NH

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