approaches ... logistic, Lotka-Volterra, Leslie 

 Matrix are deterministic and abstract, ... 

 populations are treated independently of most of 

 the variability of the environment and biographical 

 forces . " 



Thus, although various studies provided evidence for 

 density-dependent regulation under precisely specified and 

 often unrealistic conditions, management application of the 

 principles derived has often proven inappropriate or even 

 disastrous for free-ranging populations. Wildlife managers 

 have actually paid too much attention to population theorists. 



Similarly, impressions left by early writers, when left 

 unchallenged for decades, became unconsciously assumed "law". 

 For example, one of the major themes of the writings of 

 Malthus and Darwin is that of the tremendous reproductive 

 potential of species. We have been unconsciously left with 

 the impression that populations are always straining against 

 "carrying capacity". This often unrecognized assumption has 

 been inherent in much of population theory despite the fact 

 that "carrying capacity" was not defined or measured. When 

 "carrying capacity" was defined or measured, it often turned 

 out that populations were not at or near "carrying capacity". 

 Just awareness of the possibility that populations are not 

 always pressing against "carrying capacity" or "trying" to 

 exceed it can lead us to new ways of thinking about population 

 regulation and especially management. 



We believe we have shown that a multitude of factors can 

 and do affect population dynamics. The relative impact of 

 these factors can vary among species and among species 

 populations inhabiting different environments. For the mule 

 deer population inhabiting the widely fluctuating environment 

 we studied, important limiting factors included: the length 

 of time green forage was available, the energy demand by deer, 

 predation, emigration rate, and hunter harvest. All these 

 factors were influenced or controlled to some degree by 

 weather, the first 3 especially so. All limiting factors 

 interacted such that the opportunity to observe density- 

 dependent regulation did not occur. 



It is possible that conditions leading to density- 

 dependent regulation could occur, given changes in the 

 environment. For example, limitation of emigration by fencing 

 or lack of dispersal sinks, annihilation of predators, and/or 

 cessation of hunting singly or in combination could result in 

 density-related resource shortages leading to poor condition. 

 Thus, population dynamics could be altered toward density- 

 dependent regulation. We believe, however, that many, if not 

 most, free-ranging "natural" large mammal populations are 

 usually limited by variable extrinsic factors below densities 



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