Plant growth, phenological and morphological traits of nine and exotic invasive woody plant species in Patagonia

Abstract

International audienceNative (NA) woody species of andean-patagonian forest are mainly evergreen (EV=83%) while invasive (IN) species of the same eco region are deciduous (DE=88%). Plant phenology, shoot growth, shoot and fruit morphology were compared between five IN and four NA species in order to determine if studied traits can be explained the IN success. We studied five plants by species and 3-5 shoots by plant. Studied NA species were Ribes magellanicum, (RM, DE), Aristotelia chilensis (AC, wintergreen), Berberis microphylla (BM, EV), B. darwinii (BD, EV). IN included the DE species Rosa rubiginosa (RR), R. canina (RC), R. multiflora (RM), Crataegus monogyna (CM) and Sorbus aucuparia (SA). Shoot extension period, leaves density and seed production varied among species independently of their origin. Specific leaf area (SLA, cm2/g) of DE species was higher for IN than in NA species. Flowering was axilary (RM), occurred on small unbranched shoots (AC, BM, BD) or at the apex of branching shoots (IN). Flowers emerged before (NA), during (CM, SA) or after (RR, RC, RM) shoot extension. NA mature fruits remained on plants during November-March (mean±ES, 139±9 days) while those of IN from March to November (196±19 days) representing an autumn-winter resource for vertebrates. Comparatively higher seed mass, SLA and leaf turnover and different seed dispersion period of IN (compared to NA) could explain the high invasiveness of IN studied species