Conservation of Biodiversity Notes

Conservation of Biodiversity

A4.2 Introduction

• Guiding Questions:
  • What factors are causing the sixth mass extinction of species?
  • How can conservationists minimize the loss of biodiversity?
• Earth's biodiversity allows it to withstand environmental pressures through evolution and adaptation.
• Human influence is causing a sixth mass extinction.
• Efforts are being made by government and private enterprises to minimize human impacts and preserve species.
• It is crucial to reconsider humans' role in stewarding the planet.

A4.2.1 - Biodiversity in Many Forms

• Biodiversity is the variety of life in an area, including ecosystem, species, and genetic diversity.
• A healthy coral reef has high biodiversity.
• Ecosystem health is maintained by the interactions between life forms like animals, plants, fungi, and microorganisms.
• Biodiversity can be studied at three levels:
  • Ecosystem
  • Species
  • Genetics

Ecosystem Diversity

• Ecosystem diversity measures the types of ecosystems in a location.
• The Great Barrier Reef exemplifies high ecosystem diversity due to its numerous individual reefs and islands with varying climates and life forms.
• The reef system stretches over 2,300 km.
• Each reef has its own ecosystem with high biodiversity, contributing to regional stability and diversity.

Species Diversity

• Species diversity, also known as species richness, is the number of different species in a community.
• Species evenness measures the relative abundance of each species.
• Healthy ecosystems exhibit high species richness and evenness.
• Table 1: Compares species evenness and diversity in two coral reef communities.
  • Community 1: 11 Hard corals, 23 Fish, 155 Sponges, 118 Echinoderms, 307 Total
  • Community 2: 63 Hard corals, 146 Fish, 64 Sponges, 21 Echinoderms, 294 Total
• Species evenness is often more important than species biodiversity.

Genetic Diversity

• Every organism has a unique set of genes that determine its characteristics.
• The gene pool is the collection of all gene types or alleles in a population.
• Greater genetic diversity leads to more stable populations that can withstand environmental pressures.
• Larger populations generally have higher genetic diversity.
• Small populations face the risk of genetic diseases due to a reduced gene pool.
• The Florida cougar population in the mid-1990s suffered from genetic weaknesses.
• Biologists introduced eight female cougars from Texas to increase genetic diversity in the Florida population.

A4.2.2 - Biodiversity Change Over Time

• Millions of species have been discovered, but many more remain to be discovered.
• Fossil evidence suggests that there are more species alive today than at any time in the past.
• High extinction rates in the last few hundred years have reduced diversity due to human activities.
• The fossil record indicates that there are more species alive today than in any other geological time period.
• The number of species alive today, and in the past, are estimates because biologists are discovering new species and the fossil record is incomplete.
• Speciation, the formation of new species, occurs under certain conditions.
• Prolonged periods with higher speciation rates than extinction rates result in a higher number of species.
• Adaptive radiation occurs when organisms reach islands and undergo speciation due to different resources and environmental challenges.
• Charles Darwin was inspired by adaptive radiation on the Galapagos Islands.

Nature of Science

• Classification is pattern recognition; observations can be classified in different ways.
• "Splitters" recognize more species than "lumpers" in any taxonomic group.
• Early attempts to classify organisms were based on physical characteristics.
• New tools for determining genetic descent are primarily based on common DNA sequences and are considered to be more reliable.
• Classifying organisms into taxa is not always exact; lumpers emphasize similarities, while splitters emphasize differences.

A4.2.3 - Human Activities and Species Extinction

• Anthropogenic species extinction is extinction caused by human activity.
• Most extinctions in the last few hundred years have been anthropogenic.
• There have been five previous mass extinction events before humans.
• The most recent was about 65 million years ago caused by an asteroid strike.
• Scientists propose that we are in a sixth, anthropogenic extinction event.

Case Studies of Anthropogenic Extinction

• North Island Giant Moa (Dinornis novaezealandiae):
  • Extinct by 1300 CE due to hunting by Polynesian people in New Zealand.
  • Moas were large, herbivorous, wingless birds, with females reaching about 3 m in height.
• Caribbean Monk Seal (Neomonachus tropicalis):
  • Declared extinct in 2008; possibly extinct decades earlier.
  • Killed by European colonists for oil and food; easy targets due to lack of fear of humans.
• Your Choice of Extinct Species:
  • Research a species from your area that became extinct due to anthropogenic factors.

A4.2.4 - Human Activities and Ecosystem Loss

• Ecosystem loss is often caused by habitat destruction like deforestation.
• Study only causes that are directly or indirectly anthropogenic.

