A phylogenetically distinct lineage of Pyrenopeziza brassicae associated with chlorotic leaf spot of Brassicaceae in North America

Light leaf spot, caused by the ascomycete Pyrenopeziza brassicae Sutton & Rawlinson, is an established disease of Brassicaceae in the United Kingdom (UK), continental Europe, and Oceania (OC, including New Zealand and Australia). The disease was reported in North America (NA) for the first time in 2014 on Brassica spp. in the Willamette Valley of western Oregon, followed by detection in Brassica juncea cover crops and on B. rapa weeds in northwestern Washington in 2016. Preliminary DNA sequence data and field observations suggest that isolates of the pathogen present in NA might be distinct from those in the UK, continental Europe, and OC. Comparisons of isolates from these regions genetically (multilocus sequence analysis, MAT gene sequences, and rep-PCR DNA fingerprinting), pathogenically (B. rapa inoculation studies), biologically (sexual compatibility), and morphologically (colony and conidial morphology) demonstrated two genetically distinct evolutionary lineages. Lineage 1 comprised isolates from the UK, continental Europe, and OC, and included the P. brassicae type specimen. Lineage 2 contained the NA isolates associated with recent disease outbreaks in the Pacific Northwest region of the USA. Symptoms caused by isolates of the two lineages on B. rapa and B. juncea differed, so ‘chlorotic leaf spot’ is proposed for the disease caused by lineage 2 isolates of P. brassicae. Isolates of the two lineages differed in genetic diversity as well as sensitivity to the fungicides carbendazim and prothioconazole

A simplified approach for producing Tier 2 enteric-methane emission factors based on East African smallholder farm data

Context: Accurate reporting of livestock greenhouse-gas (GHG) emissions is important in developing effective mitigation strategies, but the cost and labour requirements associated with on-farm data collection often prevent this effort in low- and middle-income countries. Aim: The aim of this study was to investigate the precision and accuracy of simplified activity data collection protocols in African smallholder livestock farms for country-specific enteric-methane emission factors. Method: Activity data such as live weight (LW), feed quality, milk yield, and milk composition were collected from 257 smallholder farms, with a total herd of 1035 heads of cattle in Nandi and Bomet counties in western Kenya. The data collection protocol was then altered by substituting the actual LW measurements with algorithm LW (ALG), feed quality (FQ) data being sourced from the Feedipedia database, reducing the need for daily milk yield records to a single seasonal milk measurement (MiY), and by using a default energy content of milk (MiE). Daily methane production (DMP) was calculated using these simplified protocols and the estimates under individual and combined protocols were compared with values derived from the published (PUBL) estimation protocol. Key results: Employing the algorithm LW showed good agreement in DMP, with only a small negative bias (7%) and almost no change in variance. Calculating DMP on the basis of Feedipedia FQ, by contrast, resulted in a 27% increase in variation and a 27% positive bias for DMP compared with PUBL. The substitutions of milk (MiY and MiE) showed a modest change in variance and almost no bias in DMP. Conclusion: It is feasible to use a simplified data collection protocol by using algorithm LW, default energy content of milk value, seasonal single milk yield data, but full sampling and analysis of feed resources is required to produce reliable Tier 2 enteric-methane emission factors. Implications: Reducing enteric methane emissions from the livestock is a promising pathway to reduce the effects of climate change, and, hence, the need to produce accurate emission estimates as a benchmark to measure the effectiveness of mitigation options. However, it is expensive to produce accurate emission estimates, especially in developing countries; hence, it is important and feasible to simplify on-farm data collection

A simplified approach for producing Tier 2 enteric methane emission factors based on East African smallholder farm data

