64 Mountain Lions of the Black Hills
years when harvest was allowed (fig. 4.14), thus providing circumstantial evidence of
reduced density dependence with increased food availability. However, additional har-
vest provided more detailed information on mortality and indicated an increase in
mortality after the initiation of harvest; thus, any compensation between natu ral and
harvest mortality was minimal and difficult to quantify (i.e., once the population had
begun to decrease, total mortality increased, indicating that harvest mortality was
additive [added to natu ral mortality] rather than being compensated by natu ral mor-
tality). More recent studies of this phenomenon have provided support for both types
of mortality: additive and partially compensatory (Wolfe et al. 2015). The size of the
study areas evaluated by Wolf and colleagues (2015) were 11% and 15% of the entire
Black Hills region, which might suggest that there could be portions of the Black
Hills where mountain lion mortality is partially compensatory; thus, the scale evalu-
ated by Fecske, Thompson, and Jenks (2011) may have masked local effects.
Population Modeling
From our long- term collection of information on population size, mortalities, litter
size, survival, and sex ratio, as well as reference to published information on population
dynamics of other mountain lion populations, we were able to construct a population
model for Black Hills lions. We had used population reconstruction to model the pop-
ulation to carry ing capacity (K), and at that time we had generated estimates of popu-
lation size via mark- recapture models (Jansen 2011), we merged three approaches to
generate a population curve through time (fig. 4.15). We used population reconstruc-
tion and rate of growth to generate the curve to 2007, mark- recapture estimates for
2008–2009, and reproductive information and mortality, including harvest, to model
the population to 2013.
For the mark- recapture estimates, we attempted to maintain a sample of 50 radio-
collared lions, and we focused our efforts on adults, to improve the chances that the ani-
mals would remain in the Black Hills during the harvest season. Variation in the harvest
of radio- collared mountain lions and the low harvest of radio- collared males, in part
because a lower number of adult males than females were radio- collared, resulted in
reasonable estimates for females but not for other age and sex classes of this population.
Our model is a repre sen ta tion of how this population likely changed through time,
but like any model, it suffers from a number of unknowns. For example, we knew that
a large proportion of subadult males were leaving the region (emigrating) but had vir-
tually no information to generate rates of immigration for the model; thus, we as-
sumed that these rates were equivalent to one another. Nevertheless, the semi- isolated
nature of the Black Hills and long- term study of the population helped to limit exter-
nal influences on this population. One other issue that should be addressed is the lack
of variation in our annual estimates. As mentioned, the model is a repre sen ta tion of