Howard FerrisDepartment of Nematology

University of California, DavisNovember, 2010

Stewardshipof

Soil Ecosystem Services

CO2

carbohydratesand

proteins

carbohydratesand

amino acids

bacteria

nematodes

fungi

CO2

NH3

NO3

protozoanematodes

nematodesarthropods

fungi

arthropodsnematodes

NH3

otherorganisms

NH3

CO2 CO2

C

N

Carbon and energy transfer• Carbon is respired by all

organisms in the food web

• The amounts of Carbon and Energy available limit the size and activity of the web

The soil ecosystem is strongly affected by type and frequency of Carbon and Energy input

0

100

200

300

400

500

600

700

800

0 50 100 150 200 250 300 350 400

Time

Inp

ut

Bio

mas

s

Infrequent (Punctuated) Resource Input

Carbon and Energy Subsidy Effects

Prey resources

Predators

0

100

200

300

400

500

600

700

800

0 50 100 150 200 250 300 350 400

Time

Inp

ut

Bio

mas

s

Frequent (Continuous) Resource Input

Carbon and EnergySubsidy Effects

Prey resources

Predators

• Consistent N-yield over 75 years without input

• N-yield similar to that of high input wheat

Structure Index

Basal Index

From Glover et al., 2010

Land-use change in Kansas

Resource Inputs:Bottom up effects on Soil Ecosystem Structureand Function

Community Ecology

Individual speciesservices

Aggregateecosystem services

Soil Ecosystem Functions - metabolic and behavioral activitiesof organisms that impact the biotic or abiotic components of the ecosystem

Feeding: Ingestion, assimilation, defecation and excretion Behavior: Movement, activity, migration

Functions may be classified, subjectively, as Services, Disservices (or Neutral)

Disservices:Damage plants of agricultural or ornamental significanceInjure humans and vertebrate animals

Services:Sequester and redistribute minerals

Mineralize organic moleculesAccelerate turnoverRegulate and suppress pests

Alter substrate to provide access to other organismsRedistribute organisms in spaceBiodegrade toxinsReduce soil erosionIncrease agricultural production

Provide Services Provide Disservices

Management tradeoffs?

Management of Soil Organisms….to enhance services and reduce disservices

Nematode Sensitivity to Mineral Fertilizer

Concentration (mM-N)

0 0.1 1

Sta

ndar

dize

d C

ount

s

0

50

100

150

200

X

X X X X

c-p 1 c-p 2 c-p 3 c-p 4 c-p 5 X

Ammonium sulfate

0.50.050.02

Nematode guild

Tenuta and Ferris, 2004

Soil Ecosystem – environmental effects on Structure

Fungi exploit nematodes through:

1. traps and networks that remainattached to the hyphae.

2. spores that detach from hyphae

Feeding and Redistributing Organisms

Some Ecosystem Functions

0

20

40

60

80

100

0 5 10 20 40 80 160

Nematode Abundance

Bac

teria

l Cel

ls

Positive feedback Overgrazing

0

20

40

60

80

100

0 5 10 20 40 80 160

Nematode Abundance

Bac

teria

l Cel

ls

0

20

40

60

80

100

0 5 10 20 40 80 160

Nematode Abundance

Bac

teria

l Cel

ls

Positive feedback Overgrazing

Distribution of organisms to new resources

bacteria and bacterivore nematodes

0 nematodes

Fu et al. 2005

Behavioral Ecology

5 nematodes 20 nematodes

Exploiting Ecosystem Services:The N-Mineralization Service of Bacterivore Nematodes

T0

M0

Aug Sep Oct Nov Dec Jan Feb Mar Apr May

Cover cropCover crop

Irrigation

temperature

moisture

activity

Taking it to the field……Soil Ecosystem Management – an experiment

Ferris et al., 2004

Ferris et al., 2004

0

2

4

6

8

10

12

14

5 10 15 20 25 30 35 40 45

Organic Matter C:N Ratio

N (

µg

/g S

oil

)

+Cephalobus-Cephalobus

Nitrogen mineralization

0

100

200

300

400

500

600

1-A

pr

8-A

pr

15-A

pr

22-A

pr

29-A

pr

6-M

ay

13-M

ay

20-M

ay

27-M

ay

3-Ju

n

10-J

un

17-J

un

24-J

un

1-Ju

l

8-Ju

l

15-J

ul

22-J

ul

29-J

ul

Functional ComplementarityN- mineralization

Mesorhabditis

Cruznema

Rhabditis

Total N

0100200300400500600700800900

1-A

pr

8-A

pr

15-A

pr

22-A

pr

29-A

pr

6-M

ay

13-M

ay

20-M

ay

27-M

ay

3-Ju

n

10-J

un

17-J

un

24-J

un

1-Ju

l

8-Ju

l

15-J

ul

22-J

ul

29-J

ul

Functional ContinuityN-mineralization

Mesorhabditis

Acrobeloides bod

Total N

A diverse functional guild of bacterivores supports….

