Biodiversity, Ecosystem Functions and Services Flashcards
What functions do ecosystems provide?
Properties of the ecosystem - carbon and organic matter.
Processes of the ecosystem - fluxes of energy, matter and nutrients, NPP and decomposition.
Services of the ecosystem - directly or indirectly benefit humans
How are experiments set up to study Biodiversity - Ecosystem Function relationships? (BEF)
Grassland plots and plant productivity
Easy to set up, manipulate and estimate NPP
Ecotrons and mesocosms - control the environment
How can a positive/saturating BEF relationship arise from the sampling effect or selection probability effect?
Few high performing species might have large effect on ecosystem process.
Increasing species richness increases likelihood these species are present.
Purely statistical argument.
Monoculture of high performing species will have similar level of ecosystem functioning as diverse community.
How can a BEF relationship arise from complementary effect?
Different species use resource in different ways
Mixture of species can extract more resources than monoculture
Over-yielding in plant context
Reduced interspecific competition from niche partitioning
Facilitation e.g some species may alleviate harsh conditions or provide an essential resource.
How can a BEF relationship arise from insurance hypothesis?
Biodiversity buffers fluctuations in ecosystem functioning over time
Species differ in their ability to contribute to ecosystem functioning as environment changes
As species richness increases, more likely that species that function well under particular environmental conditions will be present
Similar to sampling effect but include temporal variation
Identities of high performing species change over time
Grassland plots with high biodiversity were more resistant to drought.
How can a BEF relationship arise from redundant species hypothesis?
Minimum diversity needed for ecosystem functioning
Before this minimum, most species are redundant in their roles
Above this minimum, adding/removing species has no detectable effect on ecosystem functioning
Key feature of soil communities - many species carry out the same processes as detritivores
What is the problem with using species richness to measure ecosystem functioning?
Carries little ecological information about species differences and species can vary in their functionality, similar to communities.
What is functional diversity?
The diversity of functional trait values - ecological roles represented.
Mechanistic link to ecosystem function
Better predictor than species richness.
Overall, how does biodiversity affect ecosystem functioning?
Increases the stability of ecosystems through time.
Saturating curve, longer experiments show more linear curve.
Identity, diversity and functional traits control ecosystem functioning.
Natural communities show uneven distributions of species abundances.
Dominant species make the number of species less important.
What are the four ecosystem services and examples?
Provisioning - food, water, raw materials, medicines
Regulating - air quality, local climate, carbon storage, pollination
Supporting - habitats and maintenance of genetic diversity
Cultural - recreation, tourism, spiritual
