Ch 3 - Biodiversity and Conservation

3.1 - An Introduction to Biodiversity

• Biodiversity: broad concept encompassing total diversity which includes diversity of species, genetic diversity, habitat diversity

  1. Species diversity: usually in communities, product of number of species and their relative proportions

  2. Habitat diversity: range of habitats in an ecosystem or biome

  3. Genetic diversity: range of genetic material present in a population of a species

• Smaller populations have lower genetic diversity than a larger one because of the small gene pool

• Scattered populations (animals) / plant-wise (humans) have high genetic diversity

• Many ecological niches due to layering of forests result in habitat diversity

• The number of species present in an area is often used to indicate general patterns of biodiversity.

• Richness is a measure of the number of different species in an area; more species means a richer environment

  • Abundance is the number of individual organisms in a species. We can measure abundance on a small scale as they appear in a forest, for a larger scale, environmentalists tend to measure abundance by the amount of organisms all around the world

  • Richness does not take into account the rarity of a species

• A biodiversity hotspot is a region with high levels of biodiversity that is under threat from human activities

  • 70% of the habitat has been lost

  • They cover 3.2% of the land surface

  • Tend to have large densities of human habitation nearby

  • contains more than 1.5k of plants which are endemic

• The Diversity Index is a quantitative measure of the diversity of a species in a community, it includes calculations and information about the availability and rarity of species in a specific community.

  • measuring species is important for biologists and environmentalists to comprehend the structure of the community which habitats a diverse number of species

3.2 - Origins of Biodiversity

• Biodiversity arises from evolutionary processes

  • variation in biological areas can be beneficial to, damaged to, or have no impact on the survival of the individual

  • Environmental change gives new challenges to the species, those that are suited survive, and those that are not suited will not survive

• Natural selection: those more adapted to their environment will flourish and reproduce and those less adapted do not survive for long

  • survival of the fittest

  • contributions to evolution of biodiversity over time

  • give new challenges to the species so those better suited will survive

• Speciation: gradual change of a species when populations of the same species become separated. They cannot interbreed since they inhabit the characteristics of other species

  • a slow process can be sped up by humans using artificial selection

  • only processes of animals and plants, also by genetic engineering

  • separation may have geographically or reproductive causes

• Isolation of species can be caused by:

  • physical barriers: will split up gene pool, which results in species developing in different directions

    • Examples: Mountain range, ocean

  • land bridges: allows species to invade new areas and for species to relocate, created from lowering of sea levels

    • Created from the lowering of sea levels

• Isolation factors are:

  • Geographical factors: island formation, loss of land bridges and mountain ranges

  • Behavioural factors: reproductive displays, songs, daily activity

  • Genetic factors: inability to produce fertile offspring due to genetic different

  • Reproductive factors: anatomical different especially in reproductive organs

• Continental drift: caused from drifting of the globe, results in new and diverse habits

  • changing climate conditions force species to adapt which increases biodiversity

  • distribution of continents caused climatic variations and variation in food supply, both contribute to evolution

• Plate tectonics: study of the movement of the plates. When plates move and meet due to continental drift, they might:

  • slide past each other, diverge

  • converge: collide and both face upwards

  • collide and one sinks underneath the other

• The earth is 4.6 billion years old

  • Current era: Cenozoic

  • Current time period: quaternary tertiary

• Isolation of populations → caused by environmental changes the surface is divided into curstal, tectonic plates which moved throughout geological time

• Mass extinctions have been caused by a contribution of factors, some of which are tectonic movements, super volcanic eruption, climate change, and meteor impact which resulted in a new direction in evolution and increased biodiversity.

  • Extinctions are caused by:

    • Climate change over a period of time, as the dust incoming from volcanic eruptions led to increasing solar radiation which causes plants to die due to a lack of ability to photosynthesize. Many species are affected by this as well since food webs collapse over time.

    • Volcanic eruptions and the impact of meteors which release large amounts of harmful dust and ashes into the atmosphere.

