Data Analysis

Data were gathered on the relationship between the biodiversity indices and the structures of pekarangan. The relationships were calculated by four indices: the Margalef, Shannon-Wienner, Simpson, and S0rensen indices. Those indices, which have different functions, show some significant results related to heterogeneity in

pekarangan.

17.3.4.1 Species Richness (Margalef Index)

The Margalef index is a species diversity index divided into two types of species richness (how many types are there) and assessment of species evenness or dom­inance (how individual species are distributed among the community). The Margalef index was one of the first attempts to compensate for the effect of sample size by dividing the number of species in a sample by the natural log of the number of species collected (Death 2008).

The index is thus

D = (S – 1)/lnN (17.1)

where S is the total number of species in a sample and N is the total number of individual in the pekarangan.

17.3.4.2 Species Diversity (Shannon-Wiener Index)

The Shannon-Wiener index is most sensitive to the number of species in a sample and considered to be biased toward measuring species richness, because determin­ing the degree to which each factor contributes to diversity is impossible from the calculated value of H’ alone (Elliott and Knoepp 2005).

The index is thus

s

H = 5>;lnp) (17.2)

i=1

where S is the total number of species, andp, is the frequency of the ith species (the probability that any given individual belongs to the species, hence p).