tailieunhanh - From Individuals to Ecosystems 4th Edition - Chapter 10

Chapter 10 The Population Dynamics of Predation Introduction: patterns of abundance and the need for their explanation We turn now to the effects of predation on the population dynamics of the predator and its prey, where even a limited survey of the data reveals a varied array of patterns. | Chapter 10 The Population Dynamics of Predation Introduction patterns of abundance and the need for their explanation We turn now to the effects of predation on the population dynamics of the predator and its prey where even a limited survey of the data reveals a varied array of patterns. There are certainly cases where predation has a profoundly detrimental effect on a prey population. For example the vedalia ladybird beetle Rodolia cardinalis is famous for having virtually eradicated the cottony cushion-scale insect Icerya purchasi a pest that threatened the California citrus industry in the late 1880s see Section . On the other hand there are many cases where predators and herbivores have no apparent effect on their prey s dynamics or abundance. For example the weevil Apion ulicis has been introduced into many parts of the world in an attempt to control the abundance of gorse bushes Ulex europaeus and it has often become well established. The situation in Chile however is fairly typical where despite eating on average around half and sometimes up to 94 of the seeds produced it has had no appreciable impact on gorse invasiveness Norambuena Piper 2000 . There are also examples that appear to show predator and prey populations linked together by coupled oscillations in abundance Figure but there are many more examples in which predator and prey populations fluctuate in abundance apparently independently of one another. It is clearly a major task for ecologists to develop an understanding of the patterns of predator-prey abundance and to account for the differences from one example to the next. It is equally clear though that none of these predator and prey populations exist as isolated pairs but rather as parts of multispecies systems and that all these species are affected by environmental conditions. These broader issues of what determines a species abundance are taken up again in Chapter 14. However as with any complex process in science we .