Pasture production in cleared and uncleared grazing systems of central Queensland, Australia

Kaur, Kamaljit; Jalota, Rajesh K.; Midmore, David J.; Rolfe, John

doi:10.1071/rj05012

Cited by 9 publications

(8 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our results imply that the introduction and spread of buffel grass is associated with a substantial change in bird species composition, but the process and closer delineation of this change may need further, more tightly focused research; and the interpretation of our results is hampered by the lack of such previous investigation of the consequences to birds of buffel grass invasion, and perhaps by associations between buffel grass establishment and other environmental variation. Nonetheless, previous studies have demonstrated that buffel grass may have a major impact on floristic diversity (Fairfax & Fensham 2000; Franks 2002; Jackson 2005; Kaur et al . 2005) and on fire intensity (Butler & Fairfax 2003; Clarke et al .…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Impacts of clearing, fragmentation and disturbance on the bird fauna of Eucalypt savanna woodlands in central Queensland, Australia

Hannah

Woinarski²,

Catterall

et al. 2007

Austral Ecology

View full text Add to dashboard Cite

This study reports on the responses of bird assemblages to woodland clearance, fragmentation and habitat disturbance in central Queensland Australia, a region exposed to very high rates of vegetation clearance over the last two to three decades. Many previous studies of clearing impacts have considered situations where there is a very sharp management contrast between uncleared lands and cleared areas: in this situation, the contrast is more muted, because both cleared lands and uncleared savanna woodlands are exposed to cattle grazing, invasion by the exotic grass Cenchrus ciliaris and similar fire management. Bird species richness (at the scale of a 1-ha quadrat) was least in cleared areas (8.1 species), then regrowth areas (14.6 species), then uncleared woodlands (19.9 species). Richness at this scale was unrelated to woodland fragment size, connectivity or habitat condition; but declined significantly with increasing abundance of miners (interspecifically aggressive colonial honeyeaters). At whole of patch scale, richness increased with fragment size and decreased with abundance of miners. This study demonstrates complex responses of individual bird species to a regional management cocktail of disturbance elements. Of 71 individual bird species modelled for woodland fragment sites, the quadrat-level abundance of 40 species was significantly related to at least one variable representing environmental position (across a rainfall gradient), fragment condition, fragment size and/or connectivity. This study suggests that priorities for conservation management include: cessation of broad-scale clearing; increased protection for regrowth (particularly where this may bolster connectivity and/or size of woodland fragments); control of miners; maintenance of fallen woody debris in woodlands; increase in fire frequency; and reduction in the incidence of grazing and exotic pasture grass.

show abstract

Section: Discussionmentioning

confidence: 99%

“…But vegetation clearance is but part of a more complex disturbance regime in this region. Cleared areas have usually been sown with exotic pasture, particularly buffel grass Cenchrus ciliaris , which allows an increased grazing intensity, at least in the short term (Kaur et al . 2005).…”

Section: Introductionmentioning

confidence: 99%

Impacts of clearing, fragmentation and disturbance on the bird fauna of Eucalypt savanna woodlands in central Queensland, Australia

Hannah

Woinarski²,

Catterall

et al. 2007

Austral Ecology

View full text Add to dashboard Cite

show abstract

“…In addition to altered N and C relations, we found that P contents of grasses were elevated at cleared sites, which is a potential cause for increased pasture production at least in the short to medium term after clearing (Scanlan 2002;Kaur et al 2005). Causes for improved P nutrition of grasses at cleared sites include reduced competition from woody species, but how well native and exotic grasses acquire P depends on species' abilities as well as soil properties.…”

Section: Discussionmentioning

confidence: 86%

“…There is evidence that removal of trees from these savannas increases pasture production in the short-term (<10 years) (Scanlan 2002), but long-term consequences of clearing are largely unknown (Schmidt and Lamble 2002). In semi-arid Eucalyptus savanna and Acacia woodland, pasture production decreased significantly in the long term (~30 years) (Kaur et al 2005).…”

