CHAPTER 13 



MANAGEMENT IMPLICATIONS 



Management Philosophy and Theory 



As indicated in Chapter 1, most population and habitat 

 management for ungulates has been based on the belief that 

 density-dependent regulatory processes are in fact operating 

 on/within the population and that they apply at all population 

 levels (are logistic). It is most commonly assumed that 

 intraspecif ic density-dependent competition for resources 

 (especially food) defines "carrying capacity" (K). In most 

 models, K is displayed as relatively stable and influenced 

 primarily by the animals through grazing and browsing 

 pressure. Generally, because of their reproductive potential, 

 populations are portrayed as always straining to exceed 

 "carrying capacity" (inherently irruptive). 



Some of the more common concepts or "principles" derived 

 from density-dependent theory and applied in deer management 

 include: compensatory reproduction, compensatory mortality, 

 maximum sustained yield, intraspecif ic competition for food, 

 winter "bottleneck", "doomed" surplus (insignificance of 

 predation) , finite "carrying capacity", the "law of 

 diminishing returns", and various approaches to habitat 

 management. Many of these concepts, "principles", or "laws" 

 have come to have a life of their own, without recognition of 

 the assumptions behind them. 



For mule deer in the Missouri River Breaks (MRBMD), 

 density-dependent processes were not consistent, precise, or 

 predeterministic (if they occurred at all). Variable effects 

 of limiting factors led to both low recruitment/high mortality 

 and further population declines at low densities and high 

 recruitment/low mortality and further increases at high 

 densities. "Carrying capacity" was not easily or simply 

 definable whatever criteria were used. Forage production and 

 quality as well as usable space fluctuated independently of 

 density. Population growth rate declined to zero or below at 

 low as well as high densities. It also was explosive at both 

 relatively high and low densities. Expected compensation in 

 reproduction and mortality was not observed. Gradually, it 

 became obvious that management concepts based on density- 

 dependent population regulation seldom applied. 



Our discussion of management implications and 

 recommendations centers on mule deer in fluctuating 

 environments that include predators and dispersal sinks. We 

 suspect that many of our findings and concepts will apply in 

 some degree to other areas, and perhaps to other species in 

 similar environments. However, we caution the reader against 



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