Elk reproductive response to removal of calving season disturbance by humans

We evaluated elk (Cerous elaphus) reproductive success following removal of human disturbance during calving season, by comparing data from 2 segregated groups of free-ranging elk (control and treatment) from I pre-disturbance year, 2 disturbance years, and 2 post-disturbance years. Treatment-group elk were subjected to simulated recreational activity during calving season in disturbance years but not in pre- or post-disturbance years. Control animals experienced only ambient levels of disturbance throughout the study, and their calf/cow proportions (proportion of marked adult female elk maintaining a calf in Jul and Aug) were similar throughout the 5 years. We observed reduced productivity of treatment-group elk compared to controls during disturbance years after adjusting for nontreatment year differences. We hypothesized that productivity would return to, or potentially exceed, pre-disturbance levels following removal of disturbance. Producfivity rebounded following release from disturbance, and full recovery was achieved by the second post-disturbance year. However, we did not observe productivity in excess of pre-disturbance years, as might be expected if release from energetic demands of maintaining a calf in I year increases probability of maintaining a calf in the following year. Our results are consistent with hypotheses that human-induced disturbance during parturition periods can reduce reproductive success and that removal of disturbance can allow productivity to recover to pre-disturbance levels. Managers of wildlife and wildlife habitat should consider potential impacts of human-induced disturbance on wildlife populations. Wildlife populations, depressed by human-induced disturbance during the neonatal period, may have the ability to rebound if the disturbance is removed.