Global growth and stability of agricultural yield decrease with pollinator dependence
Global growth and stability of agricultural yield decrease with pollinator dependence
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DOI：
10.1073/pnas.1012431108
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发表时间：
2011-04-05
影响因子：
11.1
通讯作者：
Harder, Lawrence D.
中科院分区：
文献类型：
--
作者：
Garibaldi, Lucas A.;Aizen, Marcelo A.;Harder, Lawrence D.
人类的福利取决于农业生产的数量和稳定性，这是由作物产量和耕种面积决定的。随着农民投入的资源和对环境敏感的生态系统服务提供的资源，产量逐渐增加。随着投入的增加，产量增长不断下降，促使更多的土地转为耕种，但有侵蚀生态系统服务的风险。为了探索农业生产的相互依赖及其对生态系统服务的稳定性，我们提出并检验了一个基于Jensen不等式的产量-资源关系的通用图形模型，并考虑了对土地非农化的影响。对于动物授粉作为影响作物产量的资源的情况，该模型预测，对于对授粉者依赖程度更高的作物，不完全和可变的花粉传递会更多地降低产量平均值和稳定性(与变异性相反)。联合国粮食及农业组织在1961-2008年间收集的数据支持这些预测。具体地说，尽管大多数作物的全球产量都有所增加，但对传粉者的依赖程度更高的作物在相对产量和产量增长方面的平均值和稳定性较低。较低的产量增长通过增加土地耕作来补偿，以提高授粉者依赖型作物的产量。面积稳定性也随着授粉者的依赖而降低，因为它与作物间的产量稳定性呈正相关。这些结果表明，花粉限制阻碍了授粉者依赖型作物的产量增长，降低了全球农业生产的时间稳定性，同时促进了有偿退耕还田。虽然我们研究了作物授粉，但我们的模型适用于其他生态系统服务，其对人类福利的好处随着接近最大值而减慢。
Human welfare depends on the amount and stability of agricultural production, as determined by crop yield and cultivated area. Yield increases asymptotically with the resources provided by farmers' inputs and environmentally sensitive ecosystem services. Declining yield growth with increased inputs prompts conversion of more land to cultivation, but at the risk of eroding ecosystem services. To explore the interdependence of agricultural production and its stability on ecosystem services, we present and test a general graphical model, based on Jensen's inequality, of yield-resource relations and consider implications for land conversion. For the case of animal pollination as a resource influencing crop yield, this model predicts that incomplete and variable pollen delivery reduces yield mean and stability (inverse of variability) more for crops with greater dependence on pollinators. Data collected by the Food and Agriculture Organization of the United Nations during 1961-2008 support these predictions. Specifically, crops with greater pollinator dependence had lower mean and stability in relative yield and yield growth, despite global yield increases for most crops. Lower yield growth was compensated by increased land cultivation to enhance production of pollinator-dependent crops. Area stability also decreased with pollinator dependence, as it correlated positively with yield stability among crops. These results reveal that pollen limitation hinders yield growth of pollinator-dependent crops, decreasing temporal stability of global agricultural production, while promoting compensatory land conversion to agriculture. Although we examined crop pollination, our model applies to other ecosystem services for which the benefits to human welfare decelerate as the maximum is approached.