Is Cupressus sempervirens native in Italy? An answer from genetic and palaeobotanical data

Abstract

This study represents the first large-scale analysis using nuclear molecular markers to assess genetic diversity and structure of Cupressus sempervirens L.. Genetic and fossil data were combined to infer the possible role of human activity and evolutionary history in shaping the diversity of cypress populations. We analysed 30 populations with six polymorphic nuclear microsatellite markers. Dramatic reductions in heterozygosity and allelic richness were observed from east to west across the species range. Structure analysis assigned individuals to two main groups separating central Mediterranean and eastern populations. The two main groups could be further divided into five subgroups which showed the following geographical distributions: Turkey with the Greek islands Rhodes and Samos, Greece (Crete), Southern Italy, Northern Italy, Tunisia with Central Italy. This pattern of genetic structure is also supported by SAMOVA and Barrier analyses. Palaeobotanical data indicated that Cupressus was present in Italy in the Pliocene, Pleistocene and Holocene. Furthermore, our molecular survey showed that Italian cypress populations experienced bottlenecks that resulted in reduced genetic diversity and allelic richness and greater genetic differentiation. Recent colonization or introduction may also have influenced levels of diversity detected in the Italian populations, as most individuals found in this range today have multilocus genotypes that are also present in the eastern range of the species. The data reveal a new interpretation of the history of cypress distribution characterized by ancient eastern populations (Turkey and Greek islands) and a mosaic of recently introduced trees and remnants of ancient, depauperate populations in the central Mediterranean range.

Long-term human impacts on genetic structure of Italian walnut inferred by SSR markers

“…This result was not surprising because of the large sample sizes and extensive ranges sampled in the studies of black walnut. Nevertheless, the genetic diversity parameters we observed for the 29 Italian provenances and Sorrento variety were similar to values measured for other domesticated tree species such as black poplar (Van der Schoot et al 2000), Cupressus sempervirens (Bagnoli et al 2009), Fraxinus mandshurica (Hu et al 2008), and Table 1 and Fig. 1 Castanea sativa (Martin et al 2010).…”

“…Nevertheless, the response of forest tree species to habitat fragmentation depends in part on their life history characteristics, including long generation time, predominant outcrossing, and a high level of long-distance gene flow via pollen (Dutech et al 2004). In addition, the distribution of several tree species has been strongly modified by human management during the last 2,000 years, in particular around the Mediterranean basin (Bagnoli et al 2009). This is especially true for Juglans regia (Persian walnut), one of Communicated by A. Dandekar the most economically important members of the genus Juglans.…”

Multiple Approach for Plant Biodiversity Conservation in Restoring Forests

“…Variation in the barcoding loci also evidenced the occurrence of two distinct haplotypes of Taxus baccata in Italy, one shared with other European provenances and a second exclusive of South East Italy. Finally, our results confirmed the genetic diversity existing between Southern and Central Italy provenances of Cupressus sempervirens (Bagnoli et al, 2009), and divergence between Eastern and Western Alps provenances of Picea abies (Collignon & Favre, 2000), as well as between Eastern and Western Mediterranean provenances of P. halepensis (Korol et al, 2002), all previously detected with other molecular markers. Table 2.…”

Genetic comparison between natural and planted populations of Pinus brutia and Cupressus sempervirens in Syria

“…The natural distribution of C. sempervirens in Syria is scattered and restricted to some locations in the coastal mountains, where there are almost-pure stands of this species, while in other locations it occurs in combination with P. brutia (Ghazal, 2008). In addition to being important for afforestation and as ornamental plantations across the Mediterranean region, the 2 studied species have also been artificially introduced into climatically similar areas (Korol et al, 1997;Isik et al, 1999;Santini and Di Lonardo, 2000;Bagnoli et al, 2009). Widespread and landscape-forming, P. brutia and C. sempervirens are common native species in Syria that are also planted in afforestations far away from their natural range in different bioclimatic regions throughout the country.…”