Conservation of Biodiversity A4.2

• What is biodiversity?


  Biodiversity refers to the variety of life on Earth at all levels. It includes all living organisms, their genetic variation, and the ecosystems they form.
• What is ecosystem diversity?

  Variety in the combinations of species living together in communities. This diversity is due to the very varied environments on earth, and the geographical ranges of organisms.
• What is species diversity?

  Variety in the body plans, internal structures, life cycles, modes of nutrition, etc of different species.

  It is often quantified in terms of species richness (the number of species) and species evenness (the distribution of organisms within species)
• What is genetic diversity?

  Variety in the gene pool of each species. This may be between geographically separated populations, and also within populations.
• Why is biodiversity important?

  - Stability: Diverse ecosystems are more resilient to disturbances.

  - Medicine: Many pharmaceuticals come from natural compounds.

  - Food Security: Genetic diversity protects against crop failures.
• How many species have been identified, and how many do scientists assume that there are?

  Over 2 million species have been discovered, named, and described so far.

  Scientists estimate that over 8 million species may exist in total - meaning millions remain undiscovered.
• What is extinction?


  Extinction is the process by which a species ceases to exist. It occurs when the last individual of a species dies, and no viable population remains to reproduce.
• What were the five mass extinctions?

  1) Ordovician-Silurian (85% of species lost)

  2) Devonian (75% of species lost)

  3) Permian-Triassic (96% of species lost)

  4) Triassic-Jurassic (80% of species lost)

  5) Cretaceous-Paleogene (76% of species lost)
• Why is discerning biodiversity difficult?

  There are differences in how humans classify organisms, and this influences how much biodiversity they assume that there is.

  - Splitters divide life into more specific species, resulting in higher species counts

  - Lumpers group organisms more broadly, resulting in lower species counts
• What is anthropogenic extinction?

  Anthropogenic extinction refers to the loss of species (directly or indirectly) due to human activity.
• What are the main causes of anthropogenic extinction?

  - Overharvesting (species are removed faster than they can reproduce)

  - Habitat destruction (fragmentation/destruction isolates populations)

  - Invasive species (outcompete, prey on or infect endemic species)

  - Pollution (damages reproductive systems, poisons species and degrades habitats)

  - Climate change (altered conditions force species migration or adaptation)
• What are some examples of anthropogenic extinction?

  1) North Island Giant Moa

  - Was a terrestrial bird

  - Lived in New Zealand

  - Went extinct due to hunting and habitat loss

  2) Caribbean Monk Seal

  - Was a marine mammal

  - Lived in the Caribbean sea

  - Went extinct due to hunting and habitat degradation

  3) Pink-headed Duck

  - Was a freshwater bird

  - Lived in India and Bangladesh

  - Went extinct due to habitat loss
• What is ecosystem loss?

  Ecosystem loss is the degradation, fragmentation or complete destruction of natural habitats due to human activity.

  It disrupts ecological networks and eliminates ecosystem services essential to life.
• What are the anthropogenic causes for ecosystem loss?

  - Land-use change (conversion of ecosystems into farmland, housing and roads)

  - Urbanisation (conversion of ecosystems, disruption of gene flow and species movement)

  - Overexploitation (loss of keystone species via logging, hunting or fishing can lead to ecosystem loss)

  - Pollution (plastic, sewage and pesticides can cause damage in sensitive ecosystems)

  - Climate change (Altered sea and rainfall levels cause the loss of climate-sensitive ecosystems)

  - Mining and dam construction (pollutes rivers and destroys habitats)

  - Leaching of fertilisers (causes algal blooms and eutrophication, and oligotrophic ecosystems are lost)
• What are some examples of ecosystem loss?

  1) MDF

  - Dipterocarps are a family of 700 species of tropical hardwood tree, and a mixed dipterocarp forest (MDF) has high diversity of this family and other tree species.

  - MDF has high quantities of merchantable timber per hectare so has been targeted for logging

  Most areas of MDF have been lost since the 1970s (especially on lowland sites where nutrient-rich soils overlie deep peat) due to logging

  - Areas of MDF have also been lost due to land conversion into palm oil plantations. Drainage during this conversion causes peat to decompose, releasing carbon dioxide into the atmosphere and contribute to global warming

  2) The Aral sea

  - The Aral sea was a lake where the salinity was higher than a freshwater lake.

  - Water management schemes in the 1960s diverted two major rivers that fed the Aral sea. This led to much of the lake becoming desert.