Case Studies of Ecosystem Loss

• Mixed Dipterocarp Forests in Southeast Asia:
  • Dipterocarp forests once dominated Southeast Asia but are being lost at about 1% per year.
  • Deforestation through clear-cutting for agriculture and palm oil plantations.
  • Palm oil is used in many products; plantations often involve monoculture.
  • Certification systems for palm oil plantations aim to reduce forest cover removal.
• Your Choice of Ecosystem Loss:
  • Research an ecosystem from your area under extreme stress due to anthropogenic activity.
  • Monocultures of large land areas are harmful from an ecological perspective.

A4.2.5 - A Biodiversity Crisis

• Evidence for a biodiversity crisis comes from reports like those by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) and the IUCN's Red List.
• Surveys need to be repeated to show changes in species richness and evenness.
• Both expert scientists and citizen scientists contribute.
• To be verifiable, evidence should come from published, peer-reviewed sources.
• Data recorded by citizens require methodological rigor.

Reliable Sources of Information

• IPBES: Provides comprehensive scientific guidance for policymakers based on studies and local input; data is regularly updated.
• IUCN Red List: Continuously updated list of threatened species, with over 140,000 species assessed; provides details of research papers used for assessment.

Nature of Science

• Local individuals (citizen scientists) provide important information, but data must be collated by a reliable scientific organization.

A4.2.6 - Causes of the Biodiversity Crisis

• Human population growth is an overarching cause.

Specific Causes

• Hunting and over-exploitation
• Urbanization
• Deforestation and land clearance for agriculture
• Pollution
• Spread of pests, diseases, and invasive species due to global transport
• The human population is over 8 billion and increasing.
• The annual growth rate peaked in the 1960s but remains positive due to increased longevity.

Link Between Human Population and Biodiversity Crisis

• Increased population requires more resources and produces more pollution.
• Ecosystems are damaged to source food, minerals, and water.
• Each damage reduces biodiversity. Examples include:
  • Over-exploitation of resources (e.g., commercial fishing)
  • Hunting (e.g., African elephants for tusks)
  • Deforestation (e.g., for minerals or agriculture)
  • Monoculture agriculture (e.g., palm oil plantations)
  • Pollution (e.g., microplastics in oceans)
  • Increased pest species (e.g., spruce bark beetle)
  • Invasive species (e.g. Burmese python)
  • Spread of disease

A4.2.7 - Conservation of Biodiversity

• No single approach is sufficient; different species need different measures.

Conservation Efforts

• In situ conservation: Managing natural areas
• Ex situ conservation: Managing species outside their natural area

In Situ Efforts

• National Parks: Preserve geology and wildlife; restrict development.
• Nature Reserves: Protect ecosystems from urbanization.
• Rewilding: Letting nature regenerate damaged areas; removing dams and roads.
• Reclamation: Rebuilding ecosystems in degraded landscapes (e.g., after mining).

Ex Situ Efforts

• Zoos Breeding Programs: Animal husbandry to continue threatened species; artificial insemination to promote genetic diversity.
• Botanic Gardens: Living store of plant material; preserve genetic material for research and restoration.
• Seed Banks: Safely store seeds for repopulation; Svalbard International Seed Vault.
• Animal tissue banks: Germplasm (sperm, eggs, embryos) and somatic tissue stored cryogenically for reproductive and DNA research.

A4.2.8 - The EDGE of Existence Programme

• Launched by the Zoological Society of London to select evolutionarily distinct and globally endangered (EDGE) species for conservation.
• Species are prioritized based on their IUCN Red List rating and unique evolutionary history using DNA sequencing.
• High EDGE score indicates priority for protection.

Nature of Science

• Species selection for conservation is complex with ethical, environmental, political, social, cultural, and economic considerations.

Guiding Questions Revisited

Factors Causing the Sixth Mass Extinction:

• Increasing human population leading to:
  • Deforestation
  • Monoculture agriculture (e.g., palm oil plantations)
  • Habitat destruction from urban development
  • Pollution
  • Excess commercial fishing
  • Unregulated hunting and poaching

Minimizing Loss of Biodiversity:

• Actions to control or minimize loss:
  • Establishing national parks and nature reserves
  • Rewilding and reclamation projects
  • Breeding programs in zoos
  • Establishing botanical gardens and seed banks
  • Establishing animal tissue banks
  • Research by organizations like IUCN, IPBES, and the EDGE of Existence programme to inform policymakers and the public.