J.M. Emlen B. Wachocki D.C. Freeman C.L. Alados 1998 <p><span>Developmental instability has been used to monitor the well-being of natural populations exposed to physical, chemical and biological stressors. Here, we use developmental instability to assess the impact of grazing on&nbsp;</span><i>Chrysothamnus greenii&nbsp;</i><span>and&nbsp;</span><i>Seriphidium novum</i><span>shrubs, and&nbsp;</span><i>Oryzopsis hymenoides</i><span>grass, common in the arid intermountain west of the U.S.A. Statistical noise in allometric relations was used as an indicator of developmental instability arising from grazing-induced stress. Unpalatable species that are not grazed (</span><i>Chrysothamnus greenii</i><span>) or species that are dormant during the winter–spring grazing period (</span><i>Oryzopsis hymenoides</i><span>) show lower allometric variability under high grazing pressure. Palatable species (</span><i>Seriphidium novum</i><span>) exhibit high developmental instability under low and high grazing pressure. Grazing pressure imposed by presumably co-adapted wild herbivores enhances developmental stability in species habituated to moderate grazing, like</span><i>Oryzopsis hymenoides</i><span>, but stresses plants such as&nbsp;</span><i>Chrysothamnus greenii&nbsp;</i><span>that prefer disturbed environments. These grazing effects are probably due to the impact grazing has on competitive relationships and not to the direct action of the herbivore on the plants.</span></p> application/pdf 10.1006/jare.1997.0317 en Elselvier Instability of development and fractal architecture in dryland plants as an index of grazing pressure article