Chapter 23- Conservation Biology

What is conservation biology?

An integrative discipline that applies ecological principles to the protection of biodiversity.

Q: What three types of biodiversity does conservation biology aim to protect?

A: Genetic diversity, species richness, and landscape (ecosystem) diversity.

Q: Why is conservation biology considered a value-based discipline?

A: Because it involves ethical judgments about the worth of biodiversity, in addition to using scientific data to guide action.

Q: What is an objective scientific question in conservation biology?

A: “How many minke whales can be sustainably harvested in the Southern Ocean?”

Q: What is a value-based question in conservation biology?

A: “Should we be harvesting whales at all?”

Q: How can species loss affect ecosystem function?

A: The removal of key species can lead to disruptions in food webs, loss of pollination, or seed dispersal, causing secondary extinctions and functional collapse.

Q: What is the "shifting baselines syndrome"?

A: It’s when each generation accepts a degraded environmental state as “normal” because they lack knowledge of past ecological conditions.

Q: Which figure illustrates the concept of overharvesting reducing predator size and abundance in marine ecosystems?

A: Figure 23.13 – It shows the long-term decline in sizes of top marine predators due to overfishing.

Q: Why is long-term ecological data important in conservation biology?

A: It helps accurately assess population declines and ecosystem changes, preventing misinterpretation of what constitutes a healthy or “normal” system.

Q: What does it mean for conservation biology to be "mission-driven"?

A: It is guided by the goal of preventing biodiversity loss and is oriented toward solving real-world ecological crises.

What is the current estimated extinction rate for birds and mammals compared to the background rate?

It is 100 to 1,000 times higher than the background extinction rate, which is 1 species per 200 years.

Who was Alwyn Gentry and what did his work reveal?

A tropical botanist who documented plant species in Central and South America and witnessed rapid species extinctions due to deforestation.

What does Interactive Figure 23.4 show?

Loss of forest cover in Western Ecuador from 1958 to 1988, resulting in the loss of over 1,000 endemic species.

How is the species–area relationship used in estimating extinction rates?

It estimates the number of species likely to go extinct due to habitat loss by examining how species richness correlates with habitat area.

What is the 'extinction vortex'?

A process where small populations become increasingly vulnerable to extinction due to genetic, demographic, and environmental stochasticity.

What did Ceballos and Ehrlich (2002) find in their study on range contraction?

173 mammal species had lost 68% of their range area in 100–200 years, with the greatest loss in Asia (83%).

What did Figure 23.6 reveal about bird pollinators and plant reproduction?

Loss of bird pollinators in New Zealand reduced the reproductive success of the shrub Rhabdothamnus solandri.

What is taxonomic homogenization?

A process where the spread of generalist and non-native species reduces the uniqueness of local biotas, leading to similar species compositions globally.

What trend did Figure 23.9 show regarding U.S. freshwater fish species?

Pairs of U.S. states now share 15 more fish species than at European colonization, indicating increased taxonomic homogenization.

What was the outcome of Cowie's survey in American Samoa?

Native snail species were declining, while non-natives (40% of individuals) were increasing, often facilitated by introduced predators.

What are the six primary threats to biodiversity identified in Concept 23.3?

Habitat loss, invasive species, overexploitation, pollution, disease, and climate change.

According to Figure 23.10, how do threats to terrestrial mammals differ from marine mammals?

Terrestrial mammals are more affected by habitat loss, while marine mammals are more threatened by pollution and accidental mortality.

What percent of Earth's land surface has been modified by humans?

Approximately 60%.

Describe the three categories of habitat alteration.

Habitat loss (conversion to another use), habitat fragmentation (breaking up continuous habitat), and habitat degradation (reduced quality for some species).

What does the 'empty forest' concept describe?

Forests that appear intact but have lost many large vertebrates due to overhunting.

What was the result of zebra mussel invasion on native freshwater mussels in North America?

Native mussel populations declined by 60–90%, with some experiencing regional extinctions.

What was the result of zebra mussel invasion on native freshwater mussels in North America?

Native mussel populations declined by 60–90%, with some experiencing regional extinctions.

What did the kudzu study by Hickman et al. (2010) demonstrate?

Kudzu invasion increased nitrogen mineralization rates and nitric oxide emissions, affecting soil chemistry and air pollution.

