Grassland productivity data across a gradient of invasive Pinus contorta abundance, northwest Patagonia, Argentina, 2020

This dataset contains total green biomass, palatable green biomass, sheep stocking rate, Pinus contorta tree density, P. contorta basal area and percentage canopy cover in sites across northwest Patagonia, during the summer of 2020. We measured total green biomass in the peak production (kg /hectare/year), as a metric for aboveground annual productivity, in five different sites and for a wide range of P. contorta abundance. We also measured palatable green biomass (kg/hectare/year), considering only those plant species foraged by sheep. We calculated the sheep stocking rate that can sustainably support the grasslands of our study based on the feeding requirement of an Ovine Livestock Unit (OLU). The OLU represents a Merino wether (castrated male sheep) with an average live weight of 40 kg that consume 365 kg of dry forage in a year in Patagonia grasslands. We counted the number of P. contorta individuals to calculate density (trees/ha) and recorded their diameter at ground level to calculate basal area (m2/ha) (an alternative measure of P. contorta abundance). Additionally, on each subplot we took a hemispheric picture to estimate the canopy cover (%) of P. contorta (a third measure of P. contorta abundance).

本数据集包含2020年夏季巴塔哥尼亚西北部多个样地的总绿色生物量、可食绿色生物量、绵羊载畜率、扭叶松（Pinus contorta）树木密度、扭叶松基面积及冠层覆盖百分比数据。我们在五个不同样地及扭叶松丰度梯度范围内，以峰值生产力（千克/公顷/年）为指标测定了总绿色生物量，以此表征地上年生产力；同时测定了可食绿色生物量（千克/公顷/年），仅包含绵羊取食的植物物种。基于绵羊畜牧单位（Ovine Livestock Unit, OLU）的饲养需求，我们计算了可可持续支撑研究区域草地的绵羊载畜率——OLU定义为巴塔哥尼亚草地中平均活重40千克、年消耗365千克干饲料的美利奴阉公羊（去势公羊）。我们通过计数扭叶松个体数量计算其密度（株/公顷），并记录其地径以计算基面积（平方米/公顷）（扭叶松丰度的另一度量指标）；此外，在每个子样地拍摄半球形照片，以估算扭叶松的冠层覆盖百分比（%）（扭叶松丰度的第三种度量指标）。