Journal Watch

Latest highlights published in New Zealand research journals, December 2009

• Building communities of learning
• Katipo at the beach this summer?
• Dinosaur footprints – a first for New Zealand
• Managing risks to save a species
• Science directions to shape future policy
• Climate change? Food miles? Carbon credits? Virtual water? Just what are the issues for New Zealand? How much are we prepared to pay to fix them?
• One hundred years of facial eczema research
• Measuring pasture quality spectroscopically
• Improving cultivar yield and performance by selective breeding
• Know about changes to journal publishing?

 

Building communities of learning

Is one author’s account of the place of scientific and indigenous knowledge in cross-cultural environmental research, management and Western-centric decision-making published in a Forum on this topic in the December issue of the Journal of the Royal Society of New Zealand. "Building communities of learning" aptly describes the findings of other research articles published in the Forum, written by a total of 22 local and overseas contributors.

The full text of each Forum article is now available online at http://www.royalsociety.org.nz/Site/publish/Journals/jrsnz/2009/default.aspx

Katipo at the beach this summer?

Jessica Costall and Russell Death of Massey University have investigated the distribution and habitat of our endemic katipo, Latrodectus katipo, an endangered species of widow spider, at seven sites along the Manawatu-Wanganui coastline. Along the 4.7 km coastline surveyed they found 151 juvenile, 74 female and 14 male katipo, mostly on driftwood. The introduced South African spider, Steatoda capensis, is alsoabundant at these sites and may be a competitor of katipo.

Costall & Death used global positioning system (GPS) data at the start and end points of their survey to calculate the area of dune searched, and used the GPS position of each spider to calculate a mean nearest neighbour distance. This showed that katipo tend to have a highly clumped distribution. The structure of katipo populations also varied considerably between sites. At Castlecliff and Wanganui South beaches very few katipo were found, and juveniles were apparently absent. In contrast, over half of the katipo found at Himatangi, Tangimoana and Foxton beaches were juveniles. There was a high degree of overlap between katipo and Steatoda capensis in the sizes of driftwood they occupied. Only 28% of the mature female katipo living in vegetation were found in marram plants, compared to 56% in spinifex. This is important for 2 reasons. Marram grass, planted in dune systems nationwide in an attempt to stabilise sand movement has had a large impact on dune systems because it displaces native sand-binding plants, such as spinifex; it also allows insufficient open space for female katipo to build a prey-catching web.

Katipo conceal themselves in their nests by day so aside from a chance meeting with one of these venomous spiders, we’re safer from them than they are from us. Why? Damage caused to dune systems by vehicle use, rubbish dumping, grazing by hares and the spread of dense-growing exotic plants like marram, have made them an endangered species. Translocations of katipo in dune systems at Wanganui and Castlecliff beaches may therefore be necessary to prevent local extinctions. Foxton, Tangimoana and Himatangi beaches comprise the largest areas of potentially suitable katipo habitat along the Manawatu-Wanganui coastline.

See New Zealand Journal of Zoology 36(4)

http://www.royalsociety.org.nz/Site/publish/Journals/nzjz/2009/default.aspx

Dinosaur footprints – a first for New Zealand

Dinosaur bones have previously been known from three locations in New Zealand, Port Waikato, inland Hawke’s Bay, and the Chatham Islands.

No fossil dinosaur footprints or tracks have been recognized in New Zealand before, and no record of dinosaurs, footprints or fossils were "known" from the South Island.

Greg Browne, GNS Science, has carried out detailed field investigations in northwest Nelson and his latest findings have been published in the December issue of the New Zealand Journal of Geology and Geophysics.

Based on the age of the six North Cape Formation localities where dinosaur footprints have been discovered, and the shape of the prints, it is concluded that they were formed by sauropods (large dinosaurs with pentadactyl (5-toed feet) thought to be of the superfamily Titanosaurida.

Dr Browne describes the geological characteristics of the rocks, the geological events that formed the rocks and how the prints came to be preserved. As a result he rules out the possibility that the structures were formed by physical or sedimentological processes.

See New Zealand Journal of Geology and Geophysics 52(4)

http://www.royalsociety.org.nz/Site/publish/Journals/nzjgg/2009/default.aspx

 

Managing risks to save a species

A conservation management programme for the oystercatcher (Haematopus chathamensis) endemic to the Chatham Islands, increased the population of this species from 144 in 1998 to 316 in 2006. It is ranked as nationally critical.

Department of Conservation scientists, Peter Moore and Clio Reid, video monitored 21 managed and 28 unmanaged nests over three breeding seasons from 1999 to 2001 to identify key threats to oystercatcher nests and assess the effectiveness of management.

