Exploring the Functional Strategies Adopted by Coastal Plants Along an Ecological Gradient Using Morpho-functional Traits

Daniela Ciccarelli,Cleusa Bona

doi:10.1007/s12237-021-00945-y

Daniela Ciccarelli, Cleusa Bona

Open Access

https://doi.org/10.1007/s12237-021-00945-y

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Abstract

Coastal dunes are characterised by strong interactions between biotic and abiotic factors along a short gradient from the shoreline to the inland region. We carried out an ecological analysis of the vegetation in a protected area of the Italian coast to evaluate the relationships among species abundance, the occurrence of morphoanatomical traits related to leaves, stems, and roots, and soil variables. Three transects were established perpendicular to the shoreline, with 27 plots distributed in the frontal dunes, backdunes, and temporarily wet dune slacks. An analysis based on community-weighted mean values showed that the pioneer communities of the frontal dunes were dominated by ruderals that are well adapted to the harsh ecological conditions of these environments, showing succulent leaves, high limb thickness values, and low values for leaf dry matter content (LDMC). The backdune vegetation was a mosaic of annual herbaceous and perennial shrub communities showing both ruderal and stress-tolerant strategies (clonality, sclerified leaves, high LDMC values, root phenolics) consistent with less extreme ecological conditions. The dune slack areas were dominated by plants showing adaptations to both arid and flooded environments, such as C4 photosynthesis, amphistomatic leaves, and abundant aerenchyma in the roots. The invasive status, C4 photosynthesis, leaf trichomes, and aerenchyma in the roots were significantly correlated with soil humidity, organic matter content, and pH. These results demonstrate the usefulness of anatomical traits (including root system traits) in understanding the functional strategies adopted by plants. Invasive species tended to occupy plots with high levels of soil moisture, suggesting an avoidance strategy for the harsh environmental conditions of coastal sand dunes. Finally, we suggest including information regarding root systems into coastal monitoring programs because they are directly linked to soil parameters useful in coastal dune management and protection.

Highlights

Coastal sand dunes are unique environments characterised by the close interaction of abiotic and biotic factors that may Communicated by Dennis F
Our aims were (1) to explore how community-weighted mean (CWM) trait values vary along the gradient from the shoreline to inland, confirming our hypotheses; (2) to test whether there are any relationships among species abundance, trait occurrence, and soil variables, and explore the usefulness of using anatomical traits as indicators of plant strategies; and (3) provide a basis for appropriate management strategies for coastal dune ecosystems using analysis of the relationship between plant functional traits and environmental factors
The most common species was Medicago littoralis Rohde ex Loisel., which was found in 63% of the plots, followed by Seseli tortuosum L. (56% of the plots), Festuca fasciculata Forssk. (52% of the plots), Helichrysum stoechas (L.) Moench (48% of the plots), Lomelosia rutifolia (Vahl) Avino & P

Summary

Introduction

Coastal sand dunes are unique environments characterised by the close interaction of abiotic and biotic factors that may Communicated by Dennis F. We expected to find ruderal species dominating the early successional communities of the shoreline-inland gradient with lower values of specific leaf area (SLA) and leaf dry matter content (LDMC), succulent and hairy leaves, and a welldeveloped root system, and stress-tolerant species in the latesuccessional communities of the backdunes with higher values of plant height, SLA, and LDMC, as well as sclerified leaves (Ciccarelli 2015; Bona et al 2020). Our aims were (1) to explore how CWM trait values vary along the gradient from the shoreline to inland, confirming our hypotheses; (2) to test whether there are any relationships among species abundance, trait occurrence, and soil variables, and explore the usefulness of using anatomical traits as indicators of plant strategies; and (3) provide a basis for appropriate management strategies for coastal dune ecosystems using analysis of the relationship between plant functional traits and environmental factors

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