Module 4 & 6

biodiversity

biodiversity

a measure of all the species of organisms, the genes they contain and the ecosystems they are part of.

3 different levels of biodiversity

- habitat biodiversity
- species biodiversity
- genetic biodiversity

habitat biodiversity

the number of different habitats found within an area. Each habitat can support a number of different species

2 examples of habitat biodiversity

- open meadows
- streams/rivers

species biodiversity

a measure of biodiversity within the community. Takes into account both species richness and species evenness

species richness

simply the number of species found in a habitat. The more species, the richer the habitat

species evenness

the number of individuals of each of the different species in a habitat

species diversity

takes into account richness and evenness. A high diversity index would indicate a large number of species (richness) with a relatively even spread of individuals (evenness)

genetic biodiversity

the variety of genes that make up a species. The more alleles present in a population, the more genetically biodiverse the population.

7 factors that affect biodiversity

- human population growth
- deforestation
- agriculture
- invasive species
- over-exploitation
- pollution
- climate change
- disease

effect of human population growth on biodiversity

- human population is increasing at a dramatic rate
- demand for food, houses, transport and goods have led to destruction and fragmentation of habitats, pollution, climate change and extinction of species

effect of deforestation on biodiversity

- deforestation occurs for timber, fuel and land
eg reduction of overall biodiversity when clear felling rainforest or reduction of species diversity if harvesting just one type of tree like rosewood

effect of agriculture on biodiversity

- natural vegetation cleared and may be replaced with monoculture destroying habitats, greatly reducing biodiversity
- natural habitats may be fragmented leaving some populations too small to survive
- the use of insecticides/herbicides to improve crop yield directly kills species and has a knock on effect along the food chain
- larger fields have lead to loss of hedgerows reducing plant species diversity and destroying habitats and "corridors" between woodlands
- selective breeding reduces genetic biodiversity eg bananas

effect of invasive species on biodiversity

- introduces species may increase rapidly in number and reduce native population due to predation and competition

effect of over-exploitation on biodiversity

- species are harvested faster than they can replenish themselves
eg over-fishing of cod in North sea

effect of pollution on biodiversity

- fertilisers and sewage eg eutrophication of water
- litter eg pollution from fishing - nets, hooks etc.
- plastics
- oil

effect of climate change on biodiversity

- species with low genetic variation may be unable to evolve to the changes in temperature and rainfall - they will need to move
- the melting ice caps and rising sea levels could lead to habitat loss and extinction
- higher temperatures and lower rainfall may lead to xerophytes becoming more dominant. Changes to whole ecosystem

effect of climate change/disease on biodiversity

- crops are no longer suitable for the areas where they used to be grown - but growing crops in new areas means that they will encounter diseases and pests for which they have evolved no resistance
- higher temperatures may provide more favourable conditions for pests for a longer time during the year
- more pests and diseases will be able to overwinter (hibernate during winter) successfully - causing infections early in the growing season causing lower yields meaning less food for humans
- human diseases will be able to thrive in new areas eg malaria carried by Anopheles mosquitos

4 reasons for maintaining biodiversity

- ethical reasons
- aesthetic reasons
- economic reasons
- ecological reasons

aesthetic reasons for maintaining biodivesity

- the presence of different plants and animals in our environment enriches our lives
- provides inspiration to artists, musicians, writers
- patients recover more rapidly from stress and injury when supported in a relatively natural environment

economic reasons for maintaining biodiversity

- maintaining biodiversity in an ecosystem improves long term productivity
- undiscovered species may have potential economic importance eg chemical/medical reasons
- in farming, biodiversity is important in maintaining soil quality and pollinating crops
- high biodiversity provides protection against abiotic stresses and disease
- species provide a gene pool which may be useful to humans in the future, thus improving profits
- potential biological control agents
- ecotourism

ecological reasons for maintaining biodiversity

- interdependence of organisms means that if one organism is removed it may have a significant effect on others:
predator/prey relationships, pollination, seed dispersal, decomposition, habitat modification

keystone species

species that play a key role in maintaining the structure of an ecological community. They have a disproportionately large effect on their environment relative to their abundance

categories of keystone species

- keystone predators
- keystone modifiers
- keystone prey
- keystone mutualists
- keystone hosts

example of a keystone species

sea stars are keystone predators. They maintain a balanced ecosystem by limiting the population of other species, such as mussels and sea urchins, which have no other predators. Without sea urchins, mussels would undergo a population explosion which would reduce the number of other species present in the area

conservation

- the maintenance of biodiversity through human action or management
- conservation is dynamic and needs to adapt to constant change
- conservation includes maintaining diversity in habitats, species and genetics within a species

