Seeing the light: urban stream restoration affects stream metabolism and nitrate uptake via changes in canopy cover
Seeing the light: urban stream restoration affects stream metabolism and nitrate uptake via changes in canopy cover
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看到光明：城市河流恢复通过树冠覆盖的变化影响河流新陈代谢和硝酸盐吸收
DOI：
10.1002/eap.1941
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发表时间：
2019
影响因子：
5
通讯作者：
Rosi, Emma J.
中科院分区：
文献类型：
--
作者：
Reisinger, Alexander J.;Doody, Thomas R.;Groffman, Peter M.;Kaushal, Sujay S.;Rosi, Emma J.
居住在城市景观中的全球人口不断增加，影响了城市河流提供的众多生态系统功能和服务。城市河流的恢复通常被用来抵消这些影响，保护或提高这些河流提供的各种功能和服务。尽管假设“如果你建立它，[功能]会来，”目前的理解，城市河流恢复河流生态系统功能的影响是基于短期的研究，可能无法捕捉随着时间的推移恢复效果的变化。我们通过研究美国马里兰州的巴尔的摩的10条城市河流（5条恢复，5条未恢复），量化了河流恢复对城市河流养分和能量动态的影响。在整个研究过程中，我们连续测量了整个河流尺度的总初级生产力（GPP）和生态系统呼吸（ER），并在所有河段按季节（春季，夏季，秋季）测量了硝酸盐（NO3--N）螺旋上升率。没有显着的恢复效果NO3--N螺旋跨越河段。然而，有一个显着的冠层覆盖效应NO3--N螺旋，直接比较成对的未恢复恢复的河段表明，恢复后，影响NO3--N螺旋考虑其他环境变化。此外，GPP：ER季节性变化，恢复和开放的树冠在夏季表现出更高的GPP：ER。 然而，恢复效果似乎取决于林冠覆盖的变化，这可能是恢复的暂时效果，是多种生态系统服务的驱动力，例如，栖息地、河岸养分处理。我们的研究结果表明，有关河流恢复的决策，包括营养效益的评估，显然需要考虑冠层覆盖的时空动态和多种生态系统服务之间的权衡。
The continually increasing global population residing in urban landscapes impacts numerous ecosystem functions and services provided by urban streams. Urban stream restoration is often employed to offset these impacts and conserve or enhance the various functions and services these streams provide. Despite the assumption that “if you build it, [the function] will come,” current understanding of the effects of urban stream restoration on stream ecosystem functions are based on short term studies that may not capture variation in restoration effectiveness over time. We quantified the impact of stream restoration on nutrient and energy dynamics of urban streams by studying 10 urban stream reaches (five restored, five unrestored) in the Baltimore, Maryland, USA, region over a two‐year period. We measured gross primary production (GPP) and ecosystem respiration (ER) at the whole‐stream scale continuously throughout the study and nitrate (NO3−‐N) spiraling rates seasonally (spring, summer, autumn) across all reaches. There was no significant restoration effect on NO3−‐N spiraling across reaches. However, there was a significant canopy cover effect on NO3−‐N spiraling, and directly comparing paired sets of unrestored‐restored reaches showed that restoration does affect NO3−‐N spiraling after accounting for other environmental variation. Furthermore, there was a change in GPP : ER seasonality, with restored and open‐canopied reaches exhibiting higher GPP : ER during summer. The restoration effect, though, appears contingent upon altered canopy cover, which is likely to be a temporary effect of restoration and is a driver of multiple ecosystem services, e.g., habitat, riparian nutrient processing. Our results suggest that decision‐making about stream restoration, including evaluations of nutrient benefits, clearly needs to consider spatial and temporal dynamics of canopy cover and trade‐offs among multiple ecosystem services.