Section: Introductionmentioning

confidence: 98%

Effect of woody vegetation clearing on nutrient and carbon relations of semi-arid dystrophic savanna

et al. 2009

View full text Add to dashboard Cite

Throughout the savanna biome, woody vegetation is cleared to increase productivity of herbaceous pasture. While clearing can result in increased pasture production of semi-arid dystrophic savannas in the short term, it is uncertain whether production is sustained in the long term. There is insufficient knowledge of how clearing affects soil nutrient and organic carbon (SOC) stocks. Using cleared-uncleared site pairs, we evaluated techniques for time-integrated assessment of nutrient and carbon relations in Australian savanna. Short-term in situ resin incubation showed that soil at cleared sites had a higher time-integrated availability of ammonium and nitrate, indicating that nitrogen (N) may turn over faster and/or is taken up slower at cleared sites than uncleared savanna. Nitrate and ammonium availability was approximately 2-fold higher in spring than in summer, likely due to greater uptake and/or loss of nitrate during summer rains. Nitrate was a prominent N source for evergreen trees, especially before summer rain, pointing to a role of trees as permanent N sinks. Stable isotope signatures of soil and vegetation indicate that N input occurs via N 2 fixing microbiotic crusts and Acacia species. 30 years after clearing, SOC contained more C 4 grass-derived carbon than uncleared savanna, but this shift in C source was not associated with the net C gain often observed in grasslands. Interactions between altered nutrient and C relations and composition of the understorey should be assessed in context of introduced buffelgrass (Cenchrus ciliaris) which had higher macronutrient concentrations than native grasses. Heterogeneity of the studied soils highlights the need for replication at several spatial scales to infer long-term dynamics with space-for-time chronosequences. We conclude that the techniques presented here are useful for gaining knowledge of the biogeochemical processes governing savannas and the systems that result from clearing.

show abstract

“…The failure of perennial grasses to recover even decades after disturbance [19] suggests that shrub removal is ineffective in the long-term. Though shrub removal might increase pasture production in the short-term (<10 years [20]), long-term studies (~30 years) suggest otherwise [21]. The imposition of grazing shortly after ploughing might retard the recovery of these systems and deplete grass soil seedbanks.…”

Section: Ploughing May Lead To Monospecific Shrub Standsmentioning

confidence: 99%

Is shrub removal an appropriate management strategy in shrub-encroached woodlands?

Daryanto

Eldridge

2011

Management of Natural Resources, Sustainable Development and Ecological Hazards III

View full text Add to dashboard Cite

Encroachment of shrubs into open woodland is a global phenomenon affecting drylands worldwide. Encroachment generally reduces pastoral productivity by reducing grass cover for livestock. Consequently, a range of mechanical methods such as ploughing have been used in an attempt to remove encroaching shrubs. Apart from the high cost, ploughing has been shown to have deleterious and often inconsistent effects on woodland ecosystems. Our work showed that soil under shrub patches contain generally higher levels of nutrients and are preferred sites of animal disturbance. However, ploughing and grazing reduced the number of vegetated patches, altered landscape heterogeneity, and often had speciesspecific effects, potentially leading to a dominance of ploughing-or grazingresistant shrub species. With ploughing resulting in reductions in soil nutrients, long-term increases in shrub density rather than reductions, and the lack of sustained grass cover, we suggest that mechanical shrub removal is an inappropriate method for managing shrub-encroached woodlands. In the context of pastoralism, alternative approaches such as time-controlled grazing or rotational grazing (similar to transhumant systems) would be more appropriate management strategies. An alternative perspective, which is increasing in popularity, is to value encroached woodlands in terms of the ecosystem benefits they provide. These include habitat for animals, sinks for carbon dioxide, ecotourism and water supplies.

show abstract

Pasture production in cleared and uncleared grazing systems of central Queensland, Australia

Cited by 9 publications

References 20 publications

Impacts of clearing, fragmentation and disturbance on the bird fauna of Eucalypt savanna woodlands in central Queensland, Australia

Impacts of clearing, fragmentation and disturbance on the bird fauna of Eucalypt savanna woodlands in central Queensland, Australia

Effect of woody vegetation clearing on nutrient and carbon relations of semi-arid dystrophic savanna

Is shrub removal an appropriate management strategy in shrub-encroached woodlands?

Contact Info

Product

Resources

About