Hide menu
Hide menu
Hide menu
 
Exploring Biodiversity homepage and contents Glossary, database, maps, links, e-mail...
The Natural History Museum   Flora-for-Fauna  

Species A occurs in many places. It has a large range.
Species B occurs in only one place. It has a small range.


Range-size rarity (RSR)  = 1/x      where x is the number of areas in which a species is recorded.

 

Species A occurs in four areas.
The RSR value of finding it in any one area is:		 1/4 = 0·25
 
Species B occurs in one area.
The RSR value of finding it in any one area is:		 1/1 = 1


We can calculate the range-size rarity for a single area by adding its individual species' RSR scores together:


Click on the blank spaces in this matrix and fill in the RSR values for each species in each of the five areas shown below (total values will be filled in automatically):
1 2 3 4 5             Areas: 1 2 3 4 5
Species A: -
Species B: - - - -
Species C:
Species D: - - -
Clear formShow answers
 TOTALS:
Think about these questions:
  • Which area has the greatest range-size rarity value? 
  • What does this tell us about its bioidversity value?

 

Home   >   Measuring biodiversity:    Biodiversity hotspots   |   Species richness   |   Range-size rarity   |   Taxic richness


Terms of use. ©2005 The Natural History Museum, Cromwell Road, London, SW7 5BD, UK. Home | Search | Email