Can the preservation of historical relicts permit the conservation of endangered plant species? The case of Silene sennenii (Caryophyllaceae)

Abstract

Allozyme electrophoresis was used to measure levels and distribution of genetic diversity in the critically endangered (CR) Silene sennenii (Caryophyllaceae), a narrow endemic plant species found in northeastern Catalonia (Spain). At present, only 5 populations remain, containing no more than 5,000 individuals, which are subjected to several human pressures such as habitat fragmentation and land use changes. Interestingly, the largest population is located in and around a fortress built in the XVIII century, a circumstance which might facilitated its preservation until now. From the 21 satisfactorily interpreted loci, low levels of genetic variation were detected (P = 20.9, A = 1.31 and He = 0.071), which may be related to small population size, isolation, and fragmentation of extant populations. Moderate to high levels of inbreeding were also found, probably as consequence of the population’s genetic structuring. The conservation of the population located in the fortress would allow the preservation of all the alleles detected at species level; nevertheless, conservation of other populations, coupled with the inclusion of S. sennenii in the Spanish Catalogue of Endangered Species, would also be desirable in order to ensure the long-term survival of the species.