miércoles, 23 de mayo de 2012

Today is International Day for Biological Diversity! Visit your favorite spot in nature and measure its biodiversity:

Today is International Day for Biological Diversity! Visit your favorite spot in nature and measure its biodiversity::


The most common use of biodiversity is to attempt to determine the number of species in a biological community, and is usually then used in determining the sensitivity of an ecosystem and the conservation statuses of its species. However, biodiversity cannot be captured in a single number, and therefore must be approached in different ways. Thus, it's best to go over those ways to find which may best suit your project.

Constructing your experiment includes these steps: (1) sampling methods, (2) collecting specimens, (3) gather and organize data, (4) run statistical tests. Always be precise and accurate!


Edit Steps


Sampling methods

  1. Decide on the project location.
    • What creatures fascinate you the most (for example, crabs)?
    • As you’re doing a project likely inspired by conservation, what ecosystems (which contain those fascinating creatures) are in dire need of conservation (for example, tropical oceans)?
    • Then, research to find which organisms are classified as threatened or endangered to specify a project location (for example, a nearby state park). Greater diversity stems from a large sample size. Thus: more area → more specimens, more specimens → more species get recorded
  2. Keep in mind that sampling areas must:

    • Be random
    • Be widely spread apart
    • Represent the entire project location
    • Be the exact same size
    • Have a known area.
  3. If applicable, choose sample areas that are both in reserves and nearby (within >8km) non-reserve areas.
  4. Select your sample method. A type of sample method is a quadrat, which is a plot of land marked off for the study of plants or animals. Although the term implies a four-sided area, this is not necessary – many shapes are satisfactory. Continuing with the above example, you may instead use baited crab pots randomly placed at specific depths and distances apart throughout applicable areas in the Evergreen Beach.
    • Seek to achieve randomness in your sampling. For example:
      • Get a map of the project location
      • Draw a precise grid with many squares on the map
      • Label each square on the map with a number
      • Use a random number generator to choose squares.
    • To ensure great distance between samples, make each square very far apart and then designate a smaller sample area within the original square chosen by the generator.

Collect specimens

  1. Educate yourself on local Possession and Collection laws before collecting. In many jurisdictions, collecting or keeping wildlife is restricted or even forbidden. Check laws online or ask a local authority or bureau responsible for wildlife for details.
  2. Collect specimens at consistent and precise time intervals.
  3. Use worldwide definitions of an individual’s category, or recognizable taxonomic unit, RTU. (for example, subspecies, species, etc).
    • If you cannot identify a species, morphospecies, give it a descriptive name and use that name consistently.
  4. Factor in what time of year and day to collect specimens.
    • Mating, spawning, and flowering seasons are the best times to collect.
  5. Define the size of adults and juveniles. Does age matter? Are you only collecting adults? Or will juveniles be included?
    • How big or small are your specimens? Are they the size of a grain of sand? Or are they as large as a tree?
    • If they’re small, devise ways to extract them. For example, use very fine filters to rinse away debris, or use Salt and Hollick’s benzene flotation method where insects accumulate at the benzene-water interface and plant matter stays in the water, etc.
    • If they’re large, collect clippings of a sort; for example, hair, toenails, leaves, etc.
  6. Consider devising a mechanism to draw them in. If your specimens are animals, what do they like to eat or to be near?
  7. Depending on your collection permit, you may be able to collect the entire sample area. In which case, identify each specimen alphabetically, numerically or alphanumerically.

Gather and organize data

  1. Collect as much as possible. You can never have too much data. Collecting everything from date and time to weather and size of specimen to the mm is fantastic. Everything could be extremely useful if, or when, you decide to collect data again.
  2. Whether independent or in a group, all data must be:
    • Precise and accurate
    • Consistent throughout
    • Clear and straightforward.

Run statistical tests

  1. Apply measurements. The most common measures of biodiversity are species richness, Simpson’s index, and Shannon’s index. Although it’s good to know what each test helps you understand, software programs have been designed to do the math for you. The most commonly used program for measuring biodiversity is EstimateS. The count of the species coupled with these tests, summarizes most of the information on biodiversity.
    • Species richness: This is the simplest measure of species diversity. Simply count the number of species found in your sample area.
    • Simpson’s index: The probability of picking two different organisms at random.
      • Aids in understanding the biodiversity across communities.
      • Gives more attention to common species rather than rare species.
      • Works very well with small samples.
    • Shannon’s index: Should only be used on random samples taken from a large community where the total number of species is known.
      • Measures the order, or disorder, observed within a specific community.
      • Can be used to determine evenness, a measure of abundance similarity among the various species in the community.

Edit Things You'll Need

  • Laboratory
  • Items to designate sample areas (e.g. – string, lasers, GPS coordinates, etc.)
  • Collection items (e.g. – gloves, jars, Tupperware, tweezers, nets, traps, etc.)
  • Biodiversity statistical software or super-statistical-brains

Edit Tips

  • Always be precise, consistent and accurate.
  • Greater diversity stems from a large sample size. Thus: more area, more specimens, more specimens more species get recorded.
  • Educate yourself on local Possession and Collection laws before collecting.




Edit Related wikiHows


Edit Sources and Citations



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