scholarly journals Hidden Consumers in Wave-exposed Boulder Beaches: Implications to Trophic Studies in Marine-terrestrial Ecotones

2021 ◽  
Author(s):  
Glenn A. Hyndes ◽  
Rebecca McCleod ◽  
Rocio Suarez Jimenez ◽  
Derek Richards
Keyword(s):  
New Zealand ◽  
Food Webs ◽  
High Energy ◽  
Sandy Beaches ◽  
Published Data ◽  
Total Biomass ◽  
Prominent Feature ◽  
Ecological Processes ◽  
Density And Biomass ◽  
Beach Cast

Abstract Invertebrate communities and ecological processes are well understood in high-energy sandy beaches, where beach-cast wrack (macrophyte detritus) often accumulates and forms hotspots of nutrient cycling as well as enhancing diversity and driving food webs. Grazing invertebrates play a key role in recycling wrack and facilitating the transfer of nutrients for spatial subsidies across this marine-terrestrial ecotone. Cobble and boulder beaches can also form a prominent feature of wave-exposed coasts and accumulate wrack, yet we know far less about the invertebrates in these beaches and their possible role for recycling wrack. Here, we determine the biomass of detrital macrophytes on, and embedded in, the boulder matrix, as well as the density and biomass of macroinvertebrates in high-energy, boulder beaches in south-eastern New Zealand. We use these data to compare densities and biomass of wrack and invertebrates with published data for sandy beaches to examine the possible importance of these understudied coastal habitats in recycling wrack and facilitating trophic subsidies. The biomass of beach-cast macroalgae exceeded 100 g DW 0.1m-2 on boulder beaches, where the kelps Durvillaea spp. and Macrocystis pyrifera were the main forms of wrack on both types of beaches. This was comparable to many other sandy beaches across the globe. However, the total biomass of invertebrates on boulder beaches in our study was higher than that reported for sandy beaches in the region and across the globe, while densities were similar or higher than those found on sandy beaches. Like sandy beaches across the globe, amphipods were abundant on boulder beaches, however, the relatively large gastropod Diloma nigerrimum was particularly dominant in this habitat. With its known high grazing rates, combined with high densities and biomass, this grazer is likely to play a disproportionately important role in the processing of beach-cast kelp and a key role in transferring nutrients back into the ocean or to adjacent terrestrial food webs.

scholarly journals Flotsam and jetsam: a global review of the role of inputs of marine organic matter in sandy beach ecosystems

2021 ◽  
Author(s):  
Glenn A. Hyndes ◽  
Emma Berdan ◽  
Cristian Duarte ◽  
Jenifer E. Dugan ◽  
Kyle A. Emery ◽  
...  
Keyword(s):  
Organic Matter ◽  
Food Webs ◽  
Food Source ◽  
Sandy Beach ◽  
Morphological Characteristics ◽  
Sandy Beaches ◽  
Marine Animals ◽  
Marine Organic Matter ◽  
Beach Cast

