Biodiversity

• Tropical = most biodiversity.
• Arctic and desert = least natural biodiversity.
• Closer to equator = more biodiversity.
• Environmental Impact Assessment (EIA) predicts impacts of a project on biodiversity of area.
• Habitat biodiversity.
• Species biodiversity.
• Genetic biodiversity.

Habitat biodversity

• Number of habitats in area.
• Greater habitat biodiversity = greater species biodiversity.

Species biodiversity

• Species richness - number of different species living in a particular area.
• Species evenness - comparison of the numbers of individuals of each species living in a community.

Genetic biodiversity

• Variety of genes that make up a species.
• Different alleles = different characteristics.
• Greater genetic biodiversity = better adaptation = easier to develop resistance to a disease.

• Each individual of the population has an equal chance of selection.
• No involvement / bias.

• Opportunistic - uses organisms that are conveniently available.
• Stratified - populations divided into strata based on characteristics. A random sample is taken from each proportional to its size.
• Systematic - different areas within an overall habitat are identified. Often uses a line or belt transect. Line transect = mark a line and take samples from intervals. Belt transect = two lines parallel and samples taken from area between.

• Pooter.
• Sweep net.
• Pitfall traps.
• Tree beating - white sheet underneath.
• Kick sampling - net is held downstream.

• Point quadrat - frame with horizontal bar. Set intervals along bar with long pins to put in ground. Each species that touches the pins is recorded.
• Frame quadrat - type and number of each species within each section of the quadrat is recorded.

Richness:

• A list should be written of each species identified so that the total number of species can be calculated.
• Identification keys used.

Evenness:

• How many of each species there are in comparison to every other species in the habitat.

• Density - count the number of organisms in a 1m by 1m square, giving the density per square metre. Absolute measure.
• Frequency - count the number of squares a particular species is present in.
• Percentage cover - an estimate by eye of the area within a quadrat that a particular plant species covers.
• Calculate the mean of the individual quadrat results to get an average value for that particular organism per metre squared. 
• Total population = mean value per metre squared x total area.

• Capture - mark - release - recapture.
• Capturing as many individuals of a species as possible, marking down the organisms you have and then releasing them back into the community.
• Greater the number recaptured, the smaller the population.
• Species evenness calculated by comparing the total number of each organism present.

• Non-living conditions.
• Wind speed - anemometer - m s -1
• Light intensity - light meter - lx
• Relative humidity - humidity sensor - mg dm-3
• pH - pH probe - pH
• Temperature - temperature probe - degrees C
• Oxygen content in water - dissolved oxygen probe - mg dm-3.
• Rapid changes can be detected.
• Human error reduced.
• Precision increased.

Simpson's Index of Diversity.

• Species richness and evenness.

• D = Simpson's index of diversity.
• N = the total number of organisms of all species.
• n = the total number of organisms of a particular species.
• Value between 0 and 1.
• Higher the value, the more diverse the habitat.

• Mutations = new allele.
• Interbreeding between two different populations - alleles passed between populations - gene flow.
• The number of possible alleles needs to decrease for genetic biodiversity to decrease:
  • Selective breeding.
  • Captive breeding programmes.
  • Rare breeds - selective breeding has been used historically to produce a breed of domestic animal animal or plant with characteristics which then become less popular.
  • Artificial cloning.
  • Natural selection.
  • Genetic bottlenecks - few individuals survive an event or change = smaller gene pool.
  • The founder effect - small number of individuals create a new colony, geographically isolated from the original.
  • Genetic drift - frequency of occurrence of an ellele will vary.

• Overexploitation:
  • Species harvested faster than it can be replenished.
  • Hunting, trade and lumber.
  • Hunting threatens a third of endangered mammals and birds.
• Habitat loss:
  • Human impact - development, ranching, agriculture, pollution.
  • Deforestation - tropical rainforests.
  • If entire population was identical due to reproduction staying within one population, one disease could wipe out the entire population.
  • Acid rain, air pollution, fertilisers, herbicides and pesticides.

• Invasive species:
  • Non-native or alien species - animals, plants, diseases transferred unnaturally.
  • Outcompete native species in their new habitat.
  • Huge problem in isolated communities.
• Climate change:
  • Average global temperature is predicted to rise by 4 degrees C by 2100.
  • Climate pattern changes = alter the composition of the patterns in species and this can post big problems.
  • Speices may not adapt in time.
• Agriculture:
  • Selective breeding reduces biodiversity.
  • Deforestation removes habitats.
  • Removal of hedgerows - mechanisation - removes habitats.
  • Chemical pesticides and herbicides - breaks food chain.
  • Monoculture - lowers biodiverswity massively as only one species is present.

The Galapagos Islands

• Habitat disturbance:
  
  • Dramatic increase in population size - strains on resources.
  • More waste and pollution.
  • Fragmentation of habitats.
• Over exploitation of resources:
  • 19th century - harvesting whales and seals for international trade.
  • Harvested faster than they could reproduce.
  • Giant tortoises taken - could survive on little food for shipping - then killed and eaten.
  • Captive breeding programme to supplement tortoise numbers.

