Lecture 13-14 Topic: Importance & Conservation of Biological diversity

Section objectives:

1. Importance of biodiversity.

2. Major factors of biodiversity loss risk.

3. Causes of habitat destruction. Deforestation

4. Sustainable strategies on biodiversity conservation.

5. International cooperation on biodiversity protection

6. Protected area and their classification

1. Importance of biodiversity

Biological diversity, or biodiversity – the variability among living organisms from all sources including terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems.

• The planet’s total number is estimated from 10 to 80 million species.

• To date, scientists have identified about 1.7 million species of the estimated total number (5-20%). About 18 000 new species are being described each year (16 969 in 2006 and 18 516 in 2007). About 75% of the new species described in 2007 were invertebrates, 11% vascular plants and nearly 7% were vertebrates

• The earth’s biodiversity is concentrated in certain areas, mostly in the tropics (40-45% of world’s species).

Abundance and Diversity

Abundance - the number of individuals of a species in an area

Diversity - the number of different species in an area

• A useful measure of the variety of ecological niches or genetic variation in a community

• Decreases as we go from the equator towards the poles

• Abundance and diversity depend on total resource availability in an ecosystem.

Biological resources, or bioresources include genetic resources, organisms or part thereof, populations, or any other biotic component of ecosystems with actual or potential use or value for humanity.

Importance of biodiversity includes the following:

• Medicinal properties of plants (25% of drugs and medicines are delivered from plants and many more plants may have but remain to be investigated);

• Potential of new sources of food;

• Pleasure from nature activities, including wildlife observation (bird watching).

• Function of an ecosystem with its full complement of species as a whole balanced system (stability of climate and sink of CO₂ , food chains, energy flow and matter cycle, homeostasis).

• Apart from benefits to humans, species simply have right to exist (biocentric worldview).

• Current Estimates of Known Living Species by Taxonomic Group (2010)

Category	Species
Vertebrate Animals
Mammals	5,490
Birds	10,000
Reptiles	9,100
Amphibians	6,440
Fishes	31,300
Total Vertebrates	62,330
Invertebrate Animals
Insects	1,000,000
Spiders and scorpions	102,250
Molluscs	85,000
Crustaceans	47,000
Corals	2,180
Others	68,830
Total Invertebrates	1,305,260
Plants
Flowering plants (angiosperms)		281,820
Conifers (gymnosperms)		1,020
Ferns and horsetails		12,000
Mosses		16,240
Red and green algae		10,130
Total Plants		321,210
Others
Lichens		17,000
Mushrooms		31,500
Brown algae		3,070
Total Others		51,570
TOTAL SPECIES		1,740,370

Stability and Resilience

Stability - a dynamic equilibrium among the physical and biological factors in an ecosystem or a

community

Resiliency - ability to recover from disturbance

3 kinds of stability or resiliency in ecosystems:

• Constancy - lack of fluctuations in composition or functions

• Inertia - resistance to perturbations

• Renewal - ability to repair damage after disturbance

Exotic Species

• Sometimes communities can be completely altered by the introduction of exotic species.

• Exotic species are often introduced by humans.

• Successful exotics tend to be prolific, opportunistic species, such as goats, cats, and pigs.

Many ecologists consider exotic species invasions the most pressing hazard for biological communities in the coming century