Ch 3: Biodiversity and Conservation

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

 Fig. 1 Measuring Biodiversity

  • 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