Unit 3 - Biodiversity and conservation

Biodiversity

A broad concept that refers to the variety of life on Earth. It includes the three different diversities; species, habitat, and genetic.

Species diversity

The variety of species per unit area; including both number of species (richness) and their relative proportions (evenness) in communities. The higher species diversity in a community, the greater the complexity.

Richness

The number of species in an area.

Eveness

The relative abundance of each species.

Habitat diversity

The range of different habitats in an ecosystem or biome.

Genetic diversity

The range of genetic material present in a population of a species.

Gene pool

All the different types of gene found within every individual of a species. A large gene pool leads to high genetic diversity.

Conservation of biodiversity

It aims to protect habitats and ecosystems, usually from human-made disturbances such as deforestation and pollution. If one conserves the habitats, it usually leads to the species and genes being conserved as well.

Quantification of biodiversity

Assessing the effect of disturbance by using diversity indices like Simpson's. This is important to conservation efforts so that areas of high biodiversity may be identified, explored, and appropriate conservation put in place where possible.

Species

A group of organisms sharing common characteristics that can interbreed and produce fertile offspring.

Habitat

The environment in which a species normally lives.

Endemic species

Species that are native to and found only within a limited area. E.g. many species on the Galápagos Islands.

Evolution

The gradual change in the genetic composition of a species over many successive generations, leading to species different from the ancestor. E.g. homo sapiens and humans.

Biological variation

Any difference between cells, individual organisms, or groups of organisms of any species caused either by genetic differences or by the effect of environmental factors on the expression of the genetic potentials.

Natural selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits. This arises from evolution. Survival of the fittest.

Charles Darwin

English natural scientist who formulated a theory of evolution by natural selection (1809-1882). He's famous for creating new concepts based on his studies on the Galápagos Islands.

Speciation

Formation of new species when populations of species become isolated and evolve differently.

Isolation of populations

When populations become separated from each other so that genes cannot be exchanged. This can occur by e.g. changes in habitat.

The role of isolation in forming new species

Natural selection happens and then speciation will occur. The Galápagos Islands are a good example to demonstrate this.

Geographical isolation

A physical barrier, such as mountains, that causes populations to be separated.

Tectonic plates

Sections of the Earth's crust that move due to convection currents. These can create geographical isolation.

Plate tectonics

The movement and reforming of tectonic plates. E.g. how our continents look today compared to Pangea 225 million years ago.

Mass exctinctions

Periods when at least 75% of all species on Earth die at the same time.

The End Triassic extinction

About 199-214 million years ago. Massive amounts of lava erupted from the mid atlantic rift which led to the break up of Pangea. It killed 80% of all species.

The Late Devonian exctinction

About 364 million years ago. Caused by global cooling and then global warming. It killed 75% of all species.

The Ordovician-Silurian exctinction

About 439 million years ago. Caused by a drop in sea levels as glaciers formed, then by rising sea levels as glaciers melted. 86% of all species died.

The total amount of species on Earth

There are about 1.8 million different species on Earth. They vary considerably, but are based on mathematical models and supported by scientific research. However, lack of finance in this area means that many habitats and groups are under-recorded.

Over 50% of all species are insects. 18% are plants and 22% are beetles. Only 1% are vertebrates (those with a backbone), yet this is the group that is often focused on in conservation.

Current rates of species loss

- These estimates vary, but naturally it should be 10-100 species per year.

- However, with human influecnces it can be from 30 k-60 k per year. The rates have greaty increased due to our impacts.

- We affect them through e.g. habitat destruction, introducing invasive species, pollution, overharvesting, and poaching/hunting.

Natural causes of species loss

- Volcanoes.

- Drought.

- Ice ages.

- Meteor impacts.

- Tectonic movements.

Habitat destruction

Destroying native habitats and replace them with for example farm lands. They can also be ruined by mining (especially since the demand of mobile phones increased).

Introducing invasive species

If new species are introduced to a new area and compete with the native species, it can lead to the native species going extinct. E.g. the grey squirrel from the UK to North America and it reduced numbers of red squirrels.

Why overharvest and hunt?

Animals are hunted for all kinds of reasons: food, medicines, souvenirs etc.

Plants can be overharvested due to a huge demand of a crop.

Threats to tropical biomes

Tropical biomes are some of the most globally biodiverse areas on Earth. They are threatened by deforestation because it destroys habitats, messes with the canopy layer and the soil, etc.

