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Abstract Grass species (family Poaceae) are globally distributed, adapted to a wide range of climates and express a diversity of functional strategies. We explored the functional strategies of grass species using the competitor, stress tolerator, ruderal (CSR) system and asked how a species’ strategy relates to its functional traits, climatic distribution and propensity to become naturalized outside its native range. We used a global set of trait data for grass species to classify functional strategies according to the CSR system based on leaf traits. Differences in strategies in relation to lifespan (annual or perennial), photosynthetic type (C3 or C4), or naturalisation (native or introduced) were investigated. In addition, correlations with traits not included in the CSR classification were analyzed, and a model was fitted to predict a species’ average mean annual temperature and annual precipitation across its range as a function of CSR scores. Values for competitiveness were higher in C4 species than in C3 species, values for stress tolerance were higher in perennials than in annuals, and introduced species had more pronounced competitive-ruderal strategies than native species. Relationships between the CSR classification, based on leaf traits, and other functional traits were analyzed. Competitiveness was positively correlated with height, while ruderality was correlated with specific root length, indicating that both above- and belowground traits underlying leaf and root economics contribute to realized CSR strategies. Further, relationships between climate and CSR classification showed that species with competitive strategies were more common in warm climates and at high precipitation, whereas species with stress tolerance strategies were more common in cold climates and at low precipitation. The findings presented here demonstrate that CSR classification of functional strategies based on leaf traits matches expectations for the adaptations of grass species that underlie lifespan, photosynthetic type, naturalization and climate.
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Plant adaptive strategy influences hydrologic services provisioning by stormwater bioretention
Saturated hydraulic conductivity (Ksat) is a key performance variable in nature-based solutions for managing stormwater such as bioretention. Ksat is well understood from a soils perspective, but not an ecological one, despite growing recognition that plant traits and soil characteristics influence one-another and may co-regulate Ksat. There are myriad plant traits that potentially influence Ksat, which makes it difficult to know where attention should be focused to inform hydrologic design. We address this knowledge gap by 1) evaluating adaptive strategy theory as an overarching framework for characterizing plant effects on Ksat, assessing fifteen bioretention systems across three U.S. states and 2), exploring the implications of this theory for spatial and temporal patterns in plant effects on Ksat driven by regional variability in planting guidance and trajectories of plant succession. Our results illustrate that adaptive strategy significantly influences Ksat, with ruderal plants tending to decrease it and stress tolerant or competitive/stress tolerant plants increasing it. These relationships are indirect, reflecting the impact of adaptive strategy on root traits and soil organic matter, which influence Ksat directly. When these relationships are evaluated in the context of established planting guidance, we find that plants recommended in arid climates tend to increase Ksat relative to bare filter media whereas plants in humid climates do not. Small biases in planting preferences can dramatically change these outcomes. For instance, established vegetation in our bioretention sites was more competitive/stress tolerant than expected, significantly increasing Ksat. We also find that plant effects on Ksat are likely to vary in response to ruderal recruitment as bioretention systems age, reducing Ksat up to 15 %. Collectively, these results illustrate that plants play an important role in bioretention hydrology, and warrant consideration during hydrologic design. They also suggest that adaptive strategy theory is a promising design tool, providing useful insights into plant effects on Ksat, both geographically and over time.
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- Award ID(s):
- 2021015
- PAR ID:
- 10540623
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Ecological Engineering
- Volume:
- 198
- Issue:
- C
- ISSN:
- 0925-8574
- Page Range / eLocation ID:
- 107148
- Subject(s) / Keyword(s):
- ecosystem services
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1016/j.ecoleng.2023.107148
