Restoration treatments improve seedling establishment in a degraded Mediterranean-type Eucalyptus ecosystem

Abstract

Restoration of degraded Mediterranean-type ecosystems (MTEs) with long, hot and dry summers is challenging. To develop management guidelines, we evaluated techniques that could improve seedling establishment in two degraded Eucalyptus gomphocephala DC (tuart) woodlands, given weed and herbivore control. These techniques aimed to mimic favourable conditions for species that primarily recruit following disturbance events (e.g. fire). Trial 1 investigated the response of 5-month-old seedlings and broadcast seed in plots that contained a created ashbed, were ripped, or were ripped and contained an ashbed. Trial 2 examined the response of 5-month-old seedlings to treatments providing a nutrient or moisture source (slow-release fertiliser tablet, chelating agent, slow-release fertiliser tablet plus chelating agent, zeolite, hydrated hydrophilic co-polymers and dry hydrophilic co-polymers). Results indicated that created ashbeds enhance establishment for a range of species and reduce weed cover, with or without ripping. Broadcast seeding was not successful in returning species to site. Higher growth rates were recorded in seedlings treated with a nutrient source. The present study has shown that it is possible to re-establish local plant species in degraded woodlands through several techniques that mimic disturbance (e.g. fire). Strong early growth may be the vital start seedlings need in MTEs in the face of reinvading weed species, herbivory and a drying climate.