Within that period they found that feral cats and an introduced rail, the weka (Gallirallus australis hectori), were the main predators, responsible for 68 and 16% of fatal events respectively. Newly hatched birds may venture from the nest to feed, so reliable data on predation of this precocial species could only be captured on video at the egg stage. Seventeen of 75 (23%) visits to active nests by predatory species (cats, weka, gulls, possums, rodents, spur-winged plovers, and hedgehogs) and 1 of 65 (2%) visits by all other animals (sheep, cattle, humans, penguins, and other birds) resulted in nest failure at filmed nests.

During the 3 years of video monitoring, Moore & Reid followed the breeding success of 129 nests. Of 79 managed nests, 58 (73%) survived and 21 (27%) failed, whereas of 50 unmanaged nests 17 (34%) survived, 32 (64%) failed and the outcome of 1(2%) was not determined. The main apparent cause of nest failure during the 3 years was destruction by predators (n = 17, 32%), followed by tidal overwash (n = 11, 21%), inviability (infertility or early dead embryo) (n = 7, 13%), abandonment (n = 5, 9%), trampling by sheep (n = 2, 4%), and unknown causes (n = 11, 21%).

Cats appear to be the principal threat. Sixteen different nests (33% of 49 filmed) were visited by cats resulting in 13 failures. Sheep appeared to be less reactive than cattle to the defensive behaviour shown by nesting oystercatchers, when these animals investigated the birds by sniffing and nuzzling them. This forced the birds to leave the nest, making the eggs vulnerable to trampling or being broken during their panicked departure.

Monitoring nests, particularly in managed areas (1998-2004) showed that stormy seas in some years were an important cause of nest failure. This was exacerbated by introduced marram grass which has reduced nesting opportunities for oystercatchers.

Management included the use of traps, stock exclusion fences, and translocation of nests. Nest platforms were placed in some managed oystercatcher territories before the start of each breeding season. The platforms consisted of car tyres tied to plywood sheets, filled and covered with sand, and given a sparse decoration of seaweed or driftwood to imitate an oystercatcher nest site. These were designed to provide a raised nest site for partial protection from high tides and to allow easy relocation of the nest up the beach should high seas threaten to inundate the nest.

Despite the threats to the birds, management in northern Chatham Island boosted productivity and helped drive a population increase over the 7-year programme.

See New Zealand Journal of Zoology 36(4)

http://www.royalsociety.org.nz/Site/publish/Journals/nzjz/2009/default.aspx

Science directions to shape future policy

A detailed appraisal of the current state of the New Zealand science system, by Prof. Jacqueline Rowarth of Massey University, has been published online in December issue of the New Zealand Journal of Agricultural Research. The recent announcement by Dr Helen Anderson, Chief Executive Officer of the Ministry of Research Science and Technology, of her intention to step down after 6 years in that role gives it particular interest. The article offers some insights into the existing science environment.

In addition, as mentioned in the article, Hon Dr Wayne Mapp, Minister for Science and Technology, stated in March that the "science system would be examined over the next 12 months with a view to reducing transaction costs faced by researchers and research organisations and finding ways to strengthen links between RS&T, tertiary education and economic development". With similar aims having been expressed by the Chief Science Adviser, Prof. Peter Gluckman, Prof. Rowarth’s article raises some timely observations for the science sector to consider.

This new article deals with big questions about funding, education, and leadership. It is a thorough scholarly appraisal supported by a significant bibliography of relevant published works.

　

Climate change? Food miles? Carbon credits? Virtual water? Just what are the issues for New Zealand? How much are we prepared to pay to fix them?

The agricultural sector is also the largest source of greenhouse gas emissions contributing 48% of New Zealand’s total source of emissions in 2007 (methane 66% and nitrous oxide 34%). Yet the New Zealand Parliament introduced legislation, on 25 November 2009, on a carbon emissions policy that excludes the agricultural sector.

Groundwater from aquifers provides untreated drinking water for some residents in Canterbury and some of the aquifers exceed New Zealand Drinking Water Standards of 11.3 mg/litre nitrate-nitrogen. It is, therefore, not surprising that the findings from a survey of 504 Canterbury respondents (31% response rate) by Ramesh Baskaran, Ross Cullen and Sergio Colombo, published in the New Zealand Journal of Agricultural Research, reveals that the majority of the respondents worry about the quality of the drinking water in their region.

New Zealand supplies one-third of global dairy trade and is the largest dairy exporter in the world despite exclusionary trade practices which confine New Zealand exporters to middle and low income countries. The dairy sector strives to maintain international competitiveness by continued increases in productivity (using fertiliser) and intensification (from low intensity sheep and beef units to high intensity dairy, crop and horticulture units). Emissions from livestock waste and fertiliser use (>22% since 1990) into waterways are expected to continue as the number of dairy farming animals increase and this will reduce water quality accordingly. About 39% of monitored groundwater in New Zealand has nitrate levels that are elevated above natural background levels.

