Hippophaë rhamnoides L. (Elaeagnaceae family) in the Pleistocene epoch of the British Isles

Abstract

Recent palaeobotanical analyses of Middle Pleistocene fossiliferous lacustrine sediments (correlated with the late Anglian and the early Hoxnian Stages) collected from East Farm, Barnham, Suffolk, UK yielded the characteristic trichomes (scales) of Hippophaë rhamnoides L. together with its pollen grains. Trichomes are rarely recorded from British Pleistocene sediments. Published palynological data suggests that this species was present at certain times to varying degrees during the British Pleistocene epoch, first being recorded in the late Early Pleistocene (Beestonian Stage). During the Middle Pleistocene it is well represented either side of the Anglian Stage/Hoxnian Stage boundary in Britain, while there are other occurrences of lower frequency in the latter part of the Pleistocene. These considerations prompted a review of the presence of this species in the British Isles during the Pleistocene.Today, in northwest Europe Hippophaë rhamnoides L. is predominantly a coastal plant with native populations found on the eastern and south-eastern coastlines of England. Elsewhere on mainland Europe it can also be found growing in river valleys and other inland areas where suitable conditions prevail. The inland British Pleistocene records probably reflect this species exploiting favourable conditions in recently deglaciated open areas. It may be regarded as a pioneer shrub occurring early on in a vegetation succession, being out-competed by later arriving tree species because of its intolerance of shade. Warmer temperatures later in the interglacial vegetation cycle may have also contributed to its demise as the seeds need a degree of cold pre-treatment to prompt germination.