Chapter 31
Wildebeest
There is another species of wild ox, called by the natives gnoo.
(G. Forster, 1777)
31.1 Wildebeest Model
The Wildebeest model is developed for a wildlife park on African grassland.
Wildebeest are eaten by lions, and shot by park rangers attempting to manage the
ecosystem. The data on the number of lions in the park is thought to be between
400 and 600. We choose 500 for the initial runs of the model. The rate at which
wildebeest are killed by the lions varies between 4.5 and 3.8 wildebeest per lion in
the first 6 years of the data (Fig. 31.1).
The wildebeest were shot by the park rangers during the first 4 years. The calf
survival rate varies from 0.35 to 0.48 during the first 6 years (Fig. 31.2). Females
constitute 70 % of the total population. The first 6 years have population census
estimates for the calves, yearlings, 2-year olds, and adults (Fig. 31.3).
The lion population of our model should depend on the availability of food,
which is in our case is mostly the non-calf population of wildebeest. This dependency is given as shown in Fig. 31.4. Note that it is critical here to specify the
graphical function in ways that extrapolate from the last entry on the non-calf
population to higher, rather than constant, lion numbers.
Given the population of YEARLINGS, TWO YEAR OLDS and ADULTS we
can calculate an average death rate assumed to apply to these “cohorts”. This death
rate is assumed to be distinct from that for calves (Fig. 31.5).
A save-disabled version of STELLA and the computer models of this book are available at
www.iseesystems.com/modelingdynamicbiologicalsystems.
B. Hannon and M. Ruth, Modeling Dynamic Biological Systems,
Modeling Dynamic Systems, DOI 10.1007/978-3-319-05615-9_31,
© Springer International Publishing Switzerland 2014
259
Wildebeest
There is another species of wild ox, called by the natives gnoo.
(G. Forster, 1777)
31.1 Wildebeest Model
The Wildebeest model is developed for a wildlife park on African grassland.
Wildebeest are eaten by lions, and shot by park rangers attempting to manage the
ecosystem. The data on the number of lions in the park is thought to be between
400 and 600. We choose 500 for the initial runs of the model. The rate at which
wildebeest are killed by the lions varies between 4.5 and 3.8 wildebeest per lion in
the first 6 years of the data (Fig. 31.1).
The wildebeest were shot by the park rangers during the first 4 years. The calf
survival rate varies from 0.35 to 0.48 during the first 6 years (Fig. 31.2). Females
constitute 70 % of the total population. The first 6 years have population census
estimates for the calves, yearlings, 2-year olds, and adults (Fig. 31.3).
The lion population of our model should depend on the availability of food,
which is in our case is mostly the non-calf population of wildebeest. This dependency is given as shown in Fig. 31.4. Note that it is critical here to specify the
graphical function in ways that extrapolate from the last entry on the non-calf
population to higher, rather than constant, lion numbers.
Given the population of YEARLINGS, TWO YEAR OLDS and ADULTS we
can calculate an average death rate assumed to apply to these “cohorts”. This death
rate is assumed to be distinct from that for calves (Fig. 31.5).
A save-disabled version of STELLA and the computer models of this book are available at
www.iseesystems.com/modelingdynamicbiologicalsystems.
B. Hannon and M. Ruth, Modeling Dynamic Biological Systems,
Modeling Dynamic Systems, DOI 10.1007/978-3-319-05615-9_31,
© Springer International Publishing Switzerland 2014
259