Conceptual baseline for a global checklist of gypsophytes

Abstract

Thelinkbetweenplantsandgypsumsoildatesbacktothe19thcentury.Inrecentyears,anincreasingnumberofarticleshavedealtwiththisveryspecialtypeofflorafromvariousperspectives.Theexistenceofcrustsonthe soil,xericityandnutritionalimbalancesthattheseplants-someofwhicharemineralaccumulators-aresubmitted to,haveturnedthemintointerestingsubjectsofstudyatdifferentlevels,fromthemoleculartothebiogeographical andmacroecologicalones.Theseplantsmightrepresentarelevantmodelforresearchonvegetalevolutionandspecialization,duetothehighnumberofendemismsthatconcentrateongypsum,someofthemverylocalandseriously endangeredinmanycases.Asamatteroffact,theHabitatsDirectiveintheE.U.doesnotonlyincludeseveralgypsophilespecies,butitalsoconsidersgypsumoutcropspriorityhabitats.Thecreationofaglobalgypsophyteschecklist may favour the possibility to increase knowledge about this interesting flora further. Nevertheless, as there are manygypsumterritoriesintheworld,theelaborationofsuchalistdemandstheparticipationofanevergrowingnumberofresearchersandlocalexperts.Fouraspectshavebeendeemedofinterestinthisresearchforthecreationofa checklist: Firstly,discussionaboutwhethertoconsider"gypsum-tolerantplant"and"gypsophyte"(gypso-fromtheGreek,gypsumand-phyte,plant)assynonymoustermsornot,ashappenswith"salt-tolerantplant"and"halophyte"(or"salttolerance"and"halophily").Inthesecondplace,thereistheterminologicalquestionthataffectsallthosewordsderived fromtherootgyps-(gypsophile,gypsicolous,gypsovag…)whichshouldbestandardizedsoastofacilitatescientific communication.Thethirdquestionisrelatedtothegypsiferoussoils,ormaybeitwouldbettertocallthemgypsichorizonsasthegypsumcontentsofthesecanbecriticalinordertodiscriminatebetweengypsophytesandplantsthatare notso.Thefourthaspectdealswiththepossibilitytousechemicalcompositionorstoichiometryinordertodiscriminatebetweengypsophytesandtherestofplants,oratleast,todiscriminatebetweentheaccumulativestrategyand othernutritionalstrategies.Finally,afifthaspectremainstobediscussed,highlighting,atleastsuperficially,whichterritories(inthiscase,countries)arethosewheretheputativeexistenceofgypsophilefloraisbelievedtoappear. Havingexaminedthesequestionsthroughtherevisionof91papersresultingfromasearchonScopusitisclearthat gypsum-tolerance and gypsophily cannot be accepted as synonyms. In addition, gypsophytes, at least for the time being,cannotbedefinedinanyotherwaybutresortingtotheclassicalorinductivecriterion,i.e.,plantsgrowingexclusivelyongypsum.Asregardssoils,thelevelofgypsumgypsophilevegetationcantolerateisfrequentlyover50%. Apartfromthat,althoughtheaccumulatorstrategyiscommonamonggypsophytes,especiallyofCaandS,thisisnot atraitthatcanbegeneralized,asisnotthefactthatthesemineralsshouldconcentrateonleaves.Roots,atleastinthe caseofCa,canalsoaccumulatelargequantities.Sofar,researchongypsophilyhasfocusedonaroundtencountries, which is noteworthy when compared to the 75 where references or signs of gysophile flora have been found; this makesitevenmoreinterestingtoelaborateachecklistthatcouldbroadenknowledgeinthisarea.

Checklist of gypsophilous vascular flora in Italy

“…Ad hoc investigations on gypsophily have been performed in only 12 countries and only five of these studies approached a functional perspective (Mota et al 2016). However, documented gypsophilous flora can be found in at least 75 countries (Pérez-García et al 2017, 2018).…”

“…Several approaches have been proposed to elucidate which plant species can be considered as best linked to gypsum substrates (Mota et al 2016). However, coping with an extremely species-rich flora over a wide territory such as Italy, using the Delphi technique (Hasson et al 2000) resulted in being the most effective way to build a checklist of gypsophilous flora by using the so-called ‘expert criterion’ (Mota et al 2008, 2009).…”

Gypsophila bermejoi G. López: A possible case of speciation repressed by bioclimatic factors

“…All gypsophytes must face difficult environmental conditions, the most notable of which are the strong xericity of their habitat, the existence of a crusty surface and important nutritional imbalances typical of these saline soils [ 47 ]. They are very interesting biochemically, not least for their tendency to accumulate certain minerals and for their capacity to synthesize secondary metabolites of interest.…”

Geobotanical Study of the Microforests of <em>Juniperus oxycedrus</em> subsp. <em>badia </em>in the Central and Southern Iberian Peninsula

“…In the Betic mountains (southern Spain) there are with some frequency marble limestone, gypsum and serpentines [35]. The rainfall values for the territories of serpentines (Sierra Bermeja) influence a wet ombrotype, very like the values precipitations of the mountains in northwestern Serbia [36] and, due to the xericity of serpentines, often appear forests and scrublands not in accordance with the ombrotype of the territory: plants living here, present ecophysiological and morpho-anatomical adaptations to support the limitations [37]. In ideal situations with good soil texture and structure and without slopes, we can assume that the water retention (WR) is maximum (100%).…”