DOI: 10.5061/dryad.905qfttht
title: Data from: Clonal integration enhances performance of an invasive grass

description: While many clonal plants are highly successful invaders, not all clonal
 plants share resources, often making the contribution of clonal
 integration (i.e., the translocation of resources among ramets) to
 invasion unclear. To determine if photosynthate translocation augments
 performance of emerging daughter ramets for a globally invasive grass
 (Imperata cylindrica), we combined a 13CO2 pulse-chase experiment with a
 greenhouse experiment manipulating light levels and rhizome attachment.
 Model simulations were also used to determine if clonal integration
 facilitated photosynthate translocation, if the performance of daughter
 ramets was enhanced by clonal integration, and if shaded ramets benefited
 relatively more from transferred photosynthate. We found that acropetal
 photosynthate transfer occurred between all sampled parent-daughter ramet
 pairs and that this resource sharing led to higher biomass and tiller
 production when rhizomes between parent and daughter ramets were intact.
 We also found that the benefits of integration to recipient clones
 outweighed the costs to donors, since there was no reduction in parent
 plant performance due to sharing. Additionally, analysis of our data show
 that photosynthate transfer was likely of greater benefit in overcoming
 growth constraints in the shade than in the full sun (posterior
 probability ~ 96.5%), a result that is further supported by our numerical
 simulations from a basic growth model. Thus, photosynthate transfer is a
 probable mechanism that explains why clonal integration can be
 particularly beneficial in heterogeneous resource environments. More
 generally, resource sharing among clonal plants may be a critical but
 underappreciated trait of invasive species.
description: Data originate from a greenhouse study of clonal integration in
 Cogongrass (Imperata cylindrica). Cogongrass ramets were transplanted into
 one end of a rectangular window box mesocosm, and allowed to grow linearly
 along length of box. In this way, the planted half constituted the
 "parent patch", while the colonized half constituted the
 "daughter patch". To assess the impact of clonal integration,
 rhizomes were severed at the midpoint of the mesocosm halfway through the
 growth cycle. Aboveground biomass, root biomass, rhizome biomass, tiller
 count, and tillers added post-severing were all assessed in both parent
 and daughter patches. If clonal integration (i.e. sharing of resources
 such as photosynthate) is important to Cogongrass performance, than
 severing should reduce performance in the daughter patch relative to
 unsevered plants. Likewise, if clonal integration incurs an expense to the
 parent plants, we would expect the parent patch in unsevered plants to
 have less biomass and tiller production relative to severed plants. We
 tested the role of clonal integration across two light environments
 (ambient and shaded) in order to check the importance of environmental
 heterogeneity in modulating the benefits of clonal integration.
 Each row in the dataset represents observations of biomass or
 tiller count from a single unique pot, and separates out by daughter
 versus parent patch.
description: Variable names and definitions: Tillers_P :
 tiller count in parent patch AGB_P: aboveground biomass
 (g) in parent patch Tillers_D: tiller count in daughter
 patch AGB_D: aboveground biomass (g) in daughter
 patch Tillers_added: tillers added in daughter patch
 after rhizome severing Light: light environment
 (A=ambient, S = shade) Rh: rhizome severing condition
 (C=cut/severed, I = intact) Block: block within
 greenhouse. RH_P: rhizome biomass (g) in parent
 patch Root_P: root biomass (g) in parent
 patch Total_P: total biomass (g) in parent
 patch RH_D: rhizome biomass (g) in daughter
 patch Root_D: root biomass (g) in daughter
 patch Total_D: total biomass (g) in daughter
 patch