Floodplain Ecology & Portfolio Effect Flashcards

Q: What is a floodplain?

A: An area periodically flooded by lateral flow during high discharge events.

Q: Why are floodplains important ecosystems?

A: They support high biodiversity and high food availability.

Q: Why do floodplains have high productivity?

A: They have warmer water, longer water residence time, shallow depths, and lots of nutrients/light.

Q: What are autotrophic pathways?

A: Food production through photosynthesis (plants/algae).

Q: What are heterotrophic pathways?

A: Food webs based on consuming organic matter/detritus.

Q: Why are floodplains important for fish?

A: They provide spawning, rearing, feeding, and growth habitat.

Q: What fish species were highlighted as floodplain-associated fishes?

A: Splittail, Chinook salmon, Delta smelt, Sacramento perch, white sturgeon, and blackfish.

Q: What is the portfolio effect?

A: Diversity within a species buffers populations against environmental variability.

Q: What kinds of diversity contribute to the portfolio effect?

A: Phenotypic diversity and life history diversity.

Q: Why is the portfolio effect called a “portfolio”?

A: Like financial investments, diversity spreads risk so one bad event doesn’t wipe everything out.

Q: How does life history diversity increase resilience?

A: Different strategies respond differently to disturbances, so some individuals survive changing conditions.

Q: What is life history diversity?

A: Variation in traits like migration timing, spawning timing, growth, or habitat use within a species.

Q: Why is life history diversity important for salmon?

A: It stabilizes populations and helps them survive environmental change.

vQ: What happens when populations become homogenized?

A: They lose adaptability and become more vulnerable to change/extinction.

Q: How do dams affect fish populations?

A: They block habitat, reduce diversity, and fragment populations.

Q: How do levees affect floodplains?

A: They disconnect rivers from floodplains and eliminate important habitat.

Q: What is lateral connectivity?

A: The connection between rivers and floodplains during flooding.

Q: Why is lateral connectivity important?

A: It allows movement of nutrients, carbon, organisms, and energy between river and floodplain systems.

Q: What does channelization do to rivers?

A: Simplifies channels and reduces habitat diversity.

Q: What do hatcheries contribute to homogenization?

A: Reduced genetic and life history diversity.

Q: What is the Flood Pulse Concept?

A: Periodic flooding connects rivers and floodplains, driving productivity and biodiversity.

Q: What happens during a flood pulse?

A: Nutrients, carbon, and organisms move between river and floodplain habitats.

Q: How does flooding affect productivity?

A: It increases primary and secondary production.

Q: What are resource subsidies?

A: Nutrients/food transferred from floodplains back into the main river.

Q: Why do fish grow faster on floodplains than rivers?

A: Floodplains have warmer water and more food availability.

Q: Why is faster fish growth important?

A: Larger fish survive better and are more resilient.

Q: What percentage of native California fishes are extinct or declining?

A: About 83%.

Q: What percentage of salmonids may be extirpated by 2100?

A: About 74%.

Q: What does “extirpated” mean?

A: Locally extinct from a region.

Q: What is reconciliation ecology?

A: Modifying human-dominated landscapes to support biodiversity.

Q: How can rice fields act like floodplains?

A: Flooded rice fields can mimic floodplain habitat for salmon and other species.

Q: How do restored floodplains strengthen the portfolio effect?

A: They support more life history diversity and habitat diversity.

Q: What is the connection between floodplains and the portfolio effect?

A: Floodplains create diverse habitats that support many life history strategies, increasing resilience.

Q: What is the major ecological problem in California rivers today?

A: Habitat loss and homogenization caused by dams, levees, hatcheries, and agriculture.

Q: How do floodplains support biodiversity?

A: They increase habitat complexity, food availability, and spawning/rearing habitat.

Q: What happens when floodplains are disconnected from rivers?

A: Reduced biodiversity, lower resilience, and loss of life history diversity.

Q: Why are salmon considered vulnerable when floodplain habitat is lost?

A: Loss of habitat reduces diversity and weakens the portfolio effect.