Genetic structure of Galium cracoviense (Rubiaceae): a naturally rare species with an extremely small distribution range

Abstract

Galium cracoviense is a narrow endemic diploid species with a highly restricted natural range of occurrence, confined to a system of limestone outcrops in an area covering ca. 25 km 2 in southern Poland. It is an excellent example of a naturally very rare species which most probably has persisted in the same area since its divergence. We used the first exhaustive inventory of its subpopulations, range-wide fine-scale sampling and AFLP fingerprinting to examine the genetic structure of G. cracoviense. The aims of the study were to verify whether this 'old rare' species maintains high levels of genetic variation despite low population resources; to infer from the spatial pattern of genetic relatedness of individuals any limitations on dispersal and gene flow that may contribute to maintenance of its highly restricted range; and to place our results in the context of conservation strategies for G. cracoviense. Based on AMOVA and PCoA we found high genetic variation (80 % polymorphic markers) and weak divergence among subpopulations, despite the spatial isolation of subpopulations (U ST = 0.11). The high genetic variation found in most subpopulations makes them equally important reservoirs of genetic diversity. In view of the microspatial genetic structure of the subpopulations revealed by autocorrelation analyses, we recommend that if plant material or seeds of this species are collected for ex situ conservation, multiple sampling of neighboring plants (distances of the first lag in autocorrelation analysis) should be avoided so that the largest range of diversity can be covered by sampling.

Reproductive ecology of the carnivorous plant Pinguicula moranensis (Lentibulariaceae)

“…This pattern of distribution agrees with that expected in a scenario characterised by limited seed dispersal (Cieślak et al . ). In addition, we also found that pollinators move over short distances.…”

Genetic diversity and population structure of naturally rare Calibrachoa species with small distribution in southern Brazil

“…Endemic species are plants that occur in specific habitats and are geographically restricted, but such plants can be sparse or abundant, meaning that they can have different population sizes and spatial arrangements ( Rabinowitz, 1981 ). A common assumption is that endemic species are rare and genetically depleted, presenting low genetic diversity and strong population differentiation ( Binks et al , 2015 ; Ciéslak et al , 2015 ). However, many examples can be found in the literature that contradict this statement ( Hou and Lou, 2011 ; Ciéslak et al , 2015 ; Turchetto et al , 2016 ).…”

“…A common assumption is that endemic species are rare and genetically depleted, presenting low genetic diversity and strong population differentiation ( Binks et al , 2015 ; Ciéslak et al , 2015 ). However, many examples can be found in the literature that contradict this statement ( Hou and Lou, 2011 ; Ciéslak et al , 2015 ; Turchetto et al , 2016 ). Absent or limited gene flow and inbreeding are putative drivers for the genetic diversity pattern associated with small or restricted population sizes ( Ellstrand and Elam, 1993 ), and several other factors can influence the genetic diversity and population structure of rare species.…”

“…Absent or limited gene flow and inbreeding are putative drivers for the genetic diversity pattern associated with small or restricted population sizes ( Ellstrand and Elam, 1993 ), and several other factors can influence the genetic diversity and population structure of rare species. These include mating system, pollination and seed dispersal vectors, life cycle, habitat specificity, demographic history, and landscape and/or climate changes ( Loveless and Hamrick, 1984 ; Shirk et al , 2014 ; Ciéslak et al , 2015 ; Shao et al , 2015 ).…”

Adenophora liliifolia: Condition of its Populations in Central Europe

“…(Šmídová et al, 2011) or Pedicularis sudetica Willd. (Hendrych and Hendrychová, 1988), became glacial or postglacial relicts, but also new local endemics appeared, e.g., Galium sudeticum Tausch, G. cracoviense Ehrend., Cochlearia polonica E. Froelich (Cieślak et al, 2007(Cieślak et al, , 2015Szeląg, 2009, 2010;Kolář et al, 2013Kolář et al, , 2015 or Sorbus sudetica (Tausch) Bluff et al (Kaplan, 2012). Climatic changes during the Quaternary Period strongly affected the species composition and the species distribution in Europe (Szafer, 1946(Szafer, -47, 1954Kaplan, 2012).…”