Micro-environmental conditions differentially affect early stages of plant development (plant emergence and establishment) in denuded areas of the Patagonian Monte

BOSCO T; BERTILLER, MB; CARRERA, AL

Manchester

Conferencia; SER2015; 2015

Society for Ecological Restoration

Direct seeding of native plants combined with litter amendments could bea key management tool for restoration of disturbed arid ecosystems. We analyzedthe effect of abiotic controls on seedling emergence and establishment ofperennial grasses (Poa ligularis, Nassella tenuis) and evergreen shrubs (Atriplex lampa, Larrea divaricata, Schinusjohnstonii) in denuded areas induced by anthropic disturbance in the PatagonianMonte. Wesowed seeds of these species in microcosms subjected to the combined effects ofUV radiation (near-ambient, am-UV; attenuated UV radiation, att-UV), high andlow soil moisture (15-25%, HSM; 5-15%, LSM), and litter cover (without litter,BS; low quality litter, LQL; high quality litter, HQL). During 7 months, we estimatedweekly the seedlings emerged (coleoptile or cotiledons visible) and the seedlingsestablished (two true leaves expanded) as percentage of emerged seedlings. Combinedeffects of the three factors affected N.tenuis emergence with the highest values under HQL and HSM for both UVtreatments. P. ligularis emergencewas higher under am-UV radiation except for HSM at BS. The establishment of P. ligularis was not affected by factorswhile that of N. tenuis was promotedby am-UV. A. lampa emergence waspromoted by am-UV in both HQL and LQL while the establishment was enhanced bythe combined effects of am-UV and HSM. L.divaricata did not emerge under att-UV and LSM in any of the three litter coverswhereas S. johnstonii mostly emergedunder am-UV and HSM at the three litter covers. The establishment of the latterspecies was not affected by factors. We concluded that abiotic factors exerteda stronger control on seedling emergence than on seedling establishment. Moreover,the combination of factors affecting emergence varied among species.  Management tools focused on manipulation of microenvironmentsof seedbeds could promote seedling emergence and establishment of targetspecies for restoration of denuded areas.