17 research outputs found

    Hiding Amongst the Palms: the Remarkable Discovery of a New Palm Bug Genus and Species (Insecta: Heteroptera: Thaumastocoridae: Xylastodorinae) from Remote Norfolk Island; its Systematics, Natural History, Palm Specialism and Biogeography

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    he discovery of a remarkable new palm bug species on Norfolk Island brings into question its systematic position within the family Thaumastocoridae, and the validity and biogeography of the three extant subfamilies. Latebracoris norfolcensis gen. nov., sp. nov. is described from remote Norfolk Island in the Southwest Pacific. The species was found on the native Norfolk Island palm Rhopalostylis baueri. The formal description of the species includes fine details of external non-genitalic and genitalic characters, supported with images from light and scanning electron microscopy. Details of the egg are described, including the shape and micropylar configuration. All nymphal stages are diagnosed morphologically and morphometrically, with the segregation of the five instars using the Brooks–Dyar Rule. The natural history of the Norfolk Island Palm Bug is documented, including the oviposition site of eggs, and microhabitat of nymphs and adults on palm infructescences, with hypotheses about development in relation to reproductive succession of the palm host. The systematic position of the Norfolk Island Palm Bug is assessed through a phylogenetic analysis of a selection of taxa of the superfamily Miroidea, using the parsimony criterion. The phylogenetic analyses were partitioned into Recent and fossil taxa, revealing monophyly of the Thaumastocoridae, and the subfamilies Thaumastocorinae and Xylastodorinae, with synapomorphy and significant resampling support. The Thaicorinae are verified as synonymous with the Xylastodorinae. The monotypic fossil subfamily Thaumastotinginae is removed from the Thaumastocoridae and treated as incertae familiae. Suprageneric relationships were corroborated in the two taxon partition analyses. An overview of host associations is given verifying palm specialism for the Xylastodorinae. The natural history, palm specialism, biogeography, morphology and systematics of the Xylastodorinae and allies are discussed in light of the discovery of Latebracoris norfolcensis

    Natural history of the australian tortoise beetle, notosacantha dorsalis (waterhouse, 1877) (coleoptera: chrysomelidae: cassidinae: notosacanthini) with summary of the genus in Australia

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    The old-world tribe Notosacanthini is hypothesized as a transitional group between "hispine" leaf miners and exophagous tortoise beetles in the Cassidinae tree of life. Their biology, morphology, and genetics may help clarify evolution in the subfamily, yet few species have been studied deeply. Detailed field and rearing studies were conducted for Notosacantha dorsalis (Waterhouse) on the phyllodinous shrub, Acacia crassa Pedley (Fabaceae), in Queensland, Australia. Adults feed on phyllode tissue by biting linear, parallel grooves in the leaf-like phyllode surface. Solitary eggs are laid in short, shallow grooves bitten into the phyllode surface and coated with secretion then with faeces. Hatching larvae mine within the phyllode, depositing frass and larval exuviae near the hatched egg capsule. After consuming most resources of the initial phyllode, larvae cut their way out of the original mine (termed the primary mine) and re-enter a second phyllode, via an entry cut in the cuticle, to make a secondary mine. This entry cut serves to eject frass and exuviae. After a period of feeding, the secondary mine serves as the pupation chamber and the adult exits via the entry cut. We outline two processes for determining the number of instars for mining larvae which showed that N. dorsalis has four instars. Two hymenopteran parasites were collected. Museum specimens of Australian Notosacantha were examined to assess species and their distributions

    Measuring the success of reforestation for restoring biodiversity and ecosystem functioning

