Functional Diversity in
Integrated Crop Management
William H. Settle
University of California, Santa Cruz
and
UNFAO Community IPM Programme
In Asia
AGRO-BIODIVERSITY:
The Challenge
"we know as little about biodiversity
in traditional tropical agro-ecosystems
as we know about biodiversity in the
tropical rainforests"
--Vandermeer and Perfecto 1995
"the neglect of agro-biodiversity in the portfolios of
lending and development organizations, as well as in
treaties and conventions that deal with environmental
conservation, is striking."
-- The World Bank report, 1996
Classification Of Agricultural
Systems By Diversity
Diversity of Species
High
Diversity of Production System
Multi-Field Type
Shifting
Cultivation
Nomadic
Pastoralism
Single-Field Type
Home
Garden
Traditional
Compound
Rotational
Fallow
Savanna
Mixed
Horticulture
Compound
Agribusiness
Pasture
Mixed
Alley
Farming
Crop
Rotation
Multi
Cropping
Alley
Cropping
Intercropping
Low
Plantations &
Orchards
Intensive
Cereal
From Swift and Anderson 1994
RESEARCH RESULTS
Five Year Study of Arthropods
In Rice Ecosystems in Indonesia
Across Differing Landscapes
And Levels of Intensification
What Proportion of Species are
“Important” ?
SPPCODE TROPHIC
sminthuridA
entomobryA
delphacidA
linyphiidA
chironomidL
lycosidA
isotomidA
delphacidD
veliidA
cicadellidG
mesoveliidA
cicadellidi
chironomidN
delphacidi
chloropidC
chironomidA
cicadellidB
veliidi
ceratopogG
podopidA
other
other
phytophage
predator
other
predator
other
phytophage
predator
phytophage
predator
phytophage
other
phytophage
predator
other
phytophage
predator
predator
phytophage
hydrophilidG predator
ceraphronF
parasitoid
hydrophilidP predator
GUILD
FAMILY
ORDER
TOTAL
%
detritiv
detritiv
plantsuc
spidweb
filterfe
spidhunt
detritiv
plantsuc
surfbug
plantsuc
surfbug
plantsuc
filterfe
plantsuc
predfly
filterfe
plantsuc
surfbug
predfly
plantsuc
sminthurid
entomobryid
delphacid
linyphiid
chironomid
lycosid
isotomid
delphacid
veliid
cicadellid
mesoveliid
cicadellid
chironomid
delphacid
chloropid
chironomid
cicadellid
veliid
ceratopogon
podopid
collembola
collembola
homoptera
araneae
diptera
araneae
collembola
homoptera
hemiptera
homoptera
hemiptera
homoptera
diptera
homoptera
diptera
diptera
homoptera
hemiptera
diptera
hemiptera
10460
5409
4752
2882
2524
2235
2098
1857
1848
1809
1500
1452
1272
1210
1170
1024
898
894
887
845
13.3
6.9
6.0
3.6
3.2
2.8
2.7
2.3
2.4
2.3
1.9
1.8
1.6
1.5
1.5
1.3
1.1
1.1
1.1
1.1
0.133
0.202
0.262
0.299
0.331
0.360
0.386
0.410
0.433
0.456
0.476
0.494
0.510
0.526
0.540
0.553
0.565
0.576
0.588
0.598
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
coleoptera
324
0.4
0.754
43
76
0.1
0.900
123
28
0.04
0.950
210
aquapred hydrophilid
larvpste
ceraphronid hymenoptera
aquapred hydrophilid
6 regions; 16 fields
coleoptera
CUM RANK
% of Total
Abundance
% of Total
Species
12 = 50% A
1.4% S
43 = 75% A
123 = 90% A
5.2% S
14.7% S
210 = 95% A
25.2% S
Total = 835 morpho-species
And, What Does “Important” Mean?