3.3 - Threats to Biodiversity

• Estimates of the total number of species vary considerably

  • Most are animals and most are terrestrial

  • ⅔ rds are in the tropics, mostly tropical rainforests

  • 50% of tropical rainforests have been cleaned by humans

• When nearly all that habitat goes, extinction rates increase rapidly

  • current rates of species loss = greater than the past due to increased human influence

  • extinction can be caused by human activities, such as: habitat destruction, invasive species, pollution, overharvesting, haunting

• Factors maintaining biodiversity:

  • complexity of the ecosystem: the more complex a system is, the more resilient its species will be

  • stage of succession: older, more resilient and stable ecosystems which undergo succession are less vulnerable than in young ecosystems

  • limiting factors: changes to materials provided will make it harder and result in species disappearing system is more likely to manage it one of abiotic factors is reduced

  • Inertia: property of an ecosystem to resist when subjected to a disruptive force

• Factors which lead to loss of biodiversity:

  • Natural hazards: naturally occurring events that may have a negative impact on the environment and humans

    • are considered natural disasters when the impact worsens

    • major cause of loss of biodiversity = loss of habitat

• Fragmentation of habitat: the process where a large area is divided up into patchwork of fragments

  • separated from each other by roads, towns, factories, fences

• Pollution: caused by humans can degrade or destroy habitats and make them unsuitable to support the range of species

  • local pollution, environmental pollution, eutrophication, climate change which alters weather patterns and shifts biomes

• Overexploitation: has escalated as human populations expand

• Introducing non-native species → can upset a natural ecosystem

• Spread of a disease → decrease biodiversity

• Modern agricultural practices: can reduce diversity with monocultures, genetic engineering and pesticides

• Vulnerability of tropical rainforests:

  • Tropical biomes: contain some of the most globally biodiverse areas in their unsustainable exploitation results in massive losses in biodiversity and their ability to perform globally impotent ecological services

    • most tropical biomes occur in less economically developed countries and there is conflict between exploitation and sustainable development and conservation

• International Union for conservation of nature (IUNC): published the red list of threatened species in several categories

  1. Extinct (EX): inability to record an organism, all individuals are dead

  2. Extinct in the wild (EW): captivity as a naturalised species outside past range

  3. Critically end (CE): considered to be in extremely high risk of extinction

  4. Vulnerable (VU): high risk of extinction

  5. Near threatened (NT): close to qualifying for one of the threatened once in the category

  6. Not evaluated (NE): not evaluated against the criteria

3.4 - Conservation to Biodiversity

• Diversity of species: in the ecosystem promotes healthy and good environment

  • extinction = normal

  • A community thrives when species evolve and adapt to changes, every species has its own ecological importance

• Why should we conserve biodiversity?

  • Direct value: food species, natural products

  • Indirect value: human rights, environmental services, scientific education values, human health, and ecocentrism

• Conservation biology: sustainable use and management if natural resources

• Preservation biology: attempts to exclude human activity in areas where humans have not yet encroached

• Conservation → protect natural resources and proper use of nature

  • Use water from water sources such as lakes

• Preservation → protect what has been built from resources and protection of nature from use

  • From water sources such as cleaning and washing

• Organisations of biodiversity conservation:

  • IGO (intergovernmental organisation): composed of different groups from different countries

  • Governmental organisations (GO’s): composed of groups funded by a national government

  • Non-governmental organisation (NGO): composed of groups run by volunteers, no relation to governments non-profit

• Approaches to conservation:

  1. CITES (conservation pn the international trade in endangered species):

     • Appendix 1: species cannot be traded internationally as they are threatened with extinction

     • Appendix 2: species can be traded internationally but with strict regulations to ensure sustainably

     • Appendix 3: a species included at the request of a country which needs help of other countries to prevent illegal exploitation

  2. Captive breeding and zoos:

     • Holding and caring for species in captivity for research and maintenance of species

     • Maltreatment and poor habitats of reserves and zoos

     • Reintroduction of species does not guarantee survival and may cause a loss of money

  3. Botanical gardens and seed banks:

     • Protection and cultivation of different species whether common or rare

     • Some plants need extra care or technology to grow and survive

  4. Flagship species:

     • Prioritised over other species

     • Most common species and known worldwide

     • If they become extinct, we failed to take care of them

  5. Keystone species:

     • Species that are considered to have a critical role in maintaining the structure of the ecosystem

• Designing protected areas: where a conservation area is within a country is a significant factor in the success of the conservation effort

  • Surrounding areas including land formations and urban areas

  • Location in a remote area where people don't usually live

  • high biodiversity

  • low population density