20 research outputs found
Killer whales and marine mammal trends in the North Pacific : a re-examination of evidence for sequential megafauna collapse and the prey-switching hypothesis
This paper is not subject to U.S. copyright. The definitive version was published in Marine Mammal Science 23 (2007): 766–802, doi:10.1111/j.1748-7692.2006.00093.x.Springer et al. (2003) contend that sequential declines occurred in North Pacific populations of harbor and fur seals, Steller sea lions, and sea otters. They hypothesize that these were due to increased predation by killer whales, when industrial whaling's removal of large whales as a supposed primary food source precipitated a prey switch. Using a regional approach, we reexamined whale catch data, killer whale predation observations, and the current biomass and trends of potential prey, and found little support for the prey-switching hypothesis. Large whale biomass in the Bering Sea did not decline as much as suggested by Springer et al., and much of the reduction occurred 50–100 yr ago, well before the declines of pinnipeds and sea otters began; thus, the need to switch prey starting in the 1970s is doubtful. With the sole exception that the sea otter decline followed the decline of pinnipeds, the reported declines were not in fact sequential. Given this, it is unlikely that a sequential megafaunal collapse from whales to sea otters occurred. The spatial and temporal patterns of pinniped and sea otter population trends are more complex than Springer et al. suggest, and are often inconsistent with their hypothesis. Populations remained stable or increased in many areas, despite extensive historical whaling and high killer whale abundance. Furthermore, observed killer whale predation has largely involved pinnipeds and small cetaceans; there is little evidence that large whales were ever a major prey item in high latitudes. Small cetaceans (ignored by Springer et al.) were likely abundant throughout the period. Overall, we suggest that the Springer et al. hypothesis represents a misleading and simplistic view of events and trophic relationships within this complex marine ecosystem
Crop Updates 2007 - Weeds
This session covers thirty two papers from different authors:
1. ACKNOWLEDGEMENTS, Alexandra Douglas CONVENOR – WEEDS DEPARTMENT OF AGRICULTURE AND FOOD
WILD RADISH MANAGEMENT
2. Decimate a wild radish seed bank in five years, Peter Newman, Sally Peltzer, Abul Hashem and Aik Cheam, Department of Agriculture and Food
3. High level of seed-set control in wild radish is achievable, Aik Cheam and Siew Lee,Department of Agriculture and Food
4. Wild radish: Best management practice, Aik Cheam and Siew Lee, Department of Agriculture and Food
5. Control of phenoxy resistant wild radish through the combined effects of wheat competition and phenoxy herbicides, Natalie Maguire and Michael Walsh, WAHRI, School of Plant Biology, University of Western Australia
6.Efficacy of florasulam on chlorsulfuron resistant and susceptible wild radish populations in Western Australia, Michael Walsh1 and Dan Cornally2, 1WAHRI, School of Plant Biology, University of Western Australia, 2Dow Agrosciences Australia
7. Does liming to increase soil pH limit the growth and development of wild radish (Raphanus raphanistrum)Matt Willis and Michael Walsh, WAHRI, School of Plant Biology, University of Western Australia
IWM TECHNIQUES AND SEEDBANKS
8. Weed trimming – a potential technique to reduce weed seed set, Glen Riethmuller, Abul Hashem and Shahab Pathan, Department of Agriculture and Food
9. Burn narrow windrows in the wind, Peter Newman1and Michael Walsh2, 1Department of Agriculture and Food, 2Research Fellow, WA Herbicide Resistance Initiative
10. Winning the Weed War with the Weed Seed Wizard! Michael Renton, Sally Peltzer and Art Diggle, Department of Agriculture and Food
HERBICIDE RESISTANCE AND GENE FLOW
