A Genecological Study of the Widespread Australian Native Grass \u3ci\u3eAustrodanthonia Caespitosa\u3c/i\u3e (Gaudich.) H.P. Linder.

The lack of commercial quantities of seed is preventing the use of native grasses in large-scale revegetation programmes. Sourcing wild-land non-local provenance seed from distant locations brings with it risks associated with maladaptation and potential genetic pollution. Understanding of intra-specific ecotypic variation and its adaptive consequences is required to both increase seed supply and retain adaptive characteristics in native plant revegetation programmes. A recently commenced genecological study on the widespread Australian native grass, Austrodanthonia caespitose, aims to examine quantitative traits in a common garden study and genetic structure (using DNA analysis) of 35 populations collected from a large geographic range. Examination of the adaptive significance of these traits using reciprocal transplant experiments will aid in the development of provenance guidelines for Australian native grasses. In this paper we report the initial findings for one of many characteristics being measured in a common garden study, namely plant transpiration efficiency

Germinable Soil Seed Bank of \u3ci\u3eBothriochloa macra\u3c/i\u3e Dominated Pasture in South-Eastern Australia

In native pastures, soil seed banks play an important role in conserving the genetic material in a plant population, influencing community structure and providing protection against adverse climatic conditions. One important native grass is Bothrichloa macra (Steud.) S.T.Blake (Red grass, Red-leg grass). This grass is a C4 indigenous perennial grass that is commonly found in native pastures in the high rainfall zone of south-eastern Australia. At Tarrawingee, NE Victoria, (36°25´S, 146°31´E) and Wymah, southern NSW, (35°58´S, 147°11´E), Australia, two sites that had Bothriochloa macra as the dominant native grass were sampled. Three hundred cores (50 mm diameter and 50 mm depth) were collected from each site and bulked in May 2005. The soil samples were spread evenly over seed raising flats and maintained in a glasshouse, under natural light and modified day/night temperatures. The samples were kept moist for periods of between 35 and 70 d. During each census, germinants were identified to the following functional groups (B. macra, broadleaf, grass and legume) and removed. At the end of each cycle remaining seedlings were counted and water withheld. The dry soil samples were then thoroughly mixed and re-watered to initiate another cohort of germination. This cycle was repeated five times over a nine-month period. These counts showed that B. macra only represented a very low proportion of the soil seed bank (1.1 to 3.4% of total germinants), with the soil seed bank dominated by annual species. Fifty-eight different species germinated from the soil seed bank, with 83% of all seeds germinating in the first two cycles. The soil seed bank of these B. macra pastures possessed characteristics typical of most soil seed banks, including poor correlation with the standing vegetation, domination by one or two species and low representation of perennial species