Oil palms and habitat destruction

Over 90% of the world's oil palm exports are produced in Malaysia and Indonesia. The global demand for palm oil has increased rapidly due to it being used in both food products and as an ingredient in bio-diesel. This means that an immense amount of trees are being chopped down and that disrupts the harmony.

Conflict for LEDCs with export and sustainability

The main issue here is that most tropical biomes are located in LEDCs which means that those countries rely economically primarly on the forest industry. They don't have the luxury like MEDCs to just stop and choose something different. LEDCs want to become MEDCs and the way there is to grow economically, which they can't do without e.g. timber.

The Red List

A list of worldwide threatened species maintained by the International Union for Conservation of Nature (IUCN). The purpose of it is to identify the species that requite conservation efforts and rank them from most necessary to least. They also want to raise awareness about which species have a higher risk to become extinct.

Conservation status

Records on how endangered a species are.

Factors to determine a species' Red List conservation status

- Population size: Smaller populations have less genetic diversity and are more likely to become extinct.

- Trophic level: Top predators are the most sensitive in the food chain.

- Reduction in population size: An indicator of that a species is under threat.

- Degree of specialization: Many species require specific things, e.g. a certain diet. If that disappears, then they are at risk for going extinct.

- Geographic range: Species that live in a restricted habitat are more likely to go extinct.

- Distribution: Species that live in small areas are more likely to go extinct than those whose habitats are spread out.

- Reproductive potential and behaviour: Animals that live for a long time and reproduce slowly, e.g. elephants, are more vulnerable for extinction.

- Degree of fragmentation: Species that live in fragmented areas, such as tropocal rainforests, may not be able to maintain large enough populations.

- Quality of habitat: Species that live in poor quality habitats are less likely to survive.

- Probability of extinction: Even without human intervention, many species are likely to go extinct and so they are in need of conservation efforts.

Fragmentation

The process or state of breaking or being broken into small or separate parts.

Case study: The Iberian lynx

The Iberian lynx. It's a predator that hunts small animals, especially rabbits. Its specialized diet made the species decline in number because rabbits did too. It also only lives in isolated locations. Therefore, habitat destruction, deterioration, and alteration have negatively impacted the lynx.

Hunting it was banned in the 1970s, which helped, but it's still hunted somewhat. The lynx is fully protected under national law in Spain and Portugal, and public awareness in education programs is also in place. Breeding and reintroduction facilities have also been made, as well as national parks.

Case study: The Falkland Island wolf

The Falkland Island wolf was the only native land mammal on the Falkland Islands. It lived in burrows and ate ground-nesting birds.

They became extinct because the people that came to live on the islands considered the wolves a threat to their sheep, and so they shot and poisoned them. The wolves were very tame and easy to find, and so they died out very quickly. Nothing major happened after they got extinct, except that numbers of its prey increased.

Case study: The American bald eagle's conservation status improving through intervention

American bald eagle. It only lived in North America and therefore became the symbol of USA. These birds can live up to 40 years in the wild. They live near large bodies of water and nest in trees. They primarily feed on fish, but also eat smaller animals like rabibits.

In the 1700s there were 300 000 - 500 000 birds, and their population size declined to about 500 pairs by the early 1950s. This was mainly due to shooting them, the use of pesticides on crops, destruction of their habitats, etc. DDT caused their egg shells to become thinner.

The population size was restored by banning DDT and having laws protecting them. In 2007 there was 10 000 pairs of them and they were removed from the list of endangered animals.

Case study: Threats to the Great Barrier Reef

The Great Barries Reef is located in the northern coastline of Australia and it's home to 1500 species of fish, 359 types of hard coral, 1/3 of the world's soft coral, 6/7 of the world's species of threatened marine turtle, and more than 30 species of marine mammals. There are also 5000-8000 molluscs and 1000s of different sponges, worms, and crustaceans. There's also 800 species of starfish and sea urchins, and 215 bird species. In short, there are a lot of species living there.

The reef is degrading due to human impacts. One of these is tourism. Corals are super sensitive and are therefore damaged by divers' fins and anchors. Tourists also break pieces off of the corals to have for souvenirs. Over-fishing is also a huge reason to the decline in biodiversity. By fishing with giant nets, species that aren't meant to be captured are captured, and the sea floor is damaged. Fertilizer runoff and sewage pollution contribute to excessive nutrients and therefore increased algal bloom.

