Tracking floristic archetypes of Patagonian steppes

EASDALE, MARCOS HORACIO; MARTIN-ALBARRACIN, VALERIA LETICIA; PERRI, DAIANA VANESA; LÓPEZ, DARDO RUBÉN; BRUZZONE, OCTAVIO AUGUSTO

APPLIED VEGETATION SCIENCE

WILEY-BLACKWELL PUBLISHING, INC

Año: 2024 vol. 27

1402-2001

Questions: Theclassification ofplant communitiesis awell-established practicein ecology. However,the factorsthat determinethe distributionof commonspecies and theextent oftheir dominanceand overlapare stillbeing debated.Large-scale studies based on field data are of great interest in theface of biodiversity changes and climatechange impacts.This researchwas designedto answerthe followingtwo questions: What are the dominant plantcommunities in the Patagonian steppes and how dothey relateto environmentalfeatures, asmeasured bylatitude, longitude,altitude, meanannual precipitationand meantemperature? Whathave beenthe recentchanges in plant communities in terms of expansion and contraction ofdifferent types of communities?Location:Patagonian steppes(South America).Methods:We useda largedatabase ofspecies-by-species vegetationcover from426monitoring plotsin theSouth AmericanPatagonian steppes,surveyed between2007 and 2019,with twodifferent assessmentdates atleast 5 yearsapart. Weapplied archetypal analysis to identifydifferent vegetation compositions at a regional scale (calledfloristic archetypes)and totrack theirchanges overtime. Inaddition, weanalyzed the relationship between floristic archetypes and spatialand meteorological variables to assess the association betweenfloristic composition and the environmental context.Results:Seven floristicarchetypes wereidentified inthe Patagoniansteppes. Thedominant and most widespread floristic archetype showed an expandingpattern in floristic trajectories and was positively associated withmean annual temperature. This floristicarchetype wascharacterized byboth drought-and grazing-tolerantspecies. Twofloristic archetypeslocated atthe longitudinalextremes showeddecreasing relativeparticipation inthe vegetationconfigurations, and thearchetype locatedtowards the westshowed apositive relationshipwith annualprecipitation, suggestinga threatened scenario in the face of drier conditions. Southernfloristic archetypes either showed a slight decrease or remainedstable.Conclusions:Patagonian steppesare dominatedby bothdrought- andgrazing-tolerant species communities andtheir spatial distribution is expanding across different biomes,whereas themore forage-preferredspecies wereassociated witha decreasingfloristic archetype. A projected drier and hotter climate scenariomay potentiate this pattern. Thefloristic archetypesframework haspotential asa monitoringtool fortracking changes invegetation compositionat amesoscale andfor identifyinghotspots of vulnerable vegetation in the faceof environmental changes.p { line-height: 115%; margin-bottom: 0.25cm; background: transparent }