2 examples of conservation

- sustainable development
- planting trees

preservation

the protection of an area by restricting or banning human interference, so that the ecosystem is kept in its original state

2 examples of preservation

- set aside areas in nature reserves
- marine conservation "no take" zones

in situ conservation

protecting species in their natural habitat:
- protected areas eg marine conservation zones and wildlife reserves
- controlling invasive species
- managing habitats - coppicing, burning, grazing
- reducing pollution
- legal protection to endangered species
- corridors to link habitats
- feeding animals

ex situ conservation

protecting a species by removing individuals from a threatened habitat and looking after them in a new area:
- zoos
- captive breeding programmes
- seedbanks
- botanic gardens
- storage of genetic material

3 principles for choosing a wildlife reserve (in situ)

- comprehensiveness - how many species are represented in the area? what are the prevailing environmental conditions?
- adequacy - is the area large enough to provide for the long term survival of all the species, populations and communities represented?
- representativeness - is there a full range of diversity within each species and set of environmental conditions?

advantages of in situ conservation

- preserves interdependent relationships
- permanently protects biodiversity and ecosystems by maintaining genetic diversity
- protects significant elements of natural and cultural heritage
- opportunity for ecologically sustainable land uses
- facilitates scientific research
- generally cheaper than ex situ conservation

disadvantages of in situ conservation

- endangered habitats may be fragmented - areas too small for long term survival
- population may already have lost much of its genetic diversity
- the conditions that caused a species to become endangered may still be present
- the area can attract poachers or ecotourists (who inadvertently cause disruption)
- conflict with local people can arise - in the past reserves have been set up with little regard for their needs: protected animals raid crops, people continue to hunt animals/harvest plant products and tourists feed animals/leave litter

advantages of ex situ conservation

- organisms are protected from predation and poaching. They are bred to increase the numbers of an indangered species
- the health of individuals can be monitored and medical assistance given as required
- populations can be divided, so if a disaster strikes one population, the other still survives
- selective breeding and genetic monitoring can be used to ensure that genetic diversity is maintained
- artificial insemination/in virto fertilisation and embryo transfer can be used to ensure reproductive success
- conservation sites also provide opportunity for research, education, tourism and fundraising

disadvantages of ex situ conservation

captive breeding is expensive and often encounters problems:
behaviour is altered as some behaviour is learnt from otber individuals in the wild. This can lead to:
- failure to breed successfully as not in natural environment
- unsuccessful reintroduction to wild as animals have not learnt necessary behaviours such as finding food, avoiding predators etc. or habitat has not been restored
gene pool is reduced due to smaller number of individuals in the "population"
Different selection pressures lead to different alleles being selected for. This can cause problems with:
- interbreeding with wild organisms (as genes are so different)
- disease resistance (as no exposure to local diseases)

2 examples of ex situ conservation of plant species

botanic gardens, seed banks

botanic gardens

- species are actively managed to provide them with the best resources to grow
- 1500 worldwide holding 35000 plant species (just over 10% of the world's flora)
- plants may be reproduced asexually or through tissue culture
- funding may be difficult

seed banks

- seeds are stored in dry conditions (dehydrated) at around -20 degrees celsius
- some seeds die when dried and frozen, so are stored in other conditions
- seeds are germinated and grown - new seeds can then be collected to ensure viability

3 advantages of seed banks

- seeds can be stored and germinated in protected surroundings
- they take up little space
- large numbers of seeds are produced so collecting them causes little disturbance to ecosystems

