Applications from food web and ecosystem theory - Ecological Applications: Toward a Sustainable World - page 241

9 Applications from food web and

ecosystem theory

Food webs link the community of species together in predator-prey, parasite-host and competitive interactions.
They also provide the ecosystem pathways along which fl ow energy and nutrients. Managers need to adopt a
broad ecosystem perspective to react to problems as diverse as human disease transmission, excessive nutrient
enrichment of water bodies, and even the loss of protection provided by intact ecosystems against fl oods and
storms.

Chapter contents
9.1 Introduction 230

9.2 Food web theory and human disease risk 234

9.3 Food webs and harvest management 236

9.3.1 Who gets top spot in the abalone food web - otters or humans? 236

9.3.2 Food web consequences of harvesting fi sh - from tuna to tiddlers 238

9.4 Food webs and conservation management 239

9.5 Ecosystem consequences of invasions 240

9.5.1 Ecosystem consequences of freshwater invaders 240

9.5.2 Ecosystem effects of invasive plants - fi xing the problem 241

9.6 Ecosystem approaches to restoration - fi rst aid by parasites and sawdust 242

9.7 Sustainable agroecosystems 245

9.7.1 Stopping caterpillars eating the broccoli - so that people can 245

9.7.2 Managing agriculture to minimize fertilizer input and nutrient loss 245

9.7.3 Constructing wetlands to manage water quality 247

9.7.4 Managing lake eutrophication 248

9.8 Ecosystem services and ecosystem health 249

9.8.1 The value of ecosystem services 249

9.8.2 Ecosystem health of forests - with all their mites 252

9.8.3 Ecosystem health in an agricultural landscape - bats have a ball 253

9.8.4 Ecosystem health of rivers - it's what we make it 254

9.8.5 Ecosystem health of a marine environment 255

Key concepts
In this chapter you will
see that some species (strong interactors and keystone species) are more infl uential in food webs
than others
recognize that managers need to understand food web relations to combat disease risk, manage
harvests, restore ecosystems and design reserves

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