Esteban Salmerón-Sánchez

Ecology, genetic diversity and phylogeography of the Iberian endemic plant Jurinea pinnata (Lag.) DC. (Compositae) on two special edaphic substrates: dolomite and gypsum

Background and aimsJurinea pinnata is an Iberian vascular plant which only grows on gypsum and dolomite, two types of rocks associated with their exclusive endemic floras. In addition, the plant has an island-like distribution which could affect the differentiation and the genetic variability of wild populations. Thus, the species provides a unique opportunity for comparing (bio)geographical and ecological (edaphic) differentiation by means of molecular markers.MethodsFor our investigation we took 24 soil samples paired with a similar number of foliar samples for nutritional analyses. Our molecular-marker approach (AFLPs) involved 16 populations.ResultsThe edaphic parameters revealed significant dissimilarities between dolomitic and gypsum soils. These differences are also found in the mineral composition of the leaves. However, molecular data revealed that the differentiation between populations correlates better with geographical isolation than with the substrate character.ConclusionsThe populations showing the greatest genetic diversity are those of the East Baetic territory where the species grow on both substrates and its populations are closer together. The plant tolerance to gypsum and dolomite can be explained either as a result of common adaptive mechanisms or of a more general adaptation to arid environments.

Iberian Baetic Endemic Flora and the Implications for a Conservation Policy

The Baetic ranges in the Iberian Peninsula are extremely rich and outstanding in biological terms. Based on the existing literature, herbarium sheets and our own field research, we provide a checklist of the endemic flora growing in the Baetic chorological province. The checklist includes 418 taxa belonging to 43 families, with the species pool concentrated within large families. The highest number of endemic species is recorded in the altitudinal range of 1300–1500 m a.s.l. Hemicryptophytes represent the most frequent life form (45.5%). Conservation priorities should concentrate on non-woody life forms (particularly on hemicryptophytes), and on high mountain areas. Most of the taxa can be ascribed to serial shrublands (36.87%), or rock- or scree-dwelling formations (26.25%), with climactic forest formations playing a minor role (3.24%). This successional position has important implications for conservation programmes. Therefore, a clear distinction should be made between serial or plagioclimactic formations (e.g. dolomite thyme-scrub communities) and degraded communities of little interest for the preservation of biodiversity (e.g. synanthropic vegetation). Astragalus nevadensis subsp. andresmolinae (Díez-Garretas & Asensi) Mota & F.J. Pérez-García is proposed as a new combination.

Extreme habitat loss in a Mediterranean habitat: Maytenus senegalensis subsp. europaea

Maytenus senegalensis subsp. europaea communities are unique vegetal formations in Europe. In fact, they are considered Priority Habitat by Directive 92/43/EEC. These are ecologically valuable plant communities found in the southeast of Spain. By combining modeling methods of environmental variables, historical photo-interpretation, and fieldwork, a chronosequence of the evolution of their extent of occurrence (EOO) has been reconstructed in 1957 and 2011. Results showed a strong regression range of M. senegalensis subsp. europaea populations. More than 26,000 ha of EOO for this species have been lost in the province of Almería. Considering the final number of polygons, this area has been fragmented 18 times since the 1950s. These results reinforce the idea that the alteration and fragmentation of habitat due to human activities is one of the most important drivers of biodiversity loss and global change. These activities are mostly intensive greenhouse agriculture and urbanization without sustainable land planning. Knowledge about the distribution of M. senegalensis subsp. europaea is of great interest for future habitat restoration. Therefore, this would be the key species to recover these damaged ecosystems.

Areas of endemism as a conservation criterion for Iberian gypsophilous flora: a multi-scale test using the NDM/VNDM program

The identification of areas of endemism is a crucial tool for both the interpretation of the spatial component of biological evolution and the plotting of priority areas as far as biodiversity conservation is concerned. Geographical isolation, aridity and special substrates are among the factors which can help to explain the restricted areas of the taxa. All these factors concur in the origin of the Iberian gypsophilous flora, rich in endemic and threatened species. Gypsum is a particularly demanding rock for plants, and gypsum outcrops are usually fragmented in space, in territories with arid conditions. Information on the presence of 71 gypsophytes was collected in 10 × 10 km Universal Transverse Mercator (UTM). The distribution of these plants was used to plot the main areas of endemism for the vascular flora on Iberian gypsum outcrops. This was carried out using the eNDeMism/Visor of eNDeMism (NDM/VNDM) program and several grid cell sizes. A total of 51 areas of endemicity were identified and represented on a map according to their program selection frequency. The South East (SE) of the Iberian Peninsula was the only area selected in all the tests. The results were also compared with other factors of interest for the conservation of gypsophilous flora like genetic diversity of four gypsophytes.