11. Frequency of herbicide resistance in wild oat (Avena fatua) across the Western Australian wheatbelt, Mechelle Owen and Stephen Powles, WA Herbicide Resistance Initiative, School of Plant Biology, University of Western Australia
12. Pollen mediated gene flow of herbicide resistance can occur over long distances doe annual ryegrass (Lolium rigidum): Results of two years with different meteorological conditions, Roberto Busi, Robert Barrett-Lennard and Stephen B. Powles, Western Australian Herbicide Resistance Initiative, School of Plant Biology – University of Western Australia
13. Doublegee has developed resistance to metsulfuron-methyl within WA wheatbelt, Dr Abul Hashem1and Dr Shahab Pathan2, 1Senior Research Officer, and 2Research Officer, Department Agriculture and Food
14. Another case of glyphosate resistance in annual ryegrass confirmes within Western Australia, Dr Abul Hashem1and Dr Shahab Pathan2, 1Senior Research Officer, and 2Research Officer, Department Agriculture and Food
15. Glyphosate resistance in the northern NSW – implications for Western Australian farming systems, Andrew Storrie, Tamworth Agricultural Institute, NSW Department of Primary Industries
ALTERNATIVES TO TRIFLURALIN, KNOCKDOWNS, TANK MIXES AND NOVEL USES
16. Alternative pre-emergent herbicides to trifluralin for annual ryegrass control, Mr David Minkey and Dr Abul Hashem, Department of Agriculture and Food,
17. Evaluation of a new pre-emergent herbicide alternative dor the control of trifluralin resistant Lolium rigidum Gaudin (annual ryegrass) in wheat and barley, Craig A. Ruchs, Syngenta Crop Protection Australia Pty Ltd and Dr Peter Boutsalis, University of Adelaide
18. Novel knockdown tank mixes: Results from 12 trials over four years, Shahab Pathan1, Abul Hashem2, Catherine Borger3, Nerys Wilkins and Julie Roche, Department of Agriculture and Food, Western Australia, and 3the University of Western Australia
19. Alternative herbicides for weed control in lupins, Peter Newman and Martin Harries, Department of Agriculture and Food
20. Novel use application of clopyealid in lupins, John Peirce, and Brad Rayner, Department of Agriculture and Food
21. A model to predict grass selective herbicide rates, John Moore, Department of Agriculture and Food
CROP AND WEED MANAGEMENT
22. Inter-row weed control in wide row lupin using knockdown-based tank mixes, Dr Abul Hashem1, Ray Fulwood2 and Chris Roberts3, 1Senior Research Officer, Department of Agriculture and Food, 2Farmer, Meckering, WA, 3Technical Officer, Department of Agriculture and Food
23. Timing of weed removal in wide-row lupins, Sally Peltzer, Shahab Pathan and Paul Matson, Department of Agriculture and Food
24. The effect of row spacing and crop density on competitiveness of lupins with wild radish, Bob French and Laurie Maiolo, Department of Agriculture and Food
25. Is delayed sowing a good strategy for weed management in lupins? Bob French, Department of Agriculture and Food
26. Delayed sowing as a strategy to manage annual ryegrass, Department of Agriculture and Food
HERBICIDE TOLERANCE
27. The effect of herbicides on nodulation in lupins, Lorne Mills1, Harmohinder Dhammu2 and Beng Tan1, 1Curtin University of Technology, and 2Department of Agriculture and Food
28. Response of new wheat varieties to herbicides, Harmohinder Dhammu, Department of Agriculture and Food
29. Herbicide tolerance of new barley varieties, Harmohinder Dhammu, Vince Lambert and Chris Roberts, Department of Agriculture and Food
30. Herbicide tolerance of new oat varieties, Harmohinder Dhammu, Vince Lambert and Chris Roberts, Department of Agriculture and Food
OTHER WEEDY MATTERS
31. Research and extension need for wild radish and other cruciferous weeds, Aik Cheam, Department of Agriculture and Food
32. e-weed – an information resource of seasonal weed management issues, Vanessa Stewartand Julie Roche, Department of Agriculture and Foo
