Topic 3: Biodiversity and conservation

Factors that help maintain biodiversity

- Complexity of the ecosystem - Stage of succession - Limiting factors - Inertia

Summarised geological timescale

- Earth formed 4.6 billion years ago - First life (bacteria) formed 4 billion years ago - Dinosaurs became extinct 65 million years ago

Organisms with large genetic diversity

- European red fox - Humans

Factors making a species prone to extinction

- Few populations of a species - Narrow geographical range - Small population size

Critics naming hotspots say that they can be misleading because they:

- Focus on vascular plants and ignore animals - Do not represent total species diversity or richness - Do not consider genetic diversity

Funding for NGOs

- Manage publicly owned lands - Fund environmental projects by monies coming from private donations

Use of media by IGOs and GOs

- Media liaison officers prepare and read written statements - Control/works with media (at least one TV channel propagates the official policy) so communicates with its decision/attitudes/policies more effectively to the public

Advantages of a habitat with high biodiversity

- Resilience and stability due to the range of plants present of which some will survive drought, floods, insect attack, disease - Genetic diversity = resistance to diseases

Approaches to conservation

- Species based - Habitat based - Mixture of both

Disadvantages of flagship species

- They take priority over others - If they became extinct, the message is we have failed - They may be in conflict with local peoples e.g. man-eating tigers

Use of media by NGOs

- Use of footage of activities to gain attention - Mobilise public protest to put pressure on governments - Gain media attention through various protests e.g. frontlines/sabotage, because access to mass media might be hindered sometimes (non-democratic regimes)

Commons factors of biodiversity hotspots

- Usually tropical rainforests - Nearer the tropics because they're fewer limiting factors in lower latitudes - Threatened areas; 70% of the habitat has already been lost - Habitat contain 1500+ plant species, which are endemic - Cover only 2.3% of the land surface - Tend to have large densities of human habitation nearby

Disadvantages of a habitat with high biodiversity on ecosystem health

- managing grazing can be difficult as plant species have different requirements and tolerance to grazing - some stable and healthy communities have few plant species so are an exception to the rule

Factors leading to loss of biodiversity

-Natural hazards -Fragmentation of habitat -Pollution

Similar groups of animals on different continents

1. African and Indian elephants 2. South American llamas and African camels, have a common ancestor of a rabbit-sized mammal

Direct reasons to conserve biodiversity - Natural products

1. Many medicines, fertilizers and pesticides we use come from plants/animals: - Guano is a fertilizer high in phosphate which is seabird droppings - Oil palms give us oil for anything from margarine to toiletries

Indirect reasons to conserve biodiversity - environmental services

1. Soil aeration depends on worms. 2. Fertilization and pollination of some food crops depend on insects. 3. Waste is broken down and recycled by decomposers.

Possible causes for the K-T extinction

1. Volcanic eruption - Deccan plateau erupted for a million years at the time of the K-T boundary 2. Meteor impact - put huge amounts of dust into the atmosphere. Evidence: Chicxulub crater in Mexico, 3. Climate change over long period, eruption or meteor would've created dust clouds, blocking sun. Plants would've died causing food webs to collapse.

Direct reasons to conserve biodiversity - Food sources

1. We eat other species (plants & animals). There are many varieties of these. 2. We need to preserve old varieties in case we need them in the future. 3. Pests and diseases can wipe out non-resistant strains.

Current extinction rate

100 species per million species per year. But the rate isn't equally spread out, and is greater in hotspots.

Living Planet Index Stage 1

100,000 years ago, modern humans spread over the Earth. Homo sapiens outcompeted Neanderthal in Europe, and led to their extinction. Page 162 for the rest

How many species are there on earth?

A conservative estimate of 7 million, excluding bacteria. But only 1.4-1.8 million species are "known to science".

Biodiversity hotspots

A region with a high level of biodiversity that is under threat from human activities. They contain high numbers of endemic plant species (only grow in that area). Hotspots are generally close to the equator because the temperature is better for plant growth; high levels of light and precipitation.

Keystone species

A species that plays a critical role in maintaining the structure of the ecosystem in which they live e.g. sea otter eating sea urchins in kelp forests. If there are no sea otters, the urchins need only eat the holdfast (anchor) of the kelp and it floats away.

Preservation of biodiversity

An ecocentric viewpoint, valuing nature for its own intrinsic worth, not as a resource that humans can exploit. Deep green ecologists argue that, whatever the cost, species should be preserved regardless of their value or usefulness to humans. Preservation biologists would argue that smallpox shouldn't be destroyed even though it diseases humans.