3 disadvantages of seed banks

- collection of seeds will cause some disturbance
- lack of genetic diversity in collected sample
- reintroduced plants may not survive in a different area

convention on international trade in endangered species (CITES)

an international agreement made by the majority of governments in the world - first agreed in 1973. Main aims:
- regulate and monitor international trade in selected species of plants and animals
- ensure that trade does not affect wild populations
- ensure that trade in wild plants is prohibited for commercial purposes and that permits for artificially propagated plants are issued
- regulate the training of less endangered wild species as agreed between the importing and exporting countries

convention on biological diversity (CBD)

signed by 150 government leaders in 1992 and other countries subsequently. Dedicated to promoting sustainable development. Member states MUST adopt ex situ conservation measures to complement in situ measures. Main aims:
- conserve biodiversity
- use compounds of ecosystems sustainably
- appropriate shared access to genetic resources
- appropriate sharing and transfer of scientific knowledge and technologies
- fair and equitable sharing of the benefits arising out of genetic resources

countryside stewardship scheme

operated 1991-2014 and again since 2019, offered governmental payments to farmers to enhance and conserve the English landscape. Aimed to make conservation a part of normal farming and land management by:
- sustaining the beauty and diversity of the landscape
- improving, extending and creating wildlife habitats
- restoring neglected land and conserving archaeological and historical features
- improving opportunities for countryside enjoyment and education
- traditional livestock and crops preserved

typical management techniques used in environmentally sensitive areas

- limiting areas tourists can visit
- controlling movement of livestock
- introducing anti-poaching measures
- replanting of forests and native plants
- limiting hunting through quotas and seasonal bans

overview of habitats on Galapagos Islands (case study)

- volcanic islands
- located nearly 1000km off coast of Ecuador
- hot, tropical islands
- unique climate
- surrounded by deep ocean
- cold water
- geographical separation
- natural selection
- allopatric speciation

main habitats on Galapagos Islands (case study)

- lowlands dominated by cacti
- subtropical forests inc. daisy trees
- treeless uplands dominated by ferns
- barren, volcanic plains
- temperate coastal waters

biodiversity on Galapagos Islands (case study)

- huge biodiversity
- unique climate and diverse range of habitats
- isolation of the islands
- resulted in the evolution of hundreds of endemic species -species found nowhere else in the world

6 threats to the Galapagos ecosystems (case study)

- population growth
- over fishing
- tourism
- previous exploitation of species
- introduced species
- pollution

population growth on Galapagos Islands (case study)

- 1990: under 10,000
- 2010: approx. 30,000
- resources required
- conservation of land
- deforestation
- pollution - plastics, litter, oil

over fishing on Galapagos Islands (case study)

many of the new immigrants cannot find work and so have taken up fishing. They have not kept to the quotas set (especially sea cucumbers)

tourism on Galapagos Islands (case study)

- tourism brings economic benefits but also can be destructive eg pollution, building hotels, trampling, invasive species
- numbers of tourists have increased over time

previous exploitation of species on Galapagos Islands (case study)

- animals easy to hunt as were not scared of humans
- giant tortoises were taken to provide food on ships
- 200,000 taken in less than 50 years

introduced species on Galapagos Islands (case study)

- humans have brought with them plants and animals - sometimes for food and sometimes accidentally. These have escaped into the wild population and damaged native species through predation and competition
- eg goats, rats, cats, insects, vegetable plants:
- goats were first introduced in mid 1970, by mid 1990s there were 1000s of them
- eat vegetation
- cause soil erosion
- less food, water and shelter for tortoises

pollution on Galapagos Islands (case study)

- the increased human population causes more rubbish including plastics
- some of this gets swept into the ocean, degrading water quality for the animals that live in it
- disasters may occur eg oil spills

conservation on Galapagos Islands (case study)

there has been considerable effort to preserve the islands in their natural state, as close as possible to the islands before they were discovered and colonised:
- 1955: 97.5% of land area declared a National Park by the Ecuadorian government
- Charles Darwin Foundation (CDF) was founded - an international non-governmental organisation dedicated to conservation on the islands
- CDF conservation projects are run in conjunction with Galapagos National Park service including eradication of introduced species that threaten endemic wildlife eg goats, rats
- 1978: Galapagos Islands declared a UNESCO World Heritage Site
- 70,000km^2 area around the islands is now a designated marine reserve and whale sanctuary

captive breeding on Galapagos Islands (case study)

ex situ conservation through breeding has occurred for tortoises. Males and females can be matched to improve genetic diversity

removal of invasive species on Galapagos Islands (case study)