Conceptual baseline for a global checklist of gypsophytes

espanolEl vinculo entre las plantas y los suelos de yeso (gipsofilia) puede remontarse hasta el siglo XIX. Durante los ultimos anos ha sido creciente el numero de articulos que se han ocupado, desde diferentes puntos de vista, de esta flora tan peculiar. La existencia de costras en el suelo, la xericidad y los desequilibrios nutricionales que afrontan estas plantas, algunas de ellas acumuladoras de ciertos minerales, las convierte en interesantes objetos de estudio a diferentes escalas, desde la molecular a la biogeografica y macroecologica. Estas plantas pueden representar un interesante modelo para el estudio de la evolucion y especiacion vegetal por el gran numero de endemismos que se concentran en los yesos, algunos de ellos muy locales y en no pocos casos seriamente amenazados. De hecho, la Directiva Habitats de la UE no solo incluye varias especies gipsofilas, sino que considera a los afloramientos de yeso un habitat prioritario. La creacion de un catalogo o checklist de gipsofitos a nivel global puede impulsar el conocimiento de esta interesante flora. Sin embargo, puesto que existen muchos territorios yesiferos repartidos por todas las regiones de la Tierra, la elaboracion de este listado requiere la participacion de un gran numero de investigadores y expertos locales. Para construir esa checklist, cuatro aspectos fueron considerados de interes en esta investigacion. En primer lugar la discusion en torno a si pueden ser considerados sinonimos “planta gipso-tolerante” (capaz de crecer sobre el yeso) y gipsofito, por analogia con “planta resistente a la salinidad” y halofito (o “tolerancia a la salinidad” y “halofilia”). Esta discusion se extenderia a los conceptos de gipso-tolerante y gipsofilia. En segundo lugar esta la cuestion terminologica que afecta sobre todo a las palabras derivadas de la raiz gyps- (gipsofilo, gipsicola, gypsovago,…), asi como a toda una serie de adjetivos complementarios (estricto, verdadero, preferente, extendido,…). En este caso la cuestion fundamental es si gipsofito y gipsofilo pueden emplearse indistintamente. La tercera cuestion esta relacionada con los suelos yesiferos o quizas sea mejor decir con los horizontes gipsicos ya que el contenido en yeso de los mismos puede ser critico a la hora de discriminar entre un gipsofito y una especie que no lo sea. El cuarto aspecto tiene que ver con la posibilidad de utilizar la composicion quimica o estequiometrica para distinguir a los gipsofitos de las plantas que no lo son o, al menos, para separar la estrategia acumuladora de otras estrategias nutricionales. Y quedaria un quinto, poner sobre la mesa aunque sea de forma somera, aquellos territorios (en este caso paises) de los que se tiene noticia que pueden tener una flora gipsofila. Tras examinar estas cuestiones a traves de la revision de 91 articulos obtenidos de una busqueda en Scopus, es evidente que no se pueden considera sinonimos la gipso-tolerancia y la gisofilia. Ademas, los gipsofitos, al menos de momento, no pueden definirse de otra manera que no sea recurriendo al criterio clasico o inductivo, i.e., plantas que crecen exclusivamente en el yeso. Por lo que respecta al suelo, el nivel de yeso que soporta la vegetacion gipsofila suele estar frecuentemente muy por encima del 50%. Por otra parte, aunque entre los gipsofitos es frecuente la estrategia acumuladora, en especial de Ca y S, no es un rasgo generalizable como tampoco lo es que esos minerales se concentren exclusivamente en las hojas. Las raices, al menos en el caso del Ca, tambien pueden acumular grandes cantidades. Hasta ahora la investigacion sobre la gipsofilia se ha concentrado en unos 10 paises, lo que contrasta con los 75 en los que se han encontrado referencias o indicios que pueden albergar flora gipsofila, circunstancia que pone de manifiesto el interes de elaborar una checklist para favorecer el conocimiento de este tipo de flora. EnglishThe link between plants and gypsum soil dates back to the 19th century. In recent years, an increasing number of articles have dealt with this very special type of flora from various perspectives. The existence of crusts on the soil, xericity and nutritional imbalances that these plants – some of which are mineral accumulators – are submitted to, have turned them into interesting subjects of study at different levels, from the molecular to the biogeographical and macroecological ones. These plants might represent a relevant model for research on vegetal evolution and specialization, due to the high number of endemisms that concentrate on gypsum, some of them very local and seriously endangered in many cases. As a matter of fact, the Habitats Directive in the E.U. does not only include several gypsophile species, but it also considers gypsum outcrops priority habitats. The creation of a global gypsophytes checklist may favour the possibility to increase knowledge about this interesting flora further. Nevertheless, as there are many gypsum territories in the world, the elaboration of such a list demands the participation of an ever growing number of researchers and local experts. Four aspects have been deemed of interest in this research for the creation of a checklist: Firstly, discussion about whether to consider “gypsum-tolerant plant” and “gypsophyte” (gypso- from the Greek, gypsum and –phyte, plant) as synonymous terms or not, as happens with “salt-tolerant plant” and “halophyte” (or “salt tolerance” and “halophily”). In the second place, there is the terminological question that affects all those words derived from the root gyps- (gypsophile, gypsicolous, gypsovag …) which should be standardized so as to facilitate scientific communication. The third question is related to the gypsiferous soils, or maybe it would better to call them gypsic horizons as the gypsum contents of these can be critical in order to discriminate between gypsophytes and plants that are not so. The fourth aspect deals with the possibility to use chemical composition or stoichiometry in order to discriminate between gypsophytes and the rest of plants, or at least, to discriminate between the accumulative strategy and other nutritional strategies. Finally, a fifth aspect remains to be discussed, highlighting, at least superficially, which territories (in this case, countries) are those where the putative existence of gypsophile flora is believed to appear. Having examined these questions through the revision of 91 papers resulting from a search on Scopus it is clear that gypsum-tolerance and gypsophily cannot be accepted as synonyms. In addition, gypsophytes, at least for the time being, cannot be defined in any other way but resorting to the classical or inductive criterion, i.e., plants growing exclusively on gypsum. As regards soils, the level of gypsum gypsophile vegetation can tolerate is frequently over 50%. Apart from that, although the accumulator strategy is common among gypsophytes, especially of Ca and S, this is not a trait that can be generalized, as is not the fact that these minerals should concentrate on leaves. Roots, at least in the case of Ca, can also accumulate large quantities. So far, research on gypsophily has focused on around ten countries, which is noteworthy when compared to the 75 where references or signs of gysophile flora have been found; this makes it even more interesting to elaborate a checklist that could broaden knowledge in this area.

