However,celllevel sciencewiil contribute very little to the well-being or survival of human civilization if we understandthe higher levels lc-t of organization so inadequatelythat we can hnd no solutions to population over- rle growth, pollution, and other forms ofsocietal and environmentaldisorders. P Odum ; Barrett Ecologyseek slnthesis, not separation.
The revival of the holistic disciplinesmay be due at leastpartly to citizen dissatisfac- is tion with the specializedscientistwho cannot respond to the large-scaleproblems ue that need urgent attention. Accordingly, we shall discuss he ecologicalprinciples at the ecosystemlevel, with appropiate attention to organism, te.
This is the philosophical basisfor the organizationo[ the chaptersin this book. Fortunately,in the past I0 years,technologicaladvanceshaveallowed humans to deal quantitativelywith large,complex systemssuch as ecosystemsand landscapes. Technologyis, of course,a double-edgedsword: it can be the means of underctandingthe whole- he nessof humans and nature or of destroyingit. Ex- in amplesof such transcending functions are behavior,development,diversity, ener- rle getics,evolution, integration,and regulation seeFig.
Natural selectionevolulion, for example,in- an volvesmutations and other direct geneticinteractionsat the organismlevel but indl- rect coevolutionaryand group selectionprocessesat higher levels.
As noted on the right-hand side ne of Figure , there are no set-pointcontrolsabovethe organismlevel no chemostats oI or thermostatsin nature. Accordingly, feedbackcontrol is much looser,resulting in ne pulsing rather than sieady states. The term homeorhesis, from the Greek meaning n- "maintaining the floq" has been suggestedfor this pulsing control.
Failure to recognizethis differencein cybernetics the sci- encedealingwith mechanismsof control or regulation has resultedin much confu- sion about the realitiesof the so-called"balanceof nature.
Becauseecology is a broad, muLtileveldiscipline, it inrerfaceswell with lraditional disciplinesthat tend to have more narrow focus.
During the past decade,there has been a rapid rise of interfacefields of study accompaniedby new societies,journals, symposium volumes, books-and new careers.
Ecological economics,one of the most important, was mentionedin the frrst sectionin this chapter. Others that are re- ceiving a greatdeal oI attention,especiallyin resourcemanagement,are agroecology, biodiversity,conservationecology,ecologlcalengineering,ecosystemhealth, ecotox- icology,environmentalerhics,and restorationecology. In the beginning, an interface effort enriches the disciplines being interfaced.
Lines of communication are established,and the experliseo[ narrowly trained "ex- perts" in each field is expanded. However, for an interfacefield ro becomea new dis- cipline, somethingnew hasto emerge,such asa new conceptor technology.
The con- cept oInonmarket goodsand services,for example,was a new concept that emerged in ecologicaleconomics,but that inidally neither rraditional ecologistsnor econo- mists would put in their textbook Daily ; Mooney and Ehrlich Throughout lhis book, we will reler to natural capital and economiccapital.
Nat- ural capital is defined as the benefits and servicessupplied to human societiesby natural ecosystems,or provided "free of cosf'by unmanagednatural systems. These benehtsand servicesinclude purificadon oI water and air by natural processes,de- composition of wastes,maintenanceof biodiversity, control of insect pests,pollina- tion o[ crops, mitigation of floods, and provision o[ natural beauty and recreation, amongothers Daily Economic capital is defined as the goods and servicesprovided by humankind, or the human workforce, tlpically expressedas the gross national product GNP.
Gross national product is the total monetary value o[ all goods and serl,rcespro- vided in a country during one year. Natural capital is typically quantifred and ex- pressedin units of energy,whereaseconomic capital is expressedin monetary units Table Only in recent years has there been an attempt to value the world's ecosystemservicesand natural capital in moneury terms.
Costanza,d'Arge, et al. Thus it is wise to protect natural ecosystems,both ecologicallyand economically,becauseof the benehtsand servicesthey provide to human societies,aswill be illustrated in the chantersthat follow.
Ifecology is to be discussedat the ecosystemlevel, for reasonsalreadyindicated,how can this complex and formidable systemlevel be dealt with? We begn by describing simplifred versionsthat encompassonly the most important, or basic,propertiesand functions. Because,in science,simplified versionsof the real world are called models, it is appropriatenow to introduce this concept.
Ultimately, however, models musr be sraristicaland mathe- matical Uormdl i[ their quantitative predictions are ro be reasonablygood. Thus, a mathematicalformulation can often be "tuned" or refined by com- puter operations to improve the "nC'to the real-world phenomenon. Above all, d. When a model does not t5- work-when it poorly mimics the real world-computer operadonscan often pro- vide cluesto the refinemenmor changesneeded.