The IUCN Red List

An international agency with a list that determines the conservation of a species based on population size, degree of specialisation, distribution, reproductive potential and behaviour, trophic level, probability of extinction etc.

Types of biodiversity

Biodiversity is the variety of life on earth. Different forms include: - genetic, species, habitat

How pollution leads to loss of biodiversity

Caused by human activities, can degrade/destroy habitats and make them unsuitable to support the ranges of species that a pristine ecosystem can support. E.g. environmental pollution by emissions from factories and transport can lead to acid deposition or photochemical smog.

Examples of hotspots

Central Chile Caribbean Islands Mesoamerica

Flagship species

Charismatic, instantly recognised, popular and can capture our imagination. They're used to spearhead biodiversity conservation and ask for funds from the public. These funds are then used to protect the habitat which will include the other species that may be under more threat. large and charismatic species used as spearheads for biodiversity conservation

How new species form

Charles Darwin's theory of evolution summarised: - Each individual is different (except identical twins; same genotype) due to inherited DNA / mutations - Each will be slightly differently adapted to its environment - Natural selection, survival of the fittest, speciation

Conservation of biodiversity

Conservation doesn't involve excluding humans from reserves or from interacting with organisms. They even consider harvesting/hunting a species as long as it's sustainable. They recognize the difficulty in excluding humans from habitats and development is needed to help people out of poverty, but not at the expense of the environment. Conservation biologists would look for ways to create income for local people from ecotourism or management of a reserve to allow education of the public by opening it up to access (anthropocentric).

Species based conservation

Focuses on conserving the species but not looking at conserving the habitat in which it lives e.g.: - CITES - Captive breeding and zoos - Botanical gardens and seed banks - Flagship species - Keystone species

Funding for IGOs and GOs

Fund environmental projects by monies coming from national budget

How conservation organisations work - GOs

Governmental organisations are part of and funded by a national government. They're highly bureaucratic and do their jobs through research, regulation, monitoring and control e.g. Environmental Protection Agency of the USA.

Cretaceous-Tertiary Extinction (K-T Extinction)

Happened 65 million years ago. Most large animals on land and sea and small oceanic plankton died, but most small animals and plants survived.

Continental drift

Has result in new / diverse species. During drifting, continents moved to different climate zones. Changing climactic conditions and food supplies forced species to adapt and resulted in an increase in biodiversity. E.g. Antartica, which once was tropical and covered in forest. However, when it went southwards, the forest gradually disappeared, snow and ice covered landscapes formed, and cold adapted species arrived or evolved.

Living Planet Index Stage 2

Humans become farmers about 10,000 years ago when there were 1-10 million humans living on Earth. Page 162 for the rest

How narrow geographical range makes a species prone to extinction

If a species only lives in one place and that place is damaged or destroyed, the habitat has gone, so the species can be lost. E.g. Golden Lion Tamarin.

How limiting factors maintains biodiversity

If it's difficult for the organism in an ecosystem to get raw materials for growth, e.g. water is limited in deserts, then any change that makes it harder may result in species disappearing. If the abiotic factors for life are abundant (water, light, heat, nutrients), the system is more likely to manage if one is reduced.

How few populations of a species makes it prone to extinction

If they're only one or two populations left then that's their only chance of survival. If that population is wiped out, the species is gone e.g. lemurs.

Species biodiversity

In communities this is a product of two variables, the number of species (richness) and their relative proportions (evenness).

Example of a loss of habitat

In the Mediterranean region, only 10% of original forest cover remains.

How inertia maintains biodiversity

Inertia - the property of an ecosystem to resist change when subjected to disruptive force Along with resilience and stability, it's key to letting planners know which site will resist, change or recover most quickly.

How conservation organisations work - IGOs

Intergovernmental organisations are composed of and answering to a group of member states e.g. UN, IPCC.

Enforceability of IGOs and GOs

International agreements and national/regional laws can lead to prosecution.

Biodiversity - an indicator of ecosystem health

It's difficult if one ecosystem is healthier than another. However, high biodiversity often suggests high ecosystem health.

Example of speciation due to physical barriers

Large flightless birds only occur on those continents that were once part of Gondwana (Africa, Oceania, South America). However, because Gondwana split up a very long time ago, the large flightless birds aren't as closely related.

