Understanding Complex Ecosystem Dynamics: A Systems and Engineering Perspective PDF
Preview Understanding Complex Ecosystem Dynamics: A Systems and Engineering Perspective
UNDERSTANDING COMPLEX ECOSYSTEM DYNAMICS A Systems and Engineering Perspective UNDERSTANDING COMPLEX ECOSYSTEM DYNAMICS A Systems and Engineering Perspective WILLIAM S. YACKINOUS AMSTERDAM (cid:129) BOSTON (cid:129) HEIDELBERG (cid:129) LONDON NEW YORK (cid:129) OXFORD (cid:129) PARIS (cid:129) SAN DIEGO SAN FRANCISCO (cid:129) SINGAPORE (cid:129) SYDNEY (cid:129) TOKYO Academic Press is an imprint of Elsevier AcademicPressisanimprintofElsevier 125LondonWall,London,EC2Y5AS,UK 525BStreet,Suite1800,SanDiego,CA92101-4495,USA 225WymanStreet,Waltham,MA02451,USA TheBoulevard,LangfordLane,Kidlington,OxfordOX51GB,UK Copyright©2015ElsevierInc.Allrightsreserved. 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ISBN:978-0-12-802031-9 LibraryofCongressCataloging-in-PublicationData AcatalogrecordforthisbookisavailablefromtheLibraryofCongress BritishLibraryCataloguinginPublicationData AcataloguerecordforthisbookisavailablefromtheBritishLibrary ForinformationonallAcademicPresspublications visitourwebsiteathttp://store.elsevier.com/ CoverCredit:JoyceYackinous PREFACE “Lookdeep,deepintonature,andthenyouwillunderstandeverythingbetter.” AlbertEinstein1 Ihavehada34-yearprofessionalcareerasasystemsengineeratBellLabo- ratories.Originally, The BellTelephone Laboratorieswas theresearchand developmentarmoftheBellSystemintheUnitedStates.Fromthe1920sto about2000,BellLabswasacknowledgedbymanytobethepremierR&D labsintheworld.Theterm“systemsengineering”wascoinedatBellLab- oratories in the 1940s. Throughout my career, I worked to solve systems problemsforBellLabsandforitsclientsacrosstheUnitedStatesandaround the world. During that time, I acquired a very significant set of skills and perspectiveswithrespecttothepracticeofsystemsengineeringandthesys- tems approach. In my Bell Labs work, I focused on building human-made systems(somewouldsay“artificial”systems).Ihavealwaysthought,how- ever,thatthissamesetofskillsandperspectivescouldbeappliedveryben- eficially to understanding natural systems—specifically natural ecological systems. After taking early retirement from Bell Labs in 2001, I began to do just that. I began to follow Einstein’s admonition (above) in earnest. Myfirsttaskwastoexplicitlydefineanddescribethesystemsandsystems engineering skillset thatIhadacquiredduring mycareer.The scienceand engineering working environment at Bell Labs was outstanding and full of opportunities. Over the years, I was fortunate2 to be in a position to earn everymajorBellLabstechnicalawardandhonorariumincludingthehighest and most prestigious—Bell Labs Fellow. As a result, I frequently had the opportunity to give talks and seminars on systems engineering both inside Bell Labs and at major universities. I gave presentations, on behalf of Bell Laboratories, to graduate engineering and computer science students and facultyatStanfordUniversity,UCBerkeley,CalTech,UCLA,University ofArizona,UniversityofTexas,PurdueUniversity,andOxfordUniversity. Myobjectiveinthesevarioustalkswastodescribemyviewoftherequired skills and perspectives necessary for the successful practice of systems 1AlbertEinstein,inTheQuotableEinstein,PrincetonUniversityPress,1996,p.32. 2Ihavefoundthatsuchopportunityandgoodfortuneisdirectlyrelatedtohavingverygoodbosses. TheywereplentifulatBellLabs.I’vehadsomeofthebest. ix x Preface engineering.Beginningwiththematerialcomprisingthetalks,Ihavedevel- oped “A Systems Engineering Skills Framework.” We will discuss that in Chapter 1. Mynexttask—andmyprimaryongoingworkobjective—wastheappli- cation of those systems and engineering skills to increase understanding of complex natural systems. Given the state of our planet’s environment, I decidedthatthemostimportantandrelevantnaturalsystemsformetocon- siderwereecologicalsystems.Ineededtoengage,therefore,inverysubstan- tial ecological system study and research. To that end, I pursued a PhD in