title: Why some plant species are rare.
abstract: Biodiversity, including plant species diversity, is threatened worldwide as a result of anthropogenic pressures such as an increase of pollutants and climate change. Rare species in particular are on the verge of becoming extinct. It is still unclear as to why some plant species are rare and others are not. Are they rare due to: intrinsic reasons, dispersal capacity, the effects of management or abiotic circumstances? Habitat preference of rare plant species may play an important role in determining why some species are rare. Based on an extensive data set of soil parameters we investigated if rarity is due to a narrow habitat preference for abiotic soil parameters. For 23 different abiotic soil parameters, of which the most influential were groundwater-table, soil-pH and nutrient-contents, we estimated species responses for common and rare species. Based on the responses per species we calculated the range of occurrence, the range between the 5 and 95 percentile of the response curve giving the habitat preference. Subsequently, we calculated the average response range for common and rare species. In addition, we designed a new graphic in order to provide a better means for presentation of the results. The habitat preferences of rare species for abiotic soil conditions are significantly narrower than for common species. Twenty of the twenty-three abiotic parameters showed on average significantly narrower habitat preferences for rare species than for common species; none of the abiotic parameters showed on average a narrower habitat preference for common species. The results have major implications for the conservation of rare plant species; accordingly management and nature development should be focussed on the maintenance and creation of a broad range of environmental conditions, so that the requirements of rare species are met. The conservation of (abiotic) gradients within ecosystems is particularly important for preserving rare species.
authors: G W
authors: GW
authors: Wieger Wamelink
authors: Alterra, Wageningen UR, Wageningen, the Netherlands.
authors: G W Weiger
authors: GW
authors: Wamelink
authors: Biometris PRI, Wageningen UR, Wageningen, the Netherlands.
authors: Paul W
authors: PW
authors: Goedhart
authors: Joep
authors: J
authors: Frissel
authors: Alterra, Wageningen UR, Wageningen, the Netherlands.
authors: Josep Y
authors: JY
authors: Frissel
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D044822:Biodiversity; D003247:Conservation of Natural Resources / Q000379:methods; D004777:Environment; D053476:Extinction, Biological; D018521:Plant Physiological Phenomena; D010944:Plants / Q000145:classification / Q000378:metabolism*; D011156:Population Density; D011157:Population Dynamics; D012987:Soil / Q000737:chemistry*; D013045:Species Specificity
chemical_list: D012987:Soil