Performance of native and introduced grasses for low-input pastures. 1. Survival and recruitment

Abstract

Differential survival and recruitment patterns are commonly ignored within plant selection and breeding programs, where attention is focused largely on selection of cultivars with high biomass and seed yields. However, in low-input situations, where fertiliser application is limited, the use of pasture species with superior survival and recruitment characteristics can offer the potential of cost-effective pasture establishment. We investigated the comparative survival and seedling recruitment of 62 native and introduced perennial grasses under low-fertility conditions within three agro-ecological zones of temperate Australia: the temperate high-rainfall pasture zone; drier mixed-farming areas and Mediterranean southern Australia. Plants were grown from seed in glasshouses and transplanted to the field as spaced plants within 6–8 weeks. At regular intervals, survival of transplanted plants and recruitment of new plants were recorded. We found high mortality over a relatively short (24-month) period among both native and introduced grasses, despite good establishment. Frost damage at the cooler sites resulted in death of some C4 plants early in the experiment. Survival of some lines declined following the dry summer of 2000–01, and lines with best survival after this time were Eragrostis curvula cv. Consol, Austrodanthonia fulva (from Dalgety and Wagga, NSW) and Paspalidium jubiflorum (from Warren, NSW). C3 grasses, which generally had poor survival were a Microlaena stipoides selection from Nile, Tasmania, and two lines of Elymus scaber (Boorowa and Tumut, NSW). The C4 grasses Chloris truncata (Girilambone, NSW) and Dichanthium sericeum (Trangie, NSW) also exhibited poor survival, although there were exceptions at some sites. The native lines A. caespitosa Tas2407, M. stipoides cv. Shannon and A. racemosa were the most successful recruiters. Introduced lines generally had lower recruitment, although two lines of D. glomerata from Spain recruited well at some sites. C4 lines generally had poor recruitment, including E. curvula cv. Consol, Bothriochloa macra, Themeda australis, Enteropogon acicularis, D. sericeum, P. jubiflorum and P. constrictum. The role of plants adapted to low-input situations is discussed, as well as the implications of the attributes of survival and recruitment for selection of new cultivars for these situations.

Influence of warming on soil water potential controls seedling mortality in perennial but not annual species in a temperate grassland

“…Therefore, even though the regeneration phase is short, it has a long‐lasting effect on ecological processes of both populations and communities (Poorter, 2007); the central tenet of the concept of the ‘regeneration niche’ (Grubb, 1977). Recruitment is particularly important in areas subject to severe disturbance or frequent drought, such as occurs in southern temperate grasslands (Waters et al ., 2005), as plant mortality is often high in such habitats.…”

Impact of deferred grazing and fertilizer on herbage production, soil seed reserve and nutritive value of native pastures in steep hill country of southern Australia

“…Post‐deferred grazing, tiller density of perennial grasses can be significantly increased due to recruitment of tillers and natural reseeding in autumn and winter (Nie et al ., ; Nie and Zollinger, ). Perennial grasses are essential components of pastures for animal production in temperate regions of Australia (Waters et al ., ). A concern with deferred grazing is the loss of pasture production and nutritive value due to lost tiller/plant numbers and the senescence and decay of plant leaves during the process of deferred grazing that would have a negative impact on pasture production and animal performance (e.g.…”

“…Given that the perennial grasses consisted of mostly C 3 native grasses such as Rytidosperma caespitosa and Microlaena stipoides (Nie and Zollinger, ), it is likely that natural reseeding from these species could be more successful (Waters et al ., ). Natural reseeding exists for improved and native pastures (L'Huillier and Aislabie, ; Hume et al ., ; Waters et al ., ), and some of the C 3 native grasses were found to be the most successful recruiters in low‐input environments in comparison with a range of improved and native species (Waters et al ., ).…”

Grazing primarily drives the relative abundance change of C4 plants in the typical steppe grasslands across households at a regional scale

“…Grazing influence on the relative abundance of C 4 plants has received much attention in the study of grasslands in North and South America (Reeder et al 2004;Altesor et al 2006;Derner et al 2006), Central Asia (Auerswald et al 2012;Ren et al 2012), South Africa (Franz-Odendaal et al 2002), Australia (Bell et al 2012) and New Zealand (Crush and Rowarth 2007). Most of these studies suggest that grazing increases the relative abundance of C 4 species in some plant communities (Reeder et al 2004;Waters et al 2005;Fanselow et al 2011). Two reasons may explain these results.…”