East Coast Of Tasmania Research Articles

Effect of collectors of the puerulus of the southern rock lobster Jasus edwardsii (Hutton, 1875) (Decapoda: Achelata: Palinuridae) on lobster catch rates in Tasmania, Australia

ABSTRACT The harvesting of the puerulus of rock, or spiny, lobsters for seed for aquaculture is a large industry throughout the Indo-Pacific region, and an increasing number of puerulus collectors are deployed. Little is known about the ‘crowding effect’ of the collectors and how catch might be influenced by their placement relative to each other owing to a lack of aggregate statistics for puerulus collectors in this region. The rock lobsters puerulus is also collected for fisheries research, as an index of puerulus catches on collectors can provide an indicator of recruitment strength. Both as a management tool and for commercial purposes, the collectors should act independently, not reducing or influencing catch rates on adjacent or other collectors in the area. We explored the independence of collectors of the puerulus of the southern rock lobster (Jasus edwardsii (Hutton, 1875)) using a long-term-data series from four sites on the east coast of Tasmania, Australia. Arrays of collectors were in grid and cross-shaped configurations, with individual collectors spaced three metres apart. Patterns in catches were examined using generalised least squares (GLS) modelling to determine if collectors filter pueruli as they swim shoreward, testing directional, neighbour, edge, and radial effects. The results revealed that there were no significant differences in puerulus settlement among collectors at this scale of spacing, meaning that arrays with collectors even as close as 3 m apart did not interfere with each other. This finding also suggests that collectors at this spacing only capture a small proportion of the available pueruli, allowing a significant number to pass through collector grids, with no significant reduction in catch of collectors further inshore. Such a result implies that it cannot be assumed that recruitment to a natural reef will be reduced by harvesting of pueruli with this type of collector and configuration.

What makes a place special? Understanding drivers and the nature of place attachment

Place attachment is a key factor in understanding human-nature interactions; Research has shown that place attachment and its influence on environmental behaviour can be positive or negative based on local circumstances. With changing environments, as with climate change, a place-based understanding of place attachment is, therefore, critical to the success of local environmental efforts. Available quantitative and qualitative measures of place attachment can be difficult to translate to spatial planning. Map-based measures provide an operational bridge to spatial planning but cannot easily glean crucial local and personal contexts. This study combined participatory mapping with psychometric scales and interviews to explore place attachment along the East Coast of Tasmania. This integration of approaches provided critical context to findings that are necessary for successful place-based planning. Our results demonstrated that participants strongly identified with the region. Spatial data emphasised the importance of surrounding natural settings, especially protected areas and coastal landscapes, and the recreational, aesthetic, and biological values of these places, to their place attachment. Interviews suggested that interaction with these natural places is critical to participant's sense of self and well-being. Consequently, some individuals expressed dissatisfaction and sometimes opposition to management decisions that restricted their continued experience of natural places.

Mapping warming reefs—An application of multibeam acoustic water column analysis to define threatened abalone habitat

Robust definition of the spatial extent of seafloor habitats and how they may be changing through time is a holy grail for ecosystem management, particularly if an ecosystem is approaching a tipping point beyond which irreversible changes may occur. Here we generate and explore a new data set for the management of warming reefs in eastern Tasmania, Australia that will significantly improve the baseline maps required for fine-scaled spatial modelling and management that is, both robust at regional scales and is highly resolved within the water column. This procedure enabled the relative density of kelp vegetation to be identified in a region that is being overwhelmed by the range extension of a destructive grazer, the Longspined Sea Urchin, Centrostephanus rodgersii. We present a new online tool to visualize multibeam water column acoustic data as surfaces of kelp density at high resolution (50 cm) scale over seafloor terrain maps (spanning a total straight-line distance of 594 km and a total area of 29.14 km2) to reveal the types of reef structure on the East Coast of Tasmania where abalone habitat is threatened by kelp loss.

Disentangling genetic from environmental effects on phenotypic variability of southern rock lobster (Jasus edwardsii) postlarvae.

