The capacity of coastal wetlands to maintain their position within a tidal frame is a key indicator of resilience to climate change. A range of techniques can be used to assess this capacity, but few studies have focussed on describing wetland elevation dynamics across timescales. In this study, annual-scale wetland elevation dynamics within intertidal coastal wetlands located at different tidal positions in south-eastern Australia were quantified using both shallow and deep rod surface elevation tables and marker horizon (rSET-MH) techniques. This was supplemented by analyses of sediment accumulation rates across the decadal-centurial timescale using ²¹⁰Pb dating techniques. The rSET-MH technique indicated slight variation in surface elevation change between sub-sites and processes contributing to surface elevation gain was a product of processes occurring over the full substrate volume. This included sediment (both mineral and organic) accretion on the surface and belowground substrate expansion in tidal positions where accommodation space and inundation frequency were higher (i.e. in the mangrove). ²¹⁰Pb data provided the means to consider sedimentation and wetland elevation trends over decadal timescales over which relative sea-level rise has been operating. Sedimentation responded to localised accommodation space processes, exceeding sea-level trends lower in the tidal frame, but corresponded to rates of sea-level rise where accommodation space was increasingly limited (i.e. higher in the tidal frame). We demonstrate that anticipated sea-level rise will create new accommodation space for wetland vegetation and that where sea-level rise is not matched by an equivalent increase in surface elevation, coastal wetlands will either die, retreat landwards, or transition to lower tidal positions that support mangroves.

沿海湿地在潮汐框架内保持其位置的能力是抵御气候变化的关键指标。可以使用一系列技术来评估这种能力，但很少有研究集中于描述跨时间尺度的湿地海拔动态。在这项研究中，利用浅杆和深杆表面高程表和标记地平线（rSET-MH）技术对位于澳大利亚东南部不同潮汐位置的潮间带沿海湿地内的年尺度湿地高程动态进行了量化。通过使用 ²¹⁰ Pb测年技术对十年至百年时间尺度的沉积物积累速率进行分析来补充这一点。 rSET-MH 技术表明子站点之间的表面高程变化存在轻微变化，并且导致表面高程增益的过程是在整个基底体积上发生的过程的产物。这包括地表沉积物（矿物和有机）沉积物和潮汐位置的地下基质扩张，其中容纳空间和淹没频率较高（即在红树林中）。 ²¹⁰ Pb 数据提供了考虑相对海平面上升的十年时间尺度内的沉积和湿地海拔趋势的方法。沉积对局部可容纳空间过程做出反应，超过了潮汐框架中海平面较低的趋势，但与可容纳空间日益有限（即潮汐框架中较高）的海平面上升速率相对应。 我们证明，预期的海平面上升将为湿地植被创造新的适应空间，并且在海平面上升与地表海拔相应增加不匹配的情况下，沿海湿地要么死亡，向陆地退缩，要么过渡到潮汐较低的位置支持红树林。