Steps towards food web management on farms CENTRALE LANOBOUWCATALOGUS 0000 0807 2635 Promotoren : Prof.Dr .Ir .E.A . Goewie Hoogleraar ind eMaatschappelijk e Aspecten van deBiologisch e Landbouw Prof.Dr .Ir .A.H.C .va nBrugge n Hoogleraar ind eBiologisch e Bedrijfssystemen Co-Promotor: Dr.W . Joenje Universitair Hoofddocent, leerstoelgroep Gewas-e n Onkruidecologie Samenstelling Promotiecommissie: Prof.Dr .Ir .P.C . Struik (Wageningen Universiteit) Prof.Dr .Ir .L .Brussaar d (Wageningen Universiteit) Dr. G.R.d eSno o (Centrum voor Milieukunde, Universiteit Leiden) Prof.Dr . T.Tscharntk e (Georg-August Universitat, Gottingen) >,i^y .'.'•'..'- .' IC Steps towards food web management on farms FransW . Smeding Proefschrift terverkrijgin g vand egraa dva n doctor opgeza gva n derecto r magnificus van Wageningen Universiteit, Prof.Dr.Ir. L. Speelman inhe t openbaar te verdedigen opwoensda g 6jun i 2001 desnamiddag so mhal ftwe e ind eAul a 1 > Smeding,F.W. , 2001 Stepstoward s food webmanagemen t on farms Ph.D.Thesis ,Wageninge n University, -With references-, With summary in English and Dutch ISBN 90-5808-414-0 Subject headings:agroecosystem , farming system, biodiversity, food web,predator , organic farming, pestmanagement , ecological infrastructure, field margin, Diptera, Carabidae, Aranae, Skylark,Alauda arvensis M/UatfZol.M^a Stellingen 1. Biologische landbouwbedrijven hebbenvoo r organismen,hoge r ind evoedselketen ,ee n groteredraagkrach tvoo r instandhoudingva n debiodiversitei t dan conventionele landbouwbedrijven. Ditproefschrift. Vergrotingva nhe tvoedselaanbo d aand ebasi sva n hetvoedselweb , isee nvoorwaard eo m deto p daarvant e vergroten,hoewe lterugkoppelingen , die dit effect tegenwerken ookt e verwachten zijn. Ditproefschrift. 3. Extrazor gva n boerenvoo r deecologisch e infrastructuur, ondermee rdoo r gericht beheer van sloten en slootkanten,heef t een sterk positiefefFec t op debiodiversitei t van het platteland.Dit proefschrift. De ontrafeling van het menselijk genoom isbelangrijk , omdatdi t onderzoekd e veronderstelde bepalendero lva ngene n inlevend e systemen relativeert. StephenJay Gouldin NRC Hcmdelsblad dd 20maart 2001. 5. Deoorspronkelijk e ideeenva nd ebiologisch e landbouwzij n doorwetenschapper s eerst als'subjectie f afgedaan, maarworde ngestaa g ontdekt alsbruikbaa r en'objectie f . Ecologisch onderzoek moetuitgaa nva nniet-begrepe n waarnemingeni nhe tvel d enmoe t deuitbreidin g van detheori e daaraandienstbaa r maken,i nplaat sva ndez evooro pt e stellen. 7. Wageningen Universiteit stoot studenten afdoo rretorisch e vragen entechnisc h vernuft, enzo u studenten aantrekken door hettone nva ntwijfe l enzor gove r actueleprobleme n in de landbouw. 8. Het opsteed sjonger e leeftijd aanspreken van rationele vermogens vankindere n leidtto t vervreemdingva nd elevend eomgevin ge nasociaa l gedrag. Stellingen bij het proefschrift vanFran sW . Smeding,Steps towards food webmanagement on farms, 6juni 2000 Tom y father andmothe r whonurture dm yinteres tan dlov e ofnatur e andth e countryside andi nmemor yo f Peter A.va n derWerf f (1949-1996) whogreatl y encouraged mei nthi swor k Preface "Our attention isdraw nb y ablackbir d screaming. It isJanuar y 28th and Ia m writing this thesis. Iloo k through thebedroo m window with mywif e and four-year-old son andw ewatc h a sparrow hawk with ablackbir d in his claws.An d Igues s that his victim is "vlek"("spot "i n English),th e female blackbird with onewhit e feather onto p of each shoulder, that lives around ourhouse . Impulsively Ira n downstairs, through the front door in anattemp t to rescue theblackbird ; but the sparrow hawk flies away carrying, of course, its prey". That evening Ifel t abi t confused about this event. How could abiologis t studying food webs, interfere with thehun t of animpressiv e bird ofprey ? Perhaps ithelpe d met o realise more profoundly that trophic interactions areno t figures buthav e to dowit h life and death. Then I remembered an intriguing story from theHind u epicMahabharata , which tells of arighteou s kingwh oprotecte d a frightened dovefro m apursuin g falcon. The falcon beggedth ekin gt o lethi m eat and warned thekin g that his interference with 'Dharma' (perhaps 'natural order', in this thesis) would create fate. However, the king stuck to hisprinciple s andpromise d the falcon aquantit y ofhi sow n flesh that equalled the weight ofth e dove. Eventually thekin g was eaten to thebone s andbot h the falcon andth e dove laughed atth ekin g and flew away. Although theMahabharat a story is mysterious tome ,i traise s an association that Ihav e wanted topu t into theprefac e of thisthesis .I tconsider s thatther e isn o doubt that man,a s part ofnature , should interfere in ecosystems to feed himself.However , ifhi s interference goesbeyon d his proper needs, and are, sot o say, 'none ofhi sbusiness' , hema y not really know what he isdoin g andma y therefore unwittingly disturb thenatura l order. Thusth e work ofmoder n biologists like Rupert Sheldrake convinced me that current biology has alimite d