Soil arthropod composition differs between old-field dominated by exotic plant species and remnant native grasslands

VILARDO, G; TOGNETTI, PM; GONZALEZ-ARZAC, A; YAHDJIAN, ML

ACTA ECOLOGICA

Elsevier

Lugar: Amsterdam; Año: 2018 vol. 91 p. 57 - 64

Sec­ondary suc­ces­sion af­ter agri­cul­ture aban­don­ment (old-fields) is mostly dom­i­nated by ex­otic grass species. Non-na­tive plant in­va­sions may al­ter soil fauna, po­ten­tially in­duc­ing plant-soil feed­backs. De­spite their im­por­tance in nu­tri­ent cy­cling and plant-soil in­ter­ac­tions, meso and macro­fauna re­ceived less at­ten­tion than bac­te­ria or fungi. Here we com­pared the com­po­si­tion of the soil arthro­pod com­mu­nity in na­tive rem­nants and plant ex­otic-dom­i­nated old-fields grass­lands in the In­land Pampa, Ar­gentina. We sam­pled in­de­pen­dent rem­nants and old-field grass­land plots within a 100 km2 agri­cul­tural land­scape to test the hy­poth­e­sis that the abun­dance of soil arthro­pod or­gan­isms is re­lated to the qual­ity of the plant bio­mass, whereas the di­ver­sity of the soil biota is re­lated to plant species rich­ness, re­sult­ing in a dif­fer­ent soil biota com­po­si­tion be­cause of dif­fer­ing plant com­mu­ni­ties. When com­pared to non-in­vaded rem­nant grass­lands, soil ac­tiv­ity and soil food-web char­ac­ter­is­tics of the old-fields sites in­cluded: 1. Higher to­tal arthro­pod abun­dance, par­tic­u­larly of Isopoda, Pseu­doescor­pi­onida and Blat­taria; 2. Lower abun­dance of Hy­menoptera and En­tho­mo­bry­omor­pha (Collem­bola); 3. Lower di­ver­sity, and even­ness, but sim­i­lar rich­ness of soil or­gan­isms or­ders; 4. Higher soil res­pi­ra­tion rates and soil tem­per­a­ture; and 5. Higher to­tal soil N and K+con­tent, but lower soil P con­tent. These re­sults il­lus­trate that soil arthro­pod com­po­si­tion can vary widely within grass­lands patches de­pend­ing on plant species com­po­si­tion. Also, the more di­verse plant com­mu­nity of rem­nant grass­lands sup­ports a more di­verse soil biota, al­though soil ac­tiv­ity is slower. Our re­sults sup­port the strong link­age be­tween plant com­mu­nity and soil arthro­pod com­po­si­tion and sug­gest that changes in soil biota com­po­si­tion might pro­mote plant-soil feed­back in­ter­ac­tions in­duc­ing the per­sis­tence of these al­ter­na­tive grass­land states in new agri­cul­tural hu­man-mod­i­fied land­scapes.