Environmental conditions experienced during the larval dispersal of marine organisms can determine the size-at-settlement of recruits. It is, therefore, not uncommon that larvae undergoing different dispersal histories would exhibit phenotypic variability at recruitment. Here, we investigated morphological differences in recently settled southern rock lobster (Jasus edwardsii) recruits, known as pueruli, along a latitudinal and temporal gradient on the east coast of Tasmania, Australia. We further explored whether natural selection could be driving morphological variation. We used double digest restriction site-associated DNA sequencing (ddRADseq) to assess differences in the genetic structure of recently settled recruits on the east coast of Tasmania over 3 months of peak settlement during 2012 (August-October). Phenotypic differences in pueruli between sites and months of settlement were observed, with significantly smaller individuals found at the northernmost site. Also, there was a lack of overall genetic divergence; however, significant differences in pairwise FST values between settlement months were observed at the southernmost study site, located at an area of confluence of ocean currents. Specifically, individuals settling into the southernmost earlier in the season were genetically different from those settling later. The lack of overall genetic divergence in the presence of phenotypic variation indicates that larval environmental history during the dispersal of J. edwardsii could be a possible driver of the resulting phenotype of settlers.

Chlorophyll-a and Sea Surface Temperature Changes in Relation to Paralytic Shellfish Toxin Production off the East Coast of Tasmania, Australia

Toxic phytoplankton have been detrimental to the fishing and aquaculture industry on the east coast of Tasmania, causing millions of dollars in loss due to contaminated seafood. In 2012–2017, shellfish stocks were poisoned by Alexandrium catenella, a dinoflagellate species that produces paralytic shellfish toxins (PST). Remote sensing data may provide an environmental context for the drivers of PST events in Tasmania. We conducted spatial and temporal trend analyses of the Multi-Scale Ultra-High-Resolution Sea Surface Temperature (MUR SST) and Ocean Color Climate Change Initiative chlorophyll-a (OC-CCI chl-a) to determine if SST and chl-a correlated with the major toxin increases from 2012 to 2017. Along with the trends, we compare the remotely sensed oceanographic parameters of SST and chl-a to toxin events off the east coast of Tasmania to provide environmental context for the high-toxin period. Spatial and temporal changes for chl-a differ based on the north, central, and southeast coast of Tasmania. For sites in the north, chl-a was 5.3% higher from the pre-PST period relative to the PST period, 5.1% along the central part of the coast, and by 6.0% in the south based on deviations from the coastal study area time series. Overall, SST has slightly decreased from 2007 to 2020 (tau = −0.011, p = 0.827) and chl-a has significantly decreased for the east coast (tau = −0.164, p = 1.58 × 10−3). A negative relationship of SST and PST values occurred in the north (r = −0.530, p = 5.32 × 10−5) and central sites (r = −0.225, p = 0.157). The correlation between satellite chl-a (from OC-CCI, Visible Infrared Imaging Radiometer Suite (VIIRS), and Moderate-Resolution Imaging Spectrometer (MODIS) Aqua) and in situ data is weak, which makes it difficult to assess relationships present between chl-a and toxin concentrations. Moving forward, the development of a regional chl-a algorithm and increased in situ chl-a collection and plankton sampling at a species level will help to improve chl-a measurements and toxic phytoplankton production monitoring around Tasmania.

Forecasting intraspecific changes in distribution of a wide-ranging marine predator under climate change

Globally, marine animal distributions are shifting in response to a changing climate. These shifts are usually considered at the species level, but individuals are likely to differ in how they respond to the changing conditions. Here, we investigate how movement behaviour and, therefore, redistribution, would differ by sex and maturation class in a wide-ranging marine predator. We tracked 115 tiger sharks (Galeocerdo cuvier) from 2002 to 2020 and forecast class-specific distributions through to 2030, including environmental factors and predicted occurrence of potential prey. Generalised Linear and Additive Models revealed that water temperature change, particularly at higher latitudes, was the factor most associated with shark movements. Females dispersed southwards during periods of warming temperatures, and while juvenile females preferred a narrow thermal range between 22 and 23 °C, adult female and juvenile male presence was correlated with either lower (< 22 °C) or higher (> 23 °C) temperatures. During La Niña, sharks moved towards higher latitudes and used shallower isobaths. Inclusion of predicted distribution of their putative prey significantly improved projections of suitable habitats for all shark classes, compared to simpler models using temperature alone. Tiger shark range off the east coast of Australia is predicted to extend ~ 3.5° south towards the east coast of Tasmania, particularly for juvenile males. Our framework highlights the importance of combining long-term movement data with multi-factor habitat projections to identify heterogeneity within species when predicting consequences of climate change. Recognising intraspecific variability will improve conservation and management strategies and help anticipate broader ecosystem consequences of species redistribution due to ocean warming.

