Conservation Biology and Climate Change: Study Guide

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Chapter 56: Conservation Biology and Climate Change

Major Threats to Biodiversity

Conservation biology identifies and addresses the main threats to Earth's biodiversity. Understanding these threats is essential for developing strategies to preserve species and ecosystems.

Habitat Destruction: The conversion of natural habitats into urban, agricultural, or industrial areas leads to loss of species and ecosystem functions.
Introduced Species: Non-native species can outcompete, prey upon, or bring diseases to native species, often causing declines or extinctions.
Overexploitation: Unsustainable harvesting of resources (e.g., overfishing, hunting) reduces populations below viable levels.
Climate Change: Alterations in temperature, precipitation, and weather patterns affect species distributions, phenology, and ecosystem processes.

Defining Endangered and Extinct Species

Conservation biology uses specific criteria to classify species at risk.

Endangered Species: Species in danger of extinction throughout all or a significant portion of their range.
Extinct Species: Species that no longer exist anywhere on Earth.
Example: The Passenger Pigeon (Ectopistes migratorius) is an example of a species that became extinct due to overexploitation and habitat loss.

Population Size and Risk of Extinction

Small populations are more vulnerable to extinction due to genetic, demographic, and environmental factors.

Genetic Drift: Random changes in allele frequencies can reduce genetic diversity in small populations.
Inbreeding: Increased likelihood of mating between relatives can lead to inbreeding depression and reduced fitness.
Demographic Stochasticity: Random fluctuations in population size can lead to extinction in small populations.
Example: The Florida panther (Puma concolor coryi) suffers from inbreeding due to a small population size.

Biodiversity Hotspots and SLOSS Debate

Biodiversity hotspots are regions with high species richness and endemism that are under threat. The SLOSS (Single Large Or Several Small) debate concerns the best reserve design for conservation.

Biodiversity Hotspot: An area with a high number of endemic species and significant habitat loss.
SLOSS Debate: Conservationists debate whether a single large reserve or several small reserves are more effective for preserving biodiversity.
Key Considerations: Edge effects, species-area relationships, and habitat connectivity.

Human Activities and Ecosystem Services

Human activities can disrupt ecosystem services, which are the benefits that humans derive from ecosystems.

Ecosystem Services: Include provisioning (food, water), regulating (climate, disease), supporting (nutrient cycling), and cultural (recreational, spiritual) services.
Disruption Examples: Deforestation reduces carbon sequestration; pollution affects water purification.

Key Terms in Conservation Biology

Understanding the following terms is essential for discussing conservation and climate change:

Biodiversity: The variety of life at genetic, species, and ecosystem levels.
Genetic Diversity: Variation in genes within a population.
Species Diversity: The number and relative abundance of species in a community.
Ecosystem Diversity: The variety of ecosystems in a region.
Habitat Fragmentation: The breaking up of continuous habitat into smaller, isolated patches.
Edge Habitat: The boundary between different habitat types, often with unique conditions.
Minimum Viable Population (MVP): The smallest population size needed for a species to survive long-term.
Effective Population Size (Ne): The number of individuals contributing genes to the next generation.
Biomagnification: The increase in concentration of toxins as they move up the food chain.
Sustainable Development: Economic development that meets present needs without compromising future generations.

Table: Comparison of Major Threats to Biodiversity

Threat	Description	Example
Habitat Destruction	Conversion of natural areas to urban or agricultural use	Deforestation in the Amazon
Introduced Species	Non-native species disrupt native ecosystems	Zebra mussels in North America
Overexploitation	Unsustainable harvesting of species	Overfishing of Atlantic cod
Climate Change	Altered temperature and precipitation patterns	Coral bleaching due to warming oceans

Key Equations

Species-Area Relationship:

Where S = number of species, A = area, c and z are constants.

Effective Population Size:

Where Ne = effective population size, Nm = number of breeding males, Nf = number of breeding females.

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