Biodiversity is also a casualty of land conversion (a 260% increase in irrigated land from 1985 to 2005) with the consequent removal of native vegetation, shelter belts and windbreaks.

The researchers used a choice statistical model to assess respondents’ willingness to pay for environmentally friendly agricultural programmes in the Canterbury region. The model advocates a socioeconomic driven solution because, despite efforts from Fonterra and regional government based on compliance, which affects farmers’ profitability, environmental deterioration is continuing.

Their statistical analyses show that, on average, respondents would be willing to pay $15.85 annually for a period of 5 years to farmers who adopt environmentally sustainable production (e.g., native habitat conservation) or as a reward for meeting management controls (e.g., stocking rate or best management practice programmes).

The study gives a broad analysis of these impacts in terms of quantitative risk assessments and cost-benefit analysis. The researchers suggest how the relative importance of each environmental impact and policies or actions could be prioritised to assign more resources (i.e., funding, training and manpower) to improve farming practices that have high social values, such as 30% reduction in nitrate leaching and water usage (currently 70% of the Canterbury region’s water is used for pasture). Protecting aquifers could be more cost effective than water treatment alternatives, say the researchers.

One hundred years of facial eczema research

Facial eczema has been a serious problem to New Zealand sheep, cattle and deer farmers for over 100 years. Margaret di Menna, Barry Smith and Chris Miles have completed a history of research into this disease.

Facial eczema (more correctly termed pithomycotoxicosis) is now known to be caused by the fungus, Pithomyces chartarum. The fungus grows on litter at the base of pasture and spores profusely under warm moist conditions in late summer and autumn. As the fungus spores it produces the toxin sporidesmin which, when eaten by sheep, cattle, goats or deer, damages the liver and causes inflammation and blockage of bile ducts. A breakdown product of chlorophyll, usually excreted in the bile, then circulates in the blood. This breakdown product reacts in sunlight, causing lesions of unpigmented skin when the affected animal is exposed to sunlight.

This, however, was unknown when the research commenced. The cause of facial eczema was thought to be a substance produced by ryegrass, or perhaps by the ryegrass endophyte, under some environmental conditions. Field research suggested that warm, moist conditions in summer and autumn were conducive to the disease, but the lag period of a week or more between stock ingesting the spores and the appearance of the symptoms made the discovery of the cause difficult.

Although the cause was not known, when toxic pasture was extracted in the laboratory a white film was deposited on the glassware. From this a "beaker test" was developed. Air and soil temperatures were used to predict facial eczema danger periods, and so assist farmers avoid the disease as far as possible.

In March 1958, a scientist collected fungal mycelium growing on a facial eczema trial plot adjoining a polo field.The operator of a gang mower, preparing the field for polo, noticed a black dust hovering over the mower. Samples of black dust collected from the mower produced a strongly positive reaction to the beaker test. This was the breakthrough. The spores were identified as Pithomyces chartarum, and animal feeding studies confirmed that this fungus caused liver damage characteristic of facial eczema.

From there the active ingredient, sporidesmin, was isolated and methods were developed to produce it in large quantities. Scientists now had the ability to produce facial eczema consistently, and could now look for management options and treatment methods.

In addition to predicting danger periods from weather conditions, farmers could now use fungal spore counts. Spores could be either washed from pasture or collected in a spore trap. The spore trap was pushed over the pasture, collecting a measured volume of air as it went. In either method the spores were counted on a microscope slide. But even when toxic pasture could be detected, avoiding facial eczema involved inconvenience and loss of grazing during danger periods. Some method was needed to reduce the growth of the fungus or to protect animals from the toxin.

It was found that fungicides sprayed on pasture inhibited the growth of Pithomyces and protected sheep from facial eczema. This research was overtaken, however, by the discovery that large doses of zinc protected animals from the effects of sporidesmin. The widespread use of zinc dosing was limited, however, by the small margin between the required dose and the toxic level. A practical method became available with the development of the zinc intra-ruminal bolus, cylindrical core of zinc oxide with a water-impermeable coating, which remains in the rumen releasing an appropriate level of zinc over several weeks.

Early in the research into facial eczema it was noted that the susceptibility of sheep within a flock varied greatly. Later research showed that there were heritable differences, both between and within sheep breeds. The final answer to facial eczema may lie in breeding for resistance in both sheep and cattle.

