scholarly journals Population Dynamics of Aerial and Terrestrial Populations of Phytophthora ramorum in a California Forest Under Different Climatic Conditions

2013 ◽  
Vol 103 (11) ◽  
pp. 1141-1152 ◽  
Author(s):  
C. A. Eyre ◽  
M. Kozanitas ◽  
M. Garbelotto

Limited information is available on how soil and leaf populations of the sudden oak death pathogen, Phytophthora ramorum, may differ in their response to changing weather conditions, and their corresponding role in initiating the next disease cycle after unfavorable weather conditions. We sampled and cultured from 425 trees in six sites, three times at the end of a 3-year-long drought and twice during a wet year that followed. Soil was also sampled twice with similar frequency and design used for sampling leaves. Ten microsatellites were used for genetic analyses on cultures from successful isolations. Results demonstrated that incidence of leaf infection tripled at the onset of the first wet period in 3 years in spring 2010, while that of soil populations remained unchanged. Migration of genotypes among sites was low and spatially limited under dry periods but intensity and range of migration of genotypes significantly increased for leaf populations during wet periods. Only leaf genotypes persisted significantly between years, and genotypes present in different substrates distributed differently in soil and leaves. We conclude that epidemics start rapidly at the onset of favorable climatic conditions through highly transmissible leaf genotypes, and that soil populations are transient and may be less epidemiologically relevant than previously thought.

2020 ◽  
Author(s):  
Nicholas C Carleson ◽  
Hazel Daniels ◽  
Paul Reeser ◽  
Alan Kanaskie ◽  
Sarah Navarro ◽  
...  

Sudden oak death caused by Phytophthora ramorum has been actively managed in Oregon since the early 2000’s. To date, this epidemic has been driven mostly by the NA1 clonal lineage of P. ramorum, but an outbreak of the EU1 lineage has recently emerged. Here we contrast the population dynamics of the NA1 outbreak first reported in 2001 to the outbreak of the EU1 lineage first detected in 2015. We tested if any of the lineages were introduced more than once. Infested regions of the forest were sampled between 2013-2018 (n = 903) and strains were genotyped at 15 microsatellite loci. Most genotypes observed were transient, with 272 of 358 unique genotypes emerging one year and disappearing the next. Diversity of EU1 was very low and isolates were spatially clustered (< 8 km apart), suggesting a single EU1 introduction. Some forest isolates are genetically similar to isolates collected from a local nursery in 2012, suggesting introduction of EU1 from this nursery or simultaneous introduction to both the nursery and latently into the forest. In contrast, the older NA1 populations were more polymorphic and spread over 30 km2. Principal component analysis supported two to four independent NA1 introductions. The NA1 and EU1 epidemics infest the same area but show disparate demographics owing to initial introductions of the lineages spaced 10 years apart. Comparing these epidemics provides novel insights into patterns of emergence of clonal pathogens in forest ecosystems.


