Assessing the global conservation status of the rock rose Helianthemum caput-felis

Abstract

The assessment of the conservation status of a species is the first step in developing a conservation strategy. IUCN Red Lists assessments are an important starting point for conservation actions and the most commonly applied method for assessing the extinction risk of a species. In this study, the global conservation status of the rock rose Helianthemum caput-felis Boiss. (Cistaceae), a perennial Mediterranean plant, was evaluated using the Red List criteria. The distribution of the species was determined by monitoring historical localities and all other suitable sites along the western Mediterranean coasts for 6 years. For each confirmed locality, the ecological and population parameters and the main threats were recorded; these data were used in a quantitative analysis of the species' extinction risk. Our findings indicate there have been several recent extinctions, and there is a continuing decline in the species' area of occurrence, habitat quality and number of reproductive plants. The main threats are related to human activities. Extinction models indicate a probability of quasi-extinction risk of c. 30% in five generations or c. 45% in three generations, with the species likely to become extinct in seven currently known localities within the next 10 years. Application of the Red List criteria indicates H. caput-felis should be categorized as Endangered. This study confirms that legal protection and passive conservation measures are insufficient to guarantee the persistence of a plant species. Active conservation and management actions are needed to protect this and other threatened species of the Mediterranean Basin.

From global to local scale: where is the best for conservation purpose?

“…Ecologically, H. caput-felis is a thermophilous plant with a growth preference for coastal areas under the direct influence of the sea, mostly on calcareous rocky cliffs (0-200 m a.s.l.) with garrigues or scrublands; it also grows on other, more idiosyncratic habitats, such as sand dunes, rocky slopes bordering inland ravines and, rarely, in open wooded areas (Sulis et al 2020). H. caput-felis is distributed throughout the western Mediterranean Basin (Iberian Peninsula, Mallorca, Sardinia, Morocco and Algeria; Fenu et al 2015;Sulis et al 2020).…”

“…The same general scheme indicated for the Sardinian populations could be adopted also for the Majorcan populations. However, a translocation program already indicated by previous analysis (Sulis et al 2020) could be carried out in suitable areas in order to stabilize the population trends by transplanting adult plants carefully selected based on a preliminary and in-depth genetic study. Such conservation actions are urgently needed for Alicante's populations, where a more general approach could be adopted.…”

“…Consequently, the pivotal question is to know whether having data and general assessments on a threatened species are (or not) determinant to identify effective conservation measures for such species. To test this question, Helianthemum caput-felis (Cistaceae) represents an emblematic plant species because it is distributed in several countries, presents populations isolated from long distances and, locally, grows in very different ecological conditions (Sulis et al 2020).…”

“…caput-felis is a long-lived half shrub that mainly grows in coastal environments, under the direct influence of the sea, but some populations are also found in other ecological contexts such as sand dunes or rocky slopes (Sulis et al 2020). It is distributed throughout the western Mediterranean Basin in several fragmented populations (Sulis et al 2020); the widest distribution and the largest populations are located in Spain, whereas the presence of this species in Sardinia and northwest Africa is restricted to small areas in unique or reduced places where often few mature plants are present (Sulis et al 2020). A recent demographic study carried out considering the whole population of this plant species highlighted that, despite inter-annual fluctuations mainly related to the reproductive traits, the population was at equilibrium under the simulated environmental stochasticity.…”

“…Nevertheless, considering their distribution, the observed decline in several populations, and the deteriorating status of the habitat quality as well as the quasi-extinction risk probability, H. caput-felis was categorized as ''Endangered'' (EN) according to the IUCN protocol (Sulis et al 2020). Accordingly, since H. caput-felis is also included in the Berne Convention and Appendix II of the Habitats Directive (European Community Council Directive 92/43/EEC), a transnational conservation strategy was proposed (Sulis et al 2020); this strategy should include both translocation programs and the protection of each locality in which this plant occurs, to avoid further decline or extirpations, habitat restoration in degraded localities and reduction of the impacts of recreational activities (Sulis et al 2020).…”