- quarantine system = prevention
- culling feral goats

sustainable development on Galapagos Islands (case study)

- the Galapagos Island National Park service does not want to preserve the islands to the complete exclusion of human residents. Some developments and sustainable agriculture and fisheries is allowed. The way they do this is by splitting the various islands into zones with varying degrees of protection
- tourism is strictly controlled - not allowed on some islands and many only with a guide. No food/bags allowed on some islands
- education plays an important role

overview of habitats in Antarctica (case study)

- almost entirely covered in a 2km thick ice sheet containing 70% of the world's fresh water
- two seasons: summer = 24hr sunlight / winter = 24hr darkness
- average winter temperature <-30 degrees celsius

organisms present in Antarctica (case study)

- endothermic organisms (eg penguins) - insulation to keep warm. Emperor penguin - the only warm-blooded animal that remains in Antarctica during the winter.
- invertebrates (eg wingless midge) live on the continent all year
- plants (eg lichens and moss) can only grow in ice-free regions, which are niche, such as sand, soil and rock

threats to biodiversity in Antarctica (case study)

- historically whaling and seal hunting took place. This has depleted numbers of these organisms and has led to soil contamination
- overfishing of some aquatic species. Especially krill which is used as food for whales, seals, penguins and albatrosses. Recent technological developments mean that large numbers of krill can be harvested quickly for use in nutritional supplements and animal feed. Most fishing takes place in areas which are important feeding grounds for these predators who cannot easily find krill elsewhere
- global warming and ozone depletion as a result of human activity
- soil contamination
- discharge of waste into the sea

conservation measures being taken in Antarctica (case study)

- use of a "trigger-level" catch size in some krill fishing areas. Once this catch size is reached fishing must be conducted equally across all fishing areas up to the total catch limit
- the Southern Ocean Whale Sanctuary was established in 1994, covering the summer feeding grounds of 80-90% of the world's whales
- Antarctic treaty. Some of its provisions include:
- scientific cooperation between nations
- protection of the Antarctic environment
- conservation of plants and animals
- designation and management of protected areas
- management of tourism

overview of habitats in Snowdonia National Park (case study)

- 2000km2 of countryside in North West Wales
- contains the highest mountain range in England and Wales
- rugged terrain
- includes lakes and fast-flowing rivers, ancient woodland and heath

organisms present in Snowodnia National Park (case study)

- hardy arctic-alpine plants in high mountain areas (eg Snowdon Lily)
- woodlands of oak, alder and wych elm on the lower slopes
- large number of bird species across the different habitats: coast (eg chough), forest (eg redstart), mountain (eg osprey)
- 40 species of land mammal present including badges, coles, deer and hedgehogs

threats to biodiversity in Snowdonia National Park (case study)

- planting of conifers. This dries out the moorland and roads have to be built to take the trees away
- grazing of sheep leaves the area very barren and reduces biodiversity in this particular habitat
- walkers dropping rubbish. This pollution can harm mammals and birds. Litter often clogs gutters along the footpath. If the footpaths are not maintained walkers may stray off the footpath and rare plants will be trodden on.
- visitors may partake in the popular activities of climbing, walking, cycling and watersports which may damage the habitat
- residents work on the land

conservation measures being taken in Snowdonia National Park (case study)

there is Park authority, whose purposes include:
- conserve and enhance the natural beauty, wildlife and cultural heritage of the area
- promote opportunities for the understanding and enjoyment of the special qualities of the park
- enhance the economic and social wellbeing of communities within the park
- the Dinorwig powerstation is located deep inside the mountain Elidir Fawr to minimise the impact to the environment whilst meeting the human demand for energy

overview of habitats in the lake district (case study)

