caa a22 4500 469096128 CHVBK 20180323133031.0 cr unu---uuuuu 170328e19921201xx s 000 0 eng 10.1007/BF00317844 doi (NATIONALLICENCE)springer-10.1007/BF00317844 Plant competition, abiotic, and long- and short-term effects of large herbivores on demography of opportunistic species in a semiarid grassland [Elektronische Daten] [D. Milchunas, W. Lauenroth, P. Chapman] Summary: The emergence and subsequent survival and growth of five opportunistic "weeds” were monitored after seed additions to long-term grazing treatments with or without current-year grazing, long-term ungrazed treatments, and removal treatments designed to eliminate plant competition from existing perennials while either leaving vegetation and soil structure unaltered or disturbed. The treatments were applied on both uplands and lowlands to assess the relative influence of macroabiotic environment versus plant competition. The long-term effects of large herbivores on the initial emergence of seedlings were greater than the effects of removing competition. Very few individuals emerged on the long-term grazed treatments that were either grazed or ungrazed during the experiment. Numbers of individuals emerging on the long-term ungrazed treatments were greater or equal to those emerging on the no-competition-undisturbed treatments, but numbers were greatest on no-competition-disturbed treatments. None of the seeded individuals on the long-term grazed, currently grazed treatments survived to the end of the growing season. There was a slightly greater end-of-season biomass of seeded species and percentage of the total population reaching reproductive status on the long-term ungrazed compared with grazed-nondefoliated treatments, and very high survival, biomass, and proportions of reproductives on both no-competition treatments. Cover types in the immediate vicinity of seedlings influenced both germination and survival, but the effects differed between species and treatments. Equal compensation to current-year herbivory occurred on long-term heavily grazed treatments even though above-ground production was much greater on long-term protected sites. Productivity varied with topography, but very few topographic main effects or interactions occurred with demographic variables of seeded species, suggesting that macroabiotic effects were of minor importance compared with grazing and plant competition. Springer-Verlag, 1992 Herbivory nationallicence Compensatory growth nationallicence Disturbance nationallicence Establishment nationallicence Landscape topography nationallicence Milchunas D. Department of Range Science, and Natural Resource Ecology Laboratory, Colorado State University, 80523, Fort Collins, CO, USA aut Lauenroth W. Department of Range Science, and Natural Resource Ecology Laboratory, Colorado State University, 80523, Fort Collins, CO, USA aut Chapman P. Statistics Department, Colorado State University, 80523, Fort Collins, CO, USA aut Oecologia Springer-Verlag 92/4(1992-12-01), 520-531 0029-8549 92:4<520 1992 92 442 https://doi.org/10.1007/BF00317844 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00317844 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Milchunas D. Department of Range Science, and Natural Resource Ecology Laboratory, Colorado State University, 80523, Fort Collins, CO, USA aut NATIONALLICENCE 700 1- Lauenroth W. Department of Range Science, and Natural Resource Ecology Laboratory, Colorado State University, 80523, Fort Collins, CO, USA aut NATIONALLICENCE 700 1- Chapman P. Statistics Department, Colorado State University, 80523, Fort Collins, CO, USA aut NATIONALLICENCE 773 0- Oecologia Springer-Verlag 92/4(1992-12-01), 520-531 0029-8549 92:4<520 1992 92 442 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer