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Modelling the distribution of Ilex aquifolium at the north‐eastem edge of its geographical range
Author(s) -
Bañuelos María José,
Kollmann Johannes,
Hartvig Per,
Quevedo Mario
Publication year - 2003
Publication title -
nordic journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.333
H-Index - 33
eISSN - 1756-1051
pISSN - 0107-055X
DOI - 10.1111/j.1756-1051.2003.tb00374.x
Subject(s) - biology , range (aeronautics) , botany , distribution (mathematics) , ecology , engineering , mathematics , mathematical analysis , aerospace engineering
Plant distribution borders are key features to characterise the ecological niche of a species and to monitor effects of climate change. Here we focus on an evergreen small tree, Ilex aquifolium, which reaches its north‐eastern range edge in Denmark. Our main objectives are to describe and to model the current distribution of the species, to identify the most important climatic and land use factors which shape this distribution pattern, and to analyse the species' habitat requirements. For this purpose we used data from a national mapping project, complemented by information from forest owners. The distribution and abundance of I. aquifolium in Denmark have markedly changed during the past 40 years. It is now found in almost all districts, although the centres of abundance still coincide with the historical records. Our model shows lower habitat suitability for the species in northern and eastern districts, where winters are more severe and spring precipitation is lower. To a lesser extent, land use influences I. aquifolium occurrence, but it is more common in areas with a high proportion of forests and/or urban sites. The analysis of habitat requirements supports these results, since I. aquifolium occurs mainly as a forest species in deciduous stands, on relatively nutrient‐rich moist soils, and under moderately high light conditions. However, some records may be the product of seed dispersal from planted individuals nearby. The results suggest that the range edge of the species has moved at least 100 km east within half a century. Since I.aquifolium is sensitive to winter frost, this change in distribution may be due to increasingly mild winter temperatures.