Plants on Rich-Magnesium Dolomite Barrens: A Global Phenomenon

SIMPLE SUMMARY: Little is known about the relationship between dolomite soils and the flora that develops on them due, among other reasons, to their diffuse separation from limestone, and the lack of a common approach and terminology. Thus, the main aim of the present review was to define what the dolomite phenomenon is, delimiting its global extent, and establishing its relationship with other edaphic phenomena on serpentine and gypsum. To achieve it, in addition to the information compiled by the authors in previous research, an extensive review relative to this topic was performed. This study’s results showed that the “dolomite phenomenon” occurs globally and is evidenced through the appearance of an endemic flora on nutrient-poor soils with high levels of magnesium. Dolomite habitats cause adaptations in plants to be more recognisable than others occurring on more bizarre rocks. Unfortunately, they have been poorly studied from an ecological, evolutionary and conservational point of view. Therefore, the definition of its universal demarcation and characteristics becomes necessary. The present review is a starting point to reach this goal. ABSTRACT: For botanists and ecologists, the close link between some plants and substrates, such as serpentine or gypsum, is well known. However, the relationship between dolomite and its flora has been much less studied, due to various causes. Its diffuse separation from limestone and the use of a vague approach and terminology that, until now, no one has tried to harmonize are among these reasons. After carrying out an extensive review, completed with data on the distribution of plants linked to dolomite, the territories in which this type of flora appears at a global level were mapped using a geographic information system software. In addition, data on soils were collected, as well as on their influence on the ionomic profile of the flora. These data were completed with the authors’ own information from previous research, which also served to assess these communities’ degree of conservation and the genetic diversity of some of their characteristic species. The results showed that the so-called “dolomite phenomenon” is widely represented and is clearly manifested in the appearance of a peculiar flora, very rich in endemisms, on dry soils, poor in nutrients, and with a high Mg level. Although dolomite habitats cause adaptations in plants which are even more recognizable than those of other rock types, they have not been widely studied from an ecological, evolutionary, and conservation point of view because, so far, neither their characteristics nor their universal demarcation have been precisely defined.