Planet Earth has always been in a State of Change;
the rate of change has never been constant
Global Issues in Nematode Ecology and Management
Commonalities and Differences in Nematode Issues across the Globe
Howard Ferris
Department of Nematology
University of California Davis
Big Issues in World Agriculture,
Economy and Ecology
1. Global climate change and mitigation measures
2. Fossil fuel depletion and costs
3. Global trade agreements
4. Land ownership and land tenure
…………and their interlinkages
Context: the need to provide food, fiber,
water, and shelter for 6.7 billion people
Big Issues in World Agriculture,
Economy and Ecology
Energy Costs
Climate Change
Mitigationslowing the process
Adaptationminimizing the effect
on services
Trade Agreements
Adaptation:
Shifts in land-use patterns
and management practices
Land Tenure
How are different nematode functional groups affected by climate
and land-use change?
Provide Services
Provide Disservices
Mitigation tradeoffs?
A simplistic analysis of climate
change effects on soil
nematodes
Temperature
Nematode winners and losers?
Higher
Lower
Higher
+++
-+
Lower
+-
---
Rainfall
But.the same factors affect growth and tolerance of hosts, prey and natural
enemies of the nematodes.
….And management decisions of the environmental steward.
So, the net outcome is unpredictable, at least by me.
Thermal amplitude of bacterivores
Physiological Ecology
We have some of the necessary information……
Ferris et al., 1995
But we need to think at a larger scale……
A conceptual framework for comparing trade-offs on ecosystem services
Foley et al., Science 309, 570 -574 (2005)
Landscape Ecology
Professor Shenglei Fu, Chinese Academy of Sciences:
Mitigation - reforestation – altering climate
Adaptation - vegetation mixes to maximize functions and services
Total area 50 ha.
Each plot 1 ha.
Treatments 14
Replications 3
Services:
•pulp production
•wildlife habitat
•pollination
•refugia
•erosion control
•groundwater quality
•carbon sequestration
•decomposition
•nutrient cycling
•nutrient retention
•mineralization
•soil quality
•esthetics
•public education
China, 2007
Farmscape Ecology
•Temperature effects
•Rhizosphere interactions
•Host effects
Mitigation/Adaptation: Coffee under tree shade – Costa Rica, 2008
Adaptations
Winter cover crop – bell beans
California, 2006
•Soil fertility
•Organic matter
•Food web activity
•Soil structure
•Fossil fuel reduction
•Habitat conservation
•Food web activity
•Soil structure
No-till soybeans, Brazil, 2006
Is life still possible
on this planet?
Sustainagility:
Migration to another
region of planet
Non-farming
livelihoods
New
farming system
Soil Fauna
Sustainagility:
Change
cropping system
Adapted from:
Meine van Noordwijk
World Agroforestry Centre
Bogor, Indonesia
Sustainagility:
Shift to non-farming
livelihood
New
cropping system
Sustainagility:
Change
farming system
New
crops/animals
Sustainagility:
Change
crops/animals
Current crops/animals
Sustainability of . . .
Land-use change in Kansas:
Soil food web effects
Community Ecology
Structure
Index
Basal
Index
From Glover et al., subm.
•Consistent N-yield
over 75 years
without input
•N-yield similar to
that of high input
wheat
Soil Food Web: Functions and Services
in relation to punctuated and continuous resource supply
F
Mineralization
O
B
Regulation
Pr
Easier to go in this direction
P
Reverting to prairie?
Need to understand invasion biology of
omnivores and predators
Some Global Issues in Nematode Management
Nematicide tradeoffs – production enhancement vs. economics, environmental
hazards and food web simplification (pesticide treadmill)
Zimbabwe, 1961
California, 1999
California, 1973
Predator Nematodes
Ten Years After Cu Application
Impact on Higher Trophic Levels
60
50
40
30
20
10
An 0ideal:
0
200
400
600
800
Biodiversity-friendly nematicides that protect roots without killing non-target soil organisms:
Cu Concentration (Kg/ha)
“immunogenic
nematicides”
Korthals et al., 1998
Global Issues in Nematode Management
Management practices in industrialized
agriculture result in food web
simplification – cp1 and cp2
bacterivores and fungivores
predominate
Reduction in cp3, 4, 5 higher trophic
levels
Farmscape Ecology
Costa Rica, 2008
Global Issues in Nematode Management
Nematode biomass in soil food web
8
7
6
