Lecture Notes: Biodiversity and Conservation Biology (Ch. 54)

Flashcards cover PVA, species–area relationships and their interpretation, climate-change niche models, evidence from biodiversity–productivity experiments, ecosystem stability (resistance and resilience), ecosystem services, and the impacts of fragmentation.

What is Population Viability Analysis (PVA)?

A model that estimates the probability that a population will avoid extinction over a specified time period, using data on age-specific survivorship and fecundity and considering threats such as habitat destruction and climate change.

How can PVA be used to assess effects of habitat loss?

By modeling scenarios (e.g., loss of a percentage of habitat) to determine whether the population would still have a high probability of persistence over a given time.

What is the Species–Area Relationship?

A relationship between habitat area and species richness described by S = cA^z; on a log-log plot the relationship is linear.

What does the exponent z represent in the Species–Area Relationship?

The slope of the line on a log–log plot, indicating how rapidly species richness changes with area.

What does the constant c in the Species–Area Equation signify?

A scaling constant; higher in species-rich regions (e.g., coral reefs) and lower in species-poor regions (e.g., Arctic tundra).

What is the general form of the Species–Area equation and its interpretation?

S = cA^z; S is species richness, A is habitat area; this equation allows predicting species richness for areas of different sizes.

What are niche-based models in climate change biology?

Models that project future species distributions by relating current distributions to abiotic variables (temperature, precipitation) and then applying changes under climate scenarios.

What have niche-based models predicted about lizard extinctions with climate change?

Projections suggest significant extinction risks; some populations may already have gone extinct and future scenarios could lead to substantial losses; projections have been validated with local data.

What is the key takeaway from Tilman et al.'s experiment on biodiversity and productivity?

Productivity (NPP) increases with both species richness and functional diversity; more diverse communities often have higher NPP, though the relationship can vary with time and context.

Name one mechanism by which biodiversity can increase productivity: Resource-use efficiency

Different species use different resources or niches, leading to more complete resource use and higher overall productivity.

Name another mechanism: Facilitation

Some species improve conditions for others (e.g., nutrient provision) and raise community productivity.

Name the third mechanism: Sampling effect

With more species, the probability of including a highly productive species increases, boosting observed productivity.

What is the difference between resistance and resilience in ecosystem stability?

Resistance is the degree to which a community remains unchanged during a disturbance; resilience is the rate or ability to recover to its pre-disturbance state after the disturbance.

What are ecosystem services?

The economic and social benefits humans obtain from biodiversity and ecosystems, including provisioning, regulating, supporting, and cultural services; biodiversity supports health, prosperity, and well-being.

Why is habitat fragmentation detrimental to biodiversity beyond area loss?

It reduces habitat quality by isolating populations, limiting gene flow, and reducing genetic diversity, and increases extinction risk.