The adaptation of plants to particular soil types has long intrigued biologists. Gypsum soils occupy large areas in many regions of the world and host a striking biological diversity, but their vegetation has been much less studied than that developing over serpentine or saline soils. Herein, we review all aspects of plant life on gypsum ecosystems, discuss the main processes driving their structure and functioning, and highlight the main conservation threats that they face. Plant communities in gypsum habitats typically show distinctive bands at very small spatial scales, which are mainly determined by topography. Plants living on gypsum soils can be classified into three categories: (i) wide gypsophiles are specialists that can penetrate the physical soil crust during early life stages and have physiological adjustments to cope with the chemical limitations imposed by gypsum soils; (ii) narrow gypsophiles are refugee plants which successfully deal with the physical soil crust and can tolerate these chemical limitations but do not show specific adaptations for this type of soils; and (iii) gypsovags are non-specialist gypsum plants that can only thrive in gypsum soils when the physical crust is absent or reduced. Their ability to survive in gypsum soils may also be mediated by below-ground interactions with soil microorganisms. Gypsophiles and gypsovags show efficient germination at low temperatures, seed and fruit heteromorphism within and among populations, and variation in seed dormancy among plants and populations. In gypsum ecosystems, spatio-temporal changes in the composition and structure of above-ground vegetation are closely related to those of the soil seed bank. Biological soil crusts (BSCs) dominated by cyanobacteria, lichens and mosses are conspicuous in gypsum environments worldwide, and are important drivers of ecosystem processes such as carbon and nitrogen cycling, water infiltration and run-off and soil stability. These organisms are also important determinants of the structure of annual plant communities living on gypsum soils. The short-distance seed dispersal of gypsophiles is responsible for the high number of very narrow endemisms typically found in gypsum outcrops, and suggests that these species are evolutionarily old taxa due to the time they need to colonize isolated gypsum outcrops by chance. Climate change and habitat fragmentation negatively affect both plants and BSCs in gypsum habitats, and are among the major threats to these ecosystems. Gypsum habitats and specialists offer the chance to advance our knowledge on restrictive soils, and are ideal models not only to test important evolutionary questions such as tolerance to low Ca/Mg proportions in soils, but also to improve the theoretical framework of community ecology and ecosystem functioning.

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Plant life on gypsum: a review of its multiple facets

Semiarid Mediterranean regions are highly susceptible to desertification processes. This study investigated the influence of increasing climate aridity in explaining the decline in vegetation cover in highly vulnerable gypsum semiarid shrublands of the Mediterranean region. For this purpose, we have used time series of percent cover of vegetation obtained from remote sensing imagery (Landsat satellites). We found a dominant trend toward decreased vegetation cover, mainly in summer and in areas affected by the most severe water stress conditions (low precipitation, higher evapotranspiration rates, and sun-exposed slopes). We show that past human management and current climate trends interact with local environmental conditions to determine the occurrence of vegetation degradation processes. The results suggest that degradation could be a consequence of the past overexploitation that has characterized this area (and many others in the Mediterranean region), but increased aridity, mainly related to global wa...

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Dryness is accelerating degradation of vulnerable shrublands in semiarid Mediterranean environments

Plant succession と土壤反應との關係に就て

Plants being sessile are challenged by biotic and abiotic stresses. Osmotic adjustment has been shown to be an effective component of stress tolerance, and accumulation of osmoprotectants (proline, glycine betaine, gamma-aminobutyric acid and sugars) is a common response observed in different plant systems. Information on the metabolic pathways of these compatible solutes for their regulation, enzymes involved and compartmentalisation are well characterised in most important plant species. Such information has prompted researchers to devise strategies for improvement of plant tolerance through the accumulation of osmolytes in plants by expression of core biosynthetic enzymes or their derivatives and expression of related transporters. Pathway engineering for overproduction of compatible solutes is being attempted through stress-inducible and/or tissuespecifi c regulation in order to avoid primary metabolic costs and minimise the pleiotropic effects. Understanding the mechanisms by which plants perceive environmental signals and transmit them to cellular machinery to activate adaptive responses is crucial for the development of crop improvement strategies to impart stress tolerance.

Osmolytes and Plants Acclimation to Changing Environment: Emerging Omics Technologies

Assessment of the visual impact of marble quarry expansion (1984-2000) on the landscape of Thasos island, NE Greece.

The southeast of the Iberian Peninsula, more precisely, the province of Almeria, has the most important gypsum quarries in Spain. Despite the severe environmental impact of these quarries, so far little attention has been paid to either the effect on the flora, especially on the more restricted endemic taxa, or to the restoration of the habitats after the end of exploitation. It is our view that restoration of gypsum quarries should aim not only at correcting the visual impact of mining on the landscape, but should also attend to the biological impact of the quarrying. Although the ‘cicatrising’ potential of gypsophytes is already well known, not all the species are able to recolonise worked-out quarries. Using species abundances, all analysis clearly show that artificial rehabilitation results in very altered communities. The preservation of the gypsum flora merits prioritary protective strategies which, at least to some extent, would make gypsum mining and nature conservation compatible.

Gypsicolous flora, conservation and restoration of quarries in the southeast of the Iberian Peninsula

From an ecological point of view, gypsum outcrops and their corresponding vegetation are not yet fully understood. Most of the studies have concentrated on merely describing these plant communities. However, some researchers have tried to differentiate between these scrublands not only in terms of their geographical location, but also in terms of their ecological behaviour. Our botanical, edaphic and ecophysiological study, which adopts this last approach, makes use of chlorophyll fluorescence to distinguish the small—sized and sparse scrublands growing on gypsum barrens from the very different shrublike Ononis tridentata communities in the gypsum outcrop of the karst in Sorbas (Almeria, Spain). In the three gypsophytes used to measure chlorophyll fluorescence values (Gypsophila struthium, Helianthemum squamatum and Teucrium turredanum), the records reveal that the environment has an impact on the Fv/Fm minimum values, however different the reaction of the species may be.

Can gypsophytes distinguish different types of gypsum habitats

https://www.um.es/analesdebiologia/numeros/30/PDF/30_02.pdf

Aportaciones al catálogo xenofítico de la provincia de almería (sureste ibérico, españa)

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M. L. Jiménez-Sánchez

Papers

Gypsicolous flora, conservation and restoration of quarries in the southeast of the Iberian Peninsula

Can gypsophytes distinguish different types of gypsum habitats

Aportaciones al catálogo xenofítico de la provincia de almería (sureste ibérico, españa)

Contribución al conocimiento de la flora de Andalucía: citas novedosas e interesantes de la provincia de Almería

Gypsophilous flora and quarries: some remarks on the preservation and restoration of gypsum outcrops