Indian Elephant Population in Thailand

=Problem definition= During the course of the 20th century, the population of indian elephants has decreased drastically, mostly due to a significant reduction of elephants' natural habitat, as well as decrease in utilization of elephants in logging industry and shift to a role of a tourist attraction. This model showcases the evolution of elephants' population in Thailand for upcoming 100 years.

=Method= The vensim modelling tool was selected for the purpose of this simulation.

=Model=

Population
Number of elephants in Thailand. Starting value is 8900. This is the variable that we are examining.

Increase
Number of elephants that are born

=Natality*Population

Decrease
Number of elephants that have died

=Mortality*Population

Natality
Ratio of newly born elephants to elephant population. Amount of newborn elephants equals fertility multiplied by number of females in reproductive age divided by 40*2 (number of reproductive years, multiplied by 2 as elephants pregnancy takes 22-24 months). We then multiply by Governement regualtion ratio.

=((Fertility*((Ratio of females*Population)*Ratio of females in reproductive age)/80)*Government regulations)/Population

Fertility
Amount of calves a female is able to have during her reproductive lifespan. 40% of elephants' population lives in wilderness and the fertility is not affected by stress therefore a wild female is able to have 10 calves, and semi-domesticated female is able to have 7 calves during her life.

=0.4*10+0.6*7

Ratio of females in reproductive age
Elephant female can have calves during her 15 to 50 years.

=0.5714

Ratio of females
Ratio of females on elephants' population

=0.53476

Government regulation
Index of government regulations <0;1>, 1 means no government regulation

=1

Mortality
Ratio of dead elephants on the elephants' population.

=((Population/Average lifespan) + Unnatural deaths)/Population

Average lifespan
=70

Unnatural deaths
Number of deaths that do not happen naturally.

=((Deaths by improper handling ratio*Population)+(Poaching ratio*Population))*Government regulations + Population*Deforestation ratio

Deaths by improper handling ratio
Ratio of deaths that happen due to unhuman behavior towards elephants and conditions they have to live in.

=0.01685

Poaching ratio
Ratio of deaths that happen because of elephants being hunted either for skin, tusks or to capture young calve.

=3.3e-05

Deforestation ratio
Ratio of deforastation in Thailand, this has a close correlation to number of elephants as this the major factor affecting the population.

=0.0035

=Results=

As we can see, we can expect a continuous decrease in elephants' population in Thailand. By the year 2119 the elephants' population in Thailand should decrease by 2492 elephants.

=Conclusion= In this simulation I created a functional model representing the evolution of elephants' population in Thailand. The results show continuous decrease over the course of following 100 years. However there is a room for improvements, like parameter deforestation ratio because nowadays the problem of deforestation is gaining on significance in general public eyes and this might lead into deforestation ratio decrease and potentially lead into elephants' population growth. In addition, also the pressure from general public as well as organizations like WWF might lead into more strict government regulations.

=Code=

=References=