Mountain Lions of the Black Hills

112 Mountain Lions of the Black Hills

considered to last 50 years or longer) (Allendorf and Luikart 2007). However, they
did not provide a threshold lower level below which we would expect to see decreased
ge ne tic diversity and the consequences of increased homozygosity, reduced survival
of offspring, and the more observable characteristics such as undescended testes and
crooked tails. Nevertheless, our results did support the conclusion that ge ne tic diver-
sity could be maintained over multiple population sizes. For example, observed hetero-
zygosity was constant despite significant changes in population size and numbers of
effective breeders (NB ) ( t a b l e 7.4). There were three years (2002, 2005, and 2013) in
which the proportion of effective breeders was above 50% but estimated population
size ranged from 66 to 138 to 145. This might suggest that the population could be con-
servatively reduced up to about 50%, and if the number of effective breeders was
maintained above 50%, then ge ne tic diversity would be preserved for at least the short
term. However, such preserved ge ne tic diversity assumes that adequate immigration
would occur to continue the incorporation of new breeders into the system. Further-
more, the ge ne tic preservation assumes that other variables (random mortality with
loss of allelic diversity) would not hamper the population.
Our improved ge ne tic analy sis using additional samples from surrounding states
and lion populations also indicated that South Dakota and eastern Wyoming lion pop-

250

200

Po

pulation siz

e 150

100

50

0

.60

Year

.55

.50

.45

.40

19961997199819992000200120022003200420052006200720082009201020112012

Pop Size

Mountain lion population estimates, NB & HO

NB

NB

HO

2013

figure 7.4. Population estimates (of the South Dakota portion of the Black Hills) of
mountain lions derived from population simulation based on quantitative and qualitative
data ( Jenks, 2013 unpublished data), observed heterozygosity, and effective number of
breeders (NB ) over time. Juarez et al. 2016.