Global warming also affects the reef because increased temperaturs cause coral bleaching. In 2002 a study showed that about 60% of all corals are at least somewhat bleached. Climate change can also cause fish to migrate and that causes a chain reaction, e.g. the birds not having enough prey to feed on.

All of the human effects have domino effects that causes the species to be extremely vulnerable to natural threats like disease and predators. E.g. the crown-of-thorns starfish that feed on corals like an alien. One starfish can destroy 6 m of corals per year. These starfish have increased in population due to human activity because reductions in water quality makes the starfish larvae thrive, as well as their predators being wiped out due to over fishing.

Corals can also be damaged by storms and cyclones.

The consequences of all this can lead to irreversible damage on the reef and the species that depend on it.

Arguments for preserving biodiversity (ex. tropical rainforests)

- Aesthetic: Pleasant to look at.

- Ecological: They are important habitats for many species. Ecosystems and their functioning.

- Economic: They provide financial income. Tourism, timber, resources that can be used for food and medicine, as well as other materials.

- Ethical: Everyone has a responsibility to protect resources for future generations. Everyone has a right to survive. The current human population has a duty to protect rainforests for future generations.

- Social: They provide homes for indigenous people and provide spiritual, cultural, and religious value to local communities.

Non-governmental organizations (NGOs)

- Non-profit organizations that provide a very wide range of services and humanitarian functions.

- They're concerned with conserving and restoring ecosystems and biodiversity with varying levels of effectiveness due to their use of media, diplomatic constraints, financial resources, and political influence.

- E.g. Greenpeace and WWF.

- They can be radical (which is often necessary if they want to be heard) and gather their own information.

- They can influence laws and agendas, but don't have the power to do it on their own.

Intergovernmental organizations (IGOs)

- They're established through international agreements to protect the environment and bring together governments to collaborate globally.

- E.g. the United Nations Environment Programme (UNEP) and IUCN.

- They are more conservative and have conventional approaches. They don't tend to be controversial.

- They gather information from research that they pay for.

- They have the power to enforce decisions via law, unlike NGOs.

International conventions on biodiversity

Work to create collaboration between nations for biodiversity conservation. A good example of this is the IUCN that created the Red List and also established international conventions to help protect biodiversity.

World Conservation Strategy (WCS)

It was created in 1980 by the IUCN, UNEP, and WWF. It was a guide that outlined a series of global priorities for actions that each country could take and strategies they could have to conserve natural resources. The WCS focused on:

- Maintaining essential life support systems (climate, water cycle, soils) and ecological processes.

- Preserving genetic diversity.

- Using species and ecosystems in a sustainable way.

In situ conservation

Conservation methods within the natural habitat. E.g. protecting the habitat of rhinos. It works within the boundaries of conservation areas or nature reserves.

Ex situ conservation

Preservation of species outside their natural habitats. E.g. botanic gardens and zoos, using captive breeding and reintroduction programs.

Designing protected areas - area size

It's debatable whether it's better to have one large area or several small ones. Usually, larger is more advantageous because it can host more species.

Edge effects

There is a change in abiotic factors at the edges of a protected area, e.g. more wind, warmer and less humid. This can attract exotic species outside of the reserve, leading to competition and overall reduction in diversity.

Designing protected areas - shape

The best shape is a circle because it has the lowest edge effects. However, shape is determined by the availabe resources and areas. Parks tend to be irregular sizes.

Designing protected areas - corridors (evaluate)

Pros:

- They allow a gene flow by immigration and emigration.

- They allow seasonal movements.

- They reduce collisions between cars and animals.

- They reduce the amount of roads.

Cons:

- Some species might breed outside of the protected areas which can lead to a reduction in numbers.

- Exotic pests and diseases from connected reserves can be introduced.

- Poachers can easily move from one reserve to another.

- Corridors can be narrow which increases edge effects.

Buffer zones

Buffer zones are areas around conservation areas that contain habitats and can either be managed or undisturbed. These act as a way to minimize disturbances from outside influences, e.g. people, agriculture, or invasion by diseases. Buffer zones are key to having successful protected areas.

Case study: Danum Valley Conservation Area (DVCA)

- A protected area in the Malaysian state of Sabah on the island Borneo.

- This is a good example of how effective conservation can be matched with local economic needs.

- The DVCA was under threat of commercial logging until the late 1980s.

- Due to the rainforest now being protected, endangered species such as orang-utans and the Borneo elephant are able to survive. There are 120 different mammal species in the DVCA.