EcologyattheUniversityofGeorgia’sEugeneP.OdumSchoolofEcology. Dr.EugeneOdumwasaveryinfluentialecologist,apioneerintheareaof systemsecology,andafounderoftheecologyprogramattheUniversityof Georgia.Dr.BernardC.PattenwasmyPhDmajorprofessorandmydoc- toral committee chairperson. He is a systems ecologist and is recognized as oneofthepremierecologicalsystemmodelersandecologicalnetworkana- lystsinthefield.IstudiedwithDr.PattenandtheSystemsandEngineering Ecology group—an interdisciplinary group of professors and graduate stu- dents at the University of Georgia. I received my PhD degree in Ecology in December 2010. My doctoral research and dissertation on “Emerging Principles of Ecological Network Dynamics” are prominently reflected in this book. AsIhave explained,the systemsandengineering skills andperspectives thatIacquiredatBellLabsareabsolutelyessentialtomyecosystemresearch. My related systems and engineering academic background also plays an important role. My early degrees—bachelors and masters—are in electrical engineering.Mymaster’sdegreework(andearlyBellLabswork)included the areas of communications theory, signal processing theory, information theory,controltheory,andnetworktheory.MymorerecentPhDacademic work has enhanced my understanding of the various important subsets of complexsystemstheory.Allofthesescientificdisciplinesandtheirassociated methods and tools contribute to my current complex system dynamics work. You will notice that throughout the book. Highly complex systems (including ecosystems) take the form of net- works.Myworkaddresseschallengingandopenissuesofcomplexsystem network dynamics. It pushes boundaries and explores frontiers. Thus far, mainstream network science has focused primarily on understanding net- work structure. Network dynamics is a much tougher issue. Melanie Mitchell,inherbookoncomplexity,hassaid,“Tounderstandthedynam- ics ... network science will have to characterize networks in which the Preface xi nodes and links continually change in both time and space. This will be a majorchallenge,tosaytheleast”(Mitchell,2009).DuncanWattshassaid, “Next to the mysteries of dynamics on a network ... the problems of networks that we have encountered up to now are just pebbles on the seashore” (Watts, 2003). In this book, we take on the challenge of understanding complex system network dynamics—specifically complex ecosystem network dynamics. Thecomplexsystemdynamicsresearchdescribedinthebookisinnova- tive and unique in many respects. The full set of experiences, approaches, methods, and tools employed here have never before been applied to eco- logical systems (or to complex systems in general). The work represents a “freshlook”atecologicalnetworkdynamics.Ihavebegunwithsubstantial systems and engineering experience and knowledge; combined that with PhD-levelstudyofecology;andfurther,havesupplementedthoseresources with additional study of complex systems theory in the areas of networks, nonlineardynamics,cellularautomata,androughness(fractals).Ihaveassim- ilated,extended,andcombinedalloftheseresourcesinnewwaystocreatea fresh view of complex system dynamics. That process is the working defi- nitionofinnovationandcreativity.Creativityis“theabilitytodiscovernew relationships, to look at subjects from new perspectives, and to form new combinations from two or more concepts already in the mind” (Evans, 1991). Scientific discovery often arises from “picking up the stick from theotherend”(Butterfield,1960).Theotherend,inthiscase,isthesystems and engineering perspective. This book clearly takes an interdisciplinary perspective and contains many newideas thatsometimes donot represent merely small, incremental changes to existing scientific paradigms. Although such new perspectives andideasareoftennecessarytopushresearchboundaries,theyarenotalways easilyacceptedbynaturalscienceinvestigatorswhoprefermoretraditional approaches and paradigms. (Thomas Kuhn (1996), in his classic book The Structure of Scientific Revolutions, comprehensively describes these