Robinson, Randall (2003) Natural recruitment of native forbs in the grassy ecosystems of south-eastern Australia. Research Master thesis, Victoria University of Technology.

Abstract

As for many lowland grassy ecosystem forbs in South-eastern Australia, the recruitment dynamics of the grassland forbs Podolepis sp. 1 sensu Jeanes 1999 (Basalt Podolepis) and Bulbine semibarbata perennial form (Leek Lily)are unknown. Podolepis sp. 1 and B. semibarbata were used as models of recruitment for a range of similar forb species. In vitro trials of P. sp. 1, 6. semibarbata and an additional 16 grassy ecosystem forb species assessed germinability, germination lag time,germination speed and duration of emergence in relation to light and dark treatments. In vivo trials assessed recruitment from seed as well as field survival of several age classes of transplants, and how there were affected by soil disturbance and invertebrate herbivory over a 50-week period. In vitro germination for most species was unspecialised with germination rates greater than 50 percent. Light was a significant or neutral factor for the majority of species but negatively affected several. Survival of juvenile and semi-mature plants of P. sp. 1 and B. semibarbata were achieved in the field,along with high levels of recruitment from seed in some instances, overcoming previous lack of success in recruitment and survival of these lowland grassy ecosystem forb species. Both recruitment from seed and survival of juveniles was markedly higher in soil-disturbed plots compared with undisturbed plots. Protection from invertebrates generally enhanced survival of seed-recruited seedlings, planted juvenile plants and semi-mature plants, especially in soildisturbed plots. The possible reasons for high recruitment and survival of Podolepis sp. 1 and Bulbine semibarbata (perennial form) in soil-disturbed and invertebrate protected plots are discussed, along with the implications of these techniques for recovery and conservation of lowland grassy ecosystem forb species in South-eastern Australia.

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