Alien seedling recruitment as a response to altitude and soil disturbance in the mountain grasslands of central Argentina |
| |
Authors: | Valeria Paiaro Arnaldo Mangeaud Eduardo Pucheta |
| |
Institution: | (1) Cátedra de Biogeografía and Instituto Multidisciplinario de Biología Vegetal (IMBIV), CONICET-Universidad Nacional de Córdoba, Casilla de Correo 495, Córdoba, 5000, Argentina;(2) Cátedra de Estadística y Biometría and Instituto de Investigaciones Entomológicas, Universidad Nacional de Córdoba, Córdoba, Argentina;(3) Present address: Departamento de Biología, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de San Juan, Av. Ignacio de la Roza 590 (O), Rivadavia, San Juan, 5400, Argentina |
| |
Abstract: | Climate and disturbance are considered key factors in explaining plant invasion, mainly by their effect on alien seedling
recruitment. We tested whether soil disturbance by digging and altitude, as a sub-set of climate, affected the seedling recruitment
of two alien species (Cirsium vulgare and Melilotus alba) in the mountain grasslands of central Argentina. We performed a seed-addition factorial experiment with altitude as a fixed
factor co-variable (6 levels), time since sowing (6 levels) as an autoregressive co-variable, and soil disturbance by digging
(two levels) and seed addition (two levels) as fixed factors. Seeds of the studied species were sown in replicated undisturbed
and disturbed soil plots, in grassland stands located every 200 m from 1200 to 2200 m a.s.l. The number of emerging seedlings
at each plot was recorded during a period of 8 months, at intervals of 30–60 days. Seedlings of both alien species emerged
at all the studied altitudes, but only the recruitment of C. vulgare increased linearly with altitude. Moreover, the time window of seedling recruitment for this species increased with altitude.
Soil disturbance produced a significant decrease in overall seedling emergence of both species; however, an increase in emergence
was observed for C. vulgare at an altitude over 2000 m a.s.l. Natural emergence inside control plots without seed addition was only observed for Cirsium vulgare, which indicates that this species was not seed limited. Our results show that altitude and the absence of disturbance do
not restrict the recruitment of C. vulgare and M. alba in these natural mountain grasslands. Moreover, these alien species seem to be tolerant to and even favoured by conditions
occurring at higher altitudes and in absence of micro-site soil disturbances in the Córdoba mountain grasslands. |
| |
Keywords: | Alien species Altitudinal gradient Cirsium vulgare Melilotus alba Micro-site disturbance Plant invasion |
本文献已被 SpringerLink 等数据库收录! |
|