Field Validation of the Southern Rock Lobster Paralytic Shellfish Toxin Monitoring Program in Tasmania, Australia.

Paralytic shellfish toxins (PST) are found in the hepatopancreas of Southern Rock Lobster Jasus edwardsii from the east coast of Tasmania in association with blooms of the toxic dinoflagellate Alexandrium catenella. Tasmania’s rock lobster fishery is one of the state’s most important wild capture fisheries, supporting a significant commercial industry (AUD 97M) and recreational fishing sector. A comprehensive 8 years of field data collected across multiple sites has allowed continued improvements to the risk management program protecting public health and market access for the Tasmanian lobster fishery. High variability was seen in toxin levels between individuals, sites, months, and years. The highest risk sites were those on the central east coast, with July to January identified as the most at-risk months. Relatively high uptake rates were observed (exponential rate of 2% per day), similar to filter-feeding mussels, and meant that lobster accumulated toxins quickly. Similarly, lobsters were relatively fast detoxifiers, losing up to 3% PST per day, following bloom demise. Mussel sentinel lines were effective in indicating a risk of elevated PST in lobster hepatopancreas, with annual baseline monitoring costing approximately 0.06% of the industry value. In addition, it was determined that if the mean hepatopancreas PST levels in five individual lobsters from a site were <0.22 mg STX equiv. kg−1, there is a 97.5% probability that any lobster from that site would be below the bivalve maximum level of 0.8 mg STX equiv. kg−1. The combination of using a sentinel species to identify risk areas and sampling five individual lobsters at a particular site, provides a cost-effective strategy for managing PST risk in the Tasmanian commercial lobster fishery.

Regional estimates of a range‐extending ecosystem engineer using stereo‐imagery from ROV transects collected with an efficient, spatially balanced design

AbstractThe redistribution of marine ecosystem engineers in response to changing climate is restructuring endemic benthic communities globally. Therefore, developing and implementing efficient monitoring programs across the complete depth range of these marine ecosystem engineers is often an urgent management priority. Traditionally, many monitoring programs have been based on a systematically selected set of survey locations that, while able to track trends at those sites through time, lack inference for the overall region being monitored. This study trialled a probabilistic sampling design to address this need, taking advantage of an important prerequisite for such designs, extensive multibeam echosounder (MBES) mapping, to inform a spatially balanced sample selection. Here, we allocated 170 remotely operated vehicles (ROVs) transects based on a spatially balanced probabilistic sampling design across three locations with extensive mapping. Generalized additive models were used to estimate the density and associated barren cover of the range‐expanding ecosystem engineer, the long spined urchin (Centrostephanus rodgersii). Estimates were generated at a reef‐wide scale across three locations on the east coast of Tasmania, Australia, representing the leading edge of the species recent range extension. Model‐based estimates of urchin density and barren cover incorporated seabed structure attributes, such as depth and ruggedness, with differences in these modelled relationships being identified between locations. Estimates ranged from 0.000065 individuals m−2 and 0.018% barren cover in the Tasman Peninsula to 0.167 individuals m−2 and 2.10% barren cover at Governor Island Marine Reserve, reflecting a north to south distributional gradient. This study highlights the value of combining probabilistic sampling designs, ROV transects, stereo video, and MBES mapping to generate reliable and robust estimates of important ecosystem species needed to protect reef‐based fishery and conservation values via adaptive and informed management.