The Galapagos Islands

• Introduced species:
  • Goats, cats, fruit and vegetables.
  • Insects carried in accidentally.
  • Red quinine tree aggressively invasive species on Santa Cruz island. Spreads rapidly. Wind-dispersed seeds.
  • Native Cacaotillo shrub eradicated.
  • Goat - damaging. Grazing, trampling, feeding or tortoise food supply.
  • Cats hunt many species e.g. lizards.
  • Management for sustainability is in place.

Aesthetic reasons:

• Entiching life experiences.
• Inspiration for artists.
• Patients suffering from stress.

Ecological reasons:

• All organisms are interdependant on each other for their survival - breaks in food chain = decline in populations.
• Keystone species - disproportionately large effect on their environment relative to their abundance.

Economic reasons:

• Deforestation - soil erosion - less ability to grow crops meaning economically dependent on imports.
• Non-sustainable removal of resources - collapse of industry.
• Large-scale habitat removal - species with economic importance may become extinct before they are discovered.
• Continuous monoculture - soil depletion.
• Monoculture can also lead to eradication of a population from one disease.
• Rich in biodiversity = tourism = income.
• Plant varieties = more cross breeding = better characteristics e.g. disease resistance.

• Sea stars:
  • Predators.
  • Limit populations e.g. mussels.
  • If removed, these species would undergo population explosion and compete for space with other organisms.
• American allogators:
  • Make burrows for nesting and to stay warm.
  • Abandoned burrows = freshwater ponds = drinking for other animals.
• Prairie dogs:
  • Up to 200 species rely on their tunnelling.
  • Food for snakes.
  • Tunnelling and droppings spreads nutrients through soil.
  • Channels rainwater into water table.

• Marine conservation zones:
  • Lundy Island - England.
  • Huge variety of marine biodiversity.
  • Vital tools in preserving species-rich areas such as tropical coral reefs.
  • Carefully designed to take into account movement patterns, dispersal rates and population dynamics of particular target species.

• Management of nature reserves:
  • Protect a particular species, assemblage of species or specific habitats.
  • Rarely left to manage themselves.
  • Prevents natural processes e.g. succession. (one species tends to take over another).
  • Active methods of management:
    • Controlled grazing.
    • Restrictinh guman access.
    • Controlling poaching.
    • Feeding animals up to reproductive age.
    • Reintroduction of species.
    • Culling or removal of invasive species.
    • Attempting to halt succession.

• Zoos:
  • Captive breeding programmes.
  • Focuses on vetrebrates despite invertebrates more likely to become extinct.
  • Generate financial support for conservation and extend public education to other issues.
  • Many threatened vertebrates - top carnivores.
  • Many habitats completely destroyed.
  • World zoos could sustain up to 900 species, with populations of 100-150 per species.
  • Reintroduction of species into wild: (problems)
    • Diseases - loss of resistance during captive breeding.
    • Behaviour - no survival instincts.
    • Genetic races - Reintroduces species may be of an entirely different genetic make-up to the original populations.
    • Habitat - the habitat needs to still be there. Introduction of new individuals to an already populated habitat will lead to stress and tensions as fight for resources and food.

• Aquaria:
  • Display and educational facilities.
  • Captive breeding programmes.
  • Marine and freshwater programmes subject to captive breeding programmes.
• Plant collections:
  • 1500  botanic gardens worldwide - 35,000 species.
  • General geographical imbalance with 230 of 1500 gardens being in the tropics - despite greater species richness there.
  • Gaps in coverage of important species.
  • Seed banks:
    • Orthodox seeds can be dried and stored at -20 degrees C.
    • Recalcitrant seeds die when dries. Things like acorns of oaks, and most of the seeds in the tropical rainforest.
    • Frozen conditions slow the rate at which they lose the ability to germinate.

International Union for the Conservation of Nature (ICUN):

• Securing agreements between nations.
• Once a year - red list published of threatened animals so countries can work together to conserve species.
• Convention on International Trade in Endangered Species (CITES) - regulates international trade of wild plant and animal specimens in their products.
• More than 35,000 species protected by CITES.

The Rio Convention:

• 1992, 172 nations Rio de Janeiro - Earth Summit.
  • Convention on Biological Diversity (CBD) requires countries to develop national strategies for sustainable development.
  • The United Nations Framework Convention on Climate Change (UNFCC) - stabalise greenhouse gas concentrations.
  • The United Nations Convention to Combat Desertification (UNCCD) - prevent fertile land into desert and reduce effects of drought.

Countryside Sterwardship Scheme (CSS):

• Local level scheme in England.
• 1991 - 2014.
• Governments pay farmers and other land managers to enhance and conserve the English landscape.
• Make conservation a part of normal farming and land management.
• Specific aims:
  • Sustaining the beauty and diversity of landscape.
  • Improving, extending and creating wildlife habitats.
  • Restoring neglected land and conserving archaeological and historic features.
  • Improving opportunities for countryside employment.
• Replaces by environmental Stewardship Scheme (ESS) - works similarly.