Temperature, precipitation, birch and fireweed chemistry, and moose (Alces alces) calf mass in northern Sweden

Data and R code used in piecewise structural equation modelling for a study that compared the direct and indirect impacts of temperature and precipitation on moose calf mass in northern Sweden. The study was initiated in 1988 in an effort to examine the impacts of climate change on common forage species of the economically and culturally important moose in Sweden. It ran until 1997 and was re-started in 2017. Temperature and precipitation variables are derived from SMHI weather station data. Average moose calf mass for study sites is derived from data from the Swedish Hunter's Association and individual hunting teams. Both weather and moose calf mass represent mean values within a 50km radius of each study site. Nitrogen and neutral detergent fibre measures are the result of near-infrared spectroscopy modelling, using 50 samples to calibrate the model. Samples were collected from 1-ha sites and included material from 30 individuals of either downy birch or fireweed. The dataset contains the following files. DataWeatherVegMoose.tsv is the data itself (TSV format, 236 rows × 10 columns). This includes the following variables: Total precipitation (mm) from the start of the growing season, defined as the first day of the first four consecutive days each calendar year that each have a mean daily temperature greater than or equal to 5 degrees C, to July 17 of that year. This is an average value for all SMHI weather stations within a 50 km radius of a site. Mean daily average temperature from the start of the growing season, defined as the first day of the first four consecutive days each calendar year that each have a mean daily temperature greater than or equal to 5 degrees C, to July 17 of that year. This is an average value for all SMHI weather stations within a 50 km radius of a site. Proportion of days from the start of the growing season, defined as the first day of the first four consecutive days each calendar year that each have a mean daily temperature greater than or equal to 5 degrees C, to July 17 of that year, when the maximum daily temperature was greater than or equal to 20 degrees C. This is an average value for all SMHI weather stations within a 50 km radius of a site. Neutral detergent fibre content of downy birch leaves at the site, based on a representative sample and calculated using Near Infrared Spectroscopy Neutral detergent fibre content of fireweed stems, leaves, and flowers at the site, based on a representative sample and calculated using Near Infrared Spectroscopy Nitrogen content of downy birch leaves at the site, based on a representative sample and calculated using Near Infrared Spectroscopy Nitrogen content of fireweed stems, leaves, and flowers at the site, based on a representative sample and calculated using Near Infrared Spectroscopy Mean date-adjusted moose calf slaughter weight for calves reportedly shot within 50km of the site. Values must represent the mean weight of at least 10 calves to be included. The documentation file Key_DataWeatherVegMoose.tsv contains detailed information about the variables in the dataset. The documentation file sites_no.tsv contains codes for the different sites where data was collected. It corresponds with the variable Site in the dataset DataWeatherVegMoose.tsv. R_code_piecewise_SEM.r is the R script used to calculate the piecewise structural equation models linking weather to moose calf mass directly and via forage chemistry. R_code_piecewise_SEM_log.txt is output of the script with session information. If R , with the packages nlme and piecewiseSEM, is installed, it can be generated by running this from a shell: Rscript R_code_piecewise_SEM.r > R_code_piecewise_SEM_log.txt本数据集包含一项分段结构方程模型（piecewise structural equation modelling）研究所用的数据与R代码，该研究对比了瑞典北部气温与降水对驼鹿幼崽体重的直接及间接影响。该项研究于1988年启动，旨在探究气候变化对瑞典在经济与文化层面均具有重要价值的驼鹿的常见饲用物种的影响，研究周期至1997年结束，并于2017年重新启动。 气温与降水变量源自瑞典气象与水文研究所（SMHI，Swedish Meteorological and Hydrological Institute）的气象站数据。研究样地的驼鹿幼崽平均体重源自瑞典猎人协会及各狩猎小队的统计数据。上述气象数据与驼鹿幼崽体重数据均为各研究样地50公里半径范围内的平均值。氮含量与中性洗涤纤维含量通过近红外光谱（Near Infrared Spectroscopy）建模得到，建模过程使用50份样本进行校准。样本采集自面积为1公顷的样地，涵盖了30株垂枝桦或柳兰的相关组织。 本数据集包含以下文件： 1. "DataWeatherVegMoose.tsv"：数据集本体，采用制表符分隔值（TSV）格式，共236行×10列。包含以下变量： - 生长季起始至当年7月17日的总降水量（单位：毫米）：生长季起始日定义为每个日历年度中首个连续4天日均温均≥5℃的首日。该值为样地50公里半径范围内所有SMHI气象站的平均数据。 - 生长季起始至当年7月17日的日均温平均值：生长季起始日定义同上。该值为样地50公里半径范围内所有SMHI气象站的平均数据。 - 生长季起始至当年7月17日期间，日最高温≥20℃的天数占比：生长季起始日定义同上。该值为样地50公里半径范围内所有SMHI气象站的平均数据。 - 样地内垂枝桦叶片的中性洗涤纤维含量：基于代表性样本通过近红外光谱法计算得到。 - 样地内柳兰的茎、叶及花的中性洗涤纤维含量：基于代表性样本通过近红外光谱法计算得到。 - 样地内垂枝桦叶片的氮含量：基于代表性样本通过近红外光谱法计算得到。 - 样地内柳兰的茎、叶及花的氮含量：基于代表性样本通过近红外光谱法计算得到。 - 据报道在样地50公里范围内射杀的驼鹿幼崽的经日期校正后的平均屠宰体重：纳入统计的样本需至少包含10头幼崽的体重均值。 2. "Key_DataWeatherVegMoose.tsv"：数据集说明文档，包含"DataWeatherVegMoose.tsv"中各变量的详细信息。 3. "sites_no.tsv"：包含各数据采集样地的编码文件，与"DataWeatherVegMoose.tsv"中的"Site"变量相对应。 4. "R_code_piecewise_SEM.r"：用于构建分段结构方程模型的R脚本，该模型通过饲用植物化学性状，将气象因子与驼鹿幼崽体重直接关联起来。 5. "R_code_piecewise_SEM_log.txt"：脚本运行输出及会话信息日志。若已安装R及"nlme"与"piecewiseSEM"包，可通过在shell中执行以下命令生成该日志：Rscript R_code_piecewise_SEM.r > R_code_piecewise_SEM_log.txt