EEB321H1 Lecture 3: L3 - Diversity Measures Continued
Document Summary
Usually use h" to denote shannon"s index. Base of log doesn"t matter but stay consistent. Shannon"s index only works with large communities: always check what the symbols mean because different people use different things. Lecture 3 how to measure species diversity continued (lecture 2 slides) Talked about metrics of richness and eveness. Also comes from probability/information theory developed during the war (measure entropy/disorder) Simpson"s index was the sum of pi. Many people find h" difficult to interpret towards common species. More in terms of species richness: = another way of expressing same thing. Want to know what the range of index is. Maximum diversity: happens when pi = 1/s for all species, so replace pi with 1/s, multiply by s species = s"s cancel out, maximum diversity happens at: Minimum diversity: hard to derive it, but will end up with. So range over which h" can vary is: When n >> s log [n/(n-s)] < h" < log s.