Data from: Environmental resource deficit may drive the evolution of intraspecific trait variation in invasive plant populations

Intraspecific trait variation within natural populations (i.e.
intra‐population trait variation, IPTV) is the basic source for selection
and can have significant ecological consequences. Higher IPTV may increase
a population's niche breath and benefit interspecies competition
under a resource‐limited environment, thus affecting the ability of a
species to move into novel habitats. However, the reciprocal influences of
variation in environmental conditions and phenotypic trait expression in
spreading plant populations are not clearly defined. We propose that
during invasion, IPTV and its relative change in response to key resource
enrichment may increase with the resource deficit of invaded sites, and
that this relationship may facilitate plant invasions into
resource‐limited environments. We analyzed the invasion trend, IPTV and
its response to water enrichment, and moisture variability among
populations of an annual grass Brachypodium hybridum in California, United
States. We incorporated a genotyping‐by‐sequencing approach, a common
garden experiment that had two water level treatments, and public plant
and climate databases. Our hypothesis was supported by the observation
that for populations that invaded sites with higher spring moisture
deficit, both their seed biomass IPTV (for the water‐enriched treatment
only) and relative change of the IPTV across water treatments were larger
when examined in the common garden experiment. A generally north to south
spreading direction was found in these B. hybridum populations, towards a
drier and warmer climate exhibiting higher moisture deficit for plant
growth. Our results suggest a role for interactions between IPTV (rather
than trait means) and environmental resource availability in promoting
plant invasions, providing new insights into the significance of IPTV in
shaping plant geographic distributions.

自然种群内的种内性状变异（即
种群内性状变异，intra-population trait variation, IPTV）是选择的基本来源，并可能产生显著的生态后果。较高的IPTV可能增加种群的生态位宽度，并在资源有限环境下有利于种间竞争，从而影响物种迁入新栖息地的能力。然而，扩散植物种群中环境条件变异与表型性状表达之间的相互影响尚未明确界定。我们提出，在入侵过程中，IPTV及其响应关键资源富集的相对变化可能随入侵位点的资源匮乏程度增加而增大，且这种关系可能促进植物入侵到资源有限的环境中。我们分析了美国加利福尼亚州一年生草本植物杂交短柄草（Brachypodium hybridum）种群的入侵趋势、IPTV及其对水分富集的响应，以及种群间的水分变异性。我们采用了基因型测序（genotyping-by-sequencing）方法、包含两种水分处理的同质园实验，以及公共植物和气候数据库。我们的假设得到以下观察结果的支持：在同质园实验中，对于入侵春季水分亏缺程度较高位点的种群，其种子生物量IPTV（仅在水分富集处理下）及跨水分处理的IPTV相对变化均更大。这些杂交短柄草种群呈现总体上从北向南的扩散方向，朝着更干燥、温暖且植物生长水分亏缺更高的气候区域。我们的结果表明，IPTV（而非性状均值）与环境资源可利用性之间的相互作用在促进植物入侵方面发挥作用，为IPTV在塑造植物地理分布中的意义提供了新见解。