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    Summary 1.Effective assessment of the success of ecological restoration projects is critical in justifying the use of restoration in natural resource management as well as improving best practice. One of the main goals of ecological restoration is the recovery of ecosystem function, yet most researchers assume that increasing species and or functional diversity equates with restoration of ecosystem function, rather than empirically demonstrating these mechanistic relationships. 2.In this study we assess how dung beetle species diversity, community composition, functional diversity and ecological functions vary along a restoration chronosequence and compare restored areas with reference (rainforest) and degraded (pasture) systems. We also directly investigate the dung beetle diversity – ecosystem functioning relationship in the context of ecological rainforest restoration by testing the predictive power of traditional taxonomic indices and functional diversity metrics for functionality. 3.Species richness, abundance, biomass and functional richness all increased with restoration age, with the oldest restoration sites being most similar to rainforest; whereas functional evenness and functional divergence decreased with restoration age. Community composition in the restored areas was clearly progressing towards the rainforest sites and deviating from the pasture sites with increasing restoration age. 4.Secondary seed dispersal rates increased with restoration age, but there was only a weak positive relationship between dung removal and soil excavation and restoration age. Biodiversity metrics explained 47–74% of the variation in functions mediated by dung beetles; however, functional trait-based indices provided greater explanatory power of functionality than traditional species-based metrics. 5.Synthesis and applications. Our results provide empirical evidence on the potential of tropical forest restoration to mitigate biodiversity losses, recovering not only faunal species diversity, but also functional diversity and ecosystem functions in a relatively short period of time. We also demonstrate that functional trait-based metrics are better predictors of functionality than traditional species-based metrics but that the relationship between restoration age, diversity and ecosystem functioning is not straightforward and depends on the functions, traits and metrics used

    The effects of land use change on native dung beetle diversity and function in Australia’s Wet Tropics

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    The impacts of land use change on biodiversity and ecosystem functions are variable, particularly in fragmented tropical rainforest systems with high diversity. Dung beetles (Scarabaeinae) are an ideal group to investigate the relationship between land use change, diversity and ecosystem function as they are easily surveyed, sensitive to habitat modification and perform many ecosystem functions. Although this relationship has been investigated for dung beetles in some tropical regions, there has been no study assessing how native dung beetles in Australia's tropical rainforests respond to deforestation, and what the corresponding consequences are for dung removal (a key ecosystem function fulfilled by dung beetles). In this study we investigated the relationship between dung beetle community attributes (determined through trapping) and function (using dung removal experiments that allowed different dung beetle functional groups to access the dung) in rainforest and cleared pasture in a tropical landscape in Australia's Wet Tropics. Species richness, abundance and biomass were higher in rainforest compared to adjacent pasture, and species composition between these land use types differed significantly. However, average body size and evenness in body size were higher in pasture than in rainforest. Dung removal was higher in rainforest than in pasture when both functional groups or tunnelers only could access the dung. Increased dung removal in the rainforest was explained by higher biodiversity and dominance of a small number of species with distinct body sizes, as dung removal was best predicted by the evenness in body size of the community. Our findings suggest that functional traits (including body size and dung relocation behaviour) present in a dung beetle community are key drivers of dung removal. Overall, our results show that deforestation has reduced native dung beetle diversity in Australian tropical landscapes, which negatively impacts on the capacity for dung removal by dung beetles in this region

    Riverine concentrations and export of dissolved silicon, and potential controls on nutrient stoichiometry, across the land–ocean continuum in Great Britain

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    Silicon (Si) is an essential nutrient element in freshwater and marine ecosystems, and its abundance relative to macro-nutrients (N, P) can impact phytoplankton communities in eutrophic rivers and estuaries. This study is the first national assessment examining (i) the primary sources (geological, biological, landcover) and controls (geomorphological, precipitation) on the transport of terrestrial dissolved silicon across Great Britain to the ocean, and (ii) the current extent and nature of its interactions with macro-nutrients in these catchments in relation to its potential impacts on phytoplankton community structure. It uses results from a year-long survey of 41 rivers along with historical data. Highest concentrations of dissolved Si (4–5.5 mg L-1) were found in rivers of the chalk- and sedimentary sandstone-based catchments of southern Great Britain and the hard sandstone catchments of Scotland. Catchment yield rates for dissolved Si varied between 0.2 and 2.6 t km−2 yr−1, with highest yields found in catchments with higher precipitation and runoff. Analysis of river N:P and dissolved Si:N ratios suggested that the sampled rivers were typically N enriched, and P limited with respect to dissolved Si. Molar dissolved Si:N ratios < 1, an indicator of river eutrophication, were associated with total nitrogen concentrations exceeding 1.8 mg L-1 or greater. The Indicator of Coastal Eutrophication index was used to assess the potential role of dissolved Si in the eutrophication of coastal waters. Negative values indicating limited eutrophication potential to non-siliceous algae were generally found, although some rivers had annual Indicator of Coastal Eutrophication index values exceeding 0, with values as high as 35 kg C km−2 day−1. In many eutrophic rivers, high dissolved Si concentrations derived from catchment lithology, kept the Indicator of Coastal Eutrophication index values below zero. Results have demonstrated that high N and P export have likely shifted most Great Britain rivers and coastal waters beyond the stoichiometric range where diatoms dominate production and into one where non-siliceous algae maybe increasingly present. Thus, future assessments of macro-nutrient management schemes, such as those involving wetlands should include dissolved Si routinely due to its stoichiometric importance