Sandy beaches are iconic interfaces that functionally link the ocean with the land by the flow of marine organic matter. These cross-ecosystem fluxes often comprise uprooted seagrass and dislodged macroalgae that can form substantial accumulations of detritus, termed ‘wrack’, on sandy beaches. In addition, the tissue of the carcasses of marine animals that regularly wash up on beaches form a rich food source (‘carrion’) for a diversity of scavenging animals. Here, we provide a global review of how wrack and carrion provide spatial subsidies that shape the structure and functioning of sandy beach ecosystems (sandy beaches and adjacent surf zones), which typically have little in situ primary production. We also examime the spatial scaling of the influence of these processes across the broader seascape and landscape, and identify key gaps in our knowledge to guide future research directions and priorities. Globally, large quantities of detrital kelp and seagrass can flow into sandy beach ecosystems, where microbial decomposers and animals remineralise and consume the imported organic matter. The supply and retention of wrack are influenced by the oceanographic processes that transport it, the geomorphology and landscape context of the recipient beaches, and the condition, life history and morphological characteristics of the taxa that are the ultimate source of wrack. When retained in beach ecosystems, wrack often creates hotspots of microbial metabolism, secondary productivity, biodiversity, and nutrient remineralization. Nutrients are produced during wrack break-down, and these can return to coastal waters in surface flows (swash) and the aquifier discharging into the subtidal surf. Beach-cast kelp often plays a key trophic role, being an abundant and preferred food source for mobile, semi-aquatic invertebrates that channel imported algal matter to predatory invertebrates, fish, and birds. The role of beach-cast marine carrion is likely to be underestimated, as it can be consumed rapidly by highly mobile scavengers (e.g. foxes, coyotes, raptors, vultures). These consumers become important vectors in transferring marine productivity inland, thereby linking marine and terrestrial ecosystems. Whilst deposits of organic matter on sandy beach ecosystems underpin a range of ecosystem functions and services, these can be at variance with aesthetic perceptions resulting in widespread activities, such ‘beach cleaning and grooming’. This practice diminishes the energetic base of food webs, intertidal fauna, and biodiversity. Global declines in seagrass beds and kelp forests (linked to global warming) are predicted to cause substantial reductions in the amounts of marine organic matter reaching many beach ecosystems, likely causing flow-on effects on food webs and biodiversity. Similarly, future sea-level rise and stormier seas are likely to profoundly alter the physical attributes of beaches, which in turn can change the rates at which beaches retain and process the influxes of wrack and animal carcasses. Conservation of the multi-faceted ecosystem services that sandy beaches provide will increasingly need to encompass a greater societal appreciation and the safeguarding of ecological functions reliant on beach-cast organic matter on innumerable ocean shores worldwide.

Causes of mortality in stranded Common Dolphin (Delphinus sp.) from New Zealand waters between 1998 and 2008

2009 ◽  
Vol 15 (3) ◽  
pp. 217 ◽  
Author(s):  
Karen A Stockin ◽  
Padraig J Duignan ◽  
Wendi D Roe ◽  
Laureline Meynier ◽  
Maurice Alley ◽  
...  
Keyword(s):  
New Zealand ◽  
Causes Of Death ◽  
Published Data ◽  
Common Dolphin ◽  
Post Mortem ◽  
Age Classes ◽  
Dolphin Population ◽  
Causes Of Mortality ◽  
Related Mortality ◽  
Beach Cast

Post-mortem examinations provide valuable information on sources of mortality for marine mammal populations. However, no published data exist to describe causes of death in the New Zealand population of Common Dolphin (Delphinus sp.). In order to examine the proportion of human and non-human induced mortality affecting this population, necropsies were conducted on 133 individuals that stranded around the New Zealand coastline between 1998 and 2008. Of these, 92.5% (n=123) were found as beach cast carcasses, with just 7.5% (n=10) as live strandings that subsequently died or that were euthanized on humane grounds. The sample included 54 males, 67 females and 12 animals of unknown sex from a range of age classes. Of the individuals for which cause of mortality could be established, 41.2% (n=35) were classified as human induced, with 28.2% (n=24) of carcasses exhibiting evidence of net entanglement. A further 10.6% and 32.9% of mortality was attributable to disease and natural (non-human related) causes, respectively. Few examples of disease were detected, but this may be at least partly a consequence of sampling constraints. Of the carcasses assessed, 68.6% of individuals exhibited some form of parasitism. Parasites identified were typical of the genus and considered to be present in low to moderate burdens. The proportion of beach cast carcasses exhibiting evidence of net entanglement suggests that fisheries-related mortality maybe higher than that previously considered for the New Zealand Common Dolphin population.