Evaluation of 22 genetic variants with Crohn's Disease risk in the Ashkenazi Jewish population: a case-control study
<p>Abstract</p> <p>Background</p> <p>Crohn's disease (CD) has the highest prevalence among individuals of Ashkenazi Jewish (AJ) descent compared to non-Jewish Caucasian populations (NJ). We evaluated a set of well-established CD-susceptibility variants to determine if they can explain the increased CD risk in the AJ population.</p> <p>Methods</p> <p>We recruited 369 AJ CD patients and 503 AJ controls, genotyped 22 single nucleotide polymorphisms (SNPs) at or near 10 CD-associated genes, <it>NOD2</it>, <it>IL23R</it>, <it>IRGM</it>, <it>ATG16L1</it>, <it>PTGER4</it>, <it>NKX2-3</it>, <it>IL12B</it>, <it>PTPN2</it>, <it>TNFSF15 </it>and <it>STAT3</it>, and assessed their association with CD status. We generated genetic scores based on the risk allele count alone and the risk allele count weighed by the effect size, and evaluated their predictive value.</p> <p>Results</p> <p>Three <it>NOD2 </it>SNPs, two <it>IL23R </it>SNPs, and one SNP each at <it>IRGM </it>and <it>PTGER4 </it>were independently associated with CD risk. Carriage of 7 or more copies of these risk alleles or the weighted genetic risk score of 7 or greater correctly classified 92% (allelic count score) and 83% (weighted score) of the controls; however, only 29% and 47% of the cases were identified as having the disease, respectively. This cutoff was associated with a >4-fold increased disease risk (p < 10e-16).</p> <p>Conclusions</p> <p>CD-associated genetic risks were similar to those reported in NJ population and are unlikely to explain the excess prevalence of the disease in AJ individuals. These results support the existence of novel, yet unidentified, genetic variants unique to this population. Understanding of ethnic and racial differences in disease susceptibility may help unravel the pathogenesis of CD leading to new personalized diagnostic and therapeutic approaches.</p
Crop Updates 2001 - Weeds
This session covers forty six papers from different authors:
1. INTRODUCTION, Vanessa Stewart, Agriculture Western Australia
PLENARY
2. Wild radish – the implications for our rotations, David Bowran, Centre for Cropping Systems
INTEGRATED WEED MANAGEMENT
IWM system studies/demonstration sites
3. Integrated weed management: Cadoux, Alexandra Wallace, Agriculture Western Australia
4. A system approach to managing resistant ryegrass, Bill Roy, Agricultural Consulting and Research Services Pty Ltd, York
5. Long term herbicide resistance demonstration, Peter Newman, Agriculture Western Australia, Cameron Weeks, Tony Blake and Dave Nicholson
6. Integrated weed management: Katanning, Alexandra Wallace, Agriculture Western Australia
7. Integrated weed management: Merredin, Vanessa Stewart, Agriculture Western Australia
8. Short term pasture phases for weed control, Clinton Revell and Candy Hudson, Agriculture Western Australia
Weed biology – implications for IWM
9. Competitivness of wild radish in a wheat-lupin rotation , Abul Hashem, Nerys Wilkins, and Terry Piper, Agriculture Western Australia
10. Population explosion and persistence of wild radish in a wheat-lupin rotation, Abul Hashem, Nerys Wilkins, Aik Cheam and Terry Piper , Agriculture Western Australia
11. Variation is seed dormancy and management of annual ryegrass, Amanda Ellery and Ross Chapman, CSIRO
12. Can we eradicate barley grass, Sally Peltzer, Agriculture Western Australia
Adoption and modelling
13. Where to with RIM? Vanessa Stewart1 and Robert Barrett-Lennard2, 1Agriculture Western Australia, 2Western Australian Herbicide Resistance Initiative (WAHRI)
14. Multi-species RIM model, Marta Monjardino1,2, David Pannell2 and Stephen Powles1 1Western Australian Herbicide Resistance Initiative (WAHRI), 2ARE, University of Western Australia
15. What causes WA grain growers to adopt IWM practices? Rick Llewellyn, WAHRI/ARE, Faculty of Agriculture, University of WA
New options for IWM?