Fraction of Total Abundance
Neutrals
37.8%
Number of Species
Parasitoids
(192 23%)
Parasitoids
Herbivores
6.8%
22.8%
Neutrals
159 (19%)
Predators
32.6%
Herbivores
173 (21%)
Predators
311 (37%)
First Cut: Trophic Composition
D
iv
A
nt
.P
Pr ste
ed
B
ug
B
o
Eg re
r
g
Pr
Fl
yi
e
ng d
Pr
Su e d
rf
B
ug
v.
Ps
t
D e
e
Le trit
iv
af
C
h
Pl
an ew
tS
Pr uc
ed k
B
Eg eet
g
Ps
Pr te
ed
F
A
qu l y
a
Fi Pre
lte
d
rF
Sp eed
id
Sp W e
b
id
.H
un
t
La
r
Number of Species per Functional Group
Functional Groups: A Heuristic Tool
120
100
Predator
Parasitoid
Herbivore
Neutral
80
60
Series1
40
20
0
Hyper Parasitoids
Hypothesized
Generalized Rice Food Web
PARASITOIDS
ARTHROPOD PREDATORS
HERBIVORES
CHIRONOMIDS
& MOSQUITOES
TUBIFICID WORMS
RICE PLANT
MICROCRUSTACEA
ROTIFERS
PHYTOPLANKTON
DETRITIVORES
PROTOZOA
CO2
P2O5
NH4
NO3
BACTERIA
OTHER
ORGANIC MATTER
Tropical Rice: Three Pathways Support
Natural Enemies
NATURAL
ENEMIES
PESTS
FILTER FEEDERS
DETRITIVORES
RICE
PLANT
MICRO-ORGANISM
CYCLE
ORGANIC MATTER
1.5 Ha ; 12 replications
750
600
450
Neutrals
Predators
Mean insects per square meter
AS PREDICTED:
Adding Organic Matter to the System
Boosts populations of “Neutrals” (Detritus
and plankton Feeders) & Predatory Insects
300
150
0
Low
High
Below water
Low
High
Water surface and Plant Canopy
Organic Matter Inputs
Indications of a Stable System
Mean per square meter
750
600
450
Neutrals
Predator
Herbivore
Parasitoids
Parallel Work in China:
Dr. Wu Jincai (et al) Jiangsu Agricultural College
Zhang Wenqing, Zhongshan University
300
High Levels of Associated
Agro-biodiversity
150
0
0
A Community-Level Pattern
of Species Assemblage
10 20 30 40 50 60 70 80
Days After Transplanting
A Clear-cut Intrinsic Mechanism
Leading to Stable & Robust
Pest Suppression
Rethinking the Old Paradigm:
Vegetative Diversity?… or Rather Foodweb Diversity
Insectary Plants
Trap Crop
?
Crop
Crop
Terrestrial Foodweb
Irrigated Rice
Aqatic Foodweb
?
