DataSheet1_Oil disturbance reduces infaunal family richness but does not affect phylogenetic diversity.docx

Infaunal organisms are susceptible to disturbances such as hypoxia and sediment contamination; changes in infaunal community structure are therefore often used as indicators of anthropogenic disturbance. Susceptibility to disturbance varies across taxa, either due to physiological factors or to behaviors or functional roles that increase exposure. Both sources of variability are likely to be heritable and shared among related taxa. Thus, we would expect oil disturbance to disproportionately affect related taxa and therefore decrease phylogenetic diversity (PD). We test this hypothesis for a shallow water marine infaunal community using a simulation approach that iteratively removes clades with shared vulnerability to oil exposure. Infauna were sampled at two sites in the Chandeleur Islands, LA, that reflect different exposures to crude oil after the Deepwater Horizon event. Seagrass and adjacent bare sediment habitats were sampled in 2015, 5 years after initial oil exposure, and again in 2016 after an acute re-oiling event. We found that strong correlation between PD and family richness masked any detectable PD patterns with oil exposure. For our full community tree, sensitivity analysis indicated that the removal of larger clades did not disproportionately reduce PD, against our prediction. For this pair of sites, PD did not provide a better metric for assessing the impacts of oil exposure than family richness alone. It is possible, however, that finer-scale taxonomic resolution of infaunal communities may better decouple PD from taxonomic richness. More work is needed to fully evaluate the impacts of disturbance on PD.

底栖生物易受缺氧和沉积物污染等干扰的影响；因此，底栖群落结构的改变常被用作人类活动干扰的指示器。底栖生物对干扰的敏感性因分类群而异，这既可能是由于生理因素，也可能是由于行为或功能角色导致的暴露增加。这两种变异来源均可能具有遗传性，并在相关分类群中共享。因此，我们预期油污干扰会不成比例地影响相关分类群，从而降低系统发育多样性（PD）。我们利用模拟方法，通过迭代移除对油暴露具有共同脆弱性的分支群来测试这一假设的浅水海洋底栖群落。底栖生物在路易斯安那州查德莱尔群岛的两个地点进行采样，这些地点反映了在深水地平线事件后对原油的不同暴露情况。在2015年，即初步油污暴露后的5年以及2016年急性复油事件后，对海草和相邻的裸露沉积物生境进行了采样。我们发现，系统发育多样性（PD）与科丰富度之间的强相关性掩盖了与油暴露相关的任何可检测的系统发育多样性（PD）模式。对于我们的完整群落树，敏感性分析表明，移除较大的分支群并没有不成比例地减少PD，这与我们的预测相反。对于这两个地点，系统发育多样性（PD）并不是评估油暴露影响比单独的科丰富度更好的指标。然而，可能的是，底栖群落更精细的分类学分辨率可能会更好地将系统发育多样性（PD）与分类丰富度分离。需要更多的工作来全面评估干扰对系统发育多样性（PD）的影响。