16. Fuzzy tramlines for more yield and less weeds, Paul Blackwell Agriculture Western Australia, and Maurice Black, Harbour Lights Estate, Geraldton
17. Inter-row knockdowns for profitable lupins, Paul Blackwell, Agriculture Western Australia and Miles Obst, Farmer Mingenew
18. Row cropping and weed control in lupins, Mike Collins and Julie Roche, Agriculture Western Australia
19. Cross seedimg suppresses annual ryegrass and increases wheat yield, Abul Hashem, Dave Nicholson and Nerys Wilkins Agriculture Western Australia
20. Weed control by chaff burial, Mike Collins, Agriculture Western Australia
HERBICIDE RESISTANCE
21. Resistance in wild oats to Fop and Dim herbicides in Western Australia, Abul Hashem and Harmohinder Dhammu, Agriculture Western Australia
22. Triazine and diflufenican resistance in wild radish: what it means to the lupin industry, Aik Cheam, Siew Lee, David Nicholson and Peter Newman, Agriculture Western Australia
23. Comparison if in situ v seed testing for determining herbicide resistance, Bill Roy, Agricultural Consulting and Research Services Pty Ltd, York
HERBICIDE TOLERANCE
24. Phenoxy herbicide tolerance of wheat, Peter Newman and Dave Nicholson, Agriculture Western Australia
25. Tolerance of wheat to phenoxy herbicides, Harmohinder S. Dhammu, Terry Piper and Mario F. D\u27Antuono, Agriculture Western Australia
26. Herbicide tolerance of new wheats, Harmohinder S. Dhammu, Terry Piper and David F. Nicholson, Agriculture Western Australia
27. Herbicide tolerance of durum wheats, Harmohinder S. Dhammu, Terry Piper and David F. Nicholson, Agriculture Western Australia
28. Herbicide tolerance of new field pea varieties, Harmohinder S. Dhammu, Terry Piper, David F. Nicholson, and Mario F. D\u27Antuono, Agriculture Western Australia
29. Herbicide tolerance of Cooke field peas on marginal soil, Harmohinder S. Dhammu, Terry Piper, David F. Nicholson, and Mario F. D\u27Antuono, Agriculture Western Australia
30. Herbicide tolerance of some annual pasture legumes adapted to coarse textured sandy soils, Clinton Revell and Ian Rose, Agriculture Western Australia
31 Herbicide tolerance of some annual pasture legumes adapted to fine textured clay soils, Clinton Revell and Ian Rose, Agriculture Western Australia
WEED CONTROL IN LUCERNE
32. Management of weeds for Lucerne establishment, Diana Fedorenko, Clayton Butterly, Stuart McAlpine, Terry Piper and David Bowran, Centre for Cropping Systems, Agriculture Western Australia
33. Management of weeds in the second year of Lucerne, Diana Fedorenko, Clayton Butterly, Stuart McAlpine, Terry Piper and David Bowran, Centre for Cropping Systems, Agriculture Western Australia
34. Residual effects of weed management in the third year of Lucerne, Diana Fedorenko, Clayton Butterly, Stuart McAlpine, Terry Piper and David Bowran, Centre for Cropping Systems, Agriculture Western Australia
35. Herbicide tolerance and weed control in Lucerne, Peter Newman, Dave Nicholson and Keith Devenish Agriculture Western Australia
HERBICIDES – NEW PRODUCTS/PRODUCE USES; USE
New products or product use
36. New herbicide options for canola, John Moore and Paul Matson, Agriculture Western Australia
37. Chemical broadleaf weed management in Peaola, Shannon Barraclough and Lionel Martin, Muresk Institute of Agriculture, Curtin University of Technology
38. Balance® - a new broad leaf herbicide for the chickpea industry, Mike Clarke, Jonas Hodgson and Lawrence Price, Aventis CropScience
39. Marshmallow – robust herbicide strategies, Craig Brown, IAMA Agribusiness
40. Affinity DF – a prospective option for selective in-crop marshmallow control, Gordon Cumming, Technical Officer, Crop Care Australasia
41. A new formulation of Carfentrazone-ethyl for pre-seeding knockdown control of broadleaved weeds including Marshmallow, Gordon Cumming, Technical Officer, Crop Care Australasia
Herbicide use
42. Autumn applied trifluralin can be effective! Bill Crabtree, Scientific Officer, Western Australian No-Tillage Farmers Association
43. Which knockdown herbicide for small ryegrass? Peter Newman and Dave Nicholson, Agriculture Western Australia
44. Poor radish control with Group D herbicides in lupins, Peter Newman and Dave Nicholson, Agriculture Western Australia
WEED ISSUES
45. Distribution and incidence of aphids and barley yellow dwarf virus in over-summering grasses in the WA wheatbelt, Jenny Hawkes and Roger Jones, CLIMA and Agriculture Western Australia
