Biodiversity

• Biodiversity


  Encompasses various levels of biological organisation, including habitat biodiversity, species biodiversity, and genetic biodiversity
• Habitat biodiversity

  • Variety of habitats within a given area, such as sand dunes, woodlands, meadows, and streams
  • Each habitat supports unique ecological communities and plays a crucial role in maintaining overall biodiversity
• Species biodiversity


  • Richness and evenness of species present in a particular habitat
  • Species richness refers to the number of different species present
  • Species evenness refers to the relative abundance of each species
  • High species richness and evenness indicate a diverse and balanced ecosystem
• Genetic biodiversity


  • Diversity of genes within a species
  • Includes variations in alleles, genotypes, and genetic traits
  • Different breeds within a species contribute to genetic biodiversity
• Samplingimportance?

  • Essential for accurately assessing habitat biodiversity
  • Allows scientists to collect data representative of the entire ecosystem
  • Provides reliable information about species composition, abundance, and distribution
• Random sampling


  • Selecting sample sites randomly within a habitat to avoid bias and ensure that all areas have an equal chance of being surveyed
• Non-random sampling


  • Includes opportunistic, stratified, and systematic sampling
  • Used depending on research objectives and habitat characteristics
• Practical investigations for collecting random and non-random samples

  1. Use of sweeping nets

  2. Use of pitfall traps

  3. Use of pooters

  4. Use of Tullgren funnels

  5. Use of kick-sampling
• Species richness

  • Measured by counting the number of different species present in a habitat
  • Provides information about the diversity of species within an ecosystem
• Species evenness

  • Assesses the relative abundance of each species compared to others in the same habitat
  • Considers how evenly individuals are distributed among species
  • High species evenness indicates a more balanced distribution of individuals among species
  • Low evenness suggests dominance by a few species
• Measuring species richness and evenness

  1. Conduct biodiversity surveys to identify and count species present in a habitat

  2. Use biodiversity indices, such as the Simpson's index, to incorporate both species richness and evenness
• Simpson's Index of Diversity (D)

  • Measure of biodiversity that accounts for both species richness and evenness within a habitat
  • Ranges from 0 to 1, where higher values indicate greater diversity
• Interpretation of Simpson's Index of Diversity

  • High value of D indicates a more diverse habitat, with many different species present in relatively equal abundance
  • Low value of D suggests low diversity, often resulting from dominance by one or a few species
  • High values of D suggest a healthy and well-balanced ecosystem
  • Low values of D may indicate ecosystem stress, habitat degradation, or species loss
• Assessing genetic biodiversity


  • Can be conducted in various populations, including captive breeding programs in zoos, populations of rare breeds, and pedigree animals
  • Quantifying genetic diversity informs management strategies to preserve genetic resources
• Calculating the proportion of polymorphic gene loci

  1. Number of polymorphic gene loci / Total number of loci

  2. Provides a quantitative measure of genetic diversity within a population

  3. Higher values indicate greater genetic diversity, lower values suggest reduced diversity
• Factors affecting biodiversity


  • Human population growth
  • Agriculture (monoculture)
  • Climate change
• Human population growth


  Leads to habitat loss, fragmentation, and degradation, reducing habitat availability and disrupting ecosystems
• Agriculture (monoculture)


  • Involves cultivating large areas with a single crop, resulting in the loss of natural habitats and reduced species diversity
  • Pesticide use and intensive farming practices further exacerbate biodiversity decline
• Climate change


  Alters temperature and precipitation patterns, shifts habitat ranges, and increases the frequency and intensity of extreme weather events, disrupting ecosystems and causing species extinctions
• Reasons for maintaining biodiversity

  • Ecological (protecting keystone species, reducing soil depletion)
  • Economic (providing valuable resources and services, supporting sustainable agriculture)
  • Aesthetic (enriching landscapes, promoting environmental stewardship)
• In situ conservation


  • Conserving biodiversity within its natural habitat, such as establishing protected areas (marine conservation zones, wildlife reserves)
  • Aims to maintain ecological processes, genetic diversity, and ecosystem resilience
• Ex situ conservation


  • Conserving biodiversity outside its natural habitat, such as seed banks, botanic gardens, and zoos
  • Provides a safety net for species facing extinction in the wild and supports breeding programs, research, and education
• International conservation agreements


  • Convention on International Trade in Endangered Species (CITES)
  • Rio Convention on Biological Diversity (CBD)
• CITES


  Regulates international trade in endangered species to ensure their survival in the wild
• CBD


  Promotes sustainable development and equitable sharing of biodiversity resources
• Countryside Stewardship Scheme (CSS)

  Local agreement that provides incentives and support for land managers to implement environmental management practices, such as habitat restoration and wildlife conservation