Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, MA 02543;
Earth Research Institute, University of California, Santa Barbara, CA 93106.
Proc Natl Acad Sci U S A. 2021 Jan 4;119(1). doi: 10.1073/pnas.2105135118.
Disentangling the roles of the external environment and internal biotic drivers of plant population dynamics is challenging due to the absence of relevant physiological and abundance information over appropriate space and time scales. Remote observations of giant kelp biomass and photosynthetic pigment concentrations are used to show that spatiotemporal patterns of physiological condition, and thus growth and production, are regulated by different processes depending on the scale of observation. Nutrient supply was linked to regional scale (>1 km) physiological condition dynamics, and kelp forest stands were more persistent where nutrient levels were consistently high. However, on local scales (<1 km), internal senescence processes related to canopy age demographics determined patterns of biomass loss across individual kelp forests despite uniform nutrient conditions. Repeat measurements of physiology over continuous spatial fields can provide insights into complex dynamics that are unexplained by the environmental drivers thought to regulate abundance. Emerging remote sensing technologies that provide simultaneous estimates of abundance and physiology can quantify the roles of environmental change and demographics governing plant population dynamics for a wide range of aquatic and terrestrial ecosystems.
由于缺乏适当的空间和时间尺度上的相关生理和丰度信息，厘清植物种群动态的外部环境和内部生物驱动因素的作用具有挑战性。通过对巨藻生物量和光合色素浓度的远程观测，结果表明生理状况的时空格局，以及因此的生长和生产力，受到不同过程的调节，这取决于观测的尺度。养分供应与区域尺度（>1 公里）的生理状况动态有关，在养分水平持续较高的地方，巨藻林更具持久性。然而，在局部尺度（<1 公里），与冠层年龄人口统计学有关的内部衰老过程决定了尽管养分条件一致，但个别巨藻林的生物量损失模式。对连续空间场进行生理学的重复测量可以深入了解复杂的动态，这些动态无法用被认为调节丰度的环境驱动因素来解释。新兴的遥感技术可以同时估算丰度和生理学，从而量化环境变化和人口统计学在广泛的水生和陆地生态系统中对植物种群动态的控制作用。