Investigating public preferences for the management of native and invasive species in the context of kelp restoration

The Southern Rock Lobster (Jasus edwardsii) is key to management of the Long Spined Sea Urchin (Centrotephanus rodgersii). The southern shift of the urchin has created ‘urchin barrens’ of the kelp forests (Ecklonia radiata and Macrocystis pyrifera) in coastal waters off the East Coast of Tasmania. Consistently high fishing efforts of large Southern Rock Lobster in the region has reduced natural predation of the urchin. A number of restoration options exist but these options have not been tested for acceptability with the public to date. In this study we estimate the willingness to pay by households in Tasmania for Southern Rock Lobster habitat and management. The willingness to pay estimates can be used in benefit-cost analysis of the various combinations of restoration options supporting decision-making in this Australian marine planning context. Results indicate that direct replanting of kelp is worth $37 per household per year for five years and a 1% increase in the area of marine reserves is worth $2 per household per year for five years. Direct intervention to control sea urchin populations by reintroducing Rock Lobsters or capturing and crushing urchins is worth $33 and $31 respectively per household per year for five years. Households did not support artificial kelp beds installations or subsidising urchin farming operations.

Generalized linear models to assess environmental drivers of paralytic shellfish toxin blooms (Southeast Tasmania, Australia)

Paralytic shellfish toxin (PST) events are often difficult to predict because synergistic processes, involving multiple temporal and spatial scales, are responsible for their development. In this study, we consider a suite of factors, from local to regional processes, driving paralytic shellfish toxin (PST) events associated with Alexandrium catenella on the east coast of Tasmania (Australia). PST concentrations in shellfish were compared against environmental variables, including daily wind speed and direction, satellite chlorophyll-a, sea surface temperature and river discharge. Relationships were tested using generalized linear models (GLMs). GLM coefficients confirm that high PST events were significantly favored by cooler temperatures and higher chlorophyll-a concentrations. PST events were seasonal, occurring between August and November and showed a significant relationship with sustained coastal upwelling and wind transition events after one to three months of predominantly upwelling winds. Satellite imagery shows evidence of cross shelf transport moderating PST events. Overall, the results suggest that a combination of factors (currents, upwelling conditions and changes in sea surface temperature) work together to initiate and moderate PST events. The use of GLMs provides a useful tool for understanding synergistic relationships. These techniques are of value for developing reliable predictive models to forecast and manage the effects of harmful and costly PST events.

Overview of Australian and New Zealand harmful algal species occurrences and their societal impacts in the period 1985 to 2018, including a compilation of historic records

Similarities and differences between Australia and New Zealand in Harmful Algal species occurrences and Harmful Algal Events impacting on human society (HAEDAT) are reported and factors that explain their differences explored. Weekly monitoring of harmful phytoplankton and biotoxins commenced in Australia in 1986 and in New Zealand in 1993. Anecdotal historic HAB records in both countries are also catalogued. In Australia, unprecedented highly toxic Paralytic Shellfish Toxin (PST)-producing blooms of Alexandrium catenella have impacted the seafood industry along the 200 km east coast of Tasmania from 2012 to present. Toxic blooms in 1986-1993 by Gymnodinium catenatum in Tasmania were effectively mitigated by closing the affected area for shellfish farming, while a bloom by this same species in 2000 in New Zealand caused significant economic damage from restrictions on the movement of greenshell mussel spat. The biggest biotoxin event in New Zealand was an unexpected outbreak of Neurotoxic Shellfish Poisoning (NSP) in 1993 in Hauraki Gulf (putatively due to Karenia cf. mikimotoi) with 180 reported cases of human poisonings as well as reports of respiratory irritation north of Auckland. Strikingly, NSP never recurred in New Zealand since and no NSP events have ever been reported in Australia. In New Zealand, Paralytic Shellfish Poisoning (PSP) was the predominant seafood toxin syndrome, while in Australia Ciguatera Fish Poisoning (CFP) was the major reported seafood toxin syndrome, while no CFP has been recorded from consumption of New Zealand fish. In Australia, Diarrhetic Shellfish Poisoning (DSP) illnesses were recorded from two related outbreaks in 1997/98 following consumption of beach harvested clams (pipis) from a previously non-monitored area, whereas in New Zealand limited DSP illnesses are known. No human illnesses from Amnesic Shellfish Poisoning (ASP) have been reported in either Australia or New Zealand. Selected examples of HABs appearing and disappearing (NSP in New Zealand, Alexandrium catenella in Tasmania), species expanding their ranges (Noctiluca, Gambierdiscus), and reputed ballast water introductions (Gymnodinium catenatum) are discussed. Eutrophication has rarely been invoked as a cause except for confined estuaries and fish ponds and estuarine cyanobacterial blooms. No trend in the number of HAEDAT events from 1985 to 2018 was discernible.