  - Water salinity significantly increased due to these water management schemes, contributing greatly to ecosystem loss.
• What is the biodiversity crisis?

  The biodiversity crisis is the ongoing, rapid decline in global species, ecosystems and genetic diversity. It is mostly caused by anthropogenic activity.
• How is biodiversity assessed and quantified?

  Biodiversity is assessed via species richness (the number of different species in a given area), and species evenness (the relative abundance of each species). The Simpson's reciprocal index quantifies biodiversity. The higher the D value, the greater the biodiversity.
• What are some other methods of assessing biodiversity?

  1) IPBES reports

  - Intergovernmental science-policy platform on biodiversity and ecosystem services

  - The 2019 report shows that biodiversity loss is faster than at any other time in human history- 75% of terrestrial and 66% of marine environments are altered by anthropogenic activity, and one million species are threatened with extinction

  2) Long-term biodiversity surveys

  - The living planate index measures global wildlife population trends

  - The IUCN red list index tracks extinction risk over time

  3) Habitat level monitoring

  - Satellites and field data can confirm degradation and loss of key habitats like the amazon rainforest, coral reefs and wetlands.

  4) Genetic and ecosystem diversity metrics

  - Declining genetic variation is documented in wild species, crops and livestock
• What are some examples of citizen science?

  Citizen science are opportunities for citizens to contribute and provide data for the biodiversity crisis.

  Examples:

  - eBird

  - iNaturalist

  - Butterfly monitoring scheme
• What are some advantages of citizen science?

  - Broad data coverage

  - Detects early signs of population shifts

  - Engages the public with conservation
• What are some disadvantages of citizen science?

  - Data may lack consistency or standardisation

  - Needs proper training and expert review

  - Peer-review may be lacking
• What are the causes of the biodiversity crisis?

  - Human population growth (drives demand for land, food and energy)

  - Over-exploitation (hunting, fishing and logging reduces populations and causes ecosystem loss)

  - Urbanisation (replaces and fragments natural habitats, isolating species)

  - Deforestation and agricultural expansion (destroys natural habitats, affecting forest-dependent species)

  - Pollution (plastic, sewage and pesticides can cause damage in sensitive ecosystems)

  - Spread of pests, diseases and invasive species (outcompete or kill endemic species)
• What is in situ conservation?

  - In situ conservation is the conservation of species within their natural ecosystems. This occurs in protected areas (e.g. national parks).

  - In situ conservation may occur through the management of nature reserves or through rewilding and ecosystem reclamation.
• How are nature reserves managed in In Situ conservation?

  In nature reserves, protected ecosystems are created and maintained through active management, e.g. controlling invasive species, restoring habitats, establishing buffer zones and establishing migration corridors.
• What is rewilding and ecosystem reclamation as a part of In Situ conservation?

  - Rewilding = reintroducing lost species to restore ecological function

  - Reclamation = repairing damaged or degraded ecosystems

  - The aim of both rewilding and reclamation is to let ecosystems self-regulate and support biodiversity
• What is Ex Situ conservation?

  Ex situ conservation is the conservation of species outside of their native ecosystems. This occurs in areas like zoos, aquariums and botanic gardens.

  Ex situ conservation includes breeding or storing species outside the wild- in zoos, aquariums and botanic gardens. This includes captive breeding and gene banking.
• What is germplasm storage (as a type of Ex Situ conservation)?

  Germplasm is genetic material (e.g. seeds, embryos, tissues) stored for future use. They preserve crop and plant diversity for food security. This protects against climate and disease-related extinction.
• What is EDGE?


  EDGE stands for Evolutionary Distinct and Globally Endangered. They refer to species that are:

  - Evolutionary unique

  - Critically endangered

  - Globally irreplaceable

  The loss of an EDGE species means the loss of an entire branch of the evolutionary tree.
• Why is EDGE conservation prioritised?

  - Preserves deep evolutionary history

  - Protects species with no closer relatives

  - Maximises long-term biodiversity retention.
• How are EDGE scores calculated?

  The EDGE score is the ED score multiplied by the GE score.

  - ED score (evolutionary distinctiveness)- How isolated a species is on the tree of life

  - GE score (Global endangerment)- How threatened the species is (based on IUCN Red list)
• What are some examples of EDGE?

  - Axolotl

  - Pangolin

  - Aye-Aye

  - Yangtze giant softshell turtle