ORCID Profile
0000-0001-5284-6428
Current Organisations
Cornell University
,
University of Tasmania
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Publisher: Coastal Education and Research Foundation
Date: 03-2017
Publisher: Informa UK Limited
Date: 03-03-2016
Publisher: MDPI AG
Date: 07-12-2016
DOI: 10.3390/S16122075
Publisher: Elsevier BV
Date: 03-2009
Publisher: Springer Science and Business Media LLC
Date: 16-05-2017
Publisher: MDPI AG
Date: 28-04-2023
DOI: 10.20944/PREPRINTS202304.1131.V1
Abstract: The emergence of cloud computing, big data analytics, and machine learning has catalysed the use of remote sensing technologies to enable more timely land management of sustainability indicators such as ground cover and grassland biomass, given the uncertainty of future climate and drought conditions. Here, we examine the potential of “regenerative agriculture”, as an adaptive grazing management strategy to minimise bare ground exposure while maximising pasture biomass productivity. High-intensity sheep grazing treatments were conducted in small fields (less than 1 hectare) for short durations (typically less than 1 day). Paddocks were subsequently spelled to allow pasture biomass recovery (treatments comprising 3, 6, 9, 12, and 15 months) with each compared with control treatments with lighter stocking rates for longer periods (2,000 DSE). Pastures were composed of wallaby grass (Austrodanthonia species), kangaroo grass (Themeda triandra), Phalaris (Phalaris aquatica, and cocksfoot (Dactylis glomerata) were destructively s led to estimate total standing dry matter (TSDM), standing green biomass, standing dry biomass and tr led biomass. We then invoked a machine learning model using Sentinel-2 imagery to quantify TSDM, standing green biomass and standing dry biomass. Faced with La Nina conditions, regenerative grazing did not significantly impact pasture productivity, with all treatments showing similar TSDM and green biomass. However, regenerative treatments significantly impacted litter fall and tr led material, with the high intensity grazing treatments causing more dry matter tr ling, increasing litter, enhancing decomposition rates and surface organic matter. Pasture digestibility was greatest for treatments with minimal spelling (3 months), whereas both standing senescent and tr led material were significantly greater for the treatment with 15-month spell periods. Estimates of TSDM using machine learning with Sentinel-2 imagery underestimated TSDM in treatment plots but explained spatiotemporal variability associated within and across treatments. The root mean square error between the measured and modelled TSDM was 903 kg DM/ha, which was less than the variability measured in the field. We conclude that regenerative grazing with short recovery periods (3-6 months) are most conducive to increasing pasture production under high rainfall conditions, and we speculate that high intensity grazing is likely to positively impact on soil organic carbon through increased litterfall and tr ling. Our study paves the way forward for using machine learning with satellite imagery to quantify pasture biomass at small scales, enabling management of pastures from afar.
Publisher: Elsevier BV
Date: 11-2017
DOI: 10.1016/J.MARPOLBUL.2017.07.010
Abstract: An increasing number of studies highlight the risk of plastic pollution in the marine environment. However, systematic longitudinal data on the distribution and abundance of plastic debris remain sparse. Here we present the results of a two-year study of plastic pollution within the Tasman Sea, contrasted with a further year of data from the same region, in order to document how the density of debris varies across years in this area. Surface net tows were collected between Hobart, Tasmania and Sydney, Australia during the spring of 2013 and 2014 and compared with a subset of data from autumn 2012 from the same region. Substantial inter-annual variation in mean plastic abundance was observed over the three year period, ranging from to 248.04-3711.64pieceskm
Publisher: IGI Global
Date: 2014
DOI: 10.4018/978-1-4666-6631-3.CH006
Abstract: The aim of this chapter is to develop a framework to guide Wave Energy Converters (WECs) sites using the coastal waters of Tasmania as a case study. This chapter proposes a combined two-stage Multi-Criteria Decision Making (MCDM) methodology to determine suitable locations for WECs siting with overlapping and minimal conflicting uses. A methodology combining MCDM and Geographic Information Systems (GIS) was developed combining the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and the Analytical Hierarchy Process (AHP). Priority rankings for each of the human uses and ocean features were prioritized using AHP and were then applied to TOPSIS analyses. A chain of optimal locations were determined, stretching from the southwest to southeast coast of Tasmania, where presently low densities of human activities overlap with high wave height. The result shows that suitable areas for harnessing WECs may not always be located in the highest wave energy areas.
