The estimation of light transmittance through grassland canopy: Searching for a suitable indirect indicator

IF 1.3 4区环境科学与生态学 Q3 ECOLOGY

Acta Oecologica-International Journal of Ecology Pub Date : 2025-06-20 DOI:10.1016/j.actao.2025.104102

Marek Czerwiński , Barbara Golińska , Artur Paszkowski , Konrad Wróblewski , Katarzyna Dąbrowska-Zielińska , Piotr Goliński

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引用次数: 0

Abstract

In grasslands, the transmittance of photosynthetically active radiation through the canopy (RLI_g) is a key factor in terms of ecosystem productivity and biodiversity. However, direct RLI_g measurement is time-consuming, and the estimation is difficult because the relationship between RLI_g and other canopy characteristics has not been sufficiently explored. We aimed to determine the relationships between RLI_g for vegetation with a different cover of forbs, and easily measurable, potential proxy indicators: average canopy height (h), fresh aboveground biomass (FM), and several indices obtained from Sentinel-2 satellites: leaf area index (LAI), normalized difference vegetation index (NDVI), enhanced vegetation index (EVI) and structure insensitive pigment index (SIPI). Empirical data was collected from 2020 to 2023 in 22 mesic grasslands located in Poland. A clear pattern of relationship with RLI_g was observed for h, FM, and LAI: the increase in these parameters coincided with the decrease in RLI_g. This decrease was strong when h, FM and LAI were still low and became moderate when h, FM, and LAI increased to a certain threshold. This shift in the RLI_g trend line was more abrupt and occurred earlier in canopies with high herb cover. This relationship can be accurately modeled using a broken line regression. Photosynthetically active radiation (PAR) is almost unavailable near the ground in swards taller than 15 cm, with LAI greater than 4.5 and aboveground biomass greater than 1.0 kg m⁻². Due to the complexity of the models obtained, practical estimation of RLI_g based on h, FM, or LAI may be difficult.

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草地冠层透光率估算：寻找合适的间接指标

在草原上，光合有效辐射通过冠层的透射率是影响生态系统生产力和生物多样性的关键因素。然而，直接测量RLIg不仅耗时，而且由于RLIg与其他冠层特征之间的关系尚未得到充分的探讨，因此估算困难。我们旨在确定不同覆盖度植被的RLIg与易于测量的潜在替代指标（平均冠层高度（h)、新鲜地上生物量（FM））以及Sentinel-2卫星获得的叶面积指数（LAI）、归一化植被指数（NDVI）、增强植被指数（EVI）和结构不敏感色素指数（SIPI））之间的关系。本文收集了波兰22个mesic草原2020 - 2023年的实证数据。h、FM和LAI与RLIg有明显的关系：这些参数的增加与RLIg的下降相吻合。当h、FM和LAI仍处于较低水平时，下降幅度较大，当h、FM和LAI达到一定阈值时，下降幅度逐渐减小。在草本盖度高的林冠层，RLIg趋势线的变化更为突然，发生时间也更早。这种关系可以用折线回归准确地建模。在高度大于15 cm、LAI大于4.5、地上生物量大于1.0 kg m−2的草地上，近地几乎不存在光合有效辐射（PAR）。由于所获得模型的复杂性，基于h、FM或LAI的RLIg的实际估计可能很困难。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Acta Oecologica-International Journal of Ecology 环境科学-生态学

CiteScore

3.60

自引率

0.00%

发文量

审稿时长

>0 weeks

期刊介绍： Acta Oecologica is venue for the publication of original research articles in ecology. We encourage studies in all areas of ecology, including ecosystem ecology, community ecology, population ecology, conservation ecology and evolutionary ecology. There is no bias with respect to taxon, biome or geographic area. Both theoretical and empirical papers are welcome, but combinations are particularly sought. Priority is given to papers based on explicitly stated hypotheses. Acta Oecologica also accepts review papers.