Proportion of Herbivores
Ln Biomass Predators
Conventional
1
y=-3.18+1.34x; r2=0.59, p<0.05
0.9
Organic
0.8
5
Bacterivore Biomass
0.7
4
Herbivore Biomass
3
2
1
0
Conventional
y=0.64-0.07(ln(x+1)); r2=0.36, p<0.01
Organic
0.6
0.5
0.4
0.3
0.2
2
3
4
0.1 Bacterivore Biomass
5
6
8
7
9
Ln Biomass Prey
0
0
200
400
Biomass of Predators
600
800
Molecular Ecology
border cells
What is the rhizosphere
effect of Theobroma on Musa?
molecular signals
Hawes et al., 1998
Farrar et al., 2003
nematodes
Hirsch et al., 2003
Other Nematode Services – enhancing soil fertility
Behavioral Ecology
An example of positive and negative feedback
bacteria and bacterivore nematodes
0 nematodes
Bacterial Cells
100
Positive feedback
Overgrazing
80
with five nematodes
60
40
20
0
0
5
10
20
40
Nematode Abundance
Fu et al. 2005
with twenty nematodes
80
160
The Importance
of Biodiversity
The Service - N mineralization
- Functional Complementarity
Mesorhabditis
600
Cruznema
500
Rhabditis
400
Total N
300
200
100
29-Jul
22-Jul
15-Jul
8-Jul
1-Jul
24-Jun
17-Jun
10-Jun
3-Jun
27-May
20-May
The Service - N mineralization
- Functional Continuity
Mesorhabditis
Acrobeloides bod
Total N
1Ap
r
8Ap
r
15
-A
pr
22
-A
pr
29
-A
pr
6M
ay
13
-M
ay
20
-M
ay
27
-M
ay
3Ju
n
10
-J
un
17
-J
un
24
-J
un
1Ju
l
8Ju
l
15
-J
ul
22
-J
ul
29
-J
ul
900
800
700
600
500
400
300
200
100
0
13-May
6-May
29-Apr
22-Apr
15-Apr
8-Apr
1-Apr
0
California, 1996
Crossover
Rotations
Depleted
Soils of
Africa – Oostenbrink, 1959
FAO - redrawn
Cereal Yields
A
4.5
4.0
B
Developed
Countries
Mt/Ha
3.5
3.0
C
Asia
Developing
2.5
2.0
Latin America
& Carribean
1.5
1.0
D
Sub-Saharan
Africa
0.5
F
A
B
C
D
E
F
Netherlands, 1965
California, 1982
2004
2001
1998
1995
1992
1989
Corn, cassava, beans - Congo
E
1986
1983
1980
1977
1974
1971
1968
1965
1962
0.0
Land-use Change: The Global Spread of Nematodes
Invasion Biology
Examples:
Citrus – Tylenchulus semipenetrans worldwide
Grapevines and their nematode complexes
Soybeans and Heterodera glycines
Cereals and grass seeds – Anguina spp.
Potatoes – Globodera and Meloidogyne spp.
Bananas and Radopholus, Helicotylenchus, Meloidogyne,
Pratylenchus.
Some nematodes
have attributes of
invaders:
Arrival
Establishment
Integration
Spread
Detection Escape
Effects of global exploration, human migration, modern transportation:
Despite regulatory efforts, major crops throughout the world support the same
nematode complexes.
Most major nematode pest problems in California are caused by non-native species.
Sugarbeet Cyst Nematode - Heterodera schachtii
sugarbeet production
sugarbeet cyst nematode
Adaptation to Nematode Globalization and Land-use Change
•Sources of resistance and other control/mitigation measures should apply in new
areas of production.
Caveat: consider the local acceptability of new varieties and the availability of
appropriate infrastructure/technology.
But…..
• Every year, we lose between 17,000 and 100,000 species as the result of human
activities (The Sixth Extinction. Leakey and Lewin, 1995)
• That represents an enormous loss of functions, services and genes.
•The problem is compounded by proprietary ownership of resistance genes and
commercialization of seed sources, reducing local selection of desirable traits.
Genetic diversity is a common legacy – it should be conserved, not owned
Svalbard Global Seed Vault will
store three million different crop
varieties in case of a worldwide
catastrophe.
Dr. Vandana Shiva’s movement concerned with saving
seeds, trading seeds, farming without corporate-derived
seed.
Ghandi: “You cannot monopolize this which we need for life.”
Global Issues in Nematode Ecology and Management:
Summary and Research Directions……
Land-use Change
Land-use Change
Impacts
Research Activities
Impacts
Research Activities
 Changes
in cropping
Changes
in cropping
 Host status and resistance
and farming systems
 Host status and resistance
 Crop rotation systems
and farming systems
 Soil food web 
management
Crop rotation systems
 Changes in nematode  Biodiversity conservation
assemblages and
 Soil food web management
 Evaluation of sustainability
 interactions
Changes in
nematode
Optimizing Ecosystem
Services
 Biodiversity
conservation
assemblages
and
of sustainability
Information Gaps  Evaluation
Research
Activities
interactions
Optimizing Ecosystem Services



