caa a22 4500 469098597 CHVBK 20180323133038.0 cr unu---uuuuu 170328e19920601xx s 000 0 eng 10.1007/BF00317703 doi (NATIONALLICENCE)springer-10.1007/BF00317703 The effects of grazers on the performance of individuals and populations of scarlet gilia, Ipomopsis aggregata [Elektronische Daten] [Joy Bergelson, Michael Crawley] Summary: I. aggregata exhibits considerable powers of regrowth following removal of its primary shoot by herbivores, but we found no evidence of overcompensation (i.e. of significantly higher plant performance where plants were exposed to ungulate herbivory) in a comparison between individuals on grazed and ungrazed sides of exclosure fences, in a comparison between artificially clipped and control plants in one population in the Okanagan National Forest, or in comparisons between grazed and ungrazed plants in 14 natural populations. We tested whether ungulate grazing affects the population size of Ipomopsis aggregata by comparing populations inside and outside deer exclosures at 7 sites in the Western United States. We found consistent, highly significant differences in plant population density on the grazed and ungrazed sides of these exlosure fences. Plant density was a modal 25-fold higher on the protected side of the fence, suggesting that exposure to ungulate grazing increases plant death rates at some stage in the life cycle. Our results show that the presence of ungulate grazers leads to a substantial decrease in plant density despite the fact that grazing on young bolting shoots has very little influence on fruit production. Since this decrease in population density is not correlated with a decrease in the fecundity of individuals, it must instead be due to other direct and indirect effects of ungulate grazers. Springer-Verlag, 1992 Herbivory nationallicence Overcompensation nationallicence Regworth nationallicence Ipomopsis aggregate nationallicence Bergelson Joy Department of Zoology, University of Washington, 98195, Seattle, WA, USA aut Crawley Michael Department of Pure and Applied Biology, Imperial College at Silwood Park, SL5 7PY, Ascot, Berks, UK aut Oecologia Springer-Verlag 90/3(1992-06-01), 435-444 0029-8549 90:3<435 1992 90 442 https://doi.org/10.1007/BF00317703 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00317703 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Bergelson Joy Department of Zoology, University of Washington, 98195, Seattle, WA, USA aut NATIONALLICENCE 700 1- Crawley Michael Department of Pure and Applied Biology, Imperial College at Silwood Park, SL5 7PY, Ascot, Berks, UK aut NATIONALLICENCE 773 0- Oecologia Springer-Verlag 90/3(1992-06-01), 435-444 0029-8549 90:3<435 1992 90 442 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer