Waterlogging affects the distribution of the saltmarsh plant Atriplex portulacoides (L.) Aellen

https://doi.org/10.1016/j.flora.2013.04.006Get rights and content

Abstract

Atriplex portulacoides is a perennial halophyte common along northern European coasts. However it has been observed to be completely absent from peat based Ombrogenic Atlantic saltmarshes. The aim of this study was to elucidate the factors affecting the in situ distribution of A. portulacoides within saltmarsh sites including its absence on peat based saltmarshes. This was carried out through three approaches: by mapping the distribution of A. portulacoides within saltmarshes on the southwest coast of Ireland; by examining the ability of rooted cuttings of A. portulacoides to establish on peat and non-peat saltmarshes in situ; and finally by investigating experimentally the tolerance of A. portulacoides to waterlogging treatments. This study indicates that a combination of multiple abiotic and biotic factors, including intolerance to high soil moisture most likely determines the distribution of A. portulacoides.

Introduction

Atriplex portulacoides L. [syn. Halimione portulacoides Aellen, Obione portulacoides (L.) Moq.] is a perennial halophyte common on saltmarshes along the coasts of Europe, North Africa and South-West Asia (Redondo-Gomez et al., 2007). It is frequently the physiognomic dominant, often forming uniform stands particularly in western European saltmarshes (Henriksen and Jensen, 1979). However, the species is typically not uniformly distributed within saltmarshes (Chapman, 1950). It has also been noted that A. portulacoides is absent from saltmarshes on peat substrate along the Irish west coast (Sheehy Skeffington and Curtis, 2000). Possible explanations for the non-uniform distribution have focused on grazing (Kiehl et al., 1996, Sheehy Skeffington and Curtis, 2000), nitrogen metabolism (Stewart et al., 1973) and drainage and aeration (Armstrong et al., 1985).

Atriplex portulacoides distribution within a saltmarsh has been correlated with good substrate drainage. Armstrong et al. (1985) noted that distribution of the species in saltmarshes was along creek banks, which are distinguished by their high degree of aeration. Within a saltmarsh, Atriplex stands occur where the water table is relatively low (−16 cm: Sanchez et al., 1998). Beeftink et al. (1978) reported the effects of disturbances on A. portulacoides communities, and found that extremely waterlogged conditions decimated the population of Atriplex, reducing cover from approximately 90% to below 5%.

Different halophytes vary greatly in their ability to oxygenate their rhizospheres (Davy et al., 2011). One mechanism to tolerate waterlogged, reducing conditions, in the substrate is the production of aerenchyma (Colmer and Flowers, 2008). Aerenchyma consists of interconnected gas channels that ameliorate oxygen transport into the submerged portions of plants (Armstrong, 1979). Spartina spp. are particularly well adapted to the reducing conditions of mud flats, as they have extensive aerenchyma systems (Dacey, 1981). However, A. portulacoides is a non-aerenchyma halophyte (Asad, 2001) and therefore relies on an aerated substrate for root metabolic activities.

Atriplex portulacoides is notably lacking from Ombrogenic Atlantic saltmarshes (Fig. 1). These are saltmarsh systems which have an underlying freshwater peat substrate (Cott et al., 2012) and occur, alongside sand, sand/mud and mud saltmarshes, along the west coast of Ireland. Although there are small pockets of A. portulacoides on the west coast, this species is absent from Ombrogenic Atlantic saltmarshes (Fig. 1). Atriplex portulacoides relies predominantly on clonal spread, producing in addition substantial quantities of seeds every year (Huiskes et al., 1995). The fruits of A. portulacoides are dispersed by tidal currents and remain buoyant for over a month (Koutstaal et al., 1987). Considering that it is not entirely excluded from the west coast of Ireland, Ombrogenic Atlantic saltmarshes are likely to be exposed to seeds of A. portulacoides.

Based on their ontogeny, it is clear that Ombrogenic Atlantic saltmarshes are poorly drained and waterlogged, as is the typical nature of peat substrates (Montemayor et al., 2008). There are other saltmarshes high in organic matter, for example on the west coast of Scotland (Adam, 1990). Waterlogging inhibits the supply of oxygen to plant roots, ultimately limiting aerobic respiration and plant growth (Pezeshki, 2001). Consequently, it can be hypothesised that the distribution of A. portulacoides on saltmarshes is limited by soil waterlogging and, as a result, the distribution of A. portulacoides on the west coast of Ireland is restricted due to the predominance of poorly drained Ombrogenic Atlantic saltmarsh systems.

In this study we investigate the factors affecting the in situ distribution of A. portulacoides within saltmarsh sites as well as absence on peat-based saltmarshes. This was carried out through three approaches: firstly, by mapping the distribution of A. portulacoides within saltmarshes on the southwest coast of Ireland. Secondly, in order to determine if A. portulacoides could grow on peat substrate in situ, the ability of rooted cuttings to establish on peat and non-peat saltmarshes was also examined. Finally, the tolerance of A. portulacoides to waterlogging treatments was investigated experimentally.

Section snippets

Vegetation mapping

The distribution of A. portulacoides was mapped at three saltmarsh sites along the Irish southwest coast: Kilbrittain (Harbour view) saltmarsh, Ballymacoda saltmarsh and Dunworley Bay saltmarsh (Fig. 2 and Table 1). At each site three, 10 m × 10 m quadrats were set up with a creek bisecting the quadrat, except for quadrat 2 at Dunworley Bay which contained several pans, but no creek. Each quadrat was further sectioned into 1 m × 1 m quadrats and the percentage cover of each plant species within was

Description of vegetation

Monospecific stands of A. portulacoides at each side of the creek were recorded in quadrat 1 (hereafter Q1) at Kilbrittain saltmarsh (Fig. 3). In quadrat 2 (Q2) the size of the creek was reduced and there was less cover of A. portulacoides. Spartina townsendii and Puccinellia maritima were the dominant species with Armeria maritima occurring in a close cropped sward. In quadrat 3 (Q3) A. portulacoides fringed the creek in clear banding patterns. At Ballymacoda saltmarsh there were different

Atriplex portulacoides preference for drier soils

Waterlogging and (lack of) soil aeration have been regarded as major factors affecting plant performance, ultimately driving the zonation patterns typical of saltmarsh systems (Armstrong et al., 1985, Tyler, 1971). This study has established that within saltmarsh sites, A. portulacoides proliferates in areas with the lowest moisture content (Fig. 6, Fig. 7). Soil moisture content was found to increase significantly with distance from the creek edge, the point at which A. portulacoides cover was

Acknowledgements

The authors would like to thank Brian McCann, Anne Buckley and John Devaney for assistance with field work and Patrick Cotter for assistance with mapping software. This work was funded by the Irish Research Council for Science Engineering and Technology. MJ acknowledges support by WoB.

References (34)

  • M.B. Montemayor et al.

    Temporal variations and spatial patterns in saline and waterlogged peat fields: 1. Survival and growth of salt marsh graminoids

    Environ. Exp. Bot.

    (2008)
  • S.R. Pezeshki

    Wetland plant responses to soil flooding

    Environ. Exp. Bot.

    (2001)
  • P. Adam

    Saltmarsh Ecology

    (1990)
  • S.E. Allen

    Chemical Analysis of Ecological Materials

    (1989)
  • W. Armstrong

    Aeration in higher plants

    Adv. Bot. Res.

    (1979)
  • W. Armstrong et al.

    Plant zonation and the effects of the spring-neap tidal cycle on soil aeration in a Humber salt marsh

    J. Ecol.

    (1985)
  • A. Asad

    Adaptation trials of Atriplex and Maireana species and their response to saline waterlogged conditions in Pakistan

    Pak. J. Biol. Sci.

    (2001)
  • W.G. Beeftink et al.

    Aspects of population dynamics in Halimione portulacoides communities

    Vegetatio

    (1978)
  • A.C. Bockelmann et al.

    Competitive exclusion of Elymus athericus from a high-stress habitat in a European salt marsh

    J. Ecol.

    (1999)
  • BSBI

    Botanical Society of the British Isles

    (2011)
  • V.J. Chapman

    Halimione portulacoides (L.) Aell.

    J. Ecol.

    (1950)
  • T.D. Colmer et al.

    Flooding tolerance in halophytes

    New Phytol.

    (2008)
  • G.M. Cott et al.

    Saltmarshes on peat substrate: where blanket bogs encounter the marine environment

    J. Coast. Res.

    (2012)
  • G.M. Cott et al.

    Saltmarshes on substrate enriched in organic matter; the case of Ombrogenic Atlantic saltmarshes

    Estuar. Coast.

    (2013)
  • S. Crooks et al.

    Drainage and elevation as factors in the restoration of salt marsh in Britain

    Restor. Ecol.

    (2002)
  • J.H. Dacey

    How aquatic plants ventilate

    Oceanus

    (1981)
  • A.J. Davy et al.

    Colonization of a newly developing salt marsh: disentangling independent effects of elevation and redox potential on halophytes

    J. Ecol.

    (2011)
  • Cited by (9)

    • Relationships between spatio-temporal changes in the sedimentary environment and halophytes zonation in salt marshes

      2017, Geoderma
      Citation Excerpt :

      Thus, S. maritima and S. perennis have been characterized as low marsh halophytes showing a high tolerance to tidal flooding (Castellanos et al., 1994; Castillo et al., 2000), whereas S. fruticosa colonises higher elevations and saltier sediments than both former species (Álvarez-Rogel et al., 2000; Batriu et al., 2011; Gonzalez-Alcaraz et al., 2014). On the other hand, H. portulacoides colonises low marshes, getting its maximum biomasses in middle marshes (Bouchard and Lefeuvre, 1996; Crooks et al., 2002), where it is associated with humid but well-drainage and oxygenated sediments (Cott et al., 2013b; Crooks et al., 2002; Onaindia and Amezaga, 1999; Sanchez et al., 1998). At higher elevations in the tidal gradient, the biotic interactions and the founder effect (Costa et al., 2003) seemed to be more important to determine the plant zonation than abiotic stresses as it is proper of the mild abiotic environment typical from middle-high marshes (Dormann et al., 2000).

    • Edaphic factors controlling the distribution of inland halophytes in an ephemeral salt lake “Sabkha ecosystem” at North African semi-arid lands

      2017, Science of the Total Environment
      Citation Excerpt :

      Depending on these limits, two kinds of halophytes are expected (i) high salt tolerant species, only encountered in soils with high salinity habitually near salt waterbody (high soil moisture), and (ii) low salt tolerant species occurring in distant soils from the waterbody (low soil moisture). Because soil salinity/moisture are not the only factors, though thought as the most important ones (González-Alcaraz et al., 2014), that influence halophyte zonation patterns (Cott et al., 2013; Soriano et al., 2014; Estrelles et al., 2015; Ribeiro et al., 2015; Veldkornet et al., 2015); the edaphic factors experiencing the same spatial variability trend as salinity/moisture are also expected to synergistically have a significant effect in shaping the presence of these species in their specific habitats. The Sabkha of Djendli (lat.

    • Biophysical properties of salt marsh canopies - Quantifying plant stem flexibility and above ground biomass

      2015, Coastal Engineering
      Citation Excerpt :

      The distribution of A. portulacoides within salt marshes depends on soil drainage as the species is lacking aerenchyma and needs aerated substrates. It thus often colonizes creek bank levees on mid- to upper marshes (Cott et al., 2013). In salt marshes of the Wadden Sea on the Eastern fringes of the North Sea A. portulacoides often forms monospecific stands in the low marsh.

    View all citing articles on Scopus
    View full text