Conservation Biology and Global Change

• Scientists have identified and described 1.8 million species, but they estimate there are actually between 10 to 100 million species on Earth.

Genetic Diversity

• Genetic diversity includes the differences in genes within a single population and the differences between separate populations.

Species Diversity

• Endangered species: Species that are at risk of disappearing completely from all or most of their habitat.

• Threatened species: Species that are likely to become endangered in the near future.

• Worldwide, 12.8% of bird species and 25% of mammal species are at risk of extinction.

Ecosystem Diversity

• Human activities are decreasing the variety of ecosystems. For example, over half of the wetlands in the US have already been drained.

Benefits of Diversity

• The genetic characteristics of wild species related to crops can be valuable for agriculture.

• 25% of prescription drugs in the US are made using substances originally found in plants.

Ecosystem Services

• Ecosystems support human life by:

  • Purifying air and water

  • Breaking down waste

  • Recycling nutrients

  • Moderating weather

Threats to Biodiversity

• Habitat Loss: The biggest threat. It breaks up habitats and destroys them.

• Introduced Species: Species that are moved to new areas and spread quickly because they don't have natural enemies. They can disrupt the balance of their new communities.

• Overharvesting: Taking more resources than a population can replace. This is especially harmful for large animals that reproduce slowly.

• Global Change: Changes in climate, air quality, and ecosystems worldwide.

Small-Population Approach

• Studies the processes that can cause small populations to die out.

Extinction Vortex

• Small populations are more likely to have inbreeding and genetic drift, which makes them decline even more.

• Losing genetic variation is a major problem because it prevents the population from adapting to changes in their environment.

Minimum Viable Population (MVP)

• MVP is the smallest population size that can survive long-term.

Effective Population Size

• Calculated using the formula: Ne = \frac{4NfNm}{Nf + Nm}, where Nf is the number of breeding females and N*m is the number of breeding males.

Declining-Population Approach

• Focuses on populations that are decreasing, no matter how big they are.

• Involves:

  • Confirming that the population is actually declining

  • Studying the species' natural history

  • Coming up with and testing ideas about what's causing the decline

  • Using the results to help the population recover

Landscape and Regional Conservation

• Aims to protect the biodiversity of entire communities, ecosystems, and landscapes.

• Ecosystem management is a part of landscape ecology.

Fragmentation and Edges

• The edges between different ecosystems have unique conditions.

• Fragmented habitats can only support fewer species.

Corridors

• Movement corridors connect separated areas, helping species spread out.

Protected Areas

• Setting up protected areas helps to reduce the loss of biodiversity.

Biodiversity Hot Spots

• Small areas that have a high number of species that are only found there and are endangered or threatened.

Zoned Reserves

• Areas that include undisturbed zones surrounded by buffer zones where some human activity is allowed.

Urban Ecology

• Focuses on rivers and streams in cities and restoring their ecosystems.

Human-Caused Changes

• Nutrient enrichment

• Accumulation of toxins

• Climate change

• Ozone depletion

Nutrient Enrichment

• Human activities move nutrients around.

• Critical load: The amount of a nutrient that an ecosystem can handle without being damaged.

• Too many nutrients can lead to runoff and dead zones in the water.

Toxins

• Toxins can become more concentrated in animals higher up the food chain through