Biological control is a time-consuming and risky endeavor (see Background section 1 for more information). Therefore it is important that biological control research considers both individual- and population-level effects. It is necessary to determine whether the introduced agent will damage the target enough to cause the invasive species' population growth rate to be reduced. In order to ask this question, researchers use experiments that manipulate herbivory along with matrix models to assess invasive species' population growth rates under different intensities of damage.
Matrix models examine the entire life-cycle of a population; they allow population growth rate to be assessed from short-term estimates of demography and short-term experiments that manipulate biotic interactions, such as herbivory done by a biological control agent. Elasticity analysis of demographic models can be used to pinpoint critical vital rates in the life cycle which, if altered, could result in large changes in the population growth rate. Elasticity analyses are important as not all underlying fitness measures contribute equally to population growth. These models can be used to guide management programs for invasive species.