5. Ecosystem function, biodiversity and ES production part II Flashcards
What is functional diversity?
A functional treat is a measurable property, phenotype, or characteristic of an organism that may influence its survival. Examples: size, color, pattern, diet.
Species have functional traits that are the result of eco-evolutionary pressures (i.e., they are related to their niche).
What are soft traits?
Soft traits can be proxies of functions. A soft trait of a flower can be: seed mass, canopy height, etc., while its functions can be light interception or resorption of nutrients.
What are the three concepts of research on species?
- Complementarity
- Stability/resilience
- Keystone species
What does complementarity mean? Provide an example.
More traits complementary in resource use means more production.
Examples:
- A variety of plants with roots at different depths survive droughts more easily
- A forest with birds of different sizes will more easily support a community of carnivores of different sizes
- Bees with different mouth lengths will pollinate different flowers
- Plants producing compounds toxic for different herbivores will more easily resist insect outbeaks
What does stability/resilience mean?
More diversity means more diversity in response to environmental drivers, which means more stable production under dynamic conditions. With a higher biodiversity, it is more likely that one species will buffer undesirable effects of environmental variation.
What does “keystone species” mean? provide an example.
Keystone species/unique traits disproportionally effect ecosystem function (more effects than losing a random species). If a keystone species would be removed, the entire ecosystem collapses.
Examples:
- Coral create diverse reef ecosystems.
- Mangrove trees support shorelines from erosion and provide protective habitats for small fish and other organisms.
- Sea otters eat sea urchins. Without the sea otter, which prevents sea urchings from overbreeding, kelp forests (which sustain a variety of other species) would be severely depleted.
What are the three different responses between diversity and functioning?
- Redundant response
- Additive response
- Idiosyncratic response
Explain and provide examples for redundant response.
The contribution of additional species is redundant above a critical level.
Higher biodiversity helps ecosystem functioning up to a certain point, then the relationship breaks and it is stable.
- Example 1: nutrient cycling in a forest ecosystem. The more decomposers, the better. However, beyond a certain point, additional decomposer species become redundant as the nutrient cycling rates are kept stable already.
- Example 2: pollination in agriculture: different bee species ensure pollination also if one species doesn’t thrive in a given year.
Explain and provide examples for additive reponse.
There is complementarity of components. All species contribute to the integrity of an ecosystem in a small but significant way such that a progressive loss of species steadily damages ecosystem function.
The more species, the more ecosystem functions.
Example 1: Pollination of wild flowers. Each species contributes to pollination in a small but significant way. As you increase the number of pollinator species, there is a progressive increase in the overall pollination rate and seed production.
Example 2: During droughts, diverse grasslands produce more than monoculture grasslands, because their traits are complementary in using the resources.
Explain and provide examples for idiosyncratic response.
Ecosystem function changes unpredictably as species richness changes.
Often happens with keystone species.
Example: Coral Reefs Ecosystem. Some fish visiting coral reefs have a disproportionately large impact on the health and functioning of a reef, such as the parrotfish. If the parrotfish goes extinct, the coral reef might largely die, which has major impacts for other species that use the coral reefs.
What is the Rivet popper hypothesis?
The Rivet popper hypothesis suggests the importance of species richness in the maintenance of ecosystems: rivets of an airplane are compared with species in an ecosystem. As the number of species lost increases, we approach a tipping point where the system can collapse.
What is the precautionary principle?
If a product, an action or a policy has a suspected risk of causing harm to the public or to the environment, protective action should be supported before there is complete scientific proof of a risk.
Does managing for ES necessarily result in a high biodiversity protecting?
No, some species are not directly serving ES.
How can humans affect ESS without reducing the amount of natural habitat?
- Habitat fragmentation
- Pollution
- Invasive species
- Overfishing
- Climate change
- Changes in species composition