Potential contribution of the wastewater sector to energy supply

2011 ◽  
Vol 63 (8) ◽  
pp. 1765-1771 ◽  
Author(s):  
S. Heubeck ◽  
R. M. de Vos ◽  
R. Craggs
Keyword(s):  
New Zealand ◽  
Potential Energy ◽  
Biological Treatment ◽  
High Energy ◽  
Technology Selection ◽  
Energy Yield ◽  
Potential Contribution ◽  
Energy Potential ◽  
Treatment Technologies ◽  
Future Potential

The biological treatment of wastewater could yield high energy fuels such as methane and alcohols, however most conventional treatment systems do not recover this energy potential. With a simple model of the energy yields of various wastewater treatment technologies it is possible to demonstrate how minor shifts in technology selection can lead the industry from being identified as predominantly energy intensive, to being recognised as a source of energy resources. The future potential energy yield is estimated by applying energy yield factors to alternative use scenarios of the same wastewater loads. The method for identifying the energy potential of wastewater was demonstrated for the New Zealand wastewater sector, but can equally be applied to other countries or regions. The model suggests that by using technologies that maximise the recovery of energy from wastewater, the potential energy yield from this sector would be substantially increased (six fold for New Zealand).

Should immunocontraception be used for wildlife population management?

2004 ◽  
Vol 26 (1) ◽  
pp. 61 ◽  
Author(s):  
DW Cooper
Keyword(s):  
Immune Response ◽  
New Zealand ◽  
Immune Responses ◽  
Fundamental Problem ◽  
Public Perceptions ◽  
Published Data ◽  
Red Foxes ◽  
European Rabbits ◽  
Selection For ◽  
Self Antigens

Immunocontraception involves eliciting an immune response against eggs, sperm or hormones so that successful reproduction is prevented. Work in Australasia is aimed at European rabbits (Oryctolagus cuniculus), red foxes (Vulpes vulpes), house mice (Mus musculus), common brushtail possums (Trichosurus vulpecula), koalas (Phascolartcos cinereus) and kangaroos (Macropus spp.), with the vaccines involved all containing self antigens or their relatives. Two fundamental problems have been inadequately addressed in this research. The first problem is that it is difficult to obtain strong immune responses against self antigens and so the vaccines may be ineffective. Most published data on the effect of immunocontraceptives on reproduction involve the use of an adjuvant of which there are many kinds. The materials enhance the immune response greatly. The most frequently used is Freund?s adjuvant which can cause chronic suffering. Its use on wildlife will lead to very negative public perceptions. There has been no convincing demonstration that successful immunocontraception is possible with any method of vaccination likely to be used in the field, if success is defined as contraception of a proportion of the population high enough for management requirements. If it is assumed that success can be achieved, the second fundamental problem arises with two potential consequences. Even with adjuvant, a substantial minority of the vaccinated animals remains fertile. The first consequence is that since failure to be contracepted is likely to be in part genetic, there is likely to be rapid selection for these non-responders. The method will become ineffective in a few generations. The second problem is that the offspring of the animals which breed will have altered immune responses. Their capacities to respond to their own pathogens or to harbor pathogens of other species in the same ecosystem are likely to be changed. The presence of chlamydia in P. cinereus and bovine tuberculosis in New Zealand T. vulpecula means that responses to these pathogens would have to be studied in offspring of immunocontracepted parents to ensure that the offspring were not more susceptible to them. New Zealand intentions to put an immunocontraceptive into a T. vulpecula gut worm must be viewed with caution by Australia. The eggs of transgenic worms will be easily transplanted either accidentally or deliberately back into Australia, and so infect T. vulpecula in Australia.

scholarly journals The correlative behavior of sandbars and shoreline along Sulina – Sf. Gheorghe beaches (Danube Delta Coast)

2016 ◽  
Vol 18 (1) ◽  
pp. 19-31
Author(s):  
Florin TĂTUI
Keyword(s):  
High Energy ◽  
Sandy Beaches ◽  
Energy Conditions ◽  
Danube Delta ◽  
Dune System ◽  
Migration Rates ◽  
System Protection ◽  
Main Driver ◽  
Southern Central