Density-dependent predation

80

85

90

95

100

0 0.1 0.2 0.3

Predator:Prey Ratio (Density Class Averages)

So

il S

up

pre

ss

ive

ne

ss

Predator: Prey Ratio

Sánchez-Moreno and Ferris, 2007

Another Ecosystem Service: Regulation of Opportunistic Species

Generalist and Specialist Predators

Amplifiable PreyTarget Prey

Predators and prey

Soil Ecosystem Complexity and theRegulation Function

Management practices in industrialized agriculture result in:

Soil ecosystem simplification

Reduction in higher trophic levels

Costa Rica, 2008

We tested nematode predator:prey hypotheses with data from banana plantations in four Central American countries……….

Ferris, Pocasangre, et al., subm.

2.8 3 3.2 3.4 3.6 3.8 4 4.2 4.4 4.6-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

Ln Amplifiable Prey Abundance

Ln P

reda

tor-

Targ

et P

rey

Ratio

y=-4.97+0.852 x; R2=0.33; p<0.0001

B

Banana Plantations - Panama

The relationships are fuzzybecause…………….

Organic Matter

Microbial Biomass

Amplifiable Prey

Predator Nematodes

Nematophagous fungi +

Target Prey+

+-

-

+

AB

Plant Roots

Root AssociateNematodes

++

Other Predators

B - +

+

Protozoa +

Other Prey+A

E6

E1

E2

E3

E4

E5

B

Trophic cascades: amplifiable and target prey – the expanded model

-B

+

+

Rhizosphere bacteria

E7

-

Enhancing Amplifiable Prey

Target Prey:the ring nematode

Environmental heterogeneity

Zones andGradients:

texturestructuretemperaturewaterO2

CO2

NO3

NH4

minerals

Soil Ecosystem – environmental factors affecting Structure

Separatemetacommunities?

Predator-prey ConnectanceOrganic Bananas and Cover Crop – Costa Rica

Winter cover crop – bell beansCalifornia, 2006

No-till soybeans, Brazil, 2006

• Soil fertility• Organic matter• Food web activity• Soil structure

• Fossil fuel reduction • Habitat conservation • Food web activity• Soil structure

Feeding the Amplifiable Prey

Plant-feedingnematodes

Fungus-feedingnematodes

Bacteria-feedingnematodes

Generalist predatornematodes

Specialist predatornematodes

Protozoa-feedingnematodes

Nematodes at each trophic level

RhabditidaePanagrolaimidae

etc.

¨ Short lifecycle¨ Small/ Mod. body size¨ High fecundity¨ Small eggs¨ Dauer stages¨ Wide amplitude¨ Opportunists¨ Disturbed conditions

AporcelaimidaeNygolaimidae

etc.

¨ Long lifecycle¨ Large body size¨ Low fecundity¨ Large eggs¨ Stress intolerant¨ Narrow amplitude¨ Undisturbed conditions

Enrichment Indicators Structure Indicators

CephalobidaeAphelenchidae,

etc.

¨ Moderate lifecycle¨ Small body size¨ Stress tolerant¨ Feeding adaptations¨ Present in all soils

Basal Fauna

Ba2

Fu2

Fu2

Ba1

Ba3

Fu3

Ca3

Ba4

Fu4

Ca4

Om4

Ba5

Fu5

Ca5

Om5

Enriched

Structured

Basal

Basalcondition

Structure trajectory

Enr

ichm

ent t

raje

ctor

y

omnivorescarnivoresfungivores

bacterivores

fungivores

bacterivores

fungivores

bacterivores

Nematode Faunal Profiles

• Enrichment index

100 (w1.cp1 + w2.Fu2)

/ (w1.cp1 + w2.cp2 )

• Structure Index = 100 wi.cpi / (wi.cpi + w2.cp2 ) for i = 3-5Ferris et al., 2001

and the Metabolic Footprint

http://plpnemweb.ucdavis.edu/nemaplex

Emergent Themes in Soil Ecosystem Stewardship:

1. Provide adequate and continuous resource supply to supportdesired functions

2. Preserve favorable conditions for component systems

3. Engineer co-location or range overlap of interacting guilds

4. Assess magnitude of services based on faunal analysis and metabolic footprints of functional components