The Nature of Northern Australia: its natural values, ecological processes and future prospects

Woinarski, John C. Z.; Mackey, Brendan; Nix, H. A.; Traill, Barry

doi:10.26530/oapen_459382

Cited by 21 publications

(4 citation statements)

References 65 publications

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“…The northern Australian savannah is one of the largest natural savannahs remaining on Earth with grasslands and shrublands that cover more than 1.5 million km 2 (Nix et al, 2013). Over the past century there have been several major degradation episodes, leaving about half of these important ecosystems in a degenerated state (Smith et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…Over the past century there have been several major degradation episodes, leaving about half of these important ecosystems in a degenerated state (Smith et al, 2007). It is a harsh environment where climate shapes the ecology, distribution and abundance of resources, affecting plant and animal species (Nix et al, 2013). There is a pronounced dry season, often lasting around 6 months, followed by violent storms and flooding rains.…”

Section: Introductionmentioning

confidence: 99%

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Wet season cyanobacterial N enrichment highly correlated with species richness and Nostoc in the northern Australian savannah

2018

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Abstract. The Boodjamulla National Park research station is situated in the north-western Queensland dry savannah, where the climate is dominated by summer monsoons and virtually dry winters. Under shrub canopies and in between the tussock grasses cyanobacterial crusts almost entirely cover the flood plain soil surfaces. Seasonality drives N fixation, and in the savannah this has a large impact on both plant and soil function. Many cyanobacteria fix dinitrogen that is liberated into the soil in both inorganic and organic N forms. We examined cyanobacterial species richness and bioavailable N spanning 7 months of a typical wet season. Over the wet season cyanobacterial richness ranged from 6 to 19 species. N-fixing Scytonema accounted for seasonal averages between 51 and 93 % of the biocrust. Cyanobacterial richness was highly correlated with N fixation and bioavailable N in 0–1 cm. Key N-fixing species such as Nostoc, Symploca and Gloeocapsa significantly enriched soil N although Nostoc was the most influential. Total seasonal N fixation by cyanobacteria demonstrated the variability in productivity according to the number of wet days as well as the follow-on days where the soil retained adequate moisture. Based on total active days per month we estimated that N soil enrichment via cyanobacteria would be ∼  5.2 kg ha−1 annually which is comparable to global averages. This is a substantial contribution to the nutrient-deficient savannah soils that are almost entirely reliant on the wet season for microbial turnover of organic matter. Such well-defined seasonal trends and synchronisation in cyanobacterial species richness, N fixation, bioavailable N and C fixation (Büdel et al., 2018) provide important contributions to multifunctional microprocesses and soil fertility.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Wet season cyanobacterial N enrichment highly correlated with species richness and Nostoc in the northern Australian savannah

2018

View full text Add to dashboard Cite

show abstract

Section: Introductionmentioning

confidence: 99%

“…Over the past century there have been several major degradation episodes, leaving about half of these important ecosystems in a degenerated state (Smith et al, 2007). It is a harsh environment where climate shapes the ecology, distribution and abundance of resources affecting plant and animal species (Nix et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Cyanobacterial species richness and Nostoc highly correlated to seasonal N enrichment in the northern Australian savannah

