US$400 billion / yr at world wide scale, Costanza et al 1997

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1 Capturing the ecosystem service of pest control: Natural enemy movement between native forests and crops Nancy A. Schellhorn CSIRO Entomology Value of Ecosystem Service of Pest Control US$4 billion / yr at world wide scale, Costanza et al 1997 Forest & woody patches in agricultural landscape mosaics provide perennial habitat important for ecosystem services of pest control, Bianchi 26 Agricultural pest problems need to be considered beyond crop boundary 1

2 Timing of natural enemy immigration & colonization is crucial Pest density Time Settle et al. 1996; Ives & Settle 1997; Landis & van der Werf 1997; Bianchi & van der Werf 23 Corbet and Rosenhiem Environ Ent 1996, Schellhorn and Andow Population Ecology 25, Schellhorn et al Aus Jrn Exp Ag 28, Bianchi et al Oikos 29 2

3 Landscape context influences immigration / colonization Type of habitats / patches Crops Grazing Land Forests Ecological Function of habitats Sources of immigrants? Change over time? Type of edges Crop-Forest Crop-Grazing land Insects are known to respond to edges / boundaries (Fagan 1999; Olson & Andow 27) *community composition (ecotone) *interaction b/t adjoining patches Theory *Meta-population *Source-sink dynamics *Refining theory - propagating sinks & ephemeral sources Vandermeer, Perfecto & Schellhorn Landscape Ecology 21 Simulation Modelling *Linking foraging behaviour, spatial distribution of prey, and prey consumption Bianchi, Schellhorn & Van der Werf, Oikos 29 Bianchi, Schellhorn, Buckley & Possingham Ecological Applications (in press) Outcome: Capture better pest control while maintaining biodiversity conservation Field Experimentation Survey Large scale experimentation 3

4 Outline I. Results from landscape scale studies w/ remnant native forests: a. natural enemy habitat occupancy & their movement b. relationship b/t pest suppression & forests II. Results from revegetation study III. Conclude with pathway to impact Link forest habitat function with ecosystem services of pest control in agricultural landscapes Sub-tropical Coastal horticulture Sub-tropical inland Cotton-Grain system Mediterranean horticulture 4

5 Ex. 1. Do predators occupy different habitats & edges, & do they move between them? Sub-tropical, coastal horticulture, Lockyer Valley, QLD Australia Gatton, QLD Low % Forest < 5% Mulgowie, QLD High % Forest < 7% 2 kms apart Bi-directional Interception Traps Riparian Remnant Forest 2 m Edge b/t RF & Crop corn / broccoli / barley / fallow corn / broccoli / barley/ fallow 2 landscapes ( block ) 2 treatments *habitat *edge Placed on mowed grass 1 year 7days bi-weekly 3 dates 5

6 15 Species of Predators (most abundant, mostly native & known function) Micraspis frenata Diomus notescens. Melangyna spp. Sphaerophoria macrogaster Coccinella transversalis Harmonia conformis Coelophora inaequalis Hippodamia variegata Simosyrphus grandicornis Episyrphus viridaureus X 2 Micromus tasmaniae Dicranolaius bellulus Asilidae Mallada signata *No difference in insect predator abundance b/t the landscapes, occupy all habitats, but there is strong species-specific habitat preference *More predators move from riparian remnant forest into the crop than vice a versa so does a pest! *A diversity of forest habitats is important 6

7 Do the landscapes differ in total predator abundance? Mean number / day Survey 1 yr low high 5 19-Sep-7 22-Aug-7 25-Jul-7 4-Jul-7 2-Jun-7 6-Jun-7 23-May-7 7-Feb-8 9-Jan-8 12-Dec-7 14-Nov-7 17-Oct-7 1-May-8 3-Apr-8 7-Mar-8 Date F=.78, df=1, P=.3822 Is the RF edge and crop occupied similarly? *Harmonia conformis only at one site - drop *All species occupied both habitat types *No difference b/t landscapes Source df X 2 P Species <.1 Habitat * Species f yr present % of Micromus tasmaniae Melangyna spp. Simosyrphus grandicornis Hippodamia variegata Coccinella transversalis Diomus notescens Coelophora inaequalis Taxonomic groupings Lacewings Hover Flies Ladybird beetles Robber Flies Red & Blue beetles Sphaerophoria macrogaster Asilidae spp1 Micraspis frenata Mallada signata Dicranolaius bellulus Asilidae spp2 Episyrphus viridaureus 7

8 Which species is where when? Habitat * Species Occupy Rip Forest Edge More than Crop X 2 = P=.9 9 X 2 = P= RFE- 72% vs C- 28% RFE- 78% vs C- 22% Dicranolaius bellulus Episyrphus viridaureus Occupy Crop More than Rip Forest Edge X 2 =8.32 P=.4 RFE- 32% vs C- 68% Sphaerophoria macrogaster All Predators - Net Daily Immigration Gatton Site Low % Forest Mulgowie Site High % Forest * Mean number / day * Crop Rip Edge Crop Rip Edge Crop Rip Edge 3.4 per day; F=2.98, df=1, P= per day; F=4.24, df=1, P=.43 8