- mires: nutrient poor, waterlogged habitats which support mosses, liverwots, lichens and sedges. These habitats are internationally scarce
- limestone pavement: solid blocks with fissures between them
- heathland: open habitat with small shrubs like heather
- cliff, rock and scree: important nesting sites for many birds

organisms present in the lake district (case study)

- water voles, natterjack toads, a number of species of bat, red deer, golden eagle, osprey etc.
- native species, some of which are under threat of extinction (eg the red squirrel and the vendance)
- plants - diverse range of arctic-alpine plant communities, specialised trees (eg dwarf junipor and dwarf willow), sundrew (a carnivorous plant) etc.

threats to biodiversity in the lake district (case study)

- invasive species, eg rhododendron and laurel, outcompete native species. Their dense canopy reduces light intensity on the woodland floor and their roots produce toxic chemicals which stop other plants growing
- the loss of hay meadows due to a preference for silage production. Hay meadows have much higher species diversity
- peat extraction and drainage for use as agricultural land has left mires under threat
- damage to cliffs and rock faces by climbers

conservation measures being taken in the lake district (case study)

- active management of the countryside - eg replanting native tree species in order to protect the fragile ecosystem
- creating new habitats, spreading information about the importance of nature conservation (eg educating schools)

overview of the ecosystem in the masia mara (case study)

- Savannah divided by the Mara river
- fertile grasslands and woodlands close to the river. More open plains further from the river
- large migrating herds of wildebeest and zebra
- "Big Five": buffalo, elephants, leopards, lions
- in the past the area was dominated by the acacia bush which provided a habitat for tetse fly (the carrier of sleeping sickness). To reduce risk of infection major tracts of acacia have been cleared

human land uses in the masia mara (case study)

farming:
- grazing - this is limited to areas on the edge of the reserve, as local tribes are prevented from entering the park. Larger herds are grazing the grassland areas, and more trees are removed for fuel, increasing the risk of soil erosion
- cultivation - this has increased in the area in recent years. As grassland has been converted into cropland, natural vegetation is removed, and nutrients in the soil are used up, leading to a reliance on fertilisers for effective crop growth

conflict between human land use and conservation in the masai mara (case study)

animals like elephants, lions and wildebeest need lots of space, and when farmland or homes disturb their traditional migration routes, some animals look elsewhere for food and land. People try to defend their homes and livelihoods, and both sides can be harmed

methods of resolving the conflict in the masai mara (case study)

- tracking the movements of elephants and lions
- conservation and protection programme - included communication equipment, vehicles and other necessary equipment and infrastructure

overview of the ecosystem in the Terai region of Nepal (case study)

- fertile land - the alluvial soil is rich in plant nutrients
- extreme biodiversity - home to many subtropical plants
- large areas of thick forest where animals such as the Bengal tiger, sloth bear and Indian rhinoceros can be found

human land uses in the Terai region of Nepal (case study)

- the fertile area is the main agricultural region of Nepal
- many areas have been clear-felled in the past for the timber trade
- use of timber by local communities for fuel and building materials

conflict between humand land use and conservation in the Teria region of Nepal (case study)

- as a result of poverty and corruption, large areas of forest have been cleared for agriculture or to sell the timber
- this removal of large parts of the forest has also worsened the effects of the monsoon flooding, causing severe disruption to communities downstream
- if deforestation in the area continues, the communities of the Terai would be left with only small, isolated pockets of forest

methods of resolving the conflict in the Terai region of Nepal (case study)

- sustainable forest management - this aims to provide a livelihood for local people, ensure the conservation of forests, and provide the state with funding for general development
- local groups develop their own operational plans, set harvesting rules, set rates and prices doe products and determine how surplus income is distributed or spent
- through the creation of cooperative networks, small forestry businesses can work together effectively

overview of the ecosystem in peat bogs (case study)

- a peat bog is a region of wet, spongy land that contains decomposing vegetation.
- undisturbed peatland is a "carbon sink", meaning that it is a store of carbon dioxide. However, once dried, peat can be used as a fuel
- peat bogs form when plant material is inhibited from fully decaying by acidic and anaerobic conditions - this usually occurs in wet/boggy areas
- plants such as sphagnum mosses, bog cotton or cottonsedge have adapted to thrive in wet conditions with few nutrients
- bogs also support a wide range of insects eg butterflies, moths, dragonflies and damselflies
- lack of predators make some peatlands ideal for birds to nest and bring up their chicks

human land uses in peat bogs (case study)