comprehension of living systems. A'righteou s ecologist'(wh o is for example interfering with food webs) should, therefore, remain modest, whilst keeping anope n mind and anope neye , both when looking atnatur e and athi s ownmotives . This might help topreven t his worst errors.Fortunatel y that afternoon my attempt to interfere with thehuntin g sparrow hawk failed, because Iwoul d not haveknow n how to care for aseverel y wounded blackbird. The small maps ofth eFlevolan d polder inthi s thesis have aspecia l meaning tome ,becaus e they echo thelarg eembroidere d map ofth eNoordoostpolde r that hung onth ewal l ofth e dining room when Iwa s achild . My grandfather devoted hisprofessiona l life topolde r reclamation. His polder service employed outstanding ecologists like W.Feeke s andD . Bakker, who were engaged onbot h applied and fundamental questions,whic hwa s much appreciated by my grandfather (som y father told me).Howeve r the aims of reclamation concentrated onth emateria l concerns of food and labour, reflecting needso f society attha t time andresultin g in large scaled rational landscapes. Following this tradition my father contributed to the development of agricultural education. It ism y sincere and modest wish that mycurren t work may contribute to the implementation of awide r scope of agricultural production, and address thephysica l aswel l asth e emotional and spiritual needs. Without the support of many people, this thesiswoul d never havebee n accomplished. Ia m grateful to: Mypromote r Eric Goewie who gavem e space and confidence tobegi n theproject , andwh o strengthened mybackbon e and inspired me inmoment s ofhesitation . My promoter Ariena van Bruggen who, after her arrival in Wageningen,neede d only ahal f word to understand the contents ofth ewor k andhelpe d me toproces s thepiled-u p field data. My co-promoter Wouter Joenje, withwho m Ishar e common interests in ecological theories and field biology, particularly ofpionee r successional stages andth epolders . The funding organisation (LNV-DWK) for supporting asmal l research group sotha t they could embark upon aprojec t with anuncertai n outcome.Howeve r thisresearc h groupwa s much strengthened thanks toth e invaluable co-operation and friendship ofth eresearcher s of Plant Research International (formerly IPO-DLO):Kee s Booij, Clasien Lock and Loes den Nijs. The supervision committee ofth eprojec t 'Food web management on farms', that enthusiastically guided theresearc h by it's reflections onou rplan s and results. The committee included: Geertd e Snoo (CML-Universiteit Leiden),Fran k vanBell e (Vereniging Natuurmonumenten), Paul Aukes (IKCNatuur) ,Pau l vanHa m (IKCLandbouw) , Tibbe Breimer (LNV-DWK), aswel l asKee s Booij, Wouter Joenje (the chairman) and EricGoewie . Myresearc h assistant, AndreMaassen , whowa s apilla r of strength with all our laborious activities,th e designer ofinstrument s and forms, companion ofth ehundred s of kilometres walked whiledat a collecting, and theon ewh o could, if asked, always help meremembe r the aimso fmy work . TheMS c students who didreconnaissanc e work for the thesis: ElkeBoesewinkel , Jacinta de Huu,Nathali e Reijers, Julien Cothenet, Edwin Coomans, HongNan , and inparticula r Bart Venhorst who also supported the field work andinsec t identification. People with whom Iexchange d ideas orwh oprovide d valuable information that contributed tothi sthesis :Gerar d Oomen,Wille mBeekman , JanDie kva nMansvelt , Sjaak Wolfert, DorineDekker , Derk Jan Stobbelaar, Karina Hendriks,Dark o Znaor, Prof.R.A.A . Oldeman, Ruurdtje Boersma, Manolis Kabourakis, AnorFiorini ,Han s Esselink (who named 'Voedselwebbeheer'), Joop Schaminee, John Vandermeer, Yvette Perfecto, Julian Park, Nigel Boatman, Flip vanKoesveld , JanJaa p van Almenkerk, Wolter van der Kooij, Rob Boeringa, HenkKloen ,Yvonn e van den Hork,Moniqu e Bulle, members ofth e PE-Phd discussion group 'Plant and Crop Ecology', Paula Westerman, Eefje den Belder, Walter Rossing. The farmers who allowed me access tothei r farms and who gave their timet o answerm y questions; inparticular , especial thanks aredu et o Maart en Piet van Andel, Carl enRin i Ferket, Jan enMarlee n van Woerden-Zeelenberg, Lex enJanni e Kruit, Henk Leenstra, Evert- JanRienks ,Jansj e Timmermans,Douw eMonsma ,He m and Marjon Cuppen, staff and residents of'Thedinghsweert ' for their hospitality and interest. Joop Overvest, Johan Jorink, Harry Alting andcolleague s (staff andworker s ofth eA.P . Minderhoudhoeve), Swifterbant, and Egbert Lantinga (chairman ofth e research team) for discussing myresearc h andimplementin g recommendations onth e ecological farm. Allth epeopl e who did the organisation behind theproject , particularly Gijsbertje Berkhout. Thestaf f ofUnifar m whower e alwayswillin g to support the project. Colleagues ofth e Biological Farming Systems groupwh o accepted my absence, whilst encouraging met o finish mythesi s research. NickyCampbel l ofCombpyne , Devon, UK for correcting the English. Wampieva n Schouwenburg for help with the final editing.