46. e-weed, Vanessa Stewart, Agriculture Western Australia
CONTRIBUTING AUTHOR CONTACT DETAIL
Crop Updates 2002 - Weeds
This session covers fifty eight papers from different authors:
1. INTRODUCTION Vanessa Stewart, DEPARTMENT OF AGRICULTURE
INTEGRATED WEED MANAGEMENT
IWM system studies / demonstration sites
2. Major outcomes from IWM demonstration sites, Alexandra Douglas Department of Agriculture
3. Integrated weed management: Katanning, Alexandra Douglas Department of Agriculture
4. Integrated weed management: Merredin, Vanessa Stewart Department of Agriculture
5. Long term resistance site: Get ryegrass numbers low and keep them low! Peter Newman and Glen Adams Department of Agriculture
6. Using pastures to manage ryegrass populations, Andrew Blake and Natalie Lauritsen Department of Agriculture
Weed biology and competition
7. Understanding the weed seed bank life if important agricultural weeds, Sally Peltzer and Paul Matson Department of Agriculture
8. Consequence of radish competition on lupin nutrients in wheat-lupin rotation, Abul Hashem and Nerys Wilkins Department of Agriculture
9. Consequence of ryegrass competition on lupin nutrients in a wheat-lupin rotation, Abul Hashem and Nerys Wilkins Department of Agriculture
10. Brome grass too competitive for early sown wheat in a dry year at Mullewa, Peter Newman and Glenn Adam Department of Agriculture
Crop establishment and weed management
11. Seeding rate, row spacing and herbicides for weed control, David Minkey Department of Agriculture
12. Effect of different seeding methods on wheat and ryegrass, Abul Hashem, Glen Riethmuller and Nerys Wilkins Department of Agriculture
13. Role of tillage implements and trifluralin on the effectiveness of the autumn tickle for stimulating annual ryegrass emergence, Tim Cusack1, Kathryn Steadman1 and Abul Hashem2,1Western Australia Herbicide Resistance Initiative, UWA; 2Department of Agriculture,
14. Timing of autumn tickle in important for non-wetting soils, Pippa Michael1, Peter Newman2 and Kathryn Steadman 2, 1Western Australia Herbicide Resistance Initiative, UWA, 2Department of Agriculture
15. Early investigation into weed seed burial by mouldboard plough, Sally Peltzer and Alex Douglas Department of Agriculture
16. Rolling post-emergent lupins to improve weed emergence and control on loamy sand, Paul Blackwell, Department of Agriculture and Dave Brindal, Strawberry via Mingenew
IWM tools
17. Crop topping in 2001: How did we do? Peter Newman and Glenn Adam Department of Agriculture
18. Wickwipers work! Peter Newman and Glenn Adam Department of Agriculture
19. Wild radish and ryegrass seed collection at harvest: Chaff carts and other devices, Michael Walsh Western Australia Herbicide Resistance Initiative, UWA and Wayne Parker Department of Agriculture
20. Improving weed control in grazed pastures using legumes with low palatability, Clinton Revell, Giles Glasson Department of Agriculture, and Dean Thomas Faculty of Agriculture, University of Western Australia
Adoption and modelling
21. Grower weed survey, Peter Newman and Glenn Adam Department of Agriculture
22. Agronomist survey, Peter Newman and Glenn Adam Department of Agriculture
23. Ryegrass RIM model stands the test of IWM field trial data, Alister Draper Western Australia Herbicide Resistance Initiative, UWA and Bill Roy, Western Australia Herbicide Resistance Initiative, UWA Agricultural Consulting and Research Services
24. Multi-species RIM: An update, Marta Monjardin1,2, David Pannell2 and Stephen Powles 1, 1Western Australia Herbicide Resistance Initiative, UWA, 2 ARE, University of Western Australia
25. RIM survey feedback, Robert Barrett-Lennard and Alister Draper Western Australia Herbicide Resistance Initiative, UWA
26. Effect of historic input and product prices on choice of ryegrass management strategies, Alister Draper1 and Martin Bent2, 1Western Australia Herbicide Resistance Initiative, UWA, 2Muresk Institute of Agriculture
27. Living with ryegrass – trading off weed control and economic performance, Martin Bent1 and Alister Draper2 , 1Muresk Institute of Agriculture, Curtin University, 2Western Australia Herbicide Resistance Initiative, UWA
HERBICIDE RESISTANCE