Publisher: MDPI AG
Date: 30-01-2022
DOI: 10.3390/RS14030665
Abstract: 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 s ling at a species level will help to improve chl-a measurements and toxic phytoplankton production monitoring around Tasmania.
Publisher: SAGE Publications
Date: 03-09-2023
DOI: 10.1177/03091333221122292
Abstract: Bio ersity assessment is constitutive in establishing conservation priorities and outcomes, and geo ersity complements species richness as a surrogate in the absence of species data, improves statistical modelling and can facilitate prediction of species distribution and abundance. Yet, geo ersity is frequently excluded, and bio ersity prioritised in conservation endeavours such as ecosystem-based management. Therefore, combined geo ersity and bio ersity assessment approaches present practical benefits to conservation such as improved collaboration between biologists and geoscientists, efficacious indicators of conservation value, and abatement of bio ersity partialities and wider inclusion of geo ersity in conservation literature. This study scientometrically analysed 240 bio ersity assessment publications to investigate geo ersity inclusiveness, methodological trends, geographic trends, environment-type trends and future directions in bio ersity assessment methods. Results showed these species richness articles frequently included geo ersity-relevant terms such as hydrological, soil, geological and geomorphological components, but the all-encompassing ‘geo ersity’ term was absent entirely. Geographic trends showed many potential economic, social, cultural and political factors influencing geo ersity inclusiveness in bio ersity assessment. For ex le, Australia’s relatively resource exploitative approach to geology and early involvement in the inception of the geo ersity concept could explain the high frequency of geological-related terms in Australian bio ersity assessments. Methodological trends showed dominance by field-based bio ersity assessments such as trapping methods, followed transects, quadrats, net methods and observations. Given the specific s le size of literature analysed, inferences from this study relate only to bio ersity assessment methods and not bio ersity discourse in its entirety. Subsequent research could investigate specific factors, such as social, economic or political, and their influence on geo ersity inclusiveness in bio ersity assessment methods.
Publisher: Elsevier BV
Date: 06-2017
Publisher: Informa UK Limited
Date: 07-11-2015
Publisher: Elsevier BV
Date: 2017
Publisher: Journal of Marine Research/Yale
Date: 07-2006
Publisher: Informa UK Limited
Date: 09-01-2018
Publisher: MDPI AG
Date: 29-05-2023
DOI: 10.3390/LAND12061142
Abstract: The emergence of cloud computing, big data analytics, and machine learning has catalysed the use of remote sensing technologies to enable more timely management of sustainability indicators, given the uncertainty of future climate conditions. Here, we examine the potential of “regenerative agriculture”, as an adaptive grazing management strategy to minimise bare ground exposure while improving pasture productivity. High-intensity sheep grazing treatments were conducted in small fields (less than 1 ha) for short durations (typically less than 1 day). Paddocks were subsequently spelled to allow pasture biomass recovery (treatments comprising 3, 6, 9, 12, and 15 months), with each compared with controls characterised by lighter stocking rates for longer periods (2000 DSE/ha). Pastures were composed of wallaby grass (Austrodanthonia species), kangaroo grass (Themeda triandra), Phalaris (Phalaris aquatica), and cocksfoot (Dactylis glomerata), and were destructively s led to estimate total standing dry matter (TSDM), standing green biomass, standing dry biomass and tr led biomass. We invoked a machine learning model forced with Sentinel-2 imagery to quantify TSDM, standing green and dry biomass. Faced with La Nina conditions, regenerative grazing did not significantly impact pasture productivity, with all treatments showing similar TSDM, green biomass and recovery. However, regenerative treatments significantly impacted litterfall and tr led material, with high-intensity grazing treatments tr ling more biomass, increasing litter, enhancing surface organic matter and decomposition rates thereof. Pasture digestibility and sward uniformity were greatest for treatments with minimal spelling (3 months), whereas both standing senescent and tr led material were greater for the 15-month spelling treatment. TSDM prognostics from machine learning were lower than measured TSDM, although predictions from the machine learning approach closely matched observed spatiotemporal variability within and across treatments. The root mean square error between the measured and modelled TSDM was 903 kg DM/ha, which was less than the variability measured in the field. We conclude that regenerative grazing with short recovery periods (3–6 months) was more conducive to increasing pasture production under high rainfall conditions, and we speculate that – in this environment - high-intensity grazing with 3-month spelling is likely to improve soil organic carbon through increased litterfall and tr ling. Our study paves the way for using machine learning with satellite imagery to quantify pasture biomass at small scales, enabling the management of pastures within small fields from afar.
