Ecosystem risk assessment of <scp>G</scp>eorgina gidgee woodlands in central <scp>Australia</scp>

Resource pulses are a key feature of semi-arid and arid ecosystems and are generally triggered by rainfall. While rainfall is an acknowledged driver of the abundance and distribution of larger animals, little is known about how invertebrate communities respond to rain events or to vegetative productivity. Here we investigate Ordinal-level patterns and drivers of ground-dwelling invertebrate abundance across 6 years of sampling in the Simpson Desert, central Australia. Between February 1999 and February 2005, a total of 174 381 invertebrates were sampled from 32 Orders. Ants were the most abundant taxon, comprising 83% of all invertebrates captured, while Collembola at 10.3% of total captures were a distant second over this period. Temporal patterns of the six invertebrate taxa specifically analysed (Acarina, ants, Araneae, Coleoptera, Collembola and Thysanura) were dynamic over the sampling period, and patterns of abundance were taxon-specific. Analyses indicate that all six taxa showed a positive relationship with the cover of non-Triodia vegetation. Other indicators of vegetative productivity (seeding and flowering) also showed positive relationships with certain taxa. Although the influence of rainfall was taxon-dependent, no taxon was affected by short-term rainfall (up to 18 days prior to survey). The abundance of Acarina, ants, and Coleoptera increased with greater long-term rainfall (up to 18 months prior to survey), whilst Araneae showed the opposite effect. Temperature and dune zone (dune crest vs. swale) also had taxon-specific effects. These results show that invertebrates in arid ecosystems are influenced by a variety of abiotic factors, at multiple scales, and that responses to rainfall are not as strong or as predictable as those seen for other taxa. Our results highlight the diversity of invertebrates in our study region and emphasize the need for targeted long-term sampling to enhance our understanding of the ecology of these taxa and the role they play in arid ecosystems.

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“…Bailey (Wardle et al . ). During rain, water runs down the dune sides and pools in the lower‐lying swales (Ludwig et al .…”

Section: Methodsmentioning

confidence: 97%

Long‐term patterns of invertebrate abundance and relationships to environmental factors in arid Australia

et al. 2016

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“…Vegetation in the interdune swales and on dune sides is predominantly spinifex ( Triodia basedowii ) grassland with small stands of gidgee trees ( Acacia georginae ) and other woody Acacia shrubs or mallee eucalypts; low‐lying clay pans fill with water temporarily after heavy rain (Wardle et al. ).…”

Section: Methodsmentioning

confidence: 99%

Population dynamics of desert mammals: similarities and contrasts within a multispecies assemblage

et al. 2016

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Understanding the temporal and spatial dynamics of species populations remains a key focus of population biology, providing vital insight into the drivers that influence demography and into sub‐populations that are vulnerable to extinction. Across regional landscapes, spatially separated sub‐populations may fluctuate in synchrony, or exhibit sub‐structuring due to subtle differences in local intrinsic and extrinsic factors. Using a long‐term data set (17–22 yr) obtained from a large (8000 km2) study region in arid central Australia, we tested firstly for regional synchrony in annual rainfall and the dynamics of five small mammal species across nine widely separated sites. Using Moran's theorem, we predicted that the spatial correlation between the regional sub‐populations of these species would equal that between local density‐independent conditions (annual rainfall). For species that showed synchronous spatial dynamics, we then used multivariate state‐space (MARSS) models to predict that regional rainfall would be positively associated with their populations, whereas species with asynchronous sub‐populations would be influenced largely by other factors. For these latter species, we used MARSS models to test four hypotheses. These were that sub‐population structures: (1) were asynchronous and governed by local site‐specific factors, (2) differed between oasis and non‐oasis sites, (3) differed between burnt and unburnt sites, and (4) differed between three sub‐regions with different rainfall gradients. We found that the spatial population dynamics of our study small mammals differed between and within families. Two species of insectivorous dasyurid marsupials showed asynchronous dynamics, which most likely tracked local conditions, whereas a larger carnivorous marsupial and two species of rodents had strongly synchronous dynamics. These latter species exhibited similar spatial correlations to local and regional rainfall events, providing evidence that the Moran effect operates for some, but not all, species in this arid system. Our results suggest that small mammal populations do not respond in similar ways to shared environmental drivers in arid regions, and hence will vary in their responses to climate change. As arid lands globally are predicted to face climatic shifts that will exacerbate rainfall‐drought cycles, we suggest that future work focuses on exploring these responses at different spatial scales across multiple dryland taxa.

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“…6.1). These events provide windows of opportunity for mass flowering and seeding of grasses and herbs, recruitment of perennial shrubs and trees, and surges of vegetative growth (Brock et al 2006;Wardle 2010;Wardle et al 2015). In turn, these pulses of primary productivity drive booms in populations of consumer organisms such as herbivorous insects, many birds Kingsford et al 2004; and mammals (Letnic and Dickman 2010).…”

Section: The Desert Channels Environmentmentioning

confidence: 99%

Lake Eyre Basin Rivers

Kingsford¹

2017

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Water is scarce in the Lake Eyre Basin in the heart of Australia. The region goes through natural cycles of boom and bust, and the flooding of the basin rivers is accompanied by spectacular responses from wildlife and vegetation. However, the Lake Eyre Basin faces the threat of diversion of water from rivers and wetlands and development of floodplains for irrigation and mining. Around the world, such water resource developments have caused widespread degradation of rivers and loss of habitats. Lake Eyre Basin Rivers outlines the environmental, social and economic values of the rivers from a diverse range of perspectives, including science, tourism, economy, engineering, policy, Traditional Owners and pastoralists. It describes the current state of the environment and the past and ongoing threats to the river systems, drawing on stories from the Murray-Darling Basin. It also provides direction for ensuring that the rivers remain free-flowing to service the environment and future generations. This book is a valuable reference for environment and government agencies, industries and policy-makers concerned with the region and will be of interest to the communities of the Lake Eyre Basin.

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Ecosystem risk assessment of Georgina gidgee woodlands in central Australia

Cited by 37 publications

References 64 publications

Long‐term patterns of invertebrate abundance and relationships to environmental factors in arid Australia

Long‐term patterns of invertebrate abundance and relationships to environmental factors in arid Australia

Population dynamics of desert mammals: similarities and contrasts within a multispecies assemblage

Lake Eyre Basin Rivers

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