Genetic analysis based on plastidial and ribosomal sequences of the endemic bi-edaphic taxon Jurinea pinnata (Lag.) DC. (Compositae) in the Guadix-Baza Basin

Jurinea pinnata (Lag.) DC. is one of the three species of the genus that grows in the Iberian Peninsula. This species grows on gypsum and dolomite, substrates rich in endemic taxa. Actually, the genus Jurinea Cass. is particularly rich in endemic taxa associated with special substrates. The island-like distribution of J. pinnata makes it an interesting case for the study of genetic differentiation processes. The geographical proximity of J. pinnata and J. humilis makes this evolutionary puzzle even more difficult to solve. These facts could affect the genetic attributes of the species as far as diversity and differentiation are concerned. Our field research involved the sampling of individuals from eight populations of J. pinnata. Of them, six were located in the Guadix-Baza Basin. We used sequences of ribosomal and plastid DNA to perform the genetic analyses. Results revealed no differences between individuals occurring on the two kinds of substrates and evidences of hybridization between J. pinnata and J. humilis. Furthermore, the phylogenetic analysis revealed a possible polyphyletic origin for the adaptation to special substrates within the Jurinea genus, while monophyly was observed in species from the Iberian Peninsula. This could indicate a more general adaptation to arid or saline environments.

A first inventory of gypsum flora in the Palearctic and Australia

Gypseous substrates are well-recognised as supporting distinctive and unique flora assemblages, including numerous gypsum endemic (gypsophile) species. Along with these, others are also frequent although their presence is not restricted to gypsum; they show a clear preference for them (gypsocline). While this phenomenon (gypsophily) has been studied regionally, and various hypotheses put forward to explain it, there has been little global synthesis. We present a preliminary check-list on the gypsophile and gypsocline flora of the Palaearctic and Australian areas as a part of a project to develop a global checklist of the World’s gypsophytes, which can broaden our ecological and biogeographical understanding of these unique environments. The database contains 935 taxa spanning 54 countries. The Irano-Turanian region —and to a lesser extent the Mediterranean region— emerged as the richest territories in terms of gypsophile species; this richness was much reduced in the Saharo-Arabian and, especially in the Eurosiberian regions. The factors that can modulate the richness of gypsophytes in a region are discussed and have been distributed into four groups: a) geological and edaphic factors; b) factors linked to the insular nature of outcrops; c) climatic variables and their interaction with the soil; d) biogeographical factors. The importance of those factors linked to insularity and, especially, to water availability is emphasized. Because the soil structure of many gypsum outcrops reduces water ability to plants, such outcrops can be regarded as “dry-islands” surrounded by less xeric substrates. The fact that gypsophytes can be grouped within a few major flowering plant clades across continents, confirms their pre-adaptations to these harsh and unique environments. Our work provides a preliminary database for exploring ecological and biogeographic issues relating to gypsophily, and we hope it will stimulate global interest in these valuable ecosystems.