Engineer pioneer plants respond to and affect geomorphic constraints similarly along water–terrestrial interfaces world‐wide

Abstract

Aim Within fluvial and coastal ecosystems world-wide, flows of water, wind and sediment generate a shifting landscape mosaic composed of bare substrate and pioneer and mature vegetation successional stages. Pioneer plant species that colonize these ecosystems at the land-water interface have developed specific traits in response to environmental constraints (response traits) and are able to modify habitat conditions by modulating geomorphic processes (effect traits). Changes in the geomorphic environment under the control of engineer plants often feed back to organism traits (feedback traits), and thereby ecosystem functioning, leading to eco-evolutionary dynamics. Here we explain the joint foundations of fluvial and coastal ecosystems according to feedback between plants and the geomorphic environment.Location Dynamic fluvial and coastal ecosystems world-wide.Method Drawing from a pre-existing model of 'fluvial biogeomorphic succession' , we propose a conceptual framework showing that fluvial and coastal 'biogeomorphic ecosystems' are functionally similar due to eco-evolutionary feedbacks between plants and geomorphology. ResultsThe relationships between plant traits and their geomorphic environments within different fluvial and coastal biogeomorphic ecosystems are identified and classified within a framework of biogeomorphic functional similarity according to three criteria: (1) pioneer plants develop specific responses to the geomorphic environment; (2) engineer plants modulate the geomorphic environment; (3) geomorphic changes under biotic control within biogeomorphic ecosystems feed back to organisms. Main conclusionsThe conceptual framework of functional similarity proposed here will improve our capacity to analyse, compare, manage and restore fluvial and coastal biogeomorphic ecosystems world-wide by using the same protocols based on the three criteria and four phases of the biogeomorphic succession model.

Groundwater controls on biogeomorphic succession and river channel morphodynamics

“…Changes in channel morphology due to pioneer vegetation dynamics have been documented in flume experiments [e.g., Hicks et al ., ; Tal and Paola , , ; Van Dijk et al ., ; Bertoldi et al ., ] and historical image analysis [e.g., Kondolf and Curry , ; Beechie et al ., ; Zanoni et al ., ; Bertoldi et al ., ; Picco et al ., ]. Links to field experiments and observations suggest that roots reinforce river sediment stability [e.g., Karrenberg et al ., ; Pollen , ; Edmaier et al ., ; Polvi et al ., ], while the flexible branches are able to protect against erosion during flooding and promote fluvial landform formation and associated ambient conditions for vegetation succession [e.g., Corenblit et al ., , ; Gurnell , , ; Gurnell et al ., ]. The engineering action of the pioneer plants, in association with fluvial landform evolution, has led to the notion of biogeomorphic succession [ Corenblit et al ., , , ], in which landform, vegetation type, and structure coevolve in time.…”

Monitoring and reconstructing past biogeomorphic succession within fluvial corridors using stereophotogrammetry

“…After 1946, photographs were taken approximately every five years. Changes in topography and vegetation canopy height during the biogeomorphic succession are indicated by the two curves (modified after Corenblit et al, 2015). There are more possibilities today to extract elevation from archived stereo-pairs that open opportunities to undertake retrospective diachronic analyses of natural environments, but the accuracy obtained will largely depend on the quality of the photographs.…”

Unsupervised detection of salt marsh platforms: a topographic method

“…Furthermore, scarps connect marsh platforms to tidal flats, and therefore represent a distinct break in elevation between the two. However, newly formed or seasonal marshes up to the establishment phase of development (Corenblit et al, 2015) have little impact on local topography and will not have formed platforms: they are unlikely to be detected by a topographic method. In this study, we therefore focus on the identification of scarps and steep channel banks as a precursor to the detection of platforms, referred to as step 4 in Fig.…”