effects.) Someoftheideasandhypothesesinthebook,therefore,maybecontrover- sial.Thatcircumstancemaygenerateanincreasedfocusonimportantcom- plex system issues and motivate scientists across disciplines to ponder and explore these issues. In my view, that would be a very desirable outcome ofthebook.Itwouldhelptofurtherourcollectiveunderstandingofcom- plex system dynamics. Throughoutthisbook,Ireferenceandquotealotofverysmartpeople. Except for afew,I knowthese peopleonly by theirwork.Their workhas xii Preface been exceedingly helpful. I quite agree with the sentiment that Thoreau3 expressed long ago in his Journals: “He who speaks with most authority onagivensubjectisnotignorantofwhathasbeensaidbyhispredecessors. He will take his place in a regular order, and substantially add his own knowledge to the knowledge of previous generations.” I certainly do not claim that I speak with “most authority”—but I am pleased to have the opportunity to express my views in this book. We began this preface with some advice from Albert Einstein. I have attemptedtolookdeepintonature.IthinkthatnowIreallydounderstand everything better. I’m still working on it .... Bill Yackinous November 2014 3 HenryDavidThoreau,Journals,December31,1859. INTRODUCTION Theprimarypurposeofmyworkinthisbookistoincreasetheunderstand- ingofcomplexsystemdynamics—inparticular,complexecologicalsystem dynamics. My systems and engineering perspective is foundational to this effort.Ibeginbydefininganddescribingpertinentsystemsandengineering skillsandpractices,includinganexplanationofthesystemsapproachandits majorelements.Consistentwiththesystemsapproach,Ithenformulatean ecosystem dynamics functionality-based framework to guidemy investiga- tions.Complexsystemstheory,acrossmanysubjectmatterareas,iscrucialto theworkofthisbook.Icoverrelevantnetworktheory,nonlineardynamics theory, cellular automata theory, and roughness (fractal) theory in some detail. This material serves as an important resource as we proceed in the book.Next,inthecontextofalloftheforegoinginvestigation,Iconstruct aviewof thecharacteristics of ecological networkdynamics.This view,in turn,isthebasisforthecentralhypothesisofthebook,i.e.,ecologicalnet- works are ever-changing networks with propagation dynamics that are punctuated,local-to-global,andperhapsmostimportantlyfractal.Toanalyze andfullytestthishypothesisIdefine,design,anddevelopaninnovativeeco- logicalnetworkdynamicsmodel.Themodelingapproachseekstoemulate features of real-world ecological networks. The approach does not make a priori assumptions about ecological network dynamics, but rather lets the dynamicsdevelopasthemodelsimulationruns.Modelanalysisresultscor- roborate the hypothesis. Additional important insights and principles are suggestedbythemodelanalysisresultsandbytheothersupportinginvesti- gations of this book—and may serve as a basis for going-forward complex systemdynamicsresearch,notonlyforecologicalsystemsbutalsoforcom- plex systems in general. “MAP” OF THE BOOK Thebookhassixmajorpartscomprisedofnineteenchapters.Thereisalso an appendix. An overview of each of the book’s components follows. Part I The Systems and Engineering Perspective PartI(Chapters1through4)providesacomprehensivelookatthesystems and engineering perspective that is foundational to the work of this book. xiii xiv Introduction Chapter 1 describes my view of systems engineering skills, the systems approach, and the associated systems perspectives that can be beneficially appliedtounderstandinghighlycomplexnaturalsystems.Chapter2discusses additionalviewsonsystemsthinkingfromthescientificcommunity—aswell as more of my own views. In Chapter 3, I detail three important concepts that I consider to be major elements of the systems approach. They are: a blend of synthesis and analysis; network thinking; and the systems triad. Note that traditional scientific research (including ecological research) is most often conducted using a reductionist approach rather than a systems approach.Chapter4addressesasignificantpotentialproblemwiththeindis- criminate use of reductionism, i.e., reductionism