Community-level riparian plant traits, Colorado River, Grand Canyon, 2013-2015

These data were compiled based on field observations and available literature. Field observations of plant cover were made in September and October of 2013 and 2014, while trait measurements were made in September and October of 2014 and 2015. Field data was collected on sandbars along the Colorado River through Grand Canyon between river miles 0 and 226. Field measurements of specific leaf area, stem specific gravity, and total cover. Plant height was taken from the Flora of North America, the Jepson Desert Manual, or A Utah Flora. Seed mass values were available from the Kew Seed Information Database (http://data.kew.org/sid/). Photosynthetic pathway was compiled from published literature. The trait values were converted to a community-level value using two matrices: a matrix of the relative species cover (species cover/total cover) and a matrix of the average trait value for each species. These two matrices were multiplied, and then summed over all species in each plot to produce a community-level trait value for each plot. Inundation was calculated as the yearly average of the number of hours for each plot that the river stage, based on stage-discharge relationships, was greater than the surveyed plot elevation using USGS streamflow data. This exceedance probability was calculated as the probability that stage height will exceed plot height for the 2013 survey plots based on the 1984 - 2013 USGS streamflow record.

本数据集基于野外实地观测与公开文献资料汇编而成。植物盖度的野外观测于2013年、2014年的9月及10月开展，功能性状测定则在2014年、2015年的9月及10月进行。野外数据采集于科罗拉多河（Colorado River）流经大峡谷（Grand Canyon）的0至226河英里河段的沙洲之上。本次野外测定的性状涵盖比叶面积、茎部比重与总盖度。植物高度数据引自《北美植物志》（Flora of North America）、《杰普森沙漠手册》（Jepson Desert Manual）及《犹他植物志》（A Utah Flora）。种子质量数据源自邱园种子信息数据库（Kew Seed Information Database，http://data.kew.org/sid/）。光合途径相关数据通过已发表文献汇编得到。功能性状值通过两种矩阵转换为群落水平数值：其一为物种相对盖度矩阵（物种盖度/总盖度），其二为各物种的平均性状值矩阵。将两种矩阵相乘后，对每个样地内的全部物种求和，即可得到对应样地的群落水平性状值。淹没时长通过美国地质调查局（USGS）径流数据计算得到：基于水位-流量关系，统计各年度内河流水位高于实测样地高程的小时数的年均值。针对2013年调查的样地，超水位概率基于1984至2013年的USGS径流记录计算得到，其定义为河流水位超过样地高程的发生概率。