Williams

Büdel

Williams

2017

Preprint

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Abstract. Boodjamulla National Park research station is situated in north-west Queensland in the dry savannah where the climate is dominated by summer monsoons and virtually dry winters. Cyanobacterial crusts almost entirely cover the flood plain soil surfaces in between the tussock grasses. Cyanobacteria fix dinitrogen that is liberated into the soil in both inorganic and organic N forms. Seasonality drives N-fixation and in the savannah, this has a large impact on both plant and soil function. In this research project, we examined the cyanobacterial species richness and bioavailable N spanning the seven months of a typical wet season. We hypothesised that cyanobacterial richness and bioavailable N would peak at the time of the heaviest rains and gradually decline in the latter stages of the wet season. We also anticipated that the abundance of N-fixing cyanobacteria would be correlated to N-fixation and N-enrichment of the surface soils. Over the wet season cyanobacterial richness ranged from 6&#8211;19 species. N-fixing Scytonema accounted on average across the season for 74&#8201;% of the biocrust in varying proportions throughout the season. Cyanobacterial richness was highly correlated with N-fixation and bioavailable N in 0&#8211;1&#8201;cm. It was established key N-fixing species such as Nostoc, Symploca and Gloeocapsa significantly enriched soil N although Nostoc was the most influential. Total seasonal N fixation by cyanobacteria demonstrated the variability in productivity according to the number of wet days as well as the follow-on days where the soil retained adequate moisture. Based on total active days per month we estimated that N-soil enrichment via cyanobacteria would be ~&#8201;5.2&#8201;kg&#8201;ha&#8722;1 annually which is comparable to global averages. This is a substantial contribution to the nutrient deficient savannah soils that are almost entirely reliant on the wet season for microbial turnover of organic matter. This seasonal pattern in atmospheric N-fixation and transformation to a bioavailable form was also present in C-fixation results from parallel research. Such well-defined seasonal trends and synchronisation in cyanobacterial species richness, N-fixation, bioavailable N and C fixation provide significant contributions to multi-functional microprocesses and soil fertility.

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A national framework for research on trophic regulation by the Dingo in Australia

Visser

Watson²,

Dickman³

et al. 2009

Pac. Conserv. Biol.

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There is increasing evidence that the Dingo Canis lupus dingo plays an important ecological role as a trophic regulator in Australian ecosystems. However, there is sufficient remaining uncertainty about the nature of this role as to hinder the development of effective management policies. This review defines strategic directions for future research on the trophic role of Dingoes by developing a national Dingo research framework. The framework aims to increase our knowledge of the influence that Dingoes have on the maintenance of biodiversity, thereby encouraging Dingo conservation and the refinement of current land-use practices. The framework begins by identifying four major bioclimatic zones across Australia that pose different questions and challenges for Dingo research. For each zone we construct a model that identifies major interactions between Dingoes and key prey or competitor species, and then used the models to identify key research needs, the possible advantages of maintaining Dingo populations within each zone, and ways to tease out unstudied interactions. Important questions identified in the review include the effects of Dingoes on native marsupial populations, vegetation communities, herbivore diets, the use of structural refugia by mesopredators, predator and prey behaviour, and the effect of habitat modification on these interactions. We briefly review legislative constraints and other factors, such as the ongoing hybridization of Dingo populations with domestic dog breeds, that may impede future studies. If research activities follow this framework, we believe that policy and management will be better informed, benefiting both the Dingo and the natural ecosystems and production systems where it occurs.

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The Nature of Northern Australia: its natural values, ecological processes and future prospects

Cited by 21 publications

References 65 publications

Wet season cyanobacterial N enrichment highly correlated with species richness and <i>Nostoc</i> in the northern Australian savannah

Wet season cyanobacterial N enrichment highly correlated with species richness and <i>Nostoc</i> in the northern Australian savannah

Cyanobacterial species richness and <i>Nostoc</i> highly correlated to seasonal N enrichment in the northern Australian savannah

A national framework for research on trophic regulation by the Dingo in Australia

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The Nature of Northern Australia: its natural values, ecological processes and future prospects

Cited by 21 publications

References 65 publications

Wet season cyanobacterial N enrichment highly correlated with species richness and &lt;i&gt;Nostoc&lt;/i&gt; in the northern Australian savannah

Wet season cyanobacterial N enrichment highly correlated with species richness and &lt;i&gt;Nostoc&lt;/i&gt; in the northern Australian savannah

Cyanobacterial species richness and &lt;i&gt;Nostoc&lt;/i&gt; highly correlated to seasonal N enrichment in the northern Australian savannah

A national framework for research on trophic regulation by the Dingo in Australia

Contact Info

Product

Resources

About

Wet season cyanobacterial N enrichment highly correlated with species richness and <i>Nostoc</i> in the northern Australian savannah

Wet season cyanobacterial N enrichment highly correlated with species richness and <i>Nostoc</i> in the northern Australian savannah

Cyanobacterial species richness and <i>Nostoc</i> highly correlated to seasonal N enrichment in the northern Australian savannah