Aim: The aim of this study is to model the past, current, and future distribution of J. phoenicea s.s., J. turbinata, and J. canariensis, based on bioclimatic variables using a maximum entropy model (Maxent) in the Mediterranean and Macaronesian regions.Location: Mediterranean and Macaronesian.Taxon: Cupressaceae, Juniperus.Methods: Data on the occurrence of the J. phoenicea complex were obtained from the Global Biodiversity Information Facility (GBIF.org), the literature, herbaria, and the authors’ field notes. Bioclimatic variables were obtained from the WorldClim database and Paleoclim. The climate data related to species localities were used for predictions of niches by implementation of Maxent, and the model was evaluated with ENMeval.Results: The potential niches of Juniperus phoenicea during the Last Interglacial period (LIG), Last Glacial Maximum climate (LGM), and Mid‐Holocene (MH) covered 30%, 10%, and almost 100%, respectively, of the current potential niche. Climate warming may reduce potential niches by 30% in RCP2.6 and by 90% in RCP8.5. The potential niches of Juniperus turbinata had a broad circum‐Mediterranean and Canarian distribution during the LIG and the MH; its distribution extended during the LGM when it was found in more areas than at present. The predicted warming in scenarios RCP2.6 and RCP8.5 could reduce the current potential niche by 30% and 50%, respectively. The model did not find suitable niches for J. canariensis during the LIG and the LGM, but during the MH its potential niche was 30% larger than at present. The climate warming scenario RCP2.6 indicates a reduction in the potential niche by 30%, while RCP8.5 so indicates a reduction of almost 60%.Main conclusions: This research can provide information for increasing the protection of the juniper forest and for counteracting the phenomenon of local extinctions caused by anthropic pressure and climate changes.

Juniperus thurifera is an important component of woodland communities of dry sites within the West Mediterranean region and is characterised by a strongly disjunctive geographic range. Two subspecies were recognised, subsp. thurifera in Europe and subsp. africana in Africa. The aim of the study was the comparison of phenetic diversity to the pattern of AFLP geographic differentiation of the species described in the literature. The examination of phenetic diversity was based on the biometrical analysis of 17 populations using 12 morphological characters of cone and seed. The differences among populations were analysed using Student’s t test, analysis of discrimination, UPGMA agglomeration and hierarchical analysis of variance. The majority of morphological characters differentiated at a statistically significant level between populations and between J. thurifera subsp. thurifera and subsp. africana. Three groups of populations were detected using multivariate statistical analyses. The first, well separated, is subsp. africana, while the following two concern subsp. thurifera. The morphological differentiation of populations appeared similar to that described on the AFLP. The Gibraltar Straight appeared to be the most important barrier.

The genetic structure and diversity of ten natural populations of Juniperus phoenicea L. from the western part of the species range have been studied using random amplified polymorphic DNA (RAPD) markers. Among 10 analyzed primers only 3 reproduced consistently across successful PCR reactions and gave 45 loci. The percentage of polymorphic loci (P) and Nei’s heterozygosity (H _e ) have average values of 64.9% and 0.177. The average expected heterozygosity of particular populations positively correlate with latitude and negatively with altitude (τ = 0.556, P = 0.025; τ = −0.494, P = 0.047, respectively). The proportion of genetic variation contributed by the differences between populations was low (G _{ST =} 0.056). The gene flow (N _m) has an average value of 4.2, and was higher in subsp. turbinata (7.3) than in subsp. phoenicea (4.1). Significant proportion of the variation (Φ_ST = 0.106) was attributable to differences among populations, as revealed in analysis of molecular variance analysis of pair-wise RAPD distances. No evidence for isolation by distance was detected in Mantel test on genetic (Φ_ST) and geographic distances. European populations differed at a higher level from the African, subsp. phoenicea from turbinata (3.97% and 3.14% of total variance, respectively). The significant level of differences between European and African populations can result from (1) the earlier divergence and considerably low level of gene flow between them, or (2) a different mutation rate within population of different continent. The results suggest rather local forest economy with J. phoenicea, without seed exchange on large distance.

The aim of the present study was biometrical comparison of three Iberian populations of Juniperus phoenicea, represented by the subsp. turbinata and subsp. phoenicea. Eight features of the cones and seeds, two of the shoots and leaves were studied.The biometrical analysis of three distant populations of J. phoenicea shows great taxonomic distances among them. Two of them, representatives of J. phoenicea subsp. turbinata, are closer related each other than to the third, which represents J. phoenicea subsp. phoenicea. These results confirm the genetic differentiation of the taxons and also the biochemical and morphologic division of them. Nevertheless, the distances between particular populations are so great that more resemble the distances between species than between subspecies.

The aim of this study was to examine the diversity of, and differentiation between, 41 natural populations representing Juniperus phoenicea complex within their geographic range using the morphological characteristics of cones, seeds, and sprouts with leaves. Seven populations of J. phoenicea s.s., 25 J. turbinata and nine J. canariensis, each represented by ∼20–30 individuals, were studied. The characteristics describing the size of cones and seeds and their proportions were different between J. phoenicea s.s., J. turbinata, and J. canariensis, and were useful in distinguishing between these three taxa. The populations of J. canariensis had a significantly higher percentage of trimerous cones, a higher number of cone scales, but a lower number of seeds, which were also larger than the seeds from other taxa. Juniperus phoenicea s.s., J. turbinata, and J. canariensis revealed a high level of multivariate differentiation, but there were no single characteristics which allowed one to distinguish between these alone. We detected significant differences between populations of J. turbinata from Europe and Africa, which supports the role of the Gibraltar Straight in the structuring of conifer species. Significant differences were also detected between European and Asiatic populations in several characters examined, indicating the important role of the Aegean Sea in the structuring of this taxon.