    Dissolved inorganic carbon export from rivers of Great Britain: Spatial distribution and potential catchment-scale controls

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    Dissolved inorganic carbon (DIC) fluxes from the land to ocean have been quantified for many rivers globally. However, CO2 fluxes to the atmosphere from inland waters are quantitatively significant components of the global carbon cycle that are currently poorly constrained. Understanding, the relative contributions of natural and human-impacted processes on the DIC cycle within catchments may provide a basis for developing improved management strategies to mitigate free CO2 concentrations in rivers and subsequent evasion to the atmosphere. Here, a large, internally consistent dataset collected from 41 catchments across Great Britain (GB), accounting for ∌36% of land area (∌83,997 km2) and representative of national land cover, was used to investigate catchment controls on riverine dissolved inorganic carbon (DIC), bicarbonate (HCO3−) and free CO2 concentrations, fluxes to the coastal sea and annual yields per unit area of catchment. Estimated DIC flux to sea for the survey catchments was 647 kt DIC yr−1 which represented 69% of the total dissolved carbon flux from these catchments. Generally, those catchments with large proportions of carbonate and sedimentary sandstone were found to deliver greater DIC and HCO3− to the ocean. The calculated mean free CO2 yield for survey catchments (i.e. potential CO2 emission to the atmosphere) was 0.56 t C km−2 yr−1. Regression models demonstrated that whilst river DIC (R2 = 0.77) and HCO3− (R2 = 0.77) concentrations are largely explained by the geology of the landmass, along with a negative correlation to annual precipitation, free CO2 concentrations were strongly linked to catchment macronutrient status. Overall, DIC dominates dissolved C inputs to coastal waters, meaning that estuarine carbon dynamics are sensitive to underlying geology and therefore are likely to be reasonably constant. In contrast, potential losses of carbon to the atmosphere via dissolved CO2, which likely constitute a significant fraction of net terrestrial ecosystem production and hence the national carbon budget, may be amenable to greater direct management via altering patterns of land use

    Systematic studies of the Australian aradidae (Hemiptera: Heteroptera)

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    Data from: Measuring the success of reforestation for restoring biodiversity and ecosystem functioning

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    Effective assessment of the success of ecological restoration projects is critical in justifying the use of restoration in natural resource management as well as improving best practice. One of the main goals of ecological restoration is the recovery of ecosystem function, yet most researchers assume that increasing species and or functional diversity equates with restoration of ecosystem function, rather than empirically demonstrating these mechanistic relationships. In this study, we assess how dung beetle species diversity, community composition, functional diversity and ecological functions vary along a restoration chronosequence and compare restored areas with reference (rain forest) and degraded (pasture) systems. We also directly investigate the dung beetle diversity – ecosystem functioning relationship in the context of ecological rain forest restoration by testing the predictive power of traditional taxonomic indices and functional diversity metrics for functionality. Species richness, abundance, biomass and functional richness all increased with restoration age, with the oldest restoration sites being most similar to rain forest, whereas functional evenness and functional divergence decreased with restoration age. Community composition in the restored areas was clearly progressing towards the rain forest sites and deviating from the pasture sites with increasing restoration age. Secondary seed dispersal rates increased with restoration age, but there was only a weak positive relationship between dung removal and soil excavation and restoration age. Biodiversity metrics explained 47–74% of the variation in functions mediated by dung beetles; however, functional trait-based indices provided greater explanatory power of functionality than traditional species-based metrics. Synthesis and applications. Our results provide empirical evidence on the potential of tropical forest restoration to mitigate biodiversity losses, recovering not only faunal species diversity, but also functional diversity and ecosystem functions in a relatively short period of time. We also demonstrate that functional trait-based metrics are better predictors of functionality than traditional species-based metrics but that the relationship between restoration age, diversity and ecosystem functioning is not straightforward and depends on the functions, traits and metrics used
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