Planting design influences green infrastructure performance: Plant species identity and complementarity in rain gardens

Abstract

Green infrastructure's capacity to mitigate urban environmental problems, like heat island effects and excessive stormwater runoff, is partially governed by its plant community. Traditionally, green infrastructure design has focused on engineered aspects, such as substrate and drainage, rather than on the properties of its living components. Since the functioning of these plant assemblages is controlled by ecophysiological processes that differ by species, the identity and relative abundance of the species used will influence green infrastructure performance. We used trait‐based modeling to derive principles for the effective composition of green infrastructure plant assemblages, parameterizing our model using the vegetation and ecophysiological traits of the species within New York City rain gardens. Focusing on two plant traits that influence rain garden performance, leaf surface temperature and stomatal conductance, we simulated the cumulative temperature and transpiration for plant communities of differing species composition and diversity. The outcomes of the model demonstrate that plant species composition, species identity, selection effects, and interspecific complementarity increase green infrastructure performance in much the way biodiversity affects ecosystem functioning in natural systems. More diverse assemblages resulted in more consistent transpiration and surface temperatures, with the former showing a positive, saturating curve as diversity increased. While the dominant factors governing individual species leaf temperature were abiotic, transpiration was more influential at the community level, suggesting that plants within diverse communities may be cooler in aggregate than any individual species on its own. This implies green infrastructure should employ a variety of vegetation; particularly plants with different statures and physical attributes, such as low‐growing ground covers, erect herbaceous perennials, and shrubs.

The Value of Vegetation in Nature-Based Solutions: Roles, Challenges, and Utilization in Managing Different Environmental and Climate-Related Problems

“…Benefits provided by plants in BRs are generally maximized when a mix of plant species is selected that have different functional attributes, like sedges and woody groundcovers, shrubs, and trees, because a number of interactions between soil and plants could affect how well-vegetated Earth barrier systems work to lower the danger of flooding. Mixed-species plantings perform better than single-species plantings [95]. The density of planted vegetation within BRs has been shown to have a great influence on maximizing the biological processing of nutrients [96,97].…”

The effect of green stormwater infrastructures in urban tier human thermal comfort—a case study in high-density urban blocks

“…In addition, the cooling effect of the rain garden (RG), a special form of green space, which retains rainwater through lower planes and permeable structures, has been veri ed in several studies (Sadeghi et al 2019). Previous studies have focused mostly on its plant species composition, species characteristics (Bruner et al 2023), and rainwater in ltration e ciency (Buzzard et al 2021;Chapman et al 2022;Kasprzyk et al 2022;Burszta-Adamiak et al 2023). Finally, surface heating can be alleviated by special ground materials (Qin 2015;Seifeddine et al 2023;Yang et al 2023), such as materials or coatings with high re ectivity, which can reduce surface temperature (Kousis and Pisello 2023) to obtain a so-called cold surface.…”