Context: Accurate livestock greenhouse gas (GHG) emissions reporting is important in developing effective mitigation strategies, but the cost and labor requirements associated with on-farm data collection often prevent this effort in low-and-middle-income countries. Aim: The aim of this study was to investigate the precision and accuracy of simplified activity data collection protocols in African smallholder livestock farms for country-specific enteric methane emission factors. Method: Activity data such as live weight (LW), feed quality, milk yield, and milk composition were collected from 257 smallholder farms with a total herd of 1,035 heads of cattle in Nandi and Bomet counties in Western Kenya. The data collection protocol was then altered by substituting actual LW measurements with algorithm LW (ALG), feed quality (FQ) data sourced from the Feedipedia database, reducing the need for daily milk yield records to a single seasonal milk measurement (MiY), and using a default energy content of milk (MiE). Daily methane production (DMP) was calculated using these simplified protocols and the estimates under individual and combined protocols were compared with values derived from the published (PUBL) estimation protocol. Key results: Employing the algorithm LW showed good agreement in DMP with only a small negative bias (7%) and almost no change in variance. Calculating DMP based on Feedipedia FQ, by contrast, resulted in a 27% increase in variation and a 27% positive bias for DMP compared to PUBL. The substitutions of milk (MiY and MiE) showed a modest change in variance and almost no bias in DMP. Conclusion: It is feasible to use a simplified data collection protocol by using algorithm LW, default energy content of milk value, seasonal single milk yield data, but full sampling and analysis of feed resources is required to produce reliable Tier 2 enteric methane emission factors. Implications: Reducing enteric methane emissions from the livestock is a promising pathway to reduce the effects of climate change hence the need to produce accurate emissions estimates as benchmark to measure the effectiveness of mitigation options. However, it is expensive to produce accurate emission estimates especially in developing countries, hence important and feasible to simplify on-farm data collection

Dealing with a traumatic past: the victim hearings of the South African truth and reconciliation commission and their reconciliation discourse

In the final years of the twentieth and the beginning of the twenty-first century, there has been a worldwide tendency to approach conflict resolution from a restorative rather than from a retributive perspective. The South African Truth and Reconciliation Commission (TRC), with its principle of 'amnesty for truth' was a turning point. Based on my discursive research of the TRC victim hearings, I would argue that it was on a discursive level in particular that the Truth Commission has exerted/is still exerting a long-lasting impact on South African society. In this article, three of these features will be highlighted and illustrated: firstly, the TRC provided a discursive forum for thousands of ordinary citizens. Secondly, by means of testimonies from apartheid victims and perpetrators, the TRC composed an officially recognised archive of the apartheid past. Thirdly, the reconciliation discourse created at the TRC victim hearings formed a template for talking about a traumatic past, and it opened up the debate on reconciliation. By discussing these three features and their social impact, it will become clear that the way in which the apartheid past was remembered at the victim hearings seemed to have been determined, not so much by political concerns, but mainly by social needs

Farm-level emission intensities of smallholder cattle (Bos indicus; B. indicus–B. taurus crosses) production systems in highlands and semi-arid regions

Ruminants are central to the economic and nutritional life of much of sub-Saharan Africa, but cattle are now blamed for having a disproportionately large negative environmental impact through emissions of greenhouse gas (GHG). However, the mechanism underlying excessive emissions occurring only on some farms is imperfectly understood. Reliable estimates of emissions themselves are frequently lacking due to a paucity of reliable data. Employing individual animal records obtained at regular farm visits, this study quantified farm-level emission intensities (EIs) of greenhouse gases of smallholder farms in three counties in Western Kenya. CP was chosen as the functional unit to capture the outputs of both milk and meat. The results showed that milk is responsible for 80–85% of total CP output. Farm EI ranged widely from 20 to >1 000 kg CO$_{2}$-eq/kg CP. Median EIs were 60 (Nandi), 71 (Bomet), and 90 (Nyando) kg CO$_{2}$-eq/kg. Although median EIs referenced to milk alone (2.3 kg CO$_{2}$-eq/kg milk) were almost twice that reported for Europe, up to 50% of farms had EIs comparable to the mean Pan-European EIs. Enteric methane (CH$_{4}$) contributed >95% of emissions and manure ∼4%, with negligible emissions attributed to inputs to the production system. Collecting data from individual animals on smallholder farms enabled the demonstration of extremely heterogeneous EI status among similar geographical spaces and provides clear indicators on how low EI status may be achieved in these environments. Contrary to common belief, our data show that industrial-style intensification is not required to achieve low EI. Enteric CH$_{4}$ production overwhelmingly drives farm emissions in these systems and as this is strongly collinear with nutrition and intake, an effort will be required to achieve an “efficient frontier” between feed intake, productivity, and GHG emissions

