ECOLOGY

by Purwaning Rohmah/BIO off A 2015 UM

QUANTITIVE ECOLOGY

How to measure biodiversity indices, species evenness, species richness, dominance, and predominance. What the meaning of the number?

Biodiversity indices are widely used to measure diversity differences between areas or within the same area but through time. Biodiversity indices and species richness data are commonly used to assess community variation across sites and at different time periods. The biodiversity index is a non-parametric tool used to describe the relationship between species number and abundance.

Biological diversity can be quantified in many different ways. The two main factors taken into account when measuring diversity are richness and evenness. Richness is a measure of the number of different kinds of organisms present in a particular area. For example, species richness is the number of different species present. However, diversity depends not only on richness, but also on evenness. Evenness compares the similarity of the population size of each species present.

There are 4 biodiversity indices that were used in study. There are Shannon Weiner  Index, Simpson’s Index, Berger-Parker Index, and Pielou’s Index.

Diversity can be analyzed using the Shannon-Wiener diversity index obtained by the parameters of species richness and abundance of the proportion of each type in a habitat. This index is one of the most simple and widely used to measure the diversity index. Shannon-Weiner index can be used to compare the environmental stability of an ecosystem.

Pada analisis Shanon-Wiener mencari indeks kemerataan (H’), indeks keragaman (E), dan indeks kekayaan jenis (R).

1.      Indeks keanekaragaman Shannon – Wiener (H¹)

            H¹ = Indeks keragaman Shannon – Wiener

Pi = Kelimpahan proporsional

A community that has a value H '<1 is said to be less stable society, if H' value between 1-2 is said to be a stable society, and if the value of H '> 2 is said to be very stable. The community size H '<1.5 indicates a relatively low species diversity, H' = 1.5 to 3.5 show the diversity of species classified as moderate and H '> 3.5 indicates a high diversity.

2.      Nilai kemerataan / Evenness (E)

            E = Evenness / Kemerataan

            H = Indeks Keanekaragaman

            S= Banyaknya spesies

If the value of e 'higher shows types increasingly spread in the community. Magnitude E '<0.3 indicates evenness is low, E' = 0.3 - 0.6 evenness classified as moderate and E '> 0.6 then evennesskind is high.

3.      Nilai kekayaan/Richness (R)

        

R         = Richness/kekayaan

S          = Banyaknya spesies

N         = Total semua jenis individu dalam komunitas

Margalef Index (1958) R = (S-1) / ln⁡N. Based Magurran (2004) the amount of R <3.5 indicates relatively low species richness, R = 3.5 - 5.0 shows the wealth of species classified as moderate and R is high if it is> 5.0.

Sources:

Magurran, A. M. 2004. Measuring Biological Diversity. Oxford: Blackwell Science Ltd.