9 Jassid C. bimaculata F 1,3 =13.92, P=.6 RF Edge 25 Exotic grass Mean number / day F 1,3 =9.35, P=.36 Forest Edge 23/1/7 23/9/7 23/8/7 23/7/7 23/6/7 23/5/7 23/12/7 23/11/7 23/2/8 23/3/8 23/1/8 23/4/8 Date 225 spp Ichneumonid parasitoids, & spp from 28 other families Chris Burwell Saul Cunningham Anna Marcora Michael Bately 68 spp bees; 1271 individuals; 5 families 13 tal abundance Number of spp Tot /7/7 2/6/7 6/6/7 1/8/7 18/7/7 29/8/7 15/8/7 26/9/7 12/9/7 24/1/7 1/1/7 2/1/8 19/12/7 5/12/7 21/11/7 7/11/7 3/1/8 16/1/8 27/2/8 13/2/8 26/3/8 12/3/8 9/4/8 21/5/8 7/5/8 23/4/8 9

10 Ex. II. How does distance to native forest remnants & composition of landscape influence pest suppression? Cotton / Grain System, Darling Downs, QLD Pest Whitefly adults Whitefly nymphs Natural enemy parasitoids Felix Bianchi grids adjacent to forest remnants grid far from 6 % Forest forest remnants 13 % Forest 1 grids in forest Habitat Characterization 1 km Whitefly nymphs 1

11 Sampling of native forest Popular Box - Eucalyptus Acacia Salt Bush Chenopods J F M A M J J A S O N D J F M A M J J A S O N D Suppression of a cotton pest is higher adjacent to native forest remnants Native forest remnants: -are a source of natural enemies for early colonization -have higher predator : pest ratio than crop Natural enemy populations are highly variable in space and time most likely due to the condition of the forest 11

12 Rapid increase in early-season pest colonization Pest density (per plan nt) a a b Oct Oct 17-2 Oct Date placed in field F 2,36 = 8.12; P <.1 Whitefly Parasitism Location Landscape Prop. colonized Far Adjacent Remnant Low NV High NV Χ 2 = 278; P <.1 Χ 2 = 589; P <.1 Higher whitefly parasitism near native forest, landscape matters 12

13 Variability in Habitat Function - Parasitoids LOW High 6%NV 13 % NV 1 15 High NV Landscape Habitat Characterization Source for Predators and Pests = high pred : pest ratio = low pred : pest ratio = crop sample HIGH Pred : Pest Ratio Crop 1 of 6 Nat Veg 5 of 6 13

14 Ex. III. What s the risk of replacing weeds with native perennial vegetation? Western flower thrips Franklinella occidentalis Tomato Spotted Wilt virus $25m crop loss annually Approach to problem: bare earth policy Revegetation by Design 4 pest thrips Western Flower, Frankliniella occidentalis Tomato, F. schultzei Onion, Thrips tabaci Plague, T. imaginis screw lid Native perennial vegetation trial and demonstration site, Northern Adelaide Plains, South Australia 7mL plastic funnel funnel filled with flowers Turpentine-soaked cotton wick airtight plastic jar thrips extracted to bottom of jar 19 weed species, 13 plant families 13 native perennial plant species, 3 plant families Treatments = adjacent (<1m) or far (>1m) vegetable crops 1 year, 524 samples, 49 dates 14

15 *High-risk weeds *Low risk options for revegetation w/ native plants *Incentive of better pest control, additional income, reduced pest control costs Adjacent (<1 m) Far (>1 m) ps present Prop portion of plants w/ thri Plant categories at, Plant categories at, Plant categories at, WFT Tomato thrips Mean number (+ 1 SD) / plant 15

16 Risk of weeds vs native perennial plants Odds ratios Brassicacea (5) 4.6 Solanaceae (2) 8. Asteraceae (3).42 Native Chenopodeacea Salt bush.8 Native Myrtaceae.7 *important reservoir of natural enemies *Revegetation 2.5 times cheaper than bare-earth (weed control over 1 yrs) *Harvesting of seeds provides income *Low growing, weed suppressive native veg, not trees Stephens et al 26. Aus J Ent 45: Schellhorn et al 29 IPM: Innovation-Development Process, Springer Press. Pp Schellhorn et al 21 Bull Ent Res (in press) 16

17 Implications Science Diversity of forest habitats is important for agricultural ecosystem services *allows flexibility throughout the year & in changing environments (cf climate change) Natural enemies are using forest habitats, moving into crops (pests too) Attacking pests early Industry change of practice Field-based and on-farm management of pests is only a part of pest management Maintaining / managing native vegetation is a key part of capturing ecosystem services Pathway to Impact Who are the natural enemies of pests? Do they attack the pests? Multi-habitat users? Do they keep pest thresholds Do they move lower for longer? from forests into crops? Change of practice Do farmers spray insecticide later in season & less overall? Outcome: Capture better pest control while maintaining biodiversity conservation Farmers maintaining / managing native forests Monitor progress Pest Suppressive Landscapes 17

18 Acknowledgements Felix Bianchi Anna Marcora Greg Daniels UQ Mulgowie Farms Chris Burwell, QLD MS Levy payers! Saul Cunningham Andy Hulthen Lynita Howie Belinda Walters Bronwyn Walsh DPI&F David Carey DPI&F 18