What is 'bycatch' in marine fisheries?

Unintended marine species caught during fishing operations, often discarded, leading to ecological damage.

What happened to cod populations as shown in Figure 23.12?

They collapsed due to overfishing and have not recovered.

What are endocrine-disrupting contaminants (EDCs)?

Persistent pollutants that interfere with hormonal systems, affecting reproduction and development, especially in marine mammals.

Which invasive predator in Lake Victoria caused the extinction of many endemic cichlid fish species?

The Nile perch.

What did Figure 23.11 reveal about nitrogen cycling in kudzu-invaded plots?

Nitrogen mineralization rates were more than seven times higher in kudzu plots, indicating altered nutrient cycling.

What does Figure 23.14 reveal about killer whales in British Columbia?

They have extremely high levels of PCBs and PBDEs, indicating heavy pollution exposure.

What caused the decline of the thylacine and now threatens Tasmanian devils?

Disease—an undetermined disease for the thylacine and facial tumor disease for the Tasmanian devil.

What is the significance of Interactive Figure 23.15?

It shows how different biomes are affected by different primary threats, such as habitat loss in the tropics and climate change in polar zones.

What is the focus of Concept 23.4 in conservation biology?

The use of multiple tools and approaches at different scales to manage declining populations.

What was the goal of the genetic rescue of the Florida panther?

To increase genetic diversity and reduce harmful traits by introducing individuals from a related Texas population.

What were the outcomes of the Florida panther genetic rescue as shown in Figure 23.16?

Panther numbers tripled, genetic diversity doubled, and abnormalities declined.

What risk was associated with the ibex genetic rescue attempt in Czechoslovakia?

Introduced ibex mated in the fall, resulting in offspring born in winter with low survival.

What is forensic conservation biology?

The use of molecular genetic tools to trace illegal wildlife products and support law enforcement.

How was DNA used to trace the source of confiscated ivory in Singapore?

Researchers created DNA profiles of tusks and matched them to reference samples from known regions, tracing the source to Zambia.

What does PVA stand for and what is its purpose?

Population Viability Analysis; used to assess extinction risks and guide conservation management decisions.

What did PVA simulations determine for Florida’s rare plant Chamaecrista keyensis?

The best fire regimes (timing and frequency of burns) to promote population growth.

What is ex situ conservation?

Conserving species outside their natural habitat, such as in zoos or botanical gardens.

How was ex situ conservation applied to save the California condor, as shown in Figure 23.17?

Through captive breeding, egg swapping, puppet feeding, and monitored reintroduction into the wild.

What challenges still threaten the California condor’s survival?

Lead poisoning, plastic ingestion, West Nile virus, and genetic drift.

Why might ex situ conservation be controversial?

It is expensive, can cause genetic and behavioral issues, and may not always lead to self-sustaining populations.

What is the main goal of Concept 23.5?

To prioritize species conservation efforts to maximize biodiversity protection with limited resources.

What are the three dimensions of rarity shown in Figure 23.18?

Geographic range, population size, and habitat specificity.

How can a species be rare but not endangered?

Some species are naturally rare but not declining or under threat, so they may not require urgent conservation action.

What is the IUCN Red List?

A global assessment system that categorizes species based on their risk of extinction using standardized criteria.

What is the purpose of the NatureServe system?

To assess conservation status in the U.S., using similar criteria to the IUCN Red List.

What does Figure 23.19 show?

Hotspots of imperiled species in the U.S., including California, Hawaii, the Florida Panhandle, and the southern Appalachians.

What is a surrogate species?

A species whose conservation is expected to benefit other species with similar habitat requirements.

What is a flagship species?

A charismatic species, like the mountain gorilla, used to gain public support for conservation efforts.

What is an umbrella species?

A species whose large habitat requirements help protect many other species when its habitat is preserved.

What is a focal species approach?

A method that selects multiple species with varying needs and threats to ensure broader protection of biodiversity.

What does Figure 23.20 depict?

The mountain gorilla as a flagship species, critically endangered due to habitat loss, hunting, and disease transmission.

Why can relying solely on surrogate species be problematic?

No single species’ habitat needs or distribution can cover all biodiversity targets, potentially missing key conservation goals.