2021 ◽  
Vol 48 (4) ◽  
pp. 79-93
Author(s):  
F. G. Oyeniyi ◽  
E. O. Ewuola

Despite their crucial importance, limited information exists about how livestock are affected by climate change in Nigeria. Changing climatic patterns are manifested through occurrences like abrupt temperature increase, dwindling rainfall pattern, rise in spells of drought and flood. These conditions exert different effects across the geographical landscape of the country, which can broadly be classed as Semiarid, Sahel and Derived Savannah, respectively as well as Forest and Montane. Livestock provide humans with the full complement of amino acids, which are the only known natural suppliers of Vitamin B12 and equally supply iron, calcium, iodine and zinc. In addition, livestock accounts for 40% of Agricultural Gross Domestic Product and significantly contributes to enhancing rural livelihood. Stress conditions are induced in livestock by harsh weather conditions that reduce the feed available to them as well as impede growth rate and reproduction efficiency and disease incidence which may eventually result in death. In the light of the livestock benefits to humanity, it is necessary to devise means of making their climate resilient. Some of the proven strategies include animal genetic improvement for stress tolerance, growing disease resistant, early maturing and drought tolerant crops, selecting for and rearing climate tolerant animal species and breeds.     Malgré leur importance cruciale, il existe peu d'informations sur la manière dont le bétail est affecté par le changement climatique au Nigéria. Le changement des modèles climatiques se manifeste par des événements tels que l'augmentation brutale de la température, la diminution des précipitations, l'augmentation des périodes de sécheresse et d'inondation. Ces conditions exercent des effets différents sur le paysage géographique du pays, qui peuvent être globalement classés comme semi-aride, sahélien et savane dérivée, respectivement, ainsi que forêt et montagne. Le bétail fournit aux humains le complément complet d'acides aminés, qui sont les seuls fournisseurs naturels connus de vitamine B12 et fournissent également du fer, du calcium, de l'iode et du zinc. En outre, l'élevage représente 40% du produit intérieur brut agricole et contribue de manière significative à l'amélioration des moyens d'existence ruraux. Les conditions de stress sont induites chez le bétail par des conditions météorologiques difficiles qui réduisent les aliments disponibles pour eux et entravent le taux de croissance, l'efficacité de la reproduction et l'incidence des maladies qui peuvent éventuellement entraîner la mort. À la lumière des avantages de l'élevage pour l'humanité, il est nécessaire de concevoir des moyens de rendre leur résilient climatique. Certaines des stratégies éprouvées comprennent l'amélioration génétique animale pour la tolérance au stress, la culture de cultures résistantes aux maladies, à maturation précoce et à la sécheresse, la sélection et l'élevage d'espèces et de races animales tolérantes au climat.


2012 ◽  
Vol 11 (11) ◽  
pp. 1313-1323 ◽  
Author(s):  
Matteo Garbelotto ◽  
Katherine J. Hayden

ABSTRACTTen years after a threatening and previously unknown disease of oaks and tanoaks appeared in coastal California, a significant amount of progress has been made toward the understanding of its causal agentPhytophthora ramorumand of the novel pathosystems associated with this exotic organism. However, a complete understanding of the ecology and epidemiology of this species still eludes us. In part, our inability to fully understand this organism is due to its phylogenetic, phylogeographic, phenotypic, and epidemiological complexities, all reviewed in this paper. Most lines of evidence suggest that the high degree of disease severity reported in California is not simply due to a generalized lack of resistance or tolerance in naïve hosts but also to an innate ability of the pathogen to survive in unfavorable climatic conditions and to reproduce rapidly when conditions become once again favorable.


2007 ◽  
Vol 16 (14) ◽  
pp. 2958-2973 ◽  
Author(s):  
S. PROSPERO ◽  
E. M. HANSEN ◽  
N. J. GRÜNWALD ◽  
L. M. WINTON

2012 ◽  
Vol 62 (4) ◽  
pp. 451-462 ◽  
Author(s):  
Małgorzata Proćków ◽  
Elżbieta Kuźnik-Kowalska ◽  
Małgorzata Lewandowska

Population dynamics of a meso-hygrophilous helicoid Bradybaena fruticum was studied in SW Poland at two localities with similar habitat but different climatic conditions. Unexpectedly, at the submontane site in Szczytna the growth appeared to be significantly faster than in the lowland site (Wrocław), where the weather conditions varied widely during the whole growing season. In Szczytna the average growth rate was 0.26 whorl/month; 0.36 whorl/month in the fast phase (juveniles from hatching till 5.0 whorls), and 0.07 whorl/month in the slow phase (snails with 5.1 whorls till lip formation). During the whole growing season, the average increment was 4.5 whorls, whereas the maximum was 5.45 whorls. In Wrocław the average growth rate was 0.05 whorl/month; 0.1 whorl/month in the fast phase, and only 0.01 whorl/month in the slow phase. The average growth of juveniles, estimated during two growing seasons, equalled 3.8 whorls; the maximum recorded value was 4.75 whorls. In the winter there was hardly any growth. In earlier studies it was found that at higher altitude the growth rate seems to decrease and therefore appears to be correlated with the thermal regime of the locality. In this study it was established that the weather patterns, like months with drought or occasional flooding, are likely to influence the population dynamics in the lowland population.