Paralytic shellfish toxin uptake, tissue distribution, and depuration in the Southern Rock Lobster Jasus edwardsii Hutton

Up to 13.6 mg STX.2HCl equiv. kg−1 of paralytic shellfish toxins (PST) have been found in the hepatopancreas of Southern Rock Lobster, Jasus edwardsii, on the east coast of Tasmania. Blooms of the toxic dinoflagellate Alexandrium catenella have been reported in this region since 2012. Experimental work was undertaken to improve the understanding of the uptake and depuration mechanisms involved. Adult male lobsters were fed highly toxic mussels (6 mg STX.2HCl equiv. kg−1) sourced from the impacted area. The apparent feed intake of the lobster was positively correlated to increasing PST levels in the hepatopancreas. Toxins accumulated rapidly in the hepatopancreas reaching a maximum of 9.0 mg STX.2HCl equiv. kg−1, then depurated at a rate of 7% per day once toxic fed was removed. However, PST were not detected at significant levels in the haemolymph of these animals. Notable increases occurred in the relative amount of several PST analogues in the hepatopancreas, including GTX2&3, C1&2 and several decarbomoyl toxins in comparison to the profile observed in contaminated mussel feed. The concentration of PST in lobster antennal glands was two orders of magnitude lower than concentrations found in the hepatopancreas. This is the first report of PST in lobster antennal glands which, along with the gills, represent possible excretion routes for PST. Implications for biotoxin risk monitoring are: lobsters will continue to feed during bloom periods and high concentrations of PST can occur; animal collection should be frequent at the start of a bloom in case of a rapid accumulation of PST; and non-lethal sampling is not possible as haemolymph PST levels do not reflect what is in the hepatopancreas.

Tsunami Inundation and Maritime Hazard Modelling for a Maximum Credible Tsunami Scenario in Southeast Tasmania, Australia

The east coast of Tasmania is directly exposed to tsunamis originating from the Puysegur subduction zone, off New Zealand’s southwest coast. However, the potential impacts of tsunami inundation for coastal communities and Hobart Airport, and risks to maritime operations in Hobart Port, are poorly understood. The purpose of this project is to simulate a maximum credible earthquake/tsunami/high tide scenario (a Mw 8.7 rupture of the Puysegur subduction zone) across a 17,000 km2 model area and provide outputs that can inform local hazard management plans. Modelling was performed using the ANUGA hydrodynamic library, along with a detailed elevation model constructed from LiDAR, photogrammetric contours and bathymetric datasets. The modelling strategy comprised three primary scenarios: a 13 h simulation of tsunami activity focusing on maritime hazard from waves and currents, with two further 4 h simulations focusing on coastal inundation for 71 coastal communities and Hobart Airport. The models were run on a variable triangulated mesh with a detailed Manning’s n surface roughness model. Tsunami erosion of sand dunes was accounted for through the development of an erosion operator. Results predict severe inundation (> 4 m flow depth) in exposed east-facing areas and the maritime hazard assessment advises that water disturbance would pose a significant threat to marine craft. The assessment suggests that the feasibility of shipping evacuation from Hobart port is questionable, given the timeframes involved and the nature of simulated water disturbance. Modelling results suggest that the dune line in front of Hobart Airport would not be breached in this instance and so inundation would not occur.

Autonomous adaptation to climate-driven change in marine biodiversity in a global marine hotspot.

