Conservation Biology and Global Change

Definition: Conservation biology integrates various scientific disciplines including:
- Ecology
- Physiology
- Molecular biology
- Genetics
- Evolutionary biology
Purpose: To conserve biological diversity at all levels which include:
- Genetic diversity
- Species diversity
- Community and ecosystem diversity

Genetic Diversity:
- Definition: Genetic diversity comprises genetic variation within a population and between populations.
- Implication: The extinction of one population reduces the genetic variation needed for adaptation to local conditions.
Species Diversity:
- Definition: Species diversity is defined as the number of species in an ecosystem or across the biosphere.
- Note: Many species remain undiscovered, thus underscoring the importance of ongoing research.
Ecosystem Diversity:
- Definition: Ecosystem diversity encompasses the variety of ecosystems present in the biosphere.
- Unique Features: Each ecosystem has distinctive physical and biological characteristics.

Example 1: Bald eagles prey on fish in rivers, but require tall trees for nesting.
- Required Diversities: This interdependence represents both species and ecosystem diversity.
Example 2: bm
Example 3: Fish that swim upstream, such as Pacific salmon, require specific adaptations related to genetic diversity and species diversity.

Impact of Local Extinction:
- The local extinction of one species can negatively affect other species within an ecosystem.
- Example: In Pacific Islands like Samoa, flying foxes (bats) serve as essential pollinators and seed dispersers for 80% of tree species. Their extinction would severely harm native plant communities.
Ecosystem Diversity Reduction:
- Human activities are diminishing ecosystem diversity.
- Over 50% of wetlands in the contiguous U.S. have been drained and replaced by other ecosystems.
- Native riparian communities suffer from overgrazing, flood controls, water diversions, and invasive species.

Reasons for Conservation:
- Biophilia: Humans have an innate connection to nature (E.O. Wilson).
- Nature, despite being considered "useless," may still hold value.
- Concern for future generations mandates conservation efforts.
- Direct benefits include harvests of medicines, food, fibers, and genetic resources (e.g., enhancing crops for virus resistance).
- The quality of the environment positively affects human health and well-being.
Ecosystem Services:
- All the processes through which natural ecosystems sustain human life are linked to biodiversity.
- Examples of Ecosystem Services:
- Water purification in wetlands
- Pest control by species such as dragonflies and decomposition of waste
- Protection against floods and extreme weather
- Pollination of plants
- Soil creation
- Recreational opportunities
- Medicinal resources: 25% of prescription drugs derive from plants.
- Total Value of Ecosystem Services: Estimated at $33 trillion, which is approximately double the gross national product of all countries globally.

Major Threats:
- Habitat loss
- Introduced species
- Overharvesting
- Climate change
- Pollution
- Human population expansion
- Urbanization
- Agriculture

Description: Recognized as the number one threat to biodiversity, driven by agriculture, urban development, forestry, mining, and pollution.
- 50% of Earth’s land surface has been altered by human activity.
- Humans utilize 50% of accessible freshwater.
- 73% of threatened or endangered species face habitat loss.
- Examples of Habitat Loss:
- Tropical dry forest: 98% gone
- Wisconsin prairie: 99.9% gone (1989 - 2014)
- Coral reefs: 70% damaged

Description: Refers to human alterations of habitat that lead to species loss, as small populations are more susceptible to extinction.

Definition: Species that move from their native location to new geographic regions and cause harm.
- Characteristics: In new environments, they often lack predators, parasites, or pathogens, allowing for rapid population growth.
- Examples of Introduced Species:
- Bull Thistle
- Japanese Stiltgrass
- Non-native species account for 40% of extinctions and cost the U.S. approximately $138 billion annually.
- Examples: Kudzu, European starling, Burmese python.
- Invasiveness:
- Invasive species are significantly harmful when transported to new regions. Examples include sea lamprey and zebra mussels in the Great Lakes, which disrupted local ecosystems by overpopulating and decimating native fish populations.

Description: Involves harvesting wild organisms at rates that exceed their capacity to rebound.
Vulnerable Species: Species with restricted habitats or low reproductive rates (e.g., whales, rhinoceroses).
Examples of Overharvesting:
- Illegally harvested ivory from elephants.
- North Atlantic Bluefin tuna: 65% of world fisheries are unsustainably fished, leading to a drastic reduction of fish populations by 50-80%.

Impacts: Primarily results in increased temperatures and severe weather patterns while redistributing water resources.

Temperature Anomalies: Changes compared to average global temperatures between 1951-1980.
Precipitation Changes: Projected variations in liquid water per year by the end of the 21st century as demonstrated by climatological models.
Ragweed Pollen as an Indicator: The length of ragweed pollen season has increased in the U.S. and Canada due to climate warming, significantly increasing allergen exposure among populations.

Population Conservation Focus: Main priorities include population size, genetic diversity, and critical habitat preservation.
- Approaches:
- Small-population approach addresses extinction risk in vulnerable populations.
- Declining population approach focuses on identifying key environmental factors of population decline.
Case Studies:
- Greater Prairie Chicken: Efforts to increase genetic diversity led to population recovery through translocation of genetic material.
- Red-Cockaded Woodpecker: Conservation actions involved habitat restoration through controlled burns and cavity excavation, responding to habitat destruction by logging.

Successful conservation requires balancing human economic demands with species needs. Not every species can be saved; ecological roles and importance play critical roles in prioritizing conservation efforts.
Emphasis should be on maintaining biodiversity and recognizing keystone species that sustain ecosystem stability and health.