Lecture 6 JD

Question 1

What is biodiversity?

Answer 1

means the variability among living organisms from all sources including terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems

Diversity of genes between species and of ecosystems

Question 2

Why should we conserve biodiversity?

Answer 2

1. Moral reasons
2. Aesthetic
3. Insurance
4. Ecosystem services

Question 3

Ecosystem services

Answer 3

Ecosystem Services are the benefits people obtain
from ecosystems. These include provisioning, regulating, and cultural services that directly affect people and supporting services needed to maintain the other services

Question 4

More diverse ecosystems are likely to be

Answer 4

more productive, more stable, have less invasive species, and better regulate water and nutrient flows

Question 5

What is the mechanistic basis to the Biodiversity-Ecosystem Service relationship?

Answer 5

Ecosystem Services are the benefits people obtain from ecosystems
➢Ecosystem functions (ecological processes) are the biological, geochemical and physical processes that take place or occur within an ecosystem. Ecosystem functions can be thought of as the capacity of ecosystems to provide services
➢Each function is the result of complex interactions between biotic (living organisms) and abiotic components of ecosystems

Question 6

Ecosystem Functions

Answer 6

underpin ecosystem services, and biodiversity driven biotic interactions underpin Ecosystem Function

Question 7

Positive relations between biodiversity and ecosystem functioning arise through:

Answer 7

(1) Resource/niche partitioning, (2) facilitation (commensalism & mutualism), and (3) “portfolio effects”

Question 8

Resource/niche partitioning

Answer 8

occurs when species differ in their resource requirements, resulting in lower competition from interspecific neighbors than from conspecifics. This may lead to a more complete resource use by more biodiverse communities (Fridley 2001).

Question 9

Facilitation

Answer 9

Facilitative or positive interactions are encounters between organisms that benefit at least one of the participants and cause harm to neither (facilitation = commensalism & mutualism).

Question 10

complementarity

Answer 10

Resource/niche partitioning and facilitation are collectively referred to as

Question 11

Portfolio Effect’

Answer 11

surmises that having higher biodiversity multiple species in a community is akin to having multiple stocks in an investment portfolio, acting as insurance against variability in the environment affecting a single species

Question 12

Interspecific Competition: Exploitation

Answer 12

David Tilman (1981) demonstrated the principle of exploitation competition using freshwater diatoms growing in a silica-limited microcosm

Dependence of aboveground plant biomass (that is, productivity) on the number of plant species seeded into the 289 plots
Diversity increased overall plant biomass, likely due to niche differentiation