Publisher: The Oceanography Society
Date: 06-2005
Publisher: Wiley
Date: 14-06-2017
Publisher: Informa UK Limited
Date: 14-06-2013
Publisher: Elsevier BV
Date: 09-2019
Publisher: American Geophysical Union (AGU)
Date: 19-06-2008
DOI: 10.1029/2008GL034081
Publisher: Elsevier BV
Date: 2019
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/RJ17065
Abstract: We examine the economic structure of Australian local government areas in the Northern Territory, South Australia and Western Australia using economic base theory and location quotients. Whereas the economic base approach is long established, in this paper we extend the three-staged geospatial visualisation method of Blackwell et al. (2017) to two additional state jurisdictions. Focusing on the economic structure of rangeland local government areas, we find that these vary significantly, implying that no single generic development policy is likely to be effective, but rather these need to be crafted in idually. We demonstrate that geospatial visualisations of employment location quotients can identify local economic vulnerability as well as opportunity.
Publisher: MDPI AG
Date: 25-10-2017
DOI: 10.3390/IJGI6110320
Publisher: Elsevier BV
Date: 2021
Publisher: Springer Science and Business Media LLC
Date: 08-07-2022
DOI: 10.1007/S10113-022-01949-5
Abstract: Climate change and related ocean warming have affected marine ecological and socioeconomic systems worldwide. Therefore, it is critically important to assess the performance of conservation mechanisms, particularly marine protected areas (MPAs) to moderate the risks of climate-related impacts. In this study, sea surface temperature trends of Australian Commonwealth MPAs are assessed against climate change management criteria, as defined in Adapting to Climate Change: Guidance for Protected Area Managers and Planners . Monthly sea surface temperature trends between 1993 and 2017 were statistically assessed using the Mann–Kendall trend test and management plans were subject to a thematic analysis. Temperature trends showed variable SST changes among the regions, with the northern reserves all showing statistically significant increases in temperature, and the Southwest Network having the least number of reserves with statistically significant increases in temperature. The thematic analysis shows that management plans address approximately half of the climate change adaptation criteria. Several management strategies, such as dynamic MPAs, replication, and translocations, are currently absent and have been suggested as necessary tools in supporting the climate readiness of Australian MPAs. This study is significant because it helps to identify and synthesize regions most vulnerable to the impacts of ocean warming and provides management suggestions make MPAs “climate ready.”
Publisher: SAGE Publications
Date: 11-11-2021
Abstract: Geo ersity assessment is recent and is passing through a stage of methodological development and consolidation. With rapid environmental change, improving the developmental states of geo ersity assessment is of paramount importance. A scientometric analysis is presented to identify knowledge gaps, current trends and avenues for future research in quantitative geo ersity assessment literature. The study is categorised into three areas of analysis: (a) methodological intentions of geo ersity assessment, (b) current trends in geo ersity assessment methods and (c) current geographic trends. A ranking tool was developed to determine whether the current methodological intentions of geo ersity assessments trend towards combined geo ersity and bio ersity assessments or towards the independent assessment of geo ersity. Results showed that about 50% of publications independently assessed geo ersity with no consideration for bio ersity, 32% discussed or reviewed geo ersity by mentioning potential links to bio ersity and 12% more strongly linked geo ersity assessment to bio ersity assessment. Tools used by scholars to determine geo ersity values varied from statistical through to the more frequently adopted geographic information systems (GIS) and spatial analytical software approaches. Study sites selected for geo ersity assessments were predominantly terrestrial at the state-wide scale. Marine assessments, or seabed geo ersity, were mostly absent from the literature, with only two publications found. Brazil in South America had many geo ersity assessments and European scholars have played crucial roles in the development of quantitative geo ersity assessment in recent years. Subsequent research will benefit from developing a unified geo ersity assessment approach, reaching a consensus on an accepted definition and standardising the geo ersity concept, broadening research site environment types and developing strategies to promote further international and intranational collaboration.
