biodiversity

  • biodiversity → the richness of biological variation, possible partly because of the many different combinations of environmental conditions on earth
  • species diversity → species richness measures the number of different kinds of organisms within a community
    • inversely related to geographic isolation (more isolated population = less rich) and environmental stress (stability of the environment, i.e. seasons and harsh conditions)
  • ecological diversity → measures the richness and complexity of a community, includes many niches, tropic levels, and ecological processes that capture energy, sustain food webs, and recycle material
  • edge effect → species richness is greater at the edges of adjacent communities, i.e. ecotone - transitional zone has a lot of richness
  • species evenness (dominance) → the extent to which the number of individuals of different species are equal or skewed
  • value and importance of biodiversity → intrinsic value, food security, drugs and medicines, ecosystem services, maintenance of ecosystem function, aesthetic/recreational/cultural benefits, environmental monitoring, biomimicry
    • ecosystem services → processes by which the environment produces resources or provides services that we often take for granted, but upon which we are dependent (.e. food, fuel, fibre, shelter and building materials, air purification, etc)
    • maintenance of ecosystem function → high levels of biodiversity increase the stability and resilience of an ecosystem
    • ecotourism → can be an important form of sustainable economic development
    • biomimicry → imitating nature’s design and processes to solve human problems, i.e. velcro, bullet trains, wind turbines, gecko tape
    • environmental monitoring → i.e. canaries in the coal mine gave an early warning for the miners to get out as it was an unhealthy environment
  • threats to biodiversity → natural causes of extinction, habitat destruction (urban sprawl, deforestation, fragmentation), hunting and fishing, commercial products and live specimens, exotic species introduction, diseases, pollution, climate change
  • natural causes of extinction → happens in periods of millions of years, in an undisturbed ecosystem, the background rate for mammals and marine animals is an annual rate of 1 extinction per 1-10 million species, i.e. approx. one species lost per decade
    • human impacts have accelerated that rate
  • the great acceleration → since 1800, the global population has grown sevenfold and the global economy has grown 30-fold
  • Anthropocene → a new geologic epoch; the impacts of humans can be detected in the lithosphere, a specific time when humans started influencing the rock strata
  • IUCN red list → list of species facing a high risk of extinction; amphibians are at the highest risk along with a high loss of corals, whose survival rate has diminished
  • living planet index → a metric developed by the WWF and the UNEP recognizes that biodiversity loss is more than just extinctions but also a decline in population and geographic range; summarizes trends in populations of over 2500 vertebrate species
  • human-caused reductions in biodiversity → increasing wealth; growing populations and poverty, have to find ways to meet the basic needs of the community, i.e. overfishing or cutting down trees
  • habitat destruction/loss → urban sprawl, destruction, fragmentation, degradation; the largest threat to species
    • theory of island biography → distant islands support fewer species than islands closer near the shore (the distance effect), larger islands support more species than small ones and have lower extinction rates as more individuals lead to more genetic diversity and increased resilience to change or destruction
    • migration → species migrate, i.e. birds need to stop and rest along their path, and if the habitats along the flyaway are destroyed, they cannot migrate properly
  • pollution → acid precipitation, ozone, depletion, climate change, direct/indirect poisoning, altered habitat from chemicals
  • overexploitation → hunting and fishing, the over-harvesting of game species; endangered species consumption, a lot of cultures enjoy eating or keeping endangered species as pets; commercial harvest, i.e. zoos, laboratories, pet industry
  • predator and pest control → many animal populations have been greatly reduced or exterminated because they are regarded as dangerous to humans or livestock, i.e. birds, coyotes, wolves, prairie dogs
  • exotic species introduction → exotic organisms are introduced into habitats where they aren’t native and become invasive when they cause economic or environmental harm, i.e. ships pouring out ballast water can cause the introduction of new species
  • conservation biology → study of human impacts on organisms, development of ways to protect biodiversity; two techniques: in situ and ex-situ
  • ex-situ conservation → zoos, aquaria, botanical gardens, collecting eggs, seeds, captive breeding to reintroduce species
    • i.e. California condor - the 27 last remaining condors were taken into captivity in 1987, and as of 2022, 561 condors were living in the wild
    • i.e. seed banks - seed collection are brought to botanical gardens to grow endangered plants, the disadvantages are that some seeds can’t be stored, are expensive and stops natural selection
  • ex-situ pros → saving the species, an opportunity for scientific studies, studying species to better understand them, successful breeding
  • ex-situ cons → expensive, inbreedings, potential loss of natural instincts
  • in-situ conservation → protecting the area or habitat where the species lives instead of bringing it into a controlled setting
    • some species act as umbrellas for protecting habitats and communities as they can rally the public (i.e. pandas or polar bears)
    • i.e. northern spotted owl - shutting down land where the owl was spotted, caused economic conflicts as people were encouraged to kill the owls rather than report it to avoid the land being shut down
  • in-situ considerations → size (how much land is enough), shape (wide vs narrow land space), cost (how much will it cost, economic benefits/disadvantages), location (value of land, environment), targeting what species and areas will be saved with limited funds
    • i.e. grizzly bears - none of NA’s big western parks are large enough to preserve grizzly bears and guarantee long-term survival; solution to create a green corridor for animals to travel from park to park
    • i.e. boreal/woodland caribou - 57 boreal caribou local populations, 17 of which are self-sustaining, 33 are not, and 7 are likely not; create corridors where the caribou can be self-sustaining
    • not all spaces are large enough to protect endangered species, so trying to create adequate space for species with large habitat requirements
  • biodiversity hotspots → identifies regions where the threat is greatest to the greatest number of species and allows conservationists to focus cost-effective efforts there; to qualify, a region must supper 1500 endemic plant species and must have lost more than 70%
    • relatively small areas of land that contain many endemic species at high risk from human activities
    • the 34 biodiversity hotspots contain 50% of all plant species and 42% of all terrestrial vertebrate species in only 2.3% of the planet’s land area