Conservation Biology Basics

Conservation Biology

• Conservation biology is an applied science, aiming to preserve species, habitats, and ecosystem services. It combines several fields, including ecology, physiology, molecular biology, genetics, economics, and evolutionary biology.
• It's distinct from environmentalism, which is a political viewpoint.

Learning Goals

• Students should differentiate between ecology, conservation biology, and environmentalism.
• Students need to understand the different reasons for conservation.
• Understanding the key factors influencing conservation is crucial, notably the trade-offs between economic interests and human impacts.

The Biodiversity Crisis

• Scientists have described nearly 2 million species.
• Biologists estimate 8.7 million species exist on Earth, potentially many more.
• Human activities significantly alter the Earth's natural systems, including habitats, carbon cycles, and nitrogen cycles.
• These alterations are contributing to the potential sixth mass extinction event, often referred to as the biodiversity crisis.
• Human activities are rapidly pushing many species to extinction.

Four Levels of Biodiversity

• Genetic diversity
• Species diversity
• Ecosystem diversity
• High level Taxonomic Diversity

Genetic Diversity

• Genetic diversity encompasses genetic variation within and between populations.
• Both natural populations and human-cultivated species lose genetic diversity.
• Zoo animals are especially vulnerable to this loss, and adapt to conditions in captivity which may not suit their survival in the wild.
• Agricultural crops that have less genetic diversity are at risk of disease.

Species Diversity

• Species diversity describes the variety of species in an ecosystem or across the biosphere.
• According to the U.S. Endangered Species Act, an endangered species is likely to go extinct throughout its range, while a threatened species is likely to become endangered in the foreseeable future.

Conservation Biologists' Concerns

• Conservation biologists are concerned about species loss due to the alarming statistics regarding extinction and biodiversity loss.
• Globally, 12% of birds, 21% of mammals, and 32% of amphibians are threatened with extinction.
• Extinctions can be local or global.

Endangered Species

• Examples of endangered species (images included in the slides):
  • Philippine eagle
  • Yangtze River dolphin (possibly extinct)
  • Rusty patched bumblebee
  • Javan rhinoceros
  • Prairie fringed orchid

Impact of Local Extinction

• The local extinction of one species can negatively impact other species in an ecosystem.
• For example, flying foxes (bats) are important pollinators and seed dispersers in Pacific Islands.

Ecosystem Diversity

• Human activities are decreasing ecosystem diversity, the variety of ecosystems on Earth.
• More than 50% of wetlands in the contiguous United States have been drained and converted to other ecosystems.

Higher Level Taxonomic Diversity

• Higher level taxonomic diversity loss is the disappearance of whole families, orders, or classes of organisms.
• The Tuatara is an example of a reptile endemic to islands off the coast of New Zealand, representing the last remaining members of the class Rhyncocephala.

Justifications for Biodiversity Conservation

• Self-interest: Intact ecosystems provide food, recreation, materials, scientific value, water, climate regulation, and other ecosystem services.
• Theistic/philosophical/aesthetic/ethical: Many people value the intrinsic worth of nature, motivating conservation efforts.

Scientific Value of Biodiversity

• Species related to agricultural crops often have important genetic qualities, enabling resistance to diseases or better yields.
• Many prescription drugs contain substances derived from plants (Examples: rosy periwinkle and Pacific yew).

Resistance to Disease, Higher Yield Varieties, Food (new plants), Medicines and Technologies

Threats to Biodiversity

• Habitat destruction and fragmentation
• Changes in ecosystem processes locally
• Introduced species
• Overharvesting
• Global change

Habitat Destruction and Fragmentation

• Most of the grasslands and forests in the Northern Hemisphere were destroyed by the 19th century.
• Grasslands in the Southern Hemisphere and tropical forests are currently disappearing at a rate of approximately 2% annually.

Fragmented Habitats

• Habitat fragmentation creates biological islands, reducing the population size of species.
• Small populations are more vulnerable to extinction from random events like natural disasters, weather, etc.
• Edge effects (the boundary between habitats) can affect species' survival.
• Some large mammals (e.g., coyotes, raccoons), however, adapt to edge habitats.

Habitat Change

• Human activities alter natural processes within remaining habitats, impacting species' survival.

Introduction of Exotics

• Human activities create worldwide faunal interchange.
• Most introduced species fail to establish themselves, but some spread rapidly, affecting native ecosystems.
• The brown tree snake is a good example of an introduced species that devastated bird populations in Guam.

Overexploitation

• Stellar's Sea Cow (a large sirenian mammal) was hunted to extinction within 30 years of its discovery due to its delicious meat, and ease of slaughter.

What Makes A Species Vulnerable to Extinction?

• Endemism
• Rarity
• Small Population Size
• Ecological Specialization
• Beauty/Usefulness to humans or is a competitor to humans

Endemism

• Species restricted to specific, smaller areas are more susceptible to extinction.

Rarity

• Naturally rare species have low population densities but might be widespread.
• Species can be difficult to track making conservation efforts problematic.

Small Population Size

• Smaller populations have lower genetic variation.
• Inbreeding depression and demographic stochasticity (random events) increase extinction risk.

Ecological Specialization

• Specialized species are more vulnerable when environmental conditions or interspecies relationships change.

Useful to Humans or a Competitor of Humans

• Species that interact with humans (e.g., competitors, hunted for food, pet trade) face an increased risk of extinction

Clicker Question:

• The Stellar's Sea Cow is extinct

Weighing Conflicting Demands

• Conserving species often requires balancing habitat needs and human demands.
• For example, habitat preservation for endangered species may conflict with various industries.
• Balancing conservation costs and economic benefits

Economic Considerations in Conservation

• Resource extraction industries may provide employment and income in the short term, but their long-term economic effect might not be consistent with conservation efforts.
• Natural areas, or specific habitats can sometimes prove greater income generators, or investment attraction, compared to some resource extraction industries.

Commercial Whaling

• The International Whaling Commission (IWC) was created to conserve whale stocks.
• The IWC voted to implement a whaling moratorium, but several countries continued their whaling practices.
• Whale watching has become a significantly larger industry than whaling.

Establishing Protected Areas

• Conservation biologists use ecological understanding to establish protected areas.
• These areas attempt to help slow the loss of biodiversity due to various factors, like habitat fragmentation or over-exploitation.

Protected Areas

• Large areas are sometimes better for larger animals that need extensive ranges for their populations to remain healthy.

Marine Reserves

• Marine reserves closed to fishing demonstrably improve fishing success in nearby areas, as they provide spawning grounds in nearby waters that did not have the protection. These spawning grounds increase the number of fishes.

Conflicting Demands

• Stingless bees, important pollinators, are threatened by the introduction of honeybees, whereas preserving their habitats will protect other species. Important resources must be set aside to protect these important insects.

Monarch Butterfly Biosphere Reserve

• The world heritage site encompasses most of the monarch overwintering sites.
• The conservation of the site, and adjacent habitats, is being threatened by the habitat loss, so it's important to preserve this habitat.

Protected Areas: Balancing Human Needs

Test your knowledge on the fundamentals of conservation biology, including biodiversity levels, species extinction, and the impact of human activities on ecosystems. This quiz covers key concepts and consequences related to genetic variation and ecosystem services.