title: Environmental context determines within- and potential between-generation consequences of herbivory.
abstract: Plant tolerance to herbivory may depend on local environmental conditions. Models predict both increased and decreased tolerance with increasing resources. Transgenerational effects of herbivory may result in cross-generation tolerance. We evaluated within- and potential between-generation consequences of deer browsing in light-gap and understory habitats in the forest-edge herb, Campanulastrum americanum. Plants were assigned to deer-browsed, simulated-herbivory, and control (undamaged) treatments in the two light environments. In light gaps, plants were eaten earlier, more frequently, and had less vegetative recovery relative to uneaten plants than in the understory. As a result, browsed light-gap plants had a greater reduction in flowers and fruit than understory plants. This reduced tolerance was in part because deer browsing damaged plants in light gaps more than those in the understory. However, in the simulated herbivory treatment, where damage levels were similar between light habitats, plants growing in high-resource light gaps also had reduced tolerance of herbivory relative to those in the forest understory. C. americanum's reproductive phenology was delayed by reduced light and the loss of the apical meristem. As a result, deer-browsed plants in the light gap flowered slightly later than uneaten plants in the understory. C. americanum has a polymorphic life history and maternal flowering time influences the frequency of annual and biennial offspring. The later flowering of deer-browsed plants in light gaps will likely result in a reduced frequency of high-fitness annual offspring and an increase in lower fitness biennial offspring. Therefore, additional between-generation costs of herbivory are expected relative to those predicted by fruit number alone.
authors.affiliation: Mountain Lake Biological Station, University of Virginia, Charlottesville, VA 22904, USA.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Lin
authors.forename: Laura F
authors.initials: LF
authors.lastname: Galloway
mesh_terms: D000818:Animals; D029422:Campanulaceae / Q000502:physiology*; D003670:Deer; D017753:Ecosystem; D005247:Feeding Behavior; D013472:Sunlight; D013997:Time Factors; D014768:Virginia
references.citation: Oecologia. 1992 Jun;90(3):435-444
references.pmid: 28313533
references.citation: Oecologia. 1981 Oct;51(1):14-18
references.pmid: 28310302
references.citation: New Phytol. 2005 Apr;166(1):93-9
references.pmid: 15760354
references.citation: Am J Bot. 2004 Jul;91(7):1046-51
references.pmid: 21653460
references.citation: Am Nat. 2001 May;157(5):555-69
references.pmid: 18707262
references.citation: Ecology. 2008 Jun;89(6):1497-502
references.pmid: 18589514
references.citation: Am Nat. 2007 Jul;170(1):113-27
references.pmid: 17853996
references.citation: Evolution. 2005 Sep;59(9):1928-35
references.pmid: 16261730
references.citation: Am Nat. 2007 Apr;169(4):443-54
references.pmid: 17253430
references.citation: Oecologia. 2008 Mar;155(2):247-55
references.pmid: 18278516
references.citation: J Evol Biol. 2007 Nov;20(6):2092-100
references.pmid: 17903186
references.citation: Am Nat. 1997 Jun;149(6):1147-55
references.pmid: 18811268
references.citation: Oecologia. 2005 May;143(4):558-65
references.pmid: 15800748
references.citation: Ecology. 2009 Aug;90(8):2139-48
references.pmid: 19739376
references.citation: Am Nat. 2008 Nov;172(5):635-47
references.pmid: 18840070
references.citation: New Phytol. 2009 Jun;182(4):1003-1012
references.pmid: 19320836
references.citation: Science. 2007 Nov 16;318(5853):1134-6
references.pmid: 18006745
references.citation: Oecologia. 2003 Aug;136(3):394-401
references.pmid: 12783294
references.citation: Am J Bot. 2001 May;88(5):832-40
references.pmid: 11353708
references.citation: Science. 2005 Feb 11;307(5711):920-2
references.pmid: 15705851