Measuring pasture quality spectroscopically

In this paper, Kensuke Kawamura, Keith Betteridge, Ieda Sanches, Mike Tuohy, Des Costall and Yoshio Inoue demonstrate the potential of a field radiometer in conjunction with a canopy pasture probe (CAPP) and global positioning system (GPS) to predict and map the spatial distribution patterns of herbage biomass and mass of nutrients, such as nitrogen (N), phosphorous (P), potassium (K), and sulphur (S) in hill country grassland.

Estimating plant nutrient requirements in a timely way, along with application of variable rate fertiliser application technologies at paddock or within-paddock scale can improve farm management practice by giving farmers the information they need to estimate feed planning and grazing strategy decision making. Predicting soil fertility over wide distances is a desired outcome of grassland management.

Conventional stepwise multiple linear regression (MLR) has been widely used to select critical wavebands for estimating biochemical components but spectral overlap of these components and multicollinearity problems are well known. Partial least squares has been used as an alternative approach, similar to principle components analyses, both of which use data compression to reduce collinear spectral variables. An alternative model for acquiring optimal remotely sensed spectral signatures, usually only detectable on cloud-free conditions, is the modified canopy pasture probe (CAPP). The probe, which has its own artificial light source enclosed within a dark chamber, works attached to a portable spectroradiometer and excludes ambient light when placed over pasture.

Using CAPP and GPS, nitrogen, which is related to chlorophyll activity, can be accurately predicted and compared within and between paddocks. Fibre parameters such as acid detergent fibre and neutral detergent fibre are also detectable, with accuracies of prediction being over 60% for field samples.

The Spectro-CAPP is well suited for hand-held experimentation but modifications would be required to provide artificial illumination if spectral imaging is to be carried out by farm vehicles over large areas on overcast days. Before this technology can be used commercially, extensive validation across seasons, landscapes (lowland and hill country, within and between regions of New Zealand) pasture types and different intervals of growth is required.

Improving cultivar yield and performance by selective breeding

Alieu Sartie, Syd Easton, and Clive Matthew wanted to find out the extent to which morphological traits, either singly or in combination, are common to different cultivars, or uniquely a property of a particular cultivar.

They collected data from two perennial ryegrass cultivars ‘Grasslands Samson’ and ‘Grasslands Impact’ and used contrasting parent plants to found a mapping population for identification of quantitative trait loci (QTL) with the aim of establishing a marker assisted selection capability as part of an ongoing ryegrass improvement programme and discovering alternate forage grass growth strategies.

Their paper reports quantitative morphological data for these cultivars, bred by AgResearch Grasslands. Both have been used widely in New Zealand and temperate Australia. Samson was developed from a breeding pool based on founder plants taken from old pastures throughout New Zealand; Impact was based on crosses between a selection for later flowering within the cultivar ‘Grasslands Nui’ and an ecotype from Galicia, Spain.

Seeds were grown in pots in a greenhouse, through the seedling growth phase and until the full emergence of the 10th leaf of the main tiller.

Cultivars differed for only 5 of the 10 variables measured, and cultivar differences detected were quite small in absolute terms, even though often of high statistical significance. Cultivars differed most in mean leaf laminar width, leaf sheath length, leaf appearance interval, ligule appearance interval, and tiller number, with Samson having broader leaves, shorter leaf-sheaths, shorter leaf and ligule appearance intervals, and fewer tillers per plant on average than Impact.

Although, cultivar differences amounted to only a small shift in the population mean for measured traits, the results indicate that prior study of individual plants selected as parents for a mapping population, with a view to purposeful choice of mapping population parents based on detailed selection criteria, would be advantageous.

Principal components analysis (PCA) identified alternative strategies for a grass plant to achieve large shoot size: either by increased leaf elongation duration, or increased leaf elongation rate (LER). This allowed the scientists to note variations in the degree to which morphological characteristics are inter-dependent, for example, longer leaf lamina length is an expected consequence of increased leaf sheath length. They concluded from the structure of the PCA that there is no intrinsic yield advantage in selecting directly for either shoot size or shoot number, but that yield is determined by a more complex interaction of multiple traits, with LER being one of the more important.

Therefore, when setting up mapping populations for quantitative trait locus discovery, they say there would be value in obtaining more detailed information about behaviour of an individual genotype selected to represent a cultivar or breeding line. PCA of multiple morphological traits appears to be a useful way to categorise agronomic differences between genotypes, and even offers potential for development of plant ideotypes.

See New Zealand Journal of Agricultural Research 52(4)

http://www.royalsociety.org.nz/Site/publish/Journals/nzjar/2009/default.aspx

Know about changes to journal publishing?

http://www.royalsociety.org.nz/Site/publish/default.aspx