2000 UN Millennium Summit: Millennium Development Goals

Largest-ever gathering of world leaders who agreed to a set of time bound and measurable goals for combating poverty, hunger, disease, illiteracy, environmental degradation and discrimination against women by 2015.

How natural hazards lead to loss of biodiversity

Naturally occurring events that have a negative effect on the environment (and humans). They're usually thought of as caused by human activity (building on a piece of land), and the major cause of loss of biodiversity is loss of habitat.

Enforceability of NGOs

No legal power - use of persuasion and public opinion to pressure governments.

How conservation organisations work - NGOs

Non-governmental organisations aren't part of a government and don't do work for profit. They can be international or local and are funded by altruists or subscriptions. They're very diverse and some are run by volunteers e.g. Greenpeace.

How species can become isolated geographically

On an island, mountain or in a body of water.

Low diversity could be indicative of?

Pollution, eutrophication, recent colonisation of a site or adverse human impact,

How to calculate species diversity

Simpsons diversity index N(N-1)/E(sigma) n(n-1)

How small population size makes a species prone to extinction

Small population = low genetic diversity. So the species has less resilience to change and can't adapt as well. E.g. snow leopard.

Indirect reasons to conserve biodiversity - biological control agents

Some species help us control invasive species without the use of chemicals, e.g. myxamatosis disease and rabbits in Australia.

The sixth mass extinction (Holocene extinction)

Started at the end of the last ice age; we're currently in it. It's caused by human activity and may be greater in both extent and rate - humans are pushing more animals to extinction faster e.g. woolly mammoths and ground sloth in New Zealand.

2002 Johannesburg Summit on sustainable development

Supposed to consolidate the Rio Earth Summit but little action came out of its deliberations.

Speciation

The gradual change of a species over a long time. When populations of the same species become separated, they cannot interbreed and if the environments they inhabit change they may start to diverge and a new species forms. Humans can speed up speciation by artificial selection of animals and plants and by genetic engineering but the natural process of speciation is a slow one. Separation may have geographical or reproductive causes.

How complexity of the ecosystem maintains biodiversity

The more complex a food web, the more resilient it is to the loss of one species or reduction in its population size. If one type prey, food source or predator is lost, the others will fill the gaps left. This resilience of more complex communities and ecosystems is a good thing for biodiversity overall. But it may not be good for species diversity as one species is lost completely but the community continues.

Habitat biodiversity

The range of different habitats per unit area in a particular ecosystem or biome e.g. tropical rainforests as there are many ecological niches due to the layering of the forests.

Genetic biodiversity

The range of genetic material present in a gene pool or population of a species.

How species can become isolated reproductively

Their mating seasons are not synchronised or their flowers mature at different times.

Mass extinctions

There's been five major ones. We think this due to rapid change of climate, natural disaster (volcanic eruption, meteorite impact ?), so species die as they can't survive the change in conditions.

Land bridges

These allow species to invade new areas. North and South America were separated for a long time and ,therefore, have rather different species. However, that's no longer the case as they're joined by the recently formed land bridge of Central America, which allow species, e.g. bears, to move from North to South or vice versa.

Conservation organisations

United Nations, Worldwide Fund for Nature, Millennium development goals.

How fragmentation of habitat leads to loss of biodiversity

When a large area is divided into fragments, separated by roads, towns, factories etc. The fragments are isolated or degraded landscape and they act as islands within an inhospitable sea of modified ecosystem.

How stage of succession maintains biodiversity

When plants/animals colonize bare land, there are few species colonizing at first. Species diversity increase with time until a climax community is reached when the species composition is stable. It may fall slightly once the climax community is reached but normally species diversity increases as succession proceeds.

Habitat conservation - designing protected areas

Where a conservation area is with a country is a significant factor in the success of the conservation. Surrounding land use for the conservation area and distance from urban centre are important factors for consideration in conservation area design.

Natural selection (survival of the fittest)

Where individuals more adapted to their environment have an advantage and flourish and reproduce but those less adapted don't survive long enough to reproduce.

How plate activity influences biodiversity

Where they meet, they may: - Slide past each other (e.g. San Andreas fault line) - Diverge (e.g. mi-Atlantic ridge), causing a physical separation of populations - Converge; colliding and both being forced upwards as mountains (e.g. the Alps), creating a physical barrier

Indirect reasons to conserve biodiversity - gene pools

Wild animals and plants are sources of genes for hybridization and genetic engineering.