Resumen de Pteridium aquilinum performance is driven by climate, soil and land-use in Southwest Asia
Laleh Amouzgar, Jamshid Ghorbani, Maryam Shokri, Rob Marrs, Josu González-Alday
Growing anthropogenic impacts on natural and semi-natural ecosystems have created a network of degraded sites throughout the world. These disturbed ecosystems are often colonized by invasive plants such as Pteridium aquilinum, which is one of the most widespread plants worldwide. In northern Iran, P. aquilinum is often found invading newly-created habitats formed after anthropogenic disturbance. This study aimed to assess the relationship between P. aquilinum performance and a range of environmental factors (soils, climate, topography and land-use) in northern Iran. In fifteen sites dominated by P. aquilinum, that spanned the regional distribution of P. aquilinum, we measured its cover, density and biomass. Pteridium aquilinum was found to occur in a variety of land-uses including abandoned agricultural lands, degraded forests and upland rangelands. The performance of P. aquilinum varied significantly between the sites and it performed better in a moderate-Mediterranean climate. Variation partitioning confirmed the importance of climate followed by soil and land-use in explaining the performance of P. aquilinum. Topographic variables did not show any significant effect on P. aquilinum. Both temperature and rainfall affected P. aquilinum performance. Density was correlated positively with early-spring rainfall whereas biomass and cover were found to have positive correlation with temperature. There was also a gradient of soil texture/pH/N/P influencing P. aquilinum. Frond density and biomass were correlated positively with sand content, N and P, but negatively with pH, lime and bulk density. Thus, soil conditions alongside temperature in spring and early summer could explain P. aquilinum cover, but for density, rainfall in early spring was the most important factor, suggesting that in northern Iran P. aquilinum performance appears to be intermediate compared to responses reported for temperate (temperature-controlled) and tropical climates (rainfall-controlled).