can isolate the target of investigation from the larger system in which it resides and thereby cause information loss. Part II A Function-Structure-Process Framework for Ecological System Dynamics In Part II (Chapters 5 through 7), I construct and describe a functionality- basedframeworkthatprovidesaunifyingcontextforexploringprinciplesof ecosystemdynamics.Insystemsengineering,Ihavefoundthatsuchaframe- work is essential for specifying and guiding the design and development of artificial (human-made) systems. In systems ecology, such a framework is equally essential for understanding natural systems. Chapter 5 provides an overviewofthisecosystemdynamicsframework—whichconsistsofopera- tional, developmental, and core functional tiers. In Chapter 6, one of the core ecological system functions, regulation/adaptation, is discussed in detail. Chapter 7 addresses the developmental tier. I make the case that thespeciesevolutionfunctionprovidesthebasisforauniversaldevelopment model. The operational tier becomes our focus in Parts IV and V of the book. (All of the elements of the framework are discussed, to varying degrees, throughout the book.) Part III Complex Systems Theory: Networks, Nonlinear Dynamics, Cellular Automata, and Fractals (Roughness) InPartIII(Chapters8through12),weconductanextensivereviewofthe pertinent extant complex systems theory. Chapters 8 and 9 cover network theory. Those two chapters address the structure aspects and the dynamics aspects, respectively, of complex networks. Chapter 10 reviews nonlinear dynamics theory. Chapter 11 is about cellular automata investigations and associatedemergingcomplexsystemprinciples.Chapter12addressesfractals Introduction xv (roughness theory). In some areas, I provide additional commentary based on my systems, engineering, and ecological perspectives. The material of PartIIIservesasavaluableandnecessaryresourceforourwork.Application and, in some cases, extensions of the theory contribute to a “synthesis of ideas” that is pursued in the subsequent parts of the book. Part IV A View of the Characteristics of Ecological Network Dynamics Basedonknowledgeofthesystemsapproach(PartI),theecosystemdynam- icsframework (PartII), and applicablecomplex systemstheory (PartIII), a viewofthecharacteristicsofecologicalnetworkdynamicsisconstructedin PartIV(Chapters13–15).First,wedoabitmoreinvestigationtoproperly set thestage. Chapter 13addresses thehuman perceptualcontext in which weareworking,especiallythehumantendencytoseesmoothness,stability, andcontinuityinthenaturalworld—evenwhentheyareabsent.Chapter14 considers the nature of order and complexity in ecological systems—and their relationships—to gain additional insights into the behavior of highly complexsystems.Nowwearereadytoproceedwiththedynamicscharac- teristics.Chapter15describesacomprehensiveviewofthebehavioralchar- acteristicsofecologicalnetworkdynamics,whichisthebasisforthecentral hypothesisofthebook:ecologicalnetworksareever-changing,“flickering” networks with propagation dynamics that are punctuated, fractal, local-to- global, and enabled by indirect effects. Part V Modeling Ecological Network Dynamics and the Generation and Analysis of Results In Part V (Chapters 16–18), I describe the development of an innovative ecologicalnetworkdynamicsmodel,thegenerationofresults,andtheanal- ysis of those results in order to test our central characteristics hypothesis. Model requirements are the subject of Chapter 16. Model software design and development are covered in Chapter 17. The software implements the ecological network operational model, the required analysis activities, andtheneededgraphicscapabilities.Chapter18isallaboutresults.Ecolog- ical network dynamics results are generated, displayed, and analyzed. The specific dynamics results categories are: operational propagation flow; network propagation events; propagation path length; indirect effects; and network connectivity. The characteristics hypothesis is fully tested—and corroborated.
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