Spatial and temporal diversity  Intercropping,
Information Gaps
Research Activities
Scale:
from diversity
molecular
to
multicropping
Spatial
and temporal
 Intercropping,
 Scale:
from molecular to
multicropping
 GIS
landscape
 GIS
landscape
 Multidisciplinary  Multidisciplinary

taxonomy
and
 Alpha
Alpha
taxonomy
and
functional guilds
teams
functional guilds  teams
Multivariate analysis
Organismal level:
 Functional complementarity
 Modeling
and
continuity

Multivariate
analysis
 Functional
complementarity
Nematode
and System Management
•Adapt knowledge from
 Modeling
and continuity
biological
models and microcosm
Goals
Research
Activities







experiments
diagnostics
Exclusion
and
avoidance
Nematode and
System
Management  Molecular
Goals
Research Activities
 Rotation experiments
Host
status,
resistance
Exclusion and avoidance  Molecular diagnostics
Farmscape
and Landscape levels:
 Food web
management
 Rotation
experiments
Host
status, resistance
Cropping
system
design
management to scale of
Cropping system design  Food web management
 Sources•Adapt
of genes
 Sources of genes
Biological
Biological
regulationregulation
system
 Ecological amplitudes
 Ecological
amplitudes
Conservation
of soil
Conservation
of
soil

Immunogenic
•Develop a biodiversity-friendly
biodiversity

Immunogenic
nematicides
biodiversity
landscape
nematicides
Global Issues in Nematode Ecology and Management:
Summary and Research Directions……











Land-use Change
Impacts
Research Activities
Changes in cropping
 Host status and resistance
and farming systems
 Crop rotation systems
 Soil food web management
Changes in nematode  Biodiversity conservation
assemblages and
 Evaluation of sustainability
interactions
Thank you
Optimizing Ecosystem Services
Information Gaps
Research Activities
Spatial and temporal diversity  Intercropping,
Scale: from molecular to
multicropping
 GIS
landscape
 Multidisciplinary
Alpha taxonomy and
teams
functional guilds
 Multivariate analysis
Functional complementarity
 Modeling
and continuity
Nematode and System Management
Goals
Research Activities
Exclusion and avoidance  Molecular diagnostics
 Rotation experiments
Host status, resistance
Cropping system design  Food web management
 Sources of genes
Biological regulation
 Ecological amplitudes
Conservation of soil
 Immunogenic
biodiversity
nematicides
Organismal level:
•Adapt knowledge from
biological models and microcosm
experiments
Farmscape and Landscape levels:
•Adapt management to scale of
system
•Develop a biodiversity-friendly
landscape