Increasing status of non-native vascular plants in the Sefton Coast sand-dune system, north Merseyside, UK

Abstract

<jats:p>Over 460 non-native (alien) taxa were recorded in a Sefton Coast sand-dune vascular plant inventory, their proportion in the flora increasing after 1999. Between 2005/06 and 2018, twice as many non-native as native plants were found. An analysis of occurrences of native and non-native taxa in six major habitat types found that a higher proportion of aliens was present in scrub/woodland and disturbed ground, while native plants had more occurrences in fixed dunes/dune grasslands, dune heath and wetlands. No differences between the two groups were detected for strandline/shingle and embryo/mobile dune habitats. Twenty-four non-native and 14 native taxa showed invasive characteristics in the duneland. The former included especially Hippophae rhamnoides and Rosa rugosa, both constituting major threats to sand-dune biodiversity. Particularly invasive native plants were Arrhenatherum elatius, Betula spp., Salix cinerea, and Ulex europaea. The main findings accord with studies elsewhere in Britain and Europe showing recent increases of neophytes in semi-natural habitats and that both non-native and native species can have invasive traits. The open habitats of coastal dunes seem to be particularly susceptible to plant invasions.</jats:p>

Distribution and ecology of Equisetum variegatum (Variegated Horsetail) (Equisetaceae) on the Sefton Coast sand-dunes, north Merseyside, UK

“…Only 5% of the vascular associates of E. variegatum were non-native, a much lower proportion than the 37% aliens for the dune flora as a whole (Smith, 2015). Smith (2020) found that Sefton dune wetlands supported a significantly lower number of non-natives than native vascular plants. He suggested that this is because alien plants are less likely to have evolved the adaptations needed to thrive in soils that are subjected to seasonal flooding and waterlogging, with associated low oxygen levels and high sulphide concentrations.…”

Fifteen years of habitat, floristic and vegetation change on a pioneer sand-dune and slack system at Ainsdale, north Merseyside, UK

“…The only vegetation management during the study period was regular uprooting by volunteers of large numbers of seedling Hippophae rhamnoides (Sea Buckthorn), a shrub that was introduced to this coast in the 1890s and is extremely invasive (Isermann et al, 2007;Smith, 2009Smith, , 2020. Some evidence of rabbit (Oryctolagus cuniculus) grazing was apparent early in the study but, after about 2015, none was seen.…”