28. Glyphosate resistance in WA and Australia: Where are we at? Paul Neve1, Art Diggle2, Patrick Smith3, Mechelle Owen1, Abul Hashem2, Christopher Preston4and Stephen Powles1,1Western Australian Herbicide Resistance Initiative, University of Western Australia, 2Department of Agriculture, 3CSIRO Sustainable Ecosystems, 4CRC for Australian Weed Management and Department of Applied and Molecular Ecology, Waite Campus, University of Adelaide
29. We need you weeds: A survey of knockdown resistance in the WA wheatbelt, Paul Neve1, Mechelle Owen1, Abul Hashem2 and Stephen Powles1 1Western Australian Herbicide Resistance Initiative, University of Western Australia, 2Department of Agriculture
30. A test for resistance testing, Mechelle Owen, Tracey Gillam, Rick Llewellyn and Steve Powles,Western Australia Herbicide Resistance Initiative, University of Western Australia
31. In field testing for herbicide resistance, a purpose built multi-treatment spray boom with results from 2001, Richard Quinlan, Elders Ltd
32. Advantages and limitations of a purpose built multi-treatment spray boom, Richard Quinlan, Elders Ltd
33. Group F resistant wild radish: What’s new? Aik Cheam, Siew Lee Department of Agriculture, and Mike Clarke Aventis Crop Science
34. Cross resistance of Brodal® resistant wild radish to Sniper®, Aik Cheam and Siew Lee, Department of Agriculture
35. Managing a biotype of wild radish with Group F and Group C resistance, Aik Cheam, Siew Lee, David Nicholson, Peter Newman Department of Agriculture and Mike Clarke, Aventis Crop Science
HERBICIDE TOLERANCE
36. Herbicide tolerance of new wheat varieties, Harmohinder S. Dhammu, Terry Piper and David Nicholson, Agriculture Western Australia
37. Response of barley varieties to herbicides, Harmohinder S. Dhammu, Terry Piper, Department of Agriculture
38. Tolerance of barley to phenoxy herbicides, Harmohinder S. Dhammu, Terry Piper, Department of Agriculture and Chad Sayer, Nufarm Australia Limited
39. Response of Durum wheats to herbicides, Harmohinder S. Dhammu, Terry Piper, Department of Agriculture
40. Response of new field pea varieties to herbicides, Harmohinder S. Dhammu, Terry Piper and David Nicholson, Department of Agriculture
41. Herbicide tolerance of Desi chickpeas on marginal soil, Harmohinder S. Dhammu, Terry Piper and David Nicholson, Department of Agriculture
42. Herbicide tolerance of newer lupin varieties, Terry Piper, Harmohinder Dhammu and David Nicholson, Department of Agriculture
43. Herbicide tolerance of some annual pasture legumes, Clinton Revell and Ian Rose, Department of Agriculture
44. Herbicide tolerance of pasture legumes, Andrew Blake, Department of Agriculture
HERBICIDES – NEW PRODUCTS/PRODUCT USES; USE
45. Knockdown herbicides do not reliably kill small grass weeds, Peter Newman and Glenn Adam, Department of Agriculture
46. ‘Hair Cutting’ wheat with Spray.Seed®: Does it work? Peter Newman and Glenn Adam, Department of Agriculture
47. ‘Haircutting’: Does the number one cut work? Robert Barrett-Lennard1 and Jerome Critch2,1WA Herbicide Resistance Initiative, University of WA, 2Student, University of WA
48. Hammer EC (Carfentrazone-ethyl): A mixing partner for glyphosate to enhance the control of difficult broadleaf weeds, Gordon R. Cumming, Crop Care Australasia
49. Marshmallow control in reduced tillage systems, Sam Taylor, Wesfarmers Landmark
50. Herbicide options for summer germinating marshmallow, Vanessa Stewart, Department of Agriculture
51. Dual Gold® safe in a dry year at Coorow, Peter Newman and Glenn Adam, Department of Agriculture
52. The effect of glyphosate, paraquat and diquat as a crop topping application on the germination of barley, John Moore and Roslyn Jettner, Department of Agriculture
53. Herbicide options for melon control, Vanessa Stewart, Department of Agriculture
54. Herbicide options for the control of Chloris truncate (windmill grass) Vanessa Stewart, Department of Agriculture
55. Allelopathic effects of crop, pasture and weed residues on subsequent crop and pasture establishment, Stuart Bee1, Lionel Martin1, Keith Devenish2 and Terry Piper2, 1Muresk Institute of Agriculture, Curtin University of Technology, Northam, Western Australia, 2Centre for Cropping Systems, Department of Agriculture
WEED ISSUES
56. Role of Roundup ReadyÒ canola in the farming system, Art Diggle1, Patrick Smith2, Paul Neve3, Felicity Flugge4, Amir Abadi5 and Stephen Powles3, 1Department of Agriculture; 2CSIRO, Sustainable Ecosystems; 3Western Australian Herbicide Resistance Initiative; 4Centre for Legumes in Mediterranean Agriculture; 5Touchstone Consulting
