L15 - Soil biodiversity and ecosystem functioning Flashcards
How much have humans increased species extinction rates?
By as much as 1,000 times over background rates typical in Earth’s history
What percentage of mammal, bird, and amphibian species are threatened with extinction?
10–30% of these species are currently threatened
How does species loss impact ecosystems?
It reduces the efficiency of resource capture, biomass production, and nutrient recycling
How many soil families are globally recognized, and how many are rare?
909 soil families, with 332 classified as rare.
What percentage of soil families are endangered or extinct?
88 are endangered, and 17 are extinct
What impact does intensive agriculture have on soil biodiversity?
It reduces diversity within soil functional groups and trophic levels and can eliminate functional groups such as earthworms.
What is the redundancy hypothesis in biodiversity-function theory?
Functional redundancy exists within communities, so ecosystem function is maintained if biomass of main trophic groups is preserved.
What is the rivet hypothesis?
Every species plays a unique role, with a linear relationship between biodiversity and ecosystem function.
What is the insurance hypothesis in ecosystem stability?
Diverse communities are more resilient, buffering ecosystems against species loss due to environmental change.
What did experiments at Cedar Creek, USA, demonstrate about biodiversity and stability?
Higher species diversity was positively correlated with stability in plant productivity over 10 years
What did Heiki Setala’s boreal forest experiments reveal?
Soil organism diversity positively affects decomposition rates, supporting the redundancy hypothesis.
What is the relationship between soil biodiversity and ecosystem multifunctionality?
Strong positive correlation; higher soil biodiversity supports multiple ecosystem functions simultaneously.
How does microbial diversity affect ecosystem stability during drought?
Greater bacterial and fungal diversity stabilized plant productivity, decomposition, and carbon assimilation under drought conditions.
What did the global study of drylands reveal about microbial diversity?
Bacterial diversity positively correlated with ecosystem multifunctionality across 78 drylands and 179 Scottish locations.
What abiotic and biogeographic factors predict ecosystem multifunctionality?
Soil pH, climate, and distance from the equator are as important as microbial diversity in predicting ecosystem function.