POPULATION AND BREEDING OF THE GENTOO PENGUIN PYGOSCELIS PAPUA AT MARION ISLAND, 1994/95–2002/03

The numbers of gentoo penguins Pygoscelis papua breeding at subantarctic Marion Island fell by 40&#37 from 1994/95 to 2002/03, from 1 352 pairs to 806 pairs. Apart from a slight increase in 1998/99, there was a steady decrease in numbers breeding between 1995/96 and 2000/01, when the population stabilized. There is indication that in some years not all breeders nested and that some birds relocated to another colony after disturbance. From first clutches, pairs on average fledged between 0.01 chicks in 1997/98 and 0.58 chicks in 2002/03 (mean 0.38 &#177 0.21). In 1994/95, replacement clutches increased the overall production of fledged chicks by 11&#37. Based on demographic parameters measured at other localities, the production of chicks at Marion Island was inadequate to maintain the population during the period 1995/96–2000/01. Consistency in trends in breeding success at five colonies suggests that factors operating at a mesoscale, rather than those specific to particular colonies, often influenced breeding success. Laying was later than normal in 1997/98, when there was almost total breeding failure with large losses of eggs and small chicks to returning Subantarctic skuas Catharacta antarctica. Future research on this Near Threatened species at Marion Island must take full account of its susceptibility to human disturbance.Afr. J. mar. Sci. 25: 463–47

POPULATION, BREEDING, DIET AND CONSERVATION OF THE CROZET SHAG PHALACROCORAX [ATRICEPS] MELANOGENIS AT MARION ISLAND, 1994/95–2002/03

The number of Crozet shags or cormorants Phalacrocorax [atriceps] melanogenis breeding at subantarctic Marion Island decreased by 68&#37 from 841 pairs in 1994/95 to 272 pairs in 2002/03. The mean number of pairs at colonies also decreased and was significantly related to the overall number of birds breeding in any given season. The decreases coincided with a period of warming and reduced precipitation at Marion Island and with a decrease in the number of gentoo penguins Pygoscelis papua breeding there. Both these seabird species forage inshore and there is considerable overlap in their diets. Nototheniid fish and the decapod Nauticaris marionis continued to be important in the diet of Crozet shags, but a change in dominance among nototheniid prey suggests availability of prey to shags changed after the mid 1980s. Crozet shags breed for the first time when aged three years. It is probable that about 25&#37 of the mature population did not breed in 1997/98, coincident with a strong El Niño Southern Oscillation event. In four seasons, breeding pairs on average fledged 0.30 chicks from first clutches, an amount thought inadequate to sustain the population. Crozet shags at the Prince Edward Islands should now be regarded as Endangered. Placing breeding colonies in the most highly protected zone on Marion Island, considering the establishment of an ex situ population and undertaking a genetic study of the specific status of the Crozet shag are recommended conservation measures.Afr. J. mar. Sci. 25: 537–54

Genetic analysis of Pyrenopeziza brassicae, cause of light leaf spot of brassicas, in the European Union, Oceania, and North America