While governments and natural resource managers grapple with how to respond to climatic changes, many marine-dependent individuals, organisations and user-groups in fast-changing regions of the world are already adjusting their behaviour to accommodate these. However, we have little information on the nature of these autonomous adaptations that are being initiated by resource user-groups. The east coast of Tasmania, Australia, is one of the world's fastest warming marine regions with extensive climate-driven changes in biodiversity already observed. We present and compare examples of autonomous adaptations from marine users of the region to provide insights into factors that may have constrained or facilitated the available range of autonomous adaptation options and discuss potential interactions with governmental planned adaptations. We aim to support effective adaptation by identifying the suite of changes that marine users are making largely without government or management intervention, i.e. autonomous adaptations, to better understand these and their potential interactions with formal adaptation strategies.

Taxonomic and conservation status of Dockrillia striolata (Rchb.f.) Rauschert (Orchidaceae) in Tasmania'

Dockrillia striolata (Rchb.f.) Rauschert, known as the yellow rock-orchid, occurs in New South Wales, Victoria and along the east coast of Tasmania. Within Tasmania, populations occur on the islands of the Furneaux Group and on mainland Tasmania (Kelvedon Hills south of Swansea through to wukalina/Mount William in the northeast). The taxonomy of the species is revised, with subsp. chrysantha no longer recognised as distinct based on a morphological examination of flower size and other characters. The species is restricted to Devonian granite-type rocks and Jurassic dolerite, usually in near-coastal areas and in various vegetation types. A review of the conservation status indicates that the species does not qualify as threatened under the Tasmanian Threatened Species Protection Act 1995, with it being well reserved throughout its range, an extent of occurrence of ca. 7500 km2, represented by at least 30 well-defined subpopulations, no apparent historical or contemporary declines in any population parameters, nor any identifiable risks.

QPCR Assays for the Detection and Quantification of Multiple Paralytic Shellfish Toxin-Producing Species of Alexandrium.

Paralytic shellfish toxin producing dinoflagellates have negatively impacted the shellfish aquaculture industry worldwide, including in Australia and New Zealand. Morphologically identical cryptic species of dinoflagellates that may differ in toxicity, in particular, species of the former Alexandrium tamarense species complex, co-occur in Australia, as they do in multiple regions in Asia and Europe. To understand the dynamics and the ecological drivers of the growth of each species in the field, accurate quantification at the species level is crucial. We have developed the first quantitative polymerase chain reaction (qPCR) primers for A. australiense, and new primers targeting A. ostenfeldii, A. catenella, and A. pacificum. We showed that our new primers for A. pacificum are more specific than previously published primer pairs. These assays can be used to quantify planktonic cells and cysts in the water column and in sediment samples with limits of detection of 2 cells/L for the A. catenella and A. australiense assays, 2 cells/L and 1 cyst/mg sediment for the A. pacificum assay, and 1 cells/L for the A. ostenfeldii assay, and efficiencies of >90%. We utilized these assays to discriminate and quantify co-occurring A. catenella, A. pacificum, and A. australiense in samples from the east coast of Tasmania, Australia.

Experimental uptake and depuration of paralytic shellfish toxins in Southern Rock Lobster, Jasus edwardsii

In October 2012, paralytic shellfish toxins (PST) were detected in the hepatopancreas of Southern Rock Lobsters (Jasus edwardsii) collected from the east coast of Tasmania, Australia. This resulted in the first commercial closure in Australia for this species. Questions were raised on how the toxins were transferred to the lobsters, how long the toxins would persist, whether PST-contaminated hepatopancreas posed a risk to human health, and what management strategies could be applied. The aim of this study was to investigate whether PST-contaminated mussels are a potential vector enabling toxin accumulation in J. edwardsii and to collect information on toxin uptake, distribution and depuration rates and toxin profiles under controlled experimental settings. Lobsters were fed mussels naturally contaminated with PST for a period of 28 days in an experimental setting; following this, lobsters were allocated to either fed or starved treatment groups. PST were not detected in the tail tissue of lobsters at any stage of the experiment. Lobster hepatopancreas contained mean levels of 2.4 mg STX.2HCl eq/kg after 28 days of uptake, although substantial variability in total toxicity was observed. The PST profile of the hepatopancreas was similar to that of the contaminated mussels used as feed. Significant differences were noted in the PST depuration rates between fed and starved treatment groups. The daily depuration rate for total PST was estimated to be 0.019 and 0.013 mg STX.2HCl eq/kg for the fed and starved treatment groups respectively using a constant-rate decay model. After 42 days of depuration, total PST (STX equivalents) levels in the hepatopancreas of all lobsters were below 0.8 mg STX.2HCl eq/kg, which represents the regulatory level applied to bivalves. This result indicates that long-term holding to depurate PST may potentially be used as a risk management tool.