Linking Species:
Predators / Parasitoids
Foodwebs:
Not Necess. Coevolved
Linking Species:
Pests
Foodwebs:
Not Necess. Coevolved
Linking Species:
“Neutrals
Foodwebs:
Highly Coevolved
Large-scale Factors Affect
Intrinsic Mechanisms
ÆIndirect Management: Farmers do not Usually Manage Arthropod
Biodiversity Directly, They Manage Factors that Affect Arthropods,
(Whether they are aware of the impacts or not)
SPATIAL SCALE**
LANDSCAPE HETEROGENEITY **
PESTICIDES**
WATER MANAGEMENT**
INTRINSIC ECOLOGICAL
MECHANISMS
RESIDUE MANAGEMENT**
PLANT GENETICS
AND DIVERSITY
4
* Disturbance at the Plot-to-Landscape Level
2
0
1093
Non-Treated Treated
Untreated
750
Mean per square meter
Mean yield: tons/ha
Insecticide-Induced Resurgence
6
a
Parasitoid
Predator
Herbivore
Neutrals
600
450
150
150
10
20
30
40
F Carbofuran
A Azodrin
450
300
0
b
600
300
0
Treated
750
50
60
70
80
0
0
10
Days After Transplanting
20
F
30
A
F A
40
50
60
70
80
Landscape – Level Influences
High Global Disturbance:
Large–Scale Synchronous Planting
Landscape Favors:
Long-distance Travelers
High Fecundity
Relatively Large &
Robust Arthropods
= Pests
Farmer’s Plot
Rice
Dry Fallow
Hypothetical Individual Range of Arthropod movement
Low Global Disturbance:
Non-Synchronous Planting
Landscape Favors:
Long-lived Generalists
(Predators)
Highly Efficient Searchers
(Parasitoids)
Farmer’s Plot
Rice
Dry Fallow
Newly Flooded
Hypothetical Individual Range of Arthropod movement
Large-Scale Synchrony
Delays Predator Arrival Time
Predators
Synchronous
Proportion of plants
Predators present
1.0
65
96
86
75
Non-Synchronous
1.0
0.9
0.9
0.8 44
54
35
0.7
0.8
0.6 21 28
0.5
14
0.4
0.6
0.3
0.3
0.2
0.1
0.0
0
18
33
5
72
63
43
11 25
86
0.7
0.5
0.4
7
0.2
100
200
300
0.1
0.0
400
0
100
200
Number of predators per square meter
.
300
400
Large-Scale Synchrony
Leads to Lowered Agro-biodiversity
Rank-Abundance Curves
Log abundance for each species
0
Herbivores
50
150
0
Neutrals
Parasitoids
3
50
150
Predators
North-West
(Synchronous)
2
1
0
Central
(non-synchronous)
3
2
1
0
0
50
150
0
50
Species Ranking
150
Non-Synchronous Planting Not Only Leads to
More Stable Arthropod Ecology, … but
ÆMore Stable Labor Requirements
ÆMore Stable Input Costs
ÆMore Stable Harvest Prices
Æ Left to their own, Farmers Drift
away from Enforced Synchronous
plantings
Caveats: Cases Where Heterogeneity
Does Not Work Well
Æ Extreme Fine-scale Heterogeneity (1-5 ha): Tungro Virus
Æ Swidden Systems: a case in which high biodiversity is
NOT correlated with good pest suppression
Æ Areas Subject to High Pesticide Use
Arthropod Diversity and
Agro-Ecosystem Function
Relative Abundance
α
Richness
β
Species Diversity
Function of Pest Suppression
Is an Emergent Property
resulting from complex
interactions of the
whole System
Individual Life
Histories
Species
Spatial
Distribution
Timing &
Duration
Arthropod
Communities
Management
Trophic
Relations
Environment
Magnitude
Spatial Distribution
Availability
Type
Resources
Climate
Etc.
Timing &
Duration
Structural Habitat
Food
Water
Refuge
Mate
Etc.
Farmer Training
“The Field Is Our Book”
Promote Questioning, not Scientific Jargon
Conclusion:
Research Agenda at the Ecosystem Level
-- study agricultural systems within-crop and across a continua of
landscapes and management intensities (Build Capacity in-Country)
-- seek to understand the range of mechanisms (both in
terms of nutrient-flow and community dynamics) that
support the “service” in question.
-- seek to understand how these mechanisms
are affected by large-scale factors that
underlie ecosystem function (the “ecological context”)
-- look to see how what the implications are for policy
and management
-- take responsibility for educating people in a practical way !
Exploring Further Case Studies
in Areas of High Natural Biodiversity
Æ Kalimantan: helping farmers transition out of Slash & Burn
Æ Thailand: Improving Production Systems with the Hill Tribal
people on the Border with Burma
Æ Mali: Exploring the Relationship Between Rice Cultivation
and Natural Wetland Regia in the Niger River
Inland Delta
Thank You !