title: The impact of physical disturbance and increased sand burial on clonal growth and spatial colonization of Sporobolus virginicus in a coastal dune system.
abstract: Dune plants are subjected to disturbance and environmental stresses, but little is known about the possible combined effects of such factors on growth and spatial colonization. We investigated how clones of Sporobolusvirginicus, a widespread dune species, responded to the independent and interactive effects of breakage of rhizomes, breakage position and burial regime. Horizontal rhizomes were severed at three different internode positions relative to the apex to span the range of damage by disturbance naturally observed or left intact, and apical portions exposed to two burial scenarios (ambient vs. increased frequency) for three months in the field. The performance of both parts of severed rhizomes, the apical portion and the remaining basal portion connected to clone containing four consecutive ramets, was compared with that of equivalent parts in intact rhizomes. Apical portions severed proximal to the third internode did not survive and their removal did not enhance branching on their respective basal portions. Severing the sixth or twelfth internode did not affect survival and rhizome extension of apical portions, but suppressed ramet production and reduced total biomass and specific shoot length. Their removal enhanced branching and ramet production on basal portions and changed the original rhizome growth trajectory. However, the gain in number of ramets in basal portions never compensated for the reduction in ramet number in apical portions. Recurrent burial increased biomass allocation to root tissues. Burial also stimulated rhizome extension only in intact rhizomes, indicating that disturbance interacts with, and counteracts, the positive burial effect. These results suggest that disturbance and recurrent burial in combination reduces the regeneration success and spread capacity of S. virginucus. Since global change leads to increasingly severe or frequent storms, the impact of disturbance and burial on clones could be greater in future and possibly prevent colonization of mobile dunes by the species.
authors: Department of Biology, University of Pisa, Pisa, Italy. ebalestri@biologia.unipi.it
authors: Elena
authors: E
authors: Balestri
authors: Claudio
authors: C
authors: Lardicci
mesh_terms: D000704:Analysis of Variance; D002999:Clone Cells; D017753:Ecosystem; D007558:Italy; D015999:Multivariate Analysis; D018517:Plant Roots / Q000254:growth & development; D018520:Plant Shoots / Q000033:anatomy & histology / Q000254:growth & development; D006109:Poaceae / Q000254:growth & development* / Q000502:physiology*; D027343:Rhizome / Q000254:growth & development; D012987:Soil
chemical_list: D012987:Soil
references: PLoS One. 2012;7(10):e47561
references: 23077636
references: Ecol Lett. 2006 Feb;9(2):228-41
references: 16958887
references: New Phytol. 2004 Jun;162(3):697-704
references: 33873769
references: Science. 2000 Sep 22;289(5487):2068-74
references: 11000103
references: PLoS One. 2011;6(9):e23942
references: 21912652
references: Science. 1985 Oct 25;230(4724):434-5
references: 17816073
references: Am J Bot. 2003 Oct;90(10):1416-24
references: 21659093
references: Oecologia. 2008 May;156(1):169-78
references: 18246372