Residual presence and impact assessment of herbicide for gorse control at long point reserve, Tasmania, Australia

Gorse (Ulex europaeus) is an invasive weed managed extensively throughout temperate areas of the world. At Long Point Reserve on the east coast of Tasmania, management has been highly effective, reducing the cover of the gorse population by 90% using cut-and-paint applications of glyphosate and spot-spraying of GrazonTM Extra. Considerable quantities of GrazonTM Extra have been applied repeatedly over a 10-year period and there is concern over whether the herbicide is persisting in the soil and impacting native plant recruitment. We collected soil samples and quantified plant species richness across sites with a range of spray frequencies. No herbicide residues were detected in the soil and plant species richness did not differ between treated and untreated areas. Given the moderate persistence of the active ingredients of GrazonTM Extra (picloram and triclopyr), detection in the soil was expected; however, it appears these herbicides have either quickly dissipated, leached to other areas or the skill of the spray contractor resulted in little spray drift or excess herbicide application. This research suggests good practice chemical control of gorse does not negatively affect native species, although this may be situation-specific.

A new and unusual species of Amastigogonus Brölemann, 1913 from Tasmania, Australia (Diplopoda, Spirostreptida, Iulomorphidae).

Amastigogonus insularis sp. n. is described from Schouten and Tasman Islands off the east coast of Tasmania, and a key is presented for the identification of males of Tasmanian Amastigogonus species. The new species differs from the 10 previously described species of Amastigogonus in having a reduced coxite process on the anterior gonopod.

Changes in small organic N during early stages of soil development

During the early stages of ecosystem development there are increases in plant and soil microbial biomass, nutrient availability and rates of nutrient cycling; but little is known about how pools of small organic N vary during the initial stages of soil development. The aim of this study was to examine how the pool of small organic N compounds varies during the initial stages of soil development, and if age differentially affects D- and L-enantiomers of protein amino acids. Measurements were made at a soil chronosequence on the east coast of Tasmania that comprised a series of sub-parallel beach dunes and ridges varying in age from <100 years to 5500 years. Capillary electrophoresis-mass spectrometry was used to identify and quantify the main small organic N compounds in free, adsorbed and microbial fractions of the soil; while chiral liquid chromatography-mass spectrometry was used to quantify amino acid enantiomers in hydrolysed soil and the free, adsorbed and microbial fractions of soil.CE-MS detected 66 small (<250 Da) organic N compounds of which 63 could be positively identified. Small organic N was dominated by protein amino acids, while there were also large amounts of quaternary ammonium compounds and alkylamines. There were differences among chronosequence sites in the profile of small organic N, but these differences were not monotonically related to age and there was no evidence for a build-up of recalcitrant compounds over time. Differences were instead site-specific and related to presence/absence of particular non-protein amino acids which probably related to the presence/absence of specific plants and/or microbes that produce and/or can metabolise different non-protein amino acids.In free solution and microbial biomass D enantiomers of many amino acids were below detection limits (i.e. < 0.125 nmol g−1) and D-enantiomers were at low concentrations relative to L enantiomers such that across all ages and replicates the summed concentration of d-amino acids was 0-3-0.6% of L amino acids. There was no evidence that absolute or relative concentrations of D-enantiomers in free solution, microbial biomass or hydrolysates were larger at the older chronosequence sites. The consistent lack of an effect of soil age on D/L probably indicates that the turnover of soil proteins is comparatively rapid and thus soil proteins are similarly young even among sites in which soil age is vastly different.