Biodiversity Measurement in Relation to Diversity of Ecological Function

Bio means “Life” and Diversity means “Variety”. In short variety of life is called biodiversity. While conservation means maintaining earth biodiversity. Diversity of life in all forms and at all levels of organizations.

All the forms mean biodiversity including plants, animals, fungi, invertebrate, bacteria and level of organization refers to the diversity of gene, ecosystem as well as species. The wild life society (1993) define biodiversity:

The richness abundance and variability of plants and animals, species, communities and their ecological process that link them with one another with soil, air and water.

Types of Biodiversity

There are three types of biodiversity:

• Alpha Diversity
• Beta Diversity
• Gamma Diversity

Alpha Diversity: The type of diversity taking place within communities is called alpha diversity.

Beta Diversity: the type of diversity taking place between communities is called beta diversity.

Gamma Diversity: The diversity which is on original basis explaining difference among similar habitats.

Diversity of Ecological Function

The diversity of ecological function is enormous. Millions of species of earth interact with one another species through ecological process such as competition, parasitism, predation, mutualism etc.

Every species interacts with its physical environment through process that exchange energy and elements between living and non-living world such as biotic and abiotic factor. Such as photosynthesis, biogeochemical cycle and respiration. All these fictional interactions must total billions. The Diversity of Evolutionary Function is even more complex. It includes all ecological process because they are key elements of natural selection plus process such as genetic mutation.

Functional Diversity is clearly important. For example, management plan designed to keep a species from a becoming extinct will almost fail in long run unless the process of evolution specially natural selection, continuously allowing the species to adopt the changing environment.

Conservation biologist usually focus on maintaining structural biodiversity rather than functional biodiversity for two reasons.

1. Maintaining structural biodiversity usually more straight forward.
2. Structural biodiversity is successfully maintained functional biodiversity will probably maintain as well. E.g., if we maintain species of orchid and one of its insect pollinator together in the same ecosystem than we will probably have pollination interaction between two simultaneously we can maintain orchid genetic diversity. In short if genetic species are maintained successfully a diversity of ecological and evolutionary with probably maintain.

Measuring of Biodiversity

Biodiversity can be measured by following steps.

• Species Richness
• Species Evenness
• Simpson’s Biodiversity

Species Richness

The qualitative description of species including number of elements of biodiversity (usually number of species) is called species richness.

Species Evenness

The measure of abundance of individual in each species is called species evenness. It is the quantitative measurement. Abundance of individual in each species can be measured by:

Percentage Cover: The proportion of each quadrate occupied by the species is called percentage cover.

Population Density: No, of individual per quadrate is called population density.

Species Frequency: Population of quadrate with a species in it. When both species richness and species evenness increases the biodiversity also increases.

Percentage Cover

Species Observed	Field A	Field B
Cocksfoot Grass	57	38
Timothy Grass	32	16
Butter Cup	3	14
Clover	3	22
Thistle	1	5
Dandelion	4	5
Total (N)	100	100

Simpson’ s Biodiversity

Both have the same richness (6 species), but field b has greater evenness. So, field b is more diverse. A high value of D is good and means that b habitat is diverse, species rich and able withstand some environmental impact.

A low value for D is poor and means that habitat is low in species so a small change to the environment e.g., pollution would have a serious impact.

Diversity can be calculated by Simpson’s Index

Simpson Diversity Index (D) = 1 – [∑ (n-N)²]

n = no. of individuals

N = Total no. of individuals

Species Observed	Field A	n/N	(n/N)2
Cocksfoot Grass	57	57/100 = .57	0.3249
Timothy Grass	32	32/100 = .32	0.1024
Butter Cup	3	3/100 = .03	0.0009
Clover	3	3/100 = .03	0.0009
Thistle	1	1/100 = .01	0.0001
Dandelion	4	4/100 = .04	0.0016
Total (N)	100		∑= 0.4308

D = 1 – [∑ (n-N)²]

D = 1 – [0.4308]

= 0.5692

 

Species Observed	Field B	n/N	(n/N)2
Cocksfoot Grass	38	38/100 = .38	0.1444
Timothy Grass	16	16/100 = .16	0.0256
Butter Cup	14	14/100 = .14	0.0196
Clover	22	22/100 = .22	0.0484
Thistle	5	5/100 = .05	0.0025
Dandelion	5	5/100 = .05	0.0025
Total (N)	100		∑= 0.243

D = 1 – [∑ (n-N)²]

D = 1 – [0.243]

= 0.757

• Field b has high diversity index so has more species richness and evenness it would be more resistant to any environmental change or damage.