Lai Guan-Yu, Liu Hung-Chi, Kuo Ariel J, Huang Cho-Ying
Department of Geography, National Taiwan University, Taipei, Taiwan.
Department of Civil and Environmental Engineering, University of California, Los Angeles, Los Angeles, CA, USA.
PeerJ. 2020 Jun 12;8:e9351. doi: 10.7717/peerj.9351. eCollection 2020.
Epiphytic bryophytes (EB) are some of the most commonly found plant species in tropical montane cloud forests, and they play a disproportionate role in influencing the terrestrial hydrological and nutrient cycles. However, it is difficult to estimate the abundance of EB due to the nature of their "epiphytic" habitat. This study proposes an allometric scaling approach implemented in twenty-one 30 × 30 m plots across an elevation range in 16,773 ha tropical montane cloud forests of northeastern Taiwan to measure EB biomass, a primary metric for indicating plant abundance and productivity. A general allometry was developed to estimate EB biomass of 100 cm circular-shaped mats ( = 131) with their central depths. We developed a new point-intercept instrument to rapidly measure the depths of EB along tree trunks below 300 cm from the ground level (sampled stem surface area (SSA)) ( = 210). Biomass of EB of each point measure was derived using the general allometry and was aggregated across each SSA, and its performance was evaluated. Total EB biomass of a tree was estimated by referring to an in-situ conversion model and was interpolated for all trees in the plots ( = 1451). Finally, we assessed EB biomass density at the plot scale of the study region. The general EB biomass-depth allometry showed that the depth of an EB mat was a salient variable for biomass estimation ( = 0.72, < 0.001). The performance of upscaling from mats to SSA was satisfactory, which allowed us to further estimate mean (±standard deviation) EB biomass of the 21 plots (272 ± 104 kg ha). Since a significant relationship between tree size and EB abundance is commonly found, regional EB biomass may be mapped by integrating our method and three-dimensional remotely sensed airborne data.
附生苔藓植物（EB）是热带山地云雾林中最常见的植物物种之一，它们在影响陆地水文和养分循环方面发挥着不成比例的作用。然而，由于其“附生”栖息地的性质，很难估计EB的丰度。本研究提出了一种异速生长缩放方法，该方法在台湾东北部16773公顷热带山地云雾林的一个海拔范围内的21个30×30米的样地中实施，以测量EB生物量，这是指示植物丰度和生产力的一个主要指标。开发了一种通用的异速生长模型，以根据100厘米圆形垫子（=131个）的中心深度来估计其EB生物量。我们开发了一种新的点截距仪器，用于快速测量距地面300厘米以下树干上EB的深度（采样茎表面积（SSA））（=210个）。每个点测量的EB生物量通过通用异速生长模型得出，并在每个SSA上进行汇总，并对其性能进行了评估。通过参考一个原位转换模型估计一棵树的总EB生物量，并对样地中的所有树木进行插值（=1451棵）。最后，我们在研究区域的样地尺度上评估了EB生物量密度。通用的EB生物量-深度异速生长模型表明，EB垫子的深度是生物量估计的一个显著变量（R² = 0.72，P < 0.001）。从垫子到SSA的尺度放大性能令人满意，这使我们能够进一步估计21个样地的平均（±标准差）EB生物量（272±104千克/公顷）。由于通常发现树木大小与EB丰度之间存在显著关系，因此可以通过整合我们的方法和三维遥感航空数据来绘制区域EB生物量图。