- historically, the greatest decline has occurred through afforrestation (the establishment of a forest or stand of trees in an area where there was no forest), peat extraction and agricultural intensification, including land drainage. These activities have all contributed to the drying out of the bogs

conflict between human land use and conservation in peat bogs (case study)

- industrialised, mechanical extraction has led to a loss of 90% of UK peat bogs. Therefore there is a loss of this rare habitat and the species and genetic biodiversity it supports.
- burning peat as fuel releases trapped carbon (as carbon dioxide) in the atmosphere. This contributes to global warming; negatively impacting on many ecosystems around the globe
- land drainage for conversion to agricultural land also leads to loss of habitat. This can contribute to flooding and soil erosion downstream leading to further damage of habitats

methods of resolving the conflict in peat bogs (case study)

-conserving lowland bogs - the steps involved include:
- ensuring that the peat and vegetation is as undisturbed and wet as possible
- removal of seedling trees from the area. Trees have a high water requirement due to transpiration, therefore any seedling that has the potential to remove water from an area of peatland should be removed
- using controlled grazing to maintain the biodiversity of peatland. Grazing ensures a diverse wetland surface in terms of structure and species composition. This in turn provides a wide range of habitat for many rare insect species

population

all the organisms belonging to one species that live together in the same area, at the same time, and can interbreed

community

all the populations of different species that live in the same place at the same time and interact

habitat

the place where an organism lives

niche

the role of an organism in the ecosystem. eg how it feeds, reproduces and finds shelter. How it interacts with its biotic and abiotic environment. It is impossible for two species to have exactly the same niche in an ecosystem

producer

an organism that transfers energy from light or an inorganic compounds to organic compounds

consumer

an organism that obtains energy from organic compounds which they digest (eg carbohydrates, fats, proteins). ie feed on other organisms

decomposer

organisms that feed on dead organic matter (dead organisms or waste materials) releasing mineral ions and other matter into the soil and air

trophic level

the stage at which an organism feeds in the food chain

ecosystems

a relatively self contained unit of living organisms interacting with each other and their abiotic environment

4 features of ecosystems

- can be very large or small eg rainforests are very large, rovk pools/oak trees are very small
- dynamic - they are constantly changing
- biomass constantly flows through the environment - from one organism to another and between organisms and their non-living environment
- mineral ions are cycled between different organisms and the environment

5 examples of biotic factors

- producers
- disease (parasitism)
- mutualism
- competition
- predation

5 examples of abiotic factors

- oxygen
- water
- light intensity
- temperature
- pH

explanation of the process of biomass/energy transfer

- all organisms need energy and materials
- plants use light energy in photosynthesis to produce organic compounds eg glucose
- the products of photosynthesis are used for respiration, or, together with mineral ions, are incorportated into tissues and organs
- this biomass can then be passed through the food chain

energy and biomass losses along food chain

1. sun provides light energy for producer, although most of this energy is lost as it is not used in photosynthesis
2. producer respires, passes some energy onto 1st consumer through feeding, the rest is lost as heat energy from respiration, or death
3. 1st consumer loses some energy as heat from respiration, death, egestion and excretion, the rest is passed onto 2nd consumer through feeding
4. 2nd consumer loses the energy as heat from respiration, death, egestion and excretion

ecological efficiency

the efficiency with which biomass or energy is transferred from one trophic level to the next

ecological efficiency formula

biomass/energy of higher trophic level / biomass/energy of lower trophic level x100

transfer of energy from sun to producer

<3% of sunlight energy falling on an ecosystem is converted by photosynthesis. Reasons for this loss include:
- light not hitting the plant
- light falling on non-photosynthesising parts of a plant eg roots/bark
- light being reflected from the leaf surface
- light may be transmitted through the leaf without entering chlorophyll molecules
- energy may be used to heat the plant or evaporate water
- energy is lost during the biochemical reactions of photosynthesis