Longshore sandbars along wave-dominated sandy beaches are important for beach-dune system protection during storms. Our analysis is based on 6 years of seasonal and annual bathymetric surveys along 16 km of erosive, stable and accumulative low-lying non-tidal beaches northward of Sf. Gheorghe arm mouth (Danube Delta – Romanian Black Sea coast). Our results show significant correlations established between longshore sandbar crest positions and morphology with more intense coupling between the inner and outer sandbar sub-systems during high-energy conditions and more frequent along the northern erosive sector in comparison with the southern/central accumulative/stable ones. There is a good connection between the long-term shoreline mobility and sandbars offshore migration rates along different sectors of the study area, with faster sandbars movement and shorter cycle return periods along the northern erosive sector in comparison with the central (stable) and southern (accretionary) sectors. The longshore variations of the nearshore slope are the main driver of the relationship between long-term sandbars dynamics and shoreline variability along the study site.

scholarly journals Reconstruction of plant–pollinator networks from observational data

2019 ◽  
Author(s):  
Jean-Gabriel Young ◽  
Fernanda S. Valdovinos ◽  
M. E. J. Newman
Keyword(s):  
Food Webs ◽  
Observational Data ◽  
Network Structure ◽  
Rare Species ◽  
Statistical Technique ◽  
Ecological Networks ◽  
Statistical Analyses ◽  
Published Data ◽  
Statistical Errors ◽  
Plant Pollinator

Empirical measurements of ecological networks such as food webs and mutualistic networks are often rich in structure but also noisy and error-prone, particularly for rare species for which observations are sparse. Focusing on the case of plant–pollinator networks, we here describe a Bayesian statistical technique that allows us to make accurate estimates of network structure and ecological metrics from such noisy observational data. Our method yields not only estimates of these quantities, but also estimates of their statistical errors, paving the way for principled statistical analyses of ecological variables and outcomes. We demonstrate the use of the method with an application to previously published data on plant–pollinator networks in the Seychelles archipelago, calculating estimates of network structure, network nestedness, and other characteristics.

scholarly journals Crossing the front: contrasting storm-forced dispersal dynamics revealed by biological, geological and genetic analysis of beach-cast kelp

2018 ◽  
Vol 15 (140) ◽  
pp. 20180046 ◽  
Author(s):  
Jonathan M. Waters ◽  
Tania M. King ◽  
Ceridwen I. Fraser ◽  
Dave Craw
Keyword(s):  
New Zealand ◽  
Genetic Analysis ◽  
Wind Direction ◽  
Storm Events ◽  
Temperate Water ◽  
Marine Dispersal ◽  
Quantitative Analyses ◽  
Dispersal Distances ◽  
Warm Temperate ◽  
Beach Cast

The subtropical front (STF) generally represents a substantial oceanographic barrier to dispersal between cold-sub-Antarctic and warm-temperate water masses. Recent studies have suggested that storm events can drastically influence marine dispersal and patterns. Here we analyse biological and geological dispersal driven by two major, contrasting storm events in southern New Zealand, 2017. We integrate biological and physical data to show that a severe southerly system in July 2017 disrupted this barrier by promoting movement of substantial numbers of southern sub-Antarctic Durvillaea kelp rafts across the STF, to make landfall in mainland NZ. By contrast, a less intense easterly storm (Cyclone Cook, April 2017) resulted in more moderate dispersal distances, with minimal dispersal between the sub-Antarctic and mainland New Zealand. These quantitative analyses of approximately 200 freshly beach-cast kelp specimens indicate that storm intensity and wind direction can strongly influence marine dispersal and landfall outcomes.

