ABSTRACT
Ecological Theories Underlying Habitat Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242 Management Practices Based on Directional Vegetation Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242 Equilibrium and Nonequilibrium Vegetation Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243 From the Patch to the Landscape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245 Landscape Ecology and Geospatial Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246 New Habitat Management Paradigms: Increasing Landscape Heterogeneity . . . . . . . . . . . . . . . . . . . 247 Maintenance of Biological Diversity by Disturbance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249 Problems with Use of Disturbance to Manipulate Habitats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
Intermediate Disturbance Hypothesis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249 Natural versus Human-Imposed Disturbances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 Prior Disturbance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
Hypothetical Differences in Functions of Disturbance in Xeric and Mesic Environments . . . . . 250 Facilitation of Exotic Species Invasion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251 Grazing and Exotic Grasses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251 Mechanical Brush Management Treatments and Exotic Grasses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252 Fire and Exotic Grasses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252
Natural Disturbance Regimes on Unnatural Landscapes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
Ecological succession is one of the most important theories influencing wildlife management practices (Bolen and Robinson 2003: 43). Ecological theories providing the basis for predicting the outcome of habitat manipulations to benefit wildlife are often applied as generalizations across broad geographic regions. Many of the paradigms used in wildlife habitat management were developed in relatively mesic environments. These paradigms may not consistently predict outcomes of management efforts where low and erratic precipitation and periodic drought change, at least temporarily, the nature of vegetation dynamics. In arid and semiarid regions, variation in precipitation may modify or
Hewitt: “7487_c014” — 2007/5/15 — 21:50 — page 242 — #2
(Fulbright 1999; Fuhlendorf et al. 2001; Rogers et al. 2004).
