Recent studies in salt marshes have demonstrated the role of plant roots in sediment stabilisation, and hence the importance of marshes in providing coastal protection. However, the relative role of root traits and environmental factors in controlling sediment stability, and how intraspecific variability of root traits vary within and among marshes, remain poorly understood. In this study, we investigated which root trait(s) drive sediment stability (resistance to lateral erosion) in two marsh species with an important role in coastal protection (Spartina anglica and Atriplex portulacoides) and how the environment affects the expression of these traits. We sampled three marshes along salinity gradients in each of two estuaries in Wales (UK), establishing replicate plots in the respective dominant zones of each species. In all plots we sampled abiotic variables (sand, redox potential, pH, salinity) and root traits (root density, specific root density, root volume, root length density); in a subset of these plots (three per species in each marsh) we extracted soil-plant cores and assessed their erosion resistance in a flume. Sediment stability was enhanced by increases in root density and reductions in sand content. Abiotic variables affected root density in different ways depending on species: in S. anglica, redox was the only significant factor, with a positive, linear effect on root density; in A. portulacoides, redox had a non-linear (U-shaped) effect on root density, while sand had a negative effect. Collectively, these results show that (i) intraspecific variability in root density can influence sediment stability in salt marshes, and (ii) sediment properties not only influence sediment stability directly, but also indirectly via root density. These results shed light on spatial variability in the stability of salt marshes to lateral erosion and suggest that root density should be incorporated into coastal vegetation monitoring programs as an easy-to-measure root trait that links the environment to sediment stability and hence to the function and services provided by marshes.

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Bronze artifacts constitute a fundamental portion of Cultural Heritage, but effective methodologies for the removal of corrosion layers, such as those produced by the “bronze disease”, are currently missing. We propose the formulation and application of novel poly­(2-hydroxyethyl methacrylate) (pHEMA) networks semi-interpenetrated (SIPN) with poly­(acrylic acid) (PAA) to achieve enhanced capture of copper ions and removal of corrosion products. The pHEMA/PAA SIPNs were designed to improve previous pHEMA/poly­(vinylpyrrolidone) (PVP) networks, taking advantage of the chelating ability of pH-responsive carboxylic groups in PAA. Increasing the pH ionizes carboxyls, increases the porosity in pHEMA/PAA, and leads to the co-presence of enol and enolate forms of vinylpyrrolidone (VP), changing the macroporosity and decreasing the mesh size in pHEMA/PVP. The ion–matrix interaction is stronger in pHEMA/PAA, where the process occurs through an initial diffusion-limited step followed by diffusion in smaller pores or adsorption by less available sites. In pHEMA/PVP, the uptake is probably controlled by adsorption as expected, considering the porogen role of PVP in the network. Upon application of the SIPNs loaded with tetraethylenpentamine (TEPA) onto corroded bronze, copper oxychlorides dissolve and migrate inside the gels, where Cu­(II) ions form ternary complexes with TEPA and carboxylates in PAA or carbonyls in PVP. The removal of oxychlorides is more effective and faster for pHEMA/PAA than its /PVP counterpart. The selective action of the gels preserved the cuprite layers that are needed to passivate bronze against corrosion, and the pH-responsive behavior of pHEMA/PAA allows full control of the uptake and release of the Cu­(II)–TEPA complex, making these systems appealing in several fields even beyond Cultural Heritage conservation (e.g., drug delivery, wastewater treatment, agricultural industry, and food chemistry).

Summary Offspring often solicit, and compete for, limited parental care by elaborate begging behaviour. Kin selection theory predicts that competing offspring should modify the intensity of their begging depending on the degree of relatedness to their nest‐ or litter‐mates. Empirical evidence in birds, which are a key model in the study of parent‐offspring interactions, indeed indicates that a lower level of relatedness between offspring in the nest correlates with more intense begging (i.e. more ‘selfish’ behaviour). This implies that competing nestlings can recognize kin, but the mechanism underlying such discrimination is unclear. Birds have long been thought to mainly rely on visual and auditory cues in their social communication, but there is now growing evidence for the importance of olfactory cues too. To assess the potential importance of olfactory cues in modulating nestling begging behaviour, we experimentally tested in a free‐living bird, the blue tit Cyanistes caeruleus, if nestlings discriminate and adjust their begging behaviour depending on their familiarity with a conspecific nestling odour stimulus. We found that individuals responded with longer and more intense begging bouts to an unfamiliar compared with a familiar odour stimulus. Our findings provide first evidence for a role of olfaction in modulating offspring begging behaviour in a wild bird population. Although our experiment cannot differentiate between the effects of familiarity and relatedness, it raises the interesting possibility that blue tit nestlings may also discriminate between odours of close kin and less related individuals, and adjust their begging behaviour accordingly. This hypothesis requires further testing. A http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.12886/suppinfo is available for this article.