Light leaf spot (LLS), caused by Pyrenopeziza brassicae, is an important disease of Brassica napus (canola and oilseed rape) and B. oleracea (vegetable brassicas) in Europe (EU) as well as New Zealand and Australia (Oceania, OC). LLS was first reported in North America (NA) on B. juncea, B. napus, and B. rapa in six counties in western Oregon in 2014; and on B. juncea cover crops and wild B. rapa in three counties in northwestern Washington in 2016. Multi-locus sequence analysis (ITS ribosomal DNA, beta-tubulin, and elongation factor 1-α sequences) and comparison of the mating type genes (MAT1-1 and MAT1-2) grouped isolates from the EU (n = 28) and OC (n = 4) with the P. brassicae type specimen, IMI 204290, whereas isolates from NA (n = 16) represented a novel genotype. Sexual compatibility of NA and EU strains of complementary MAT1-1 and MAT1-2 genotypes is being determined to assess if NA isolates represent a distinct evolutionary lineage or a cryptic sibling species. Fungicide resistance has been documented in some EU populations of P. brassicae, but none of the NA isolates possessed amino acid substitutions E198A and L240F in the beta-tubulin sequences that confer resistance to benzimidazole fungicides; comparison of these sequences for the NA isolates revealed 100% identity to wild type EU P. brassicae isolates and the closely related fungus Rhynchosporium commune; and 98 and 99% identities to Sclerotinia sclerotiorum and Venturia inaequalis, respectively

Serum progesterone as an indicator of cyclic activity in post-partum goat does

___________________________________________________________________________________ Abstract The aim of this trial was to assess post-partum ovarian activity of the does of two South African goat breeds from their serum progesterone concentrations. Between seven and 100 days post-partum, does from the Boer goat breed and an indigenous rural goat type were allocated to two nutritional treatments within breed. One group per breed received a concentrated diet in an intensive feeding programme. The other group per breed was subjected to a low level of nutrition through the grazing of the natural pasture in an extensive (veld) grazing system. Blood samples were collected weekly from five does per breed per treatment. Serum progesterone concentrations were determined using a Gamma Coat TM [128] progesterone radioimmunoassay kit (Sorin Diagnostics, France). Large variations in serum progesterone concentrations were recorded within and between breeds and nutritional regimens. Irrespective of breed, in the extensive groups subjected to the low level of nutrition, mean peak serum progesterone concentrations never exceeded 0.2 ng/mL. This suggests that throughout the experimental period, ovarian activity remained low in the extensive groups. It was concluded that nutritional regimen plays a significant role in ensuring high ovarian activities. Furthermore, the higher mean serum progesterone levels in the Boer goat indicate an earlier and higher oestrous activity, compared to the indigenous does. __________________________________________________________________________________

Distinct degassing pulses during magma invasion in the stratified Karoo Basin – New insights from hydrothermal fluid flow modelling

Magma emplacement in organic‐rich sedimentary basins is a main driver of past environmental crises. Using a 2D numerical model, we investigate the process of thermal cracking in contact aureoles of cooling sills and subsequent transport and emission of thermogenic methane by hydrothermal fluids. Our model includes a Mohr‐Coulomb failure criterion to initiate hydrofracturing and a dynamic porosity/permeability. We investigate the Karoo Basin, taking into account host‐rock material properties from borehole data, realistic total organic carbon content, and different sill geometries. Consistent with geological observations, we find that thermal plumes quickly rise at the edges of saucer‐shaped sills, guided along vertically fractured high permeability pathways. Contrastingly, less focused and slower plumes rise from the edges and the central part of flat‐lying sills. Using a novel upscaling method based on sill‐to‐sediment ratio we find that degassing of the Karoo Basin occurred in two distinct phases during magma invasion. Rapid degassing triggered by sills emplaced within the top 1.5 km emitted ~1.6·103 Gt of thermogenic methane, while thermal plumes originating from deeper sills, carrying a 12‐times greater mass of methane, may not reach the surface. We suggest that these large quantities of methane could be re‐mobilized by the heat provided by neighboring sills. We conclude that the Karoo LIP may have emitted as much as ~22.3·103 Gt of thermogenic methane in the half million years of magmatic activity, with emissions up to 3 Gt/year. This quantity of methane and the emission rates can explain the negative δ13C excursion of the Toarcian environmental crisis. Key Points Sill geometry and emplacement depth as well as intruded host rock type are the main factors controlling methane mobilization and degassing Dehydration‐related porosity increase and pore‐pressure‐induced hydrofracturing are important mechanisms for a quick transport of methane from sill to the surface The Karoo Basin may have degassed ~22.3·103 Gt of thermogenic methane in the half million years of magmatic activit