Once a model proves to be a useful ed mimic, opponunities for experimentationare unlimited, becauseone can introduce o- new factorsor perturbationsand seehow they would affectthe system. Even when a model inadequatelymimics the real world, which is often the casein its early stages rt- of development,it remainsan exceedinglyuseful teachingand researchtool if it re- bt vealskey componentsand interactionsthat merit specialattention.
Watt , for example,stated,"We do not needa rremen- rd, dous amount o[ information about a great many variablesto build revealingmathe P. Shown are d's two properties, P1and P2,that interact, I, to produce or alfect a third prope y, P], aL. Five flow pathways,F, are shown, tar with F1 representingthe input and F6 the output for the systemas a whole. Thus, at a minimum, there are five ingredientsor componentsfor a working model of an eco- of logrcalsituation, namely, l an energ sourceor other outside forcing function, E;.
P"; 3 flow pathways, Fr, F2,. Fi, showing where energyflows or material transfersconnectpropertieswith each other and with forces; 4 interaction functions, I, where forcesand propertiesinteract to modify, amplify, or control llows or createnew "emergenC'properties;and 5 feed- back loops, L.
Figure could serveas a model for the production of photochemicalsmog in the air over Los Angeles. Under the driving force of sunlight energy,E, rheseinteract to produce photochemicalsmog, P1. In this case, rn8 the interaction function, l, is a slrrergisticor augmentativeone, in that P3is a more. Compartment diagramshowingthefjvebasjccomponents of primaryInterestrn modelingecological systems.
Or I cou]d be a seasonaiswitchi[ pr feedson plants during one part of the yearancLon animalsduring anorherseason. Or I could be a thresholdswitch il P, greatlyprelcrsanimalfood and switchesto plantsonly when P, is rcducedto a low level.
Figure l-6 is a simplilieddiagramoIa systemth fearures a feedbackloop in which "downstream,, ourput,or so;e part o[ ii. Compartmentmodelwith afeedbackorcon- trol loop that transformsa linear system into a partiallycycli- cal one. Interactionof positive and negativefeedbacksin the relation- ships of atmosphericCOr, climate warming,soilrespiration, andcarbonse' questration modifiedafter Luo et al.
By and large, natural ecosystemshave a circular or loop design mther than a linear structure. Feedbackand cybernetics,the scienceof :p- controls, are discussedin detail in Chapter 2. An increase let in CO2 has a positive greenhouseeffect on global warming and on plant growth.
This acclimation results in a negativefeedbackon la carbon sequestrationin the soil, thus reducing emissionof CO2 to the atmosphere, c'n accordingto a study by Luo et al. Odum energylanguage H. P Odum ; H. Odum are depicted as used in this book. Also, in this diagram estimatesof the amount of energ'yflow through the units are shown as indicators of the relativeim- portanceof unit functions. Once an ecosystem,ecological situation, or problem has been properly dehnedand bounded, a testablehlpothesis or serieso[ hlpotheses is developedthat can be rejectedor accepted,at leasttentatively,pending further expedmenLationor analysis.
For more on ecologicalmodeling, seePattenand Jorgensen , H. Odum , and Gundersonand Holling Energy circuit Consumer A pathwayor Usesproducer energy flowof energy for self-maintenance.
L Heatsink Degradedenergy afterusein work Twoor moreflows of energyto producea high-qualityenergy. Figule , TheH. Odumenergylanguagesymbolsusedin modeldiagramsin this book. Ecosystemmodel using energylanguagesymbolsand including estimatedratesof energyflowfor a Flor- Heatsink usedenergy ida pineforest courtesyof H.
P Odum noted that ecologyhad becomea new holistii discipline, having roots in the biologicai, physical,and social sciences,rather than jusr a iubdiscipline ofbiology. Thus, a goal of ecoiogyis to link the natural and sociaisciences. It should be noted that most disciplinesand disciplinary approachesare basedon increased specializationin isolation Fig.
Unfonunately, the multidisciplinary approaches lacked cooperation or focus. Designed to educate a wide audience about ecological science, this biology text shows you the application of ecological principles in the real world and how to use what you learn to solve problems in fields such as resource management, This is a thoroughly revised and updated edition of an authoritative introduction to ecological modelling.
This text takes an integrated approach to human ecology, blending biological ecology with social sciences approaches. The book discusses the modelling procedure in detail and gives a step-by-step presentation of the development of models. Advantages and shortcomings of each step are discussed and simple examples are used to illustrate all the steps.
With that in view, an attempt has been made in this meticulously planned volume to cover several aspects of both basic ecology and environmental biology, along with current status of various environmental problems A college text which provides a comprehensive overview of the principles and concepts of ecology, environments, and ecological technology. Designed to educate a wide audience about ecological science, this biology text shows you the application of ecological principles in the real world and how to use what you learn to solve problems in fields such as resource management, conservation biology, ecological toxicology, ecosystem health, landscape ecology, and restoration ecology.
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