biodiversity - debreceni egyetem hallgatói...

Biodiversity

1. Biodiversity

Biodiversity is the variety of different types of life found on Earth and the variations within species. It is a measure of the variety of organisms present in different ecosystems. This can refer to genetic variation, ecosystem variation, or species variation (number of species) within an area, biome, or planet.

1.1. Measuring of diversity

A diversity index is a quantitative measure that reflects how many different types (such as species) there are in a dataset, and simultaneously takes into account how evenly the basic entities (such as individuals) are distributed among those types. The value of a diversity index increases both when the number of types increases and when evenness increases. For a given number of types, the value of a diversity index is maximized when all types are equally abundant.

- diversity at species level- All kind of indices try to characterise the correlation of S : N (species number : number of individuals).

1.1.1. Shannon-Wiener index (H)

One of the most often used indices.

where: pi – relative abundance (proportion) of the species belonging to the ith type.

iei

S

ipp

obs

log1

1.1.2. Simpson-Yule index (D) or quadratic diversity

It describes what is the probability that the second sampled individual belongsto the same species as the first.

where and the index itself:

Ni – number of individuals belonging to the ith speciesNT – total individual number of the sample

2i

S

ipC

obs

2

2

T

ii N

NpC

D 1

1.1.3. Berger-Parker dominancy index

It compares the proportion of the dominant species to the total number ofindividuals.

Nmax – individual number of the dominant species

1.1.4. Evenness

- Diversity is maximal, when all species of a community are equally abundant. Evenness can express the similarity between the observed diversity and thepossible maximal diversity at the given species number. - A modified version of the index also takes into accont the possible maximum (Dmax) and minimum (Dmin) values of diversity.

TNNd max

minmax

min

DDDDEH

For example, if we use Shannon-Wiener index: Dmin = 0, Dmax = log(S), wherelog(S) is to total number of taxa, so:

SHEH log

Planted forest

The Convention on Biological Diversity has been signed on 13th june, 1992 in Rio de Janeiro at the conference of Environment and Progression of UN.

The first biodiversity day has been held on 22nd may, 2006 in Hungary.

Natural forest

1.2. Factors leading to biodiversity loss

1.2.1. Extinction

Number of species on Earth

Great extinctions in the history of Earth

Nature transforming and destructive activities of mankind are increasing. Unfortunately, extinction rate of species also accelerated. The most accurate data on the rate of species extinction are for the birds and mammals (the number of extinct mammals is 85, birds 113 from the 1600s to present day).

A quarter of terrestrial species, 28% of marine species and 29% of freshwaterspecies extinct from 1970 to 2005 according to the WWF (World Wide Fund forNature).

Biodiversity decreased with a 35% on Earth in the previous 35 years.

Species died out because of human activities (mainly hunting):

Dodo (Raphus cucullatus)

Quagga (Equus quagga quagga)Giant alka (Pinguinus impennis)

Thylacine (Thylacinus cynocephalus)

1.2.2. Habitat degradation and destruction

Only 15% of lands remained in its original state in Europe.

Surface coverage categories in Hungary.

Artificial surfaceFieldMeadow, pastureGrapeFruit treesForestReedsOther agricultural areaOther half-natural areaSurface water

1.2.3. Appearance of foreign (alien) species

Invading (invasive) species in a sandy grassland: Alianthus („tree of heaven”) in front, milkweed behind them, and acacia in the background (location: Soltszentimre).

1.2.3. Appearance of foreign (alien) species

Eastern Asiatic Clam(Sinanodonta(Anodonta) woodiana)

Black bullhead (Ameiurus melas)

1.2.3. Appearance of foreign (alien) species

Eastern Asiatic Clam(Sinanodonta(Anodonta) woodiana)

Black bullhead (Ameiurus melas)Amuri kagyló(Anodonta woodiana)Amuri kagyló(Anodonta woodiana)

Chinese sleeper or Amur sleeper (Perccottus glenii)

1.2.3. Appearance of foreign (alien) species

Fekete törpeharcsa (Ameiurus melas)Fekete törpeharcsa (Ameiurus melas)Amuri kagyló

(Anodonta woodiana)

Pond slider(Trachemys scripta)

1.2.3. Appearance of foreign (alien) species

Chinese sleeper or Amur sleeper (Perccottus glenii)

Spotted-wing vinegar fly(Drosophila suzukii)

First appearance in Hungary: Autumn, 2012

Harlequin ladybird (Harmoniaaxyridis)

First appearance in Hungary: February, 2008

1.2.4. Hunting and trade

They have a role both in extinction of species and in settling and spreading of new species.

Mouflon (Ovis aries orientalis)

Raccoon (Procyon lotor)

1.2.5. Genetic manipulation

During genetic engineering genes of one species are transferred to another species genome, thus genetically modified organisms are created. The method is most widespread in plant breeding.

Genetic modification or genetic engineering

1.2.5.1. In general, with the example of pest-resistant maize

1.2.5.2. Genetically modified bacteria

1.2.5.3. Genetically modified plants

Bacteria as vectors

Viruses as vectors

Possibility

Possibility…???...