The Tertiary relict tree Zelkova abelicea (Ulmaceae): distribution, population structure and conservation status on Crete

Abstract

Relict species provide a unique opportunity to understand past and recent biogeographical and evolutionary processes. Zelkova abelicea (Ulmaceae), which is endemic to the island of Crete (Greece), is one of the most prominent Tertiary relict trees of the Mediterranean region. We collected distribution, threat and population structure data by reviewing literature and herbaria and through field surveys at 14 study plots throughout the range of the species. The present distribution of Z. abelicea is extremely fragmented. Although the total estimated number of individuals is relatively high, the populations are dominated by dwarf, severely browsed, non-flowering individuals. The population structure is asymmetric. At most, 5% of a plot's trees are large and fruit-bearing. The asymmetric structure is particularly pronounced in isolated and small populations. Based on its limited geographical range, the fragmented spatial pattern, and data on distribution and population structure, our study confirms that Z. abelicea is a threatened species (IUCN category Endangered). Our research aim is to promote the development of new approaches for the improvement of conservation strategies for Tertiary relict trees characterized by major local disjunctions.

Phytosociological and ecological discrimination of Mediterranean cypress ('Cupressus sempervirens') communities in Crete (Greece) by means of pollen analysis

“…prunifolia, whose corresponding pollen taxa are documented in their pollen samples (Figure 2). Interestingly, in some samples of this sub-cluster Bb1a Zelkova pollen is identified, which probably corresponds to the endemic species Zelkova abelicea, one of the most prominent Tertiary relict trees of the Mediterranean region (Kozlowski et al, 2014).…”

Footprints of past intensive diversification and structuring in the genus Zelkova (Ulmaceae) in south‐western Eurasia

“…Zelkova abelicea is endemic to Crete (Greece); it has a fragmentary distribution in the four main mountain regions of Crete (Lefka Ori, Psiloritis, Dikti and Thrypti), between 900 and 1800 m a.s.l., which corresponds to the upper timberline (Kozlowski et al ., ). It grows mainly on north‐facing slopes or in and around rocky river‐beds and gullies which remain moist during dry summers (Egli, ; Søndergaard & Egli, ).…”

“…It grows mainly on north‐facing slopes or in and around rocky river‐beds and gullies which remain moist during dry summers (Egli, ; Søndergaard & Egli, ). The species is highly endangered through habitat fragmentation and destruction, overgrazing, fire and water stress (Phitos et al ., ; Søndergaard & Egli, ; Kozlowski et al ., ).…”

Surviving in a predator-free environment: Hints from a bone remodelling process in a dwarf Pleistocene deer from Crete

“…Taking into account that available data on vegetation cover during the Late Pleistocene in the Aegean area indicate that forests were present even during the Last Glacial Maximum (i.e. on Lesbo island) (Bottema and Sarpaki, 2003;Digerfeldt et al, 2000;Fletcher et al, 2010;Margari et al, 2009), the hypothesis of a presence on Crete of diversified environments, including Zelkova forests (Kozlowski et al, 2014), an environment fairly rich in nutrients, seems reasonable. If so, it might be speculated that the competition among individuals of Candiacervus ex gr.…”