- In the 1990s a hotel was built on the edge of the DVCA, which increased ecotourism. This was both good for the economy and it also raised awareness.

The Convention on International Trade in Endangered Species (CITES)

- Established in 1973.

- An international agreement aimed at regulating trade in endangered species of both plants and animals.

- It wants to ensure that the trade industry doesn't threaten the survival of the species in the wild.

- CITES protects 35 000 species (5500 animals and 29 500 plants) to different degrees.

- Membership in CITES is voluntary. Each country agrees to adopt legislation to implement CITES at a national level.

- 180 countries are in it.

Choosing in situ vs ex situ conservation

Various factors need to be considered before determining the best conservation strategy for a species:

- The size of the animal. Smaller ones are easier to keep in zoos.

- Species that are threatened by habitat loss or diseases need to conserved ex situ.

- Whether a species can be placed in a zoo also depends on the staff expertise and available spots.

- If the local people are willing to help, then in situ can be more appropriate. If there are local political problems, ex situ is better.

- Ex situ is often used because it brings in money through tourism and zoos. This means that some species are put there even if they don't really need it, e.g. lemurs.

Zoo requirements

There are certain requirements for zoos.

1. Species should not be suffering from thirst, hunger, malnutrition.

2. Species should not experience thermal and physical discomfort.

3. Species should not be in pain, have injuries, or dieases.

4. Species should be able to express their natural behaviors, meaning that they should have large enough areas to live in and to not be alone.

5. Species should not endure fear or distress. This is done by ensuring conditions and treatments to avoid mental suffering.

Even though this all sounds great on paper, this is not always the case in the real world. Zoos are not as great as they sound like.

Breeding program consideratons

They are done to conserve and re-establish species in the wild. Factors that need to be considered:

- Is it ethical to choose the mate?

- Genetics should be considered so that healthy offspring is produced.

- Is artifical insemination a possibility? This makes it easier because then one doesn't need to find a male.

- Birth control could be needed if the zoo doesn't have the capactiy for more animals.

- Keeper intervention could be needed because sometimes females reject their young offsprings.

- Updated knowledge of reproductive biology and genetics is needed.

Pros and cons of zoos

Pros:

- Educates the public about the need for conservation.

- Can make people empathize with the wildlife.

- Even though captivity isn't ideal, it can increase the population sizes of endangered animals while ensuring genetic diversity.

- Well-managed zoos that fulfill the requirments are good, e.g. enough space and a healthy diet.

Cons:

- Some animals can have problems re-adapting to the wild after spending time in a zoo. They might become easy prey for example.

- Not all species have an easy time breeding in captivity, e.g. giant pandas.

- Habitats in zoos are very different from natural ones, especially for species that have complex interactions with their environment, like orang-utans.

- There are ethical concerns for having caged animals and some people boycott that concept.

All in all, it is best to protect endangered animals in their own habitats, but when that's not possible, zoos are better than to let them go extinct.

Flagship species

- Large and charismatic species used as spearheads for biodiversity conservation.

- They are often cute or beautiful because that's how you get human empathy and attention.

- E.g. giant pandas in China. Nobody cares about some nasty endangered insect, but people will care about adorable, soft bears.

- This conservation approach is advantageous because it makes it easy to raise money for a certain species.

- However, it causes favouritism.

- Another disadvantage is that while the species may be preserved in zoos, their natural habitat continues to be destroyed, as with giant pandas.

Keystone species (ex. agouti)

A species on which other species in an ecosystem largely depend on, such that if it was removed the ecosystem would change drastically.

E.g. the agouti in tropical parts of South and Central America that feeds on nuts. The agouti is the only species there with teeth strong enough to crack the nut open. The agouti burries the nuts throughout the forest for later use, but some of these nuts germinate and grow into adult plants. So, without the agouti the Brazil nut tree wouldn't be able to distribute its seeds in the same way. And in turn, species that depend on the tree for their habitat, e.g. harpy eagles, would lose that possibility. Humans also depend on the nuts as they extract oils from them.

Keystone species are therefore very important to preserve. However, sometimes it's hard to identify them because ecosystems are complex. It's always better to conserve entire ecosystems rather than individual species.

Mixed approach of in situ and ex situ

Combining the two methods is often the best solution for species conervation. A good example of this is the giant panda conservation. They are a flagship species and humans started putting them into zoos both for money and to preserve them. However, breeding in captivity proved to be quite difficult. Therefore in situ conservation was also needed and giant panda nature reserves were established.