Publisher: American Geophysical Union (AGU)
Date: 12-2010
DOI: 10.1029/2010JC006398
Abstract: Marine ecosystems are greatly influenced by the structure and dynamics of fronts. In coastal upwelling systems, frontogenesis occurs frequently by upwelling and transport of cold water and warming in sheltered “upwelling shadow” retention sites. Monterey Bay, in the California Current upwelling system, hosts a dynamic upwelling shadow environment. Using a decade of satellite synthetic aperture radar (SAR) observations with ancillary remote sensing and in situ data, we describe recurrent surface slicks that develop along the seaward periphery of the Monterey Bay upwelling shadow, and we examine their relationships with fronts. Slick median dimensions, 17.5 km long and 0.8 km wide, describe their elongated structure. Although the typical pattern is a single slick, multiple slicks may concurrently develop in association with different types of fronts. Repeated volume surveys through a front, underlying a slick, revealed lateral mixing and interleaving of regional water types. Velocity fields from coastal HF radar show that slicks may coincide with a variety of surface circulation patterns, that they may extend contiguously across regions having very different surface velocity, and that they may be separated from the shear front of upwelling filaments by 5–10 km. Slicks occur in all seasons and may coincide with both upwelling and downwelling wind forcing. Surfactant accumulation in small‐scale convergence zones is indicated as the primary mechanism of slick formation, not ocean current shear or small‐scale air‐sea coupling. The results of this study emphasize the role of upwelling system fronts in creating small‐scale structure and dynamics that influence plankton ecology.
Publisher: Informa UK Limited
Date: 09-06-2015
Publisher: MDPI AG
Date: 25-02-2017
DOI: 10.3390/RS9030210
Publisher: Elsevier BV
Date: 11-2015
Publisher: Wiley
Date: 13-09-2015
DOI: 10.1111/JPY.12329
Abstract: Seaweed morphology is often shaped by the hydrodynamic environment. However, exposure to air at low tide represents an additional factor potentially affecting the morphology of intertidal species. Here, we examined the relationships between the morphology of Hormosira banksii, an important intertidal habitat-forming seaweed in southern Australia, and environmental factors across multiple spatial scales around the island of Tasmania, Australia. Tasmania is surrounded by a erse coastline with differences in wave exposure, tidal parameters, and temperature. We s led Hormosira from four regions (100s km apart), three sites (10s km apart) within each region, and two zones (meters apart eulittoral and sublittoral) at each site, and measured multiple morphological variables to test for differences in morphology at those different spatial scales. Thirteen environmental variables reflecting wave exposure, tidal conditions, and temperature for each site were generated to assess the relationship between Hormosira morphology and environmental variation. Morphology varied at all spatial scales examined. Most notably, north coast in iduals had a distinct morphology, generally having smaller vesicles and shorter fronds, compared to other regions. Tidal conditions were the main environmental factors separating north coast sites from other sites and tidal regime was identified as the best predictor of morphological differences between regions. In contrast to other studies, we found little evidence that wave exposure was associated with morphological variation. Overall, our study emphasizes the role of tidal conditions, associated with emersion stress during low tide, in affecting the morphology of intertidal seaweeds.
Publisher: Elsevier BV
Date: 07-2017
Publisher: MDPI AG
Date: 08-10-2023
DOI: 10.3390/RS15194866
Publisher: Elsevier BV
Date: 08-2014
DOI: 10.1016/J.MARENVRES.2014.04.006
Abstract: The transformation of estuaries by human activities continues to alter the biogeochemical balance of the coastal ocean. The disruption of this balance can negatively impact the provision of goods and services, including fisheries, commerce and transportation, recreation and esthetic enjoyment. Here we examine a link, between the Elkhorn Slough and the coastal ocean in Monterey Bay, California (USA) using a novel application of fatty acid and pigment analysis. Fatty acid analysis of filtered water s les showed biologically distinct water types between the Elkhorn Slough plume and the receiving waters of the coastal ocean. A remarkable feature of the biological content of the plume entering the coastal ocean was the abundance of bacteria-specific fatty acids, which correlated well with concentrations of colored dissolved organic matter (CDOM). Pigment analysis showed that plume waters contained higher concentrations of diatoms and cryptophytes, while the coastal ocean waters showed higher relative concentrations of dinoflagellates. Bacteria and cryptophytes can provide a source of labile, energy-rich organic matter that may be locally important as a source of food for pelagic and benthic communities. Surface and depth surveys of the plume show that the biogeochemical constituents of the slough waters are injected into the coastal waters and become entrained in the northward flowing, nearshore current of Monterey Bay. Transport of these materials to the northern portion of the bay can fuel a bloom incubator, which exists in this region. This study shows that fatty acid markers can reveal the biogeochemical interactions between estuaries and the coastal ocean and highlights how man-made changes have the potential to influence coastal ecological change.
Location: United States of America
No related grants have been discovered for Andrew Fischer.