‘Quit while you are ahead – and smell the roses!’ A survey of retired Fellows of the Australian and New Zealand College of Anaesthetists

2021 ◽  
pp. 0310057X2110057
Author(s):  
Diana Strange Khursandi ◽  
Victoria Eley
Keyword(s):  
Clinical Practice ◽  
New Zealand ◽  
Standard Deviation ◽  
Response Rate ◽  
Common Factors ◽  
Published Data ◽  
Factors Affecting ◽  
Retirement Decisions ◽  
Zealand College ◽  
The Mean

There are no published data on the age of retirement of anaesthetists in Australia and New Zealand. We surveyed 622 retired Fellows of the Australian and New Zealand College of Anaesthetists to determine their ages of complete retirement from clinical practice, demographics, and whether they had retired at the age they had intended to retire. We also aimed to explore factors affecting the decision to retire, the practice of ‘winding down’, common post-retirement activities, and the arrangement of personal and professional affairs. Responses were received from 371 specialists (response rate 60%). The mean (standard deviation) age of retirement was 65.2 (6.9) years. The mean (standard deviation) retirement ages ranged from 62.0 (7.1) years (those who retired earlier than planned) to 68.0 (4.3) years (those who retired later than they had intended). The mean (standard deviation) age of retirement of the male respondents was 66.0 (6.5) years, and for female respondents was 62.7 (7.7) years. Two hundred and thirty-three respondents (63%) reported winding down their practice prior to retirement, and 360 (97%) had made a will. Poor health and loss of confidence were the two most common factors in the retirement decisions of those who retired earlier than they had planned. Our results may assist current practitioners plan for retirement, and suggest strategies to help health services, departments and private groups accommodate individuals in winding down their practice.

scholarly journals Heterogeneity in catchment properties: a case study of Grey and Buller catchments, New Zealand

2002 ◽  
Vol 6 (2) ◽  
pp. 167-184 ◽  
Author(s):  
U. Shankar ◽  
C. P. Pearson ◽  
V. I. Nikora ◽  
R. P. Ibbitt
Keyword(s):  
New Zealand ◽  
Fractal Dimensions ◽  
Affine Scaling ◽  
Stream Networks ◽  
Ecological Processes ◽  
Spectral Parameters ◽  
Scaling Behaviour ◽  
Multifractal Spectra ◽  
Box Counting Method ◽  
Landscape Patches

Abstract. The scaling behaviour of landscape properties, including both morphological and landscape patchiness, is examined using monofractal and multifractal analysis. The study is confined to two neighbouring meso-scale catchments on the west coast of the South Island of New Zealand. The catchments offer a diverse but largely undisturbed landscape with population and development impacts being extremely low. Bulk landscape properties of the catchments (and their sub-basins) are examined and show that scaling of stream networks follow Hack’s empirical rule, with exponents ∼0.6. It is also found that the longitudinal and transverse scaling exponents of stream networks equate to νl ≈0.6 and νw≈ 0.4, indicative of self-affine scaling. Catchment shapes also show self-affine behaviour. Further, scaling of landscape patches show multifractal behaviour and the analysis of these variables yields the characteristic parabolic curves known as multifractal spectra. A novel analytical approach is adopted by using catchments as hydrological cells at various sizes, ranging from first to sixth order, as the unit of measure. This approach is presented as an alternative to the box-counting method as it may be much more representative of hydro-ecological processes at catchment scales. Multifractal spectra are generated for each landscape property and spectral parameters such as the range in α (Holder exponent) values and maximum dimension at α0, (also known as the capacity dimension Dcap), are obtained. Other fractal dimensions (information Dinf and correlation Dcor) are also calculated and compared. The dimensions are connected by the inequality Dcap≥Dinf≥Dcor. Such a relationship strongly suggests that the landscape patches are heterogeneous in nature and that their scaling behaviour can be described as multifractal. The quantitative parameters obtained from the spectra may provide the basis for improved parameterisation of ecological and hydrological models. Keywords: fractal, multifractal, scaling, landscape, patchiness

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