FINAL3-BIODIVERSITY

Question 0

Unplanned Biodiversity

Answer 0

Weeds (in field)
Surrounding (none – all)
Soil Biota
Arthropods (except releases of biocontrol agents)
Non-domesticated animals

Question 1

Planned Biodiversity

Answer 1

Crop Varieties
Some surrounding vegetation (none – all)
(e.g., other monocrops, intercrops, non-crops)
Domesticated animals

Question 2

Loss of Biodiversity in agriculture

Conventional practices

Answer 2

Conventional practices work primarily to manage a few factors perceived to be of direct importance to the system
The crop plants
A few nutrients (N,P,K)
Tillage/herbicides
Insecticides

Question 3

Loss of Biodiversity in agriculture

TREND:

Answer 3

simplification / homogenization

Homogenization + Simplification = Productivity/Profitability

Question 4

Biodiversity: The Challenge

As agroecologists: the challenge we face is to:

Answer 4

try and understand what the identities of the larger, unplanned biota,
what function they serve,
what value we wish to assign to their functions,
How management practices can be modified to optimize biodiversity, taking into consideration both short-term (profit) and long-term (sustainability) goals

Question 5

Biodiversity includes:

genetic variability~

Answer 5

Within and between species

Question 6

Biodiversity includes:

Alpha diversity~

Answer 6

Measure of a species richness and abundance within a community

Question 7

Biodiversity includes:

Beta Diversity~

Answer 7

species diversity across communities or along gradient transects

Question 8

Biodiversity includes:

Gamma Diversity~

Answer 8

Species diversity along a biogeographic region

Question 9

Identifying biodiversity

Alpha biodiversity!~

Answer 9

Spatial component: Within field

Question 10

Identifying biodiversity

Beta Diversity!~

Answer 10

Spatial Component:

Number and evenness of species over a landscape

Question 11

Gamma Diversity!~

Answer 11

Number and evenness of species over region

Question 12

Can you have a high alpha biodiversity low beta biodiversity agroecosystem?

Answer 12

YES

Question 13

Shannon-Weiner index

Answer 13

Accounts for #species and evenness

Question 14

Ecosystem functions:

Answer 14

Processes critical to ecosystem vitality
Nutrient, water, air cycling
Biomass production
Decomposition

Question 15

Ecosystem services:

Answer 15

Functions that are valued by us
Pollination services
Biological control
Soil fertility

Question 16

Stability

Answer 16

Ability to withstand disturbance

Question 17

resistance

Answer 17

ability to resist stress

Question 18

resilience

Answer 18

ability to recover after stress

Question 19

Biodiversity…

Answer 19

alpha diversity: species richness and relative abundance, planned & unplanned)

Question 20

Genetic Diversity

Answer 20

within species

Question 21

Structural Diversity…

*or Habitat Diversity defined in 4-parts:

Answer 21

(e.g., Plant architecture, habitat diversity, constructed)
(- Living fences, Deciduous borders)
*Major habitat system: e.g., terrestrial, aquatic;
*Formation type: e.g., woodland, open ground;
*Vertical layers: e.g., ground flora, shrub, high canopy;
-Traditional shaded coffee
systems
*Qualifiers: e.g., deciduous, coniferous, annual, etc

Functional: complexity of interactions among system components
Constructed diversity - terraces, ponds, etc

Question 22

Temporal Diversity

Answer 22

(e.g., Variable planting times, life histories)

Crop rotation

Question 23

Spatial Diversity

Answer 23

(e.g., beta diversity of vegetation types, or crop varieties, or crop stages, gamma diversity)
Landscape complexity
(% natural habitat in landscape)

Question 24

Functional biodiversity

Answer 24

Biological pest control
Pollination services
Nutrient cycling
Synergistic interactions eg.
 -legume/non-legume
-Plant mycorrhizae
-Microclimate modification – windbreaks, shade
Risk aversion:
-Multiple products
-Spread workload 
Landscape stability:
-Perennial ground cover, hedgerows etc reduce runoff/erosion

Question 25

Functional diversity

Answer 25

Ladybugs and carabids and pea aphid control (Losey 1998)

Question 26

Do Intercrops reduce pest damage?

Proposed mechanisms include:

Answer 26

Enemies Hypothesis

Resource Concentration Hypothesis

Question 27

Resource Concentration Hypothesis

Answer 27

more difficult for pests to find desired host and/or tend to leave more quickly

Question 28

Enemies Hypothesis:

Answer 28

increase in predators and parasitoids due to increased availability of alternate food sources

Question 29

Effect of polycultures on herbivore populations

Answer 29

decreased population: 52% of studies
increased populations: 15% of studies
no effect on population of 13% of studies
variable effect on population of 20% of studies

Question 30

Effect of polycultures on natural enemy populations:

Answer 30

increased population: 53% of studies
decreased population: 9% of studies
no effect on population of 13% of studies
variable effect on population of 25% of studies

Question 31

Non-Synchronous Planting Not Only Leads to More Stable Arthropod Ecology, … but

Answer 31

More Stable Labor Requirements
More Stable Input Costs
More Stable Harvest Prices
 Left to their own, Farmers Drift
     away from Enforced Synchronous
     plantings

Question 32

Summary: Some measures of Stability

Answer 32

Ecosystem-Level
Nutrient cycling (ability of plant-soil microbe systems to process 	nutrients)
Soil Erosion  (physical sustainability of soil system over time)

Community-Level
Species Richness (conservation as well as agronomic issue)
Functional Redundancy (systems “buffered” by multiple species having similar functions)Population-Level
Insect Pest Suppression (by “beneficials”)
Disease Suppression (e.g., rice blast example)

Economic-Level
Yield, costs and price stability (reduced reliance on volatile purchased inputs; “spreading the risk” through a variety of crops)
Input Availability (avoiding demand “bottlenecks” when costs can rise)
Demand for Labor (spread over year to provide stable work force)
Overall Profit and sustainability (integrates all of the above)