the importance of each threat in the two countries versus globally.

Lastly, you will interpret these tallies and make inferences about the relative importance of each threat at the scale of the two countries versus globally and make suggestions for conservation priorities.

You will use the following document, “

Step A. Searching the IUCN database

  • Go to the IUCN Redlist website (Links to an external site.) and choose “Other Search Options.”

    The new screen will display a series of options for searching the database. You can search species by a number of criteria, including ‘Location’ and ‘Threats’ which lists 12 categories of threats, each including several subcategories. Some of these threats are natural causes (e.g., ‘Geological events’ such as volcanoes and earthquakes), but most of the threat categories are due to human activities, directly or indirectly. This is an extraordinary database for analyzing patterns of threats to biological diversity around the world.

    Click on “Location” in the red box on the left-hand side of the screen. Expand “Land Regions” by clicking on the “+” (plus sign). Continue to use the “+” (plus signs) until you can see countries or states listed in a region of interest. Expand North America. Put a check in the box next to the United States (this will select all states and territories within the U.S.).

    Also, make sure that only the box for “Natives” is checked. To the left under “Taxa” make sure only the box for “Species” is checked. Click the red arrow to move your selection into the box on the right-hand side of the screen.

  • Under “Threats” you can limit your search to particular threats to species, or select one or more threats. The major threat types are numbered according to a four-level hierarchical system. Selecting threat types from the second level and below, switches off the levels above and vice versa. For example, selecting “9. Pollution” and “9.1.1. Sewage” will only produce results for “9. Pollution.”

    Note that the threats may have been in the past, they may be creating an impact at present, they may only be future threats, or they may be ongoing (past, present and future). Because we are interested in general classes of threats, you should search the major categories one at a time.

    Start with: 1. Residential and Commercial Development. This will select all those species at risk from any type of residential and commercial development. Click the red arrow to add your selection of threats to the search box on the right-hand side of the screen. Click on “Run Search” below the Search Criteria box.

Step B. Interpreting the results of the search

  • You will now see a list of species that meet the search criteria you have selected, that is, that occur in the U.S. and are threatened by residential and commercial development, one form of habitat loss and degradation. Look at the list of species. Do you recognize any of them? Do you have any personal knowledge of the specific habitat loss issues confronting any of them?

    Because we want to contrast threats by region, you are primarily interested in tallying the total number of species that were located by the search (see top of results screen, e.g., “Displaying species assessments 1 – 50 of 921 in total”). Record the total in your saved Data Organizing Table.

Step C. Performing the remaining searches for the U.S.

  • You want to obtain and record the total number of species in the U.S. facing different threats. So, repeat the search process, but only change the threat category. Repeat this for the following 12 categories and record the total number of species for each threat category. Use your Data Organizing Table to organize the data.

    • Threat Categories

      1. Residential & commercial development

      2. Agriculture & aquaculture

      3. Energy production & mining

      4. Transportation & service corridors

      5. Biological resource use

      6. Human intrusions and disturbance

      7. Natural system modifications

      8. Invasive and other problematic species, genes & diseases

      9. Pollution

      10. Geological events

      11. Climate change and severe weather

      12. Other options

Step D. Getting a global perspective

  • Repeat Steps A to C but now for “Location” choose a developing, tropical country such as Brazil, Peru, Vietnam, Philippines, Bangladesh, etc.

  • Finally, repeat Steps A to C but for “Location” click on the box to the left of “Land Regions.” This will extract the total species recognized anywhere on the globe on land by the IUCN in relation to the type of threat. Record these totals, as you did for U.S. and the other country, but this time for the entire globe. Recording the correct totals for the U.S., the other country and at the global level in the table is worth 20 points.

  • Convert the numbers in each threat class to a percent of the total species across all threat classes in the U.S. for the “% Total” columns in the table (number of species in a given threat category*100/total number of species). For example, if there are 921 species in your first category (Residential & commercial development) for the U.S. and the total number of species threatened in the U.S. by all 12 categories of threats is 3,500, then the percentage for the first class is 26.3%. Do this percent conversion for all 12 categories for the U.S.

  • Then do the same calculations for the other country and then for the global species tallies and fill in the table under “% Total.” Recording the correct percentages for each threat for the U.S., the other country and at the global level in the table is worth 15 points.

Step E. Comparing differences between the local and global threats

  • Using the table you prepared in the previous step, you are now able to examine if the species are distributed equally across the various threat categories in the two countries and across the globe. You will perform three tests comparing 1) the U.S. versus Global; 2) the other country versus Global; and 3) the U.S. versus the other country. For the first analysis, the null hypothesis you are testing is that the species are distributed equally across the various threat categories in the U.S. versus across the globe.

  • Perform first a chi-square test on the data for the U.S. versus Global. This is a very basic statistical analysis that is described in any introductory statistics text. You will use a chi-square calculator (Links to an external site.). Under “1. Choose data entry format” check the second option, “Enter or paste up to 2000 categories (rows).” Under “2. How will you enter the expected values?” check the second option, “Percent Expected.”

  • The first column will include the name of the 12 categories, so just copy and paste them from your table The second column will include the actual number of species (not percentages) in each of the twelve categories for the U.S. The third column (“Observed #”) will actually include the percent expected (%Total from your table) for each Global threat category. The chi-square table is set up like this from left to right: Category, Observed #, Expected. I think some clarification, rewording would help to prevent confusion. This has generally not been an issue, but I did have a student have an issue with this last week.

  • The test will return a chi-square value (χ2), degrees of freedom (df = 11 for all tests here), and a p=value. Very small p-values (p-value<0.05) are interpreted to mean that the difference is significant meaning that there is a statistically significant difference between the number of species in the different threat categories in the U.S. compared to the Global values. Write the results of this first test and your interpretations in the worksheet file. This test is worth 15 points.

  • Then run the test comparing the other country you selected versus Global (worth 15 points) and finally compare the U.S. versus the other country (worth 15 points).

Step F. Interpretation and conclusions

    • In this section, discuss which threats are most significant to species in the U.S. vs. the developing, tropical country you have chosen vs. globally. (worth 20 points)

      • Were there significant discrepancies between each country and the global level as indicated by the chi-square analysis? If so, which threat categories were most different? What accounts for these differences? This last question is fairly complex and requires you to think of the different social, economic, legal, and biological dimensions of the two countries versus that of the world in general.

      • Finally, for each country, what does your assessment of threats suggest are the most important areas on which to focus conservation actions. This, too, is a very complex question but it is the heart of why we perform threats analysis in the first place.

Be sure to include this part in your analysis.

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