Question

1. What is the effective population size of the Asian elephant population in Periyar, southern India where poaching has resulted in an adult sex-ratio of 6 males to 605 females? What would be the effective size with a ‘normal’ adult elephant sex-ratio of 1:3 (204 males to 407 females) if the census count is held constant at 611 elephants?

Formula given

4N, (N. + N)

Answer 1

effective population sex ratio when the sex ratio is male: female= 6:605

Ne= 4NmNf/(Nm+Nf)

Nm= number of males

Nf= number of females

Ne= 4$\times$6$\times$605/(6+605)

=23.76

effective population when the sex ratio is males: females= 1:3

Nf=407

Nm= 204

Ne= 4NmNf/(Nm+Nf)

= (4$\times$204$\times$407)/(204+407)

= 543.55