57. ’Weeds for Feed’ and livestock enterprise structures: A feasibility study and farmer survey in the north-easern wheatbelt, Duncan Peter and Stuart McAlpine, Department of Agriculture and Liebe Group, Buntine
58. e-weed, Vanessa Stewart, Agriculture Western Australi
The Use of Carcasses for the Analysis of Cetacean Population Genetic Structure: A Comparative Study in Two Dolphin Species
Advances in molecular techniques have enabled the study of genetic diversity and population structure in many different contexts. Studies that assess the genetic structure of cetacean populations often use biopsy samples from free-ranging individuals and tissue samples from stranded animals or individuals that became entangled in fishery or aquaculture equipment. This leads to the question of how representative the location of a stranded or entangled animal is with respect to its natural range, and whether similar results would be obtained when comparing carcass samples with samples from free-ranging individuals in studies of population structure. Here we use tissue samples from carcasses of dolphins that stranded or died as a result of bycatch in South Australia to investigate spatial population structure in two species: coastal bottlenose (Tursiops sp.) and short-beaked common dolphins (Delphinus delphis). We compare these results with those previously obtained from biopsy sampled free-ranging dolphins in the same area to test whether carcass samples yield similar patterns of genetic variability and population structure. Data from dolphin carcasses were gathered using seven microsatellite markers and a fragment of the mitochondrial DNA control region. Analyses based on carcass samples alone failed to detect genetic structure in Tursiops sp., a species previously shown to exhibit restricted dispersal and moderate genetic differentiation across a small spatial scale in this region. However, genetic structure was correctly inferred in D. delphis, a species previously shown to have reduced genetic structure over a similar geographic area. We propose that in the absence of corroborating data, and when population structure is assessed over relatively small spatial scales, the sole use of carcasses may lead to an underestimate of genetic differentiation. This can lead to a failure in identifying management units for conservation. Therefore, this risk should be carefully assessed when planning population genetic studies of cetaceans
Recommended from our members
What can Captive Whales tell us About their Wild Counterparts? Identification, Usage, and Ontogeny of Contact Calls in Belugas (Delphinapterus leucas)
Contact calls are ubiquitous in social birds and mammals. Belugas are among the most vocal of cetaceans, but the function of their calls is poorly understood. In a previous study we hypothesized that a broad band pulsed call type labeled “Type A,” serves as a contact call between mothers and their calves. Here we examined context-specific use of call types recorded from a captive beluga social group at the Vancouver Aquarium, and found that the Type A call comprised 24% to 97% of the vocalizations during isolation, births, death of a calf, presence of external stressors, and re-union of animals after separation. In contrast it comprised 4.4% of the vocalizations produced during regular sessions. We grouped 2835 Type A calls into five variants, A1 to A5. A discriminant function analysis classified 87% of calls in the same groupings that we assigned them to by ear and visual examination of spectrograms. The variants do not represent individual signatures. One variant, A1, was used by three related individuals: an adult female, her male calf and his juvenile half-sister. Our previous research documented the gradual development of the A1 variant by the male calf, until at 20 months he was producing stereotyped renditions of his mother and sister’s A1. We used our findings to generate testable predictions about the usage of these signals by wild belugas. We verified the existence of signals with the same distinctive features as the contact calls found in captivity in the repertoire of St. Lawrence Estuary herds, and documented their usage by two wild individuals from different populations. In the St. Lawrence, these were emitted by a female calling after a dead-calf. In Hudson Bay, by a temporarily restrained juvenile. We propose that these calls function in nature, a sin captivity, to maintain group cohesion, and that the variants shared by related animals are used for mother-calf recognition
