Conservation Revision Notes

Climate change refers to long-term shifts in temperature and weather patterns, often caused by increased greenhouse gas emissions. These changes can alter habitats by affecting temperature, rainfall, and seasonal cycles, which in turn influence food availability and breeding conditions for organisms.

For example, polar bears rely on sea ice to hunt seals. Rising temperatures reduce sea ice extent, limiting their hunting grounds and leading to population decline.

Such environmental changes can force species to migrate, adapt, or face extinction if they cannot cope with the new conditions. Species with specialised habitat requirements or limited mobility are particularly vulnerable.

• Changes in temperature and precipitation affect habitat suitability.
• Altered food chains disrupt species survival.
• Species may be forced to migrate or face extinction if unable to adapt.

Human activities like urban development, agriculture, deforestation, and mining destroy or fragment natural habitats. This reduces the available living space and resources for organisms, isolating populations and decreasing genetic diversity.

For instance, clearing tropical rainforests for farmland removes the homes of countless species, such as orangutans, pushing them towards endangerment.

Fragmented habitats can prevent species from finding mates or food, increasing vulnerability to predators and environmental changes.

• Loss of habitat reduces population sizes.
• Fragmentation isolates populations, limiting gene flow.
• Reduced resources increase competition and stress on species.

Direct removal of organisms through hunting, poaching, or overharvesting can rapidly decrease population numbers. When the rate of removal exceeds the species' reproductive capacity, populations decline towards extinction.

An example is the overhunting of elephants for ivory, which has severely reduced their numbers in the wild.

Unsustainable fishing practices can also deplete fish stocks faster than they can reproduce, threatening marine biodiversity.

• Population decline occurs when removal exceeds reproduction.
• Illegal poaching targets valuable species, increasing extinction risk.
• Overharvesting disrupts ecosystem balance and food webs.

Pollution introduces harmful substances into air, water, and soil, degrading habitats and poisoning organisms. Chemical pollutants like pesticides, heavy metals, and plastics can accumulate in food chains, causing health problems and mortality.

For example, pesticide runoff can kill aquatic insects, reducing food for fish and birds.

Pollution can also alter reproductive success and behaviour, further threatening species survival.

• Toxic substances damage organisms and habitats.
• Bioaccumulation leads to higher toxin levels in predators.
• Pollution reduces reproductive success and survival rates.

Non-native species introduced intentionally or accidentally can outcompete, prey on, or bring diseases to native species. Without natural predators, invasive species can spread rapidly, disrupting ecosystem balance.

For example, the introduction of the brown tree snake to Guam led to the extinction of several native bird species.

Invasive plants can also alter soil chemistry and light availability, disadvantaging native flora.

• Invasive species compete for resources with natives.
• Predation by non-native species reduces native populations.
• Disease transmission can increase mortality in native species.

Monitoring involves regularly observing and recording data on endangered species populations and their habitats to detect changes in numbers, health, or environmental conditions. This helps identify threats early and assess the effectiveness of conservation measures.

Safeguarding habitats means protecting the natural environments where species live, ensuring they have the resources needed to survive, such as food, shelter, and breeding sites. This can involve creating protected areas like national parks or wildlife reserves, controlling human activities such as deforestation or pollution, and restoring damaged ecosystems.

For example, monitoring the population of the giant panda in China includes tracking individuals using camera traps and GPS collars. Safeguarding their bamboo forest habitat prevents habitat loss and fragmentation, which are major threats to their survival.

• Regular population surveys detect declines or recoveries.
• Protected areas limit habitat destruction and human disturbance.
• Habitat restoration can improve conditions for species survival.

Education raises public awareness about endangered species and the importance of biodiversity. It encourages responsible behaviour, such as reducing pollution, avoiding illegal wildlife trade, and supporting conservation projects.

Educational programmes can target schools, local communities, tourists, and policymakers. They use materials like workshops, documentaries, and campaigns to explain how human actions impact ecosystems and how individuals can help.

For instance, community education in Madagascar teaches locals about the importance of lemurs and sustainable farming practices, reducing hunting and habitat destruction.

• Increases public support for conservation efforts.
• Promotes sustainable behaviours that reduce threats to species.
• Helps secure funding and political will for conservation projects.

Captive breeding involves breeding endangered species in controlled environments such as zoos or specialised breeding centres. This helps increase population numbers when wild populations are too small or fragmented to recover naturally.

These programmes carefully manage genetic diversity to avoid inbreeding and maintain healthy populations. Offspring can sometimes be reintroduced into the wild to bolster declining populations.

An example is the captive breeding of the California condor, which was critically endangered with fewer than 30 individuals in the 1980s. Captive breeding increased their numbers, allowing reintroduction into protected habitats.

• Increases population size when wild breeding is insufficient.
• Maintains genetic diversity through careful pairing.
• Supports reintroduction to the wild to restore populations.

Seed banks store seeds from a wide variety of plant species, especially those endangered or with agricultural importance. Seeds are dried and frozen at low temperatures to preserve their viability for many years.

This method safeguards genetic diversity and provides material for future restoration or research. Seed banks act as a backup against extinction caused by habitat loss, climate change, or disease.

For example, the Millennium Seed Bank in the UK conserves seeds from thousands of plant species worldwide, enabling restoration projects if natural populations decline or disappear.

• Preserves genetic material for long-term conservation.
• Enables restoration of plant populations after environmental damage.
• Supports research on plant genetics and adaptation.