Chapter 22 Summary

CONCEPT 22.1 Conservation biology is an integrative discipline that applies the principles of ecology to the conservation of biodiversity.

• Conservation biology is the scientific study of phenomena that affect the maintenance, loss, and restoration of biodiversity.
• Biodiversity is important to human society because of our reliance on resources and ecosystem services that derive from intact natural communities and ecosystems.
• With the growing awareness of accelerating losses of global biodiversity, ecologists saw a need for a separate discipline that would apply the principles of ecology to the preservation of species and ecosystems.
• Conservation biology is a scientific discipline instilled with the value of biodiversity.

CONCEPT 22.2 Biodiversity is declining globally, and Earth’s biota is becoming increasingly homogenized.

• Earth is losing species at an accelerating rate, largely due to humanity’s growing footprint on the planet.
• Extinction is the end point of incremental biological decline as species lose individuals and populations and become increasingly vulnerable to the problems of small populations.
• Earth’s biota is becoming increasingly homogenized due to a rise in generalist species and a decline in specialist species, losses of genetic diversity within some taxa, and probable losses of ecosystem function.

CONCEPT 22.3 The primary threats to biodiversity are habitat loss and degradation, invasive species, and overexploitation.

• Habitat degradation, fragmentation, and loss are the most important threats to biodiversity.
• Invasive species degrade local habitats by preying on or competing with native species and altering ecosystem properties.
• Overexploitation of selected species has large effects on communities and ecosystems.
• Other factors that erode the viability of populations and contribute to losses of biodiversity include air and water pollution, global climate change, and diseases.

CONCEPT 22.4 Conservation biologists use many tools and work at multiple scales to manage declining populations.

• Genetics has been used as a tool to understand and manage genetic diversity within rare species, to identify appropriate management units, and in forensic analyses of illegally harvested organisms.
• Population viability analysis (PVA) is an approach that uses demographic models to assess extinction risks and evaluate proposed management actions.
• Ex situ conservation, which involves taking organisms from the wild into human care, is a last-resort measure to rescue species on the brink of extinction.
• Laws, policies, and international treaties are vital supplements to biological methods of protecting species and habitat.

CONCEPT 22.5 Prioritizing species helps maximize the biodiversity that can be protected with limited resources.

• Conservation biologists identify those species of the highest priority for protection—the rarest and the most rapidly declining species—by assessing numbers of individuals and populations, rates of decline, and the degree of threat faced.
• Identification of surrogate species can make conservation planning more efficient by providing protection for other species with similar habitat requirements.