Recommended from our members
What can Captive Whales tell us About their Wild Counterparts? Identification, Usage, and Ontogeny of Contact Calls in Belugas (Delphinapterus leucas)
Contact calls are ubiquitous in social birds and mammals. Belugas are among the most vocal of cetaceans, but the function of their calls is poorly understood. In a previous study we hypothesized that a broad band pulsed call type labeled “Type A,” serves as a contact call between mothers and their calves. Here we examined context-specific use of call types recorded from a captive beluga social group at the Vancouver Aquarium, and found that the Type A call comprised 24% to 97% of the vocalizations during isolation, births, death of a calf, presence of external stressors, and re-union of animals after separation. In contrast it comprised 4.4% of the vocalizations produced during regular sessions. We grouped 2835 Type A calls into five variants, A1 to A5. A discriminant function analysis classified 87% of calls in the same groupings that we assigned them to by ear and visual examination of spectrograms. The variants do not represent individual signatures. One variant, A1, was used by three related individuals: an adult female, her male calf and his juvenile half-sister. Our previous research documented the gradual development of the A1 variant by the male calf, until at 20 months he was producing stereotyped renditions of his mother and sister’s A1. We used our findings to generate testable predictions about the usage of these signals by wild belugas. We verified the existence of signals with the same distinctive features as the contact calls found in captivity in the repertoire of St. Lawrence Estuary herds, and documented their usage by two wild individuals from different populations. In the St. Lawrence, these were emitted by a female calling after a dead-calf. In Hudson Bay, by a temporarily restrained juvenile. We propose that these calls function in nature, a sin captivity, to maintain group cohesion, and that the variants shared by related animals are used for mother-calf recognition
Combining Cochlear Analysis and Auditory Evoked Potentials in a Beluga Whale With High-Frequency Hearing Loss
International audienceCorrelations between inner ear morphology and auditory sensitivity in the same individual are extremely difficult to obtain for stranded cetaceans. Animals in captivity and rehabilitation offer the opportunity to combine several techniques to study the auditory system and cases of hearing impairment in a controlled environment. Morphologic and auditory findings from two beluga whales (Delphinapterus leucas) in managed care are presented. Cochlear analysis of a 21-year-old beluga whale showed bilateral high-frequency hearing loss. Specifically, scanning electron microscopy of the left ear revealed sensory cell death in the first 4.9 mm of the base of the cochlea with scar formation. Immunofluorescence microscopy of the right ear confirmed the absence of hair cells and type I afferent innervation in the first 6.6 mm of the base of the cochlea, most likely due to an ischemia. Auditory evoked potentials (AEPs) measured 1.5 years prior this beluga's death showed a generalized hearing loss, being more pronounced in the high frequencies. This individual might have had a mixed hearing loss that would explain the generalized hearing impairment. Conversely, based on AEP evaluation, her mother had normal hearing and subsequent cochlear analysis did not feature any apparent sensorineural pathology. This is believed to be the first study to compare two cochlear analysis techniques and hearing sensitivity measurements from AEPs in cetaceans. The ability to combine morphological and auditory data is crucial to validate predictions of cochlear frequency maps based on morphological features. In addition, our study shows that these three complementary analysis techniques lead to comparable results, thus improving our understanding of how hearing impairment can be detected in stranding cases