How open were European primeval forests? Hypothesis testing using palaeoecological data

Abstract

Summary 1The Vera hypothesis that large herbivores maintained an open landscape in the primeval landscape of lowland Europe is tested using palaeoecological data. The hypothesis suggests that the high abundance of Quercus and Corylus apparent in European pollen diagrams could not have derived from a landscape dominated by closed canopy forests. If natural forest landscapes were indeed more open, current forest conservation management policy across Europe would need to be reconsidered. 2 Relative proportions of Quercus and Corylus pollen are compared from regions which supported large herbivores with data from Ireland, where large herbivores were excluded. Similarity between the two data sets indicates that large herbivores were not required to maintain these taxa in the primeval landscape. 3 Fine spatial resolution pollen data from small hollows in Europe and eastern USA were also reviewed. Data from moss polsters show that percentage arboreal pollen is a reliable indicator of canopy openness in theses sites. The palaeoecological data demonstrate that open canopy forest has only ever been maintained by human exploitation. 4 Large herbivores in Europe do not therefore appear to have maintained an open landscape in primeval times although evidence suggests that they would have influenced the species composition of the forest canopy. 5 It is proposed that data sources other than pollen should be explored as proxies for past forest structure to test this hypothesis more thoroughly.

Identifying and prioritising services in European terrestrial and freshwater ecosystems

“…Temperate grasslands are among the most speciesrich vegetation types in Europe and have great conservation value (Eriksson et al 2002;Poschlod and WallisDeVries 2002;. They usually endure due to moderate human-induced disturbances such as animal husbandry, mowing and collection of firewood (Settele and Henle 2003) and are classified as 'semi-natural ' (van Dijk 1991), although their flora is spontaneous (Svenning 2002;Mitchell 2005). Likewise, European heathlands and shrublands are semi-natural ecosystems which have been coevolving for millennia with human societies and represent a distinctive set of European habitats for their biodiversity, and aesthetic and cultural values (Wessel et al 2004;Quétier et al 2007;de Bello et al 2009).…”

Effects of human land-use on the global carbon cycle during the last 6,000 years

“…Determination of human activities from pollen diagrams usually involves a combination of evidences, including changes in vegetation composition and grassland indicator species (Ren 2000;Berglund 2003). From vegetation modelling based on pollen data, studies of past landscape openness have been performed, e.g., for southern Sweden (Sugita et al 1999), for China north of the Yangtze River (Ren & Beug 2002) and recently on a European level (Mitchell 2005).…”

Riparian landscapes and human habitat preferences during the Hoxnian (MIS 11) Interglacial

“…Although it has been suggested that during the early Holocene medium-size herbivores (red deer, elk, wild pigs and aurochs) would have helped to reduce the forest canopy (Vera, 2000), a more recent study from Ireland suggests that these dense forests would have been maintained despite the herbivores (Mitchell, 2004;Moore, 2005). The absence of elephant and rhinoceros in these environments during the Holocene is the critical factor, allowing the persistence of dense woodland.…”