ess topic 3

Biodiversity

The total diversity of living systems; This includes the diversity of species; habitat diversity; and genetic diversity.

Species diversity

Species diversity in communities is a product of two variables; the number of species (richness) and their relative proportions (evenness).

Habitat diversity

Habitat diversity refers to the range of different habitats in an ecosystem or biome.

Genetic diversity

Genetic diversity refers to the range of genetic material present in a population of a species.

Endemic

Native or restricted to a particular area; e.g. the Bali Starling is found only on the island of Bali; It is endemic to Bali; It is a Bali endemic species.

Evolution

Is a gradual change in the genetic character of populations over many generations; achieved largely through the mechanism of natural selection.

Natural selection

Is an evolutionary driving force; sometimes called "survival of the fittest"; In this context; the meaning of "fitness" is understood to be "best-suited to the niche."

Natural Selection stages

1) Variation exists and there is overproduction so competition for resources; 2) Some individuals are thus fitter than others; 3) Fitter individuals reproduce more successfully; 4) Offspring inherit genes that give advantage.

Speciation

The formation of new species when populations of a species become isolated and evolve differently from other populations.

Isolation of populations: Causes

Barriers such as mountain formation; changes in rivers; sea level change; climatic change or plate movements.

Plate tectonics

The surface of the Earth is divided into crustal; tectonic plates; that have moved throughout geological time; This has led to the creation of both land bridges and physical barriers with evolutionary consequences.

Mass extinction causes

Tectonic plate movements; super-volcanic eruption; climatic changes (including drought and ice ages); and meteorite impact.

Biogeography

The study of the distribution of species and their evolution in relation to geographical distribution.

Disjunct distribution

When one species or sister species are distributed in two very different locations; e.g. New Zealand and Chile.

Plume

Location where a column of magma rises up to the surface - not associated with a plate boundary.

Core

The centre of the Earth.

Mantle

Molten rock between the core and the crust of the Earth's surface.

Aesphenosphere

The upper part of the mantle - acts like a molten plastic.

Crust

The cooled rock that floats on the mantle - divided into plates.

Palaeontology

The study of fossils.

Geomorphology

The study of the shapes of the Earth's surface.

Ratites

Ostrich-like birds that share a common ancestor; including

Adaptive radiation

A group of closely related species that have rapidly evolved from one common ancestor; usually on islands where empty niches exist.

Biodiversity hotspot

Biogeographic region that is both a significant reservoir of biodiversity and is threatened with destruction.

Invasive species

A species not native to an area which is causing a problem to local species.

Human Activities Causing Species Extinctions

Habitat destruction; introduction of invasive species; pollution; overharvesting; hunting and climate change.

Factors for Red List

Population size; degree of specialisation; distribution; reproductive potential and behaviour; geographic range and degree of fragmentation; quality of habitat; trophic level; probability of extinction.

Extinct

No longer survives on Earth.

Extinct in the wild

Only survives in zoos or botanic gardens.

Threatened

Umbrella term for Critically Endangered; Endangered and Vulnerable species.

Causes of Tropical Deforestation

Over-intensive shifting cultivation; Timber extraction; Over-collection of fuelwood for cooking and heating; and for making charcoal; Encroachment and clearance by landless peasant farmers; Clearance for pasture or crops; promoted by cheap land and government tax and financial incentives to encourage international investment - this includes Biofuels like Palm Oil and Sugar Cane.

Species and Habitat preservation arguments

Aesthetic; ecological; economic; ethical; social reasons.

Governmental Organisations (in conservation)

e.g. UNEP United Nations Environment Programme.

Non-governmental organisations (NGOs) (In conservation)

International - WWF or Greenpeace; community based e.g. Palani Hills Conservation Council or Vatakanal Trust.

Comparing effectiveness of Conservation Organisations

Use of media; speed of response; diplomatic constraints; financial resources; political influence.

Convention on Biological Diversity (CBD)

First signed in Rio at Earth Summit (1992) and uses an ecosystem approach (an integrated strategy for the management of resources).

Precautionary principle

Where there is a threat of significant reduction or loss of biological diversity; lack of full scientific certainty should not be used as a reason for postponing measures to avoid or minimize such a threat.

National Biodiversity Strategy and Action Plan (NBSAP)

Strategy is how a country intends to fulfill the objectives of the CBD; while the National Biodiversity Action Plan comprises the concrete actions to be taken to achieve the goals of the strategy.

2010 Biodiversity Convention

To achieve by 2010 a significant reduction of the current rate of biodiversity loss at the global; regional and national level as a contribution to poverty alleviation and to the benefit of all life on Earth.

Conservation Approaches

Habitat conservation; species conservation or a mixed approach.

Designing Protected Areas criteria

Size; shape; edge effects; corridors; proximity to potential human influence.

Edge effects

The effects of human impact around the boundaries of a protected area; The idea is to reduce the amount of "edge" therefore a circle is the optimal shape.

Habitat / Wildlife corridors

These are zones which link together protected areas; they may be physical bridges or simply wildlife friendly zones such as a hedge; They can increase the effective size of the habitat available to an organism.

CITES

Convention in International Trade in Endangered Species of Wild Fauna and Flora; Aims to prevent species threatened with extinction because of international trade; Parties act by banning commercial international trade in an agreed list of endangered species (Appendix-I listed species) and by regulating and monitoring trade in others that might become endangered or whose trade needs to be regulated to ensure control over trade in Appendix-I species (Appendix-II listed species).

Captive breeding programmes

These are designed to try to save what survives; ideally for subsequent release back into the wild; In extreme situations; the species may actually be extinct in the wild.

Reintroduction programmes

Following captive breeding; a species may be released into the wild to form or supplement a wild population; This sort of programme will only work if the reason for the organisms extinction no longer exists.

Charismatic species / Flagship species

These are species that might be deemed "sexy" for publicity's sake and therefore used to promote the protection of an area but thus protecting many other species.

Keystone species

Keystone species maintain the structure and integrity of an ecological community; They have a much larger influence on the community structure than other species; e.g. starfish; sea otters.

Economic arguments for preservation

May include ecotourism; the financial benefits of bioprospecting (to find medically useful drugs etc) and the value to humanity of the ecosystem services.

Ethical arguments for preservation

Intrinsic value of the species or the utilitarian value.

Aesthetic arguments for preservation

The value from seeing and enjoying beauty.

Ecological arguments for preservation

Trophic cascades; food chain effects; ecosystem services (water cycles; flood protection).

Social arguments for preservation

The rights of particular groups of people who believe they have a cultural right to the preservation of some land; Some religions and societies ascribe value to the Earth and thus prioritise its protection