Approaches for testing herbivore effects on plant population dynamics
نویسنده
چکیده
1. As plant invasions pose one of the greatest threats to biodiversity, it is critical to improve both our understanding of invasiveness and strategies for control. Much research into plant invasions and their management, including biological control, assumes strong demographic effects by natural enemies, including herbivores. However, the importance of natural enemies in the regulation of plant populations remains controversial: some ecologists contend that they rarely affect plant populations, and others that they can strongly limit plant population sizes. 2. We briefly review the conflicting views and suggest that new approaches to gather and analyse data are needed before the effects of natural enemies on plant populations can be fully characterized. 3. We outline experimental and analytical approaches that incorporate density dependence into population models and thus provide a more complete test of the long-term effects of natural enemies on plant populations. We also introduce new methods for obtaining stochastic estimates of equilibrium density, which will provide a key test of enemy effects on plant population size. 4. Synthesis and applications. Designing effective strategies for invasive plant management requires information about the factors that limit plant population size. Together, the experiments and analyses we describe measure more clearly how natural enemies influence plant population dynamics. They will provide an important tool in evaluating the role of enemy release in plant invasions and for predicting the potential success of biological control. Such information should help to prioritize strategies that are most likely to control invasive plants effectively and will contribute to risk assessment when considering the release of non-native natural enemies as biological control agents.
منابع مشابه
Simultaneous effects of food limitation and inducible resistance on herbivore population dynamics.
Many herbivore populations fluctuate temporally, but the causes of those fluctuations remain unclear. Plant inducible resistance can theoretically cause herbivore population fluctuations, because herbivory may induce plant changes that reduce the survival or reproduction of later-feeding herbivores. Herbivory can also simply reduce the quantity of food available for later feeders and this, too,...
متن کاملComparing the consequences of induced and constitutive plant resistance for herbivore population dynamics.
Although it has been suggested that induced and constitutive plant resistance should have different effects on insect herbivore population dynamics, there is little experimental evidence that plant resistance can influence herbivore populations longer than one season. We used a density-manipulation experiment and model fitting to examine the effects of constitutive and induced resistance on her...
متن کاملThe Influence of Plant and Herbivore Characteristics on the Interaction between Induced Resistance and Herbivore Population Dynamics.
Induced plant resistance may contribute to regulating or driving fluctuations in insect herbivore populations. However, experimental demonstrations of induced resistance affecting long-term herbivore population dynamics are lacking, and few models find that induced resistance drives cycles in herbivore populations. Here a simulation model is used to explore the influence of characteristics of t...
متن کاملVARIATION IN PLANT QUALITY AND THE DYNAMICS OF INSECT HERBIVORE POPULATIONS by SANDRA ELIZABETH HELMS SPIRES
1. Previous studies have demonstrated that phenotypic traits of plants have the potential to affect interactions between herbivores and their natural enemies. Consequently, the impact of natural enemies on herbivore vital rates and population dynamics may vary among plant species. This study was designed to investigate the potential for density-dependent parasitism of an aphid herbivore feeding...
متن کامل