Author(s):  
Chris Newman ◽  
Christina D. Buesching ◽  
David W. Macdonald

Adaptation to climatic conditions is a major ecological and evolutionary driver. Long-term study of European badger population dynamics in Oxfordshire reveals that rainfall and temperature patterns affect food (principally earthworm) availability, energy expended in thermoregulation, and activity patterns, with badgers able to seek refuge in their setts. Cubs prove especially vulnerable to harsh weather conditions, where drought and food shortages exacerbate the severity of pandemic juvenile coccidial parasite infections. Crucially, weather variability, rather than just warming trends, stresses badgers, by destabilising their bioclimatic niche. Summer droughts cause mortality, even driving genetic selection; and while milder winters generally benefit badgers, less time spent in torpor leads to more road casualties. Similar effects also operate over a wide spatial scale in Ireland, impacting regional badger densities and bodyweights. That even an adaptable, generalist musteloid is so variously susceptible to weather conditions highlights how climate change places many species and ecosystems at risk.


Author(s):  
Klepikov O.V. ◽  
Kolyagina N.M. ◽  
Berezhnova T.A. ◽  
Kulintsova Ya.V.

Relevance. Today, in preventive medicine, climatic conditions that have a pathological effect on the functional state of a person are increasingly being updated. the occurrence of exacerbations of many diseases can be causally associated with various weather conditions. Aim: to develop the main tasks for improving the organization of medical care for weather-dependent patients with diseases of the cardiovascular system. Material and methods. The assessment of personnel, material and technical support and the main performance indicators of an outpatient clinic was carried out on the example of the Voronezh city polyclinic No. 18 to develop the main tasks for improving the organization of medical care for weather-dependent patients with diseases of the cardiovascular system. Results. The main personnel problem is the low staffing of district therapists and specialists of a narrow service. One of the priorities for reducing the burden on medical hospitals is the organization of inpatient replacement medical care on the basis of outpatient clinics. The indicators for the implementation of state guarantees for the outpatient network for 2018, which were fully implemented, are given. The analysis of the planned load performance by polyclinic specialists is presented. Cardiological and neurological services carry out measures to reduce the risk of exacerbations of diseases with cerebral atherosclerosis, hypertension, and major neurological nosologies. Conclusion. Improving the organization of medical care for weather-dependent patients with cardiovascular diseases are: informing patients about the sources of specialized medical weather forecasts in the region, organizing the work of the medical prevention office, implementing an interdepartmental approach to providing health care to the most vulnerable groups of the population.


Author(s):  
A.A. Dronic A.A. ◽  

The article presents an assessment of the stability of introduced cherry varieties to spring return frosts in 2020 in the conditions of the sharply continental climate of the Astrakhan region. As a result of unfavorable weather conditions, the total damage score of all varieties was 2-5 points. Almost all the studied varieties showed an insufficient level of resistance to recurrent frosts.


2018 ◽  
Vol 1 (94) ◽  
pp. 55-61
Author(s):  
R.O. Myalkovsky

Goal. The purpose of the research was to determine the influence of meteorological factors on potato yield in the conditions of the Right Bank Forest-steppe of Ukraine. Methods.Field, analytical and statistical. Results.It was established that among the mid-range varieties Divo stands out with a yield of 42.3 t/ha, Malin white – 39.8 t/ha, and Legend – 37.1 t/ ha. The most favourable weather and climatic conditions for the production of potato tubers were for the Divo 2011 variety with a yield of 45.9 t/ha and 2013 – 45.1 t/ha. For the Legenda variety 2016, the yield of potato tubers is 40.6 t/ha and 2017 – 43.2 t/ha. Malin White 2013 is 41.4 t/ha and 2017 42.1 t/ha. The average varieties of potatoes showed a slightly lower yield on average over the years of research. However, among the varieties is allocated Nadiyna – 40.3 t/ha, Slovyanka – 37.2 t/ ha and Vera 33.8 t/ha. Among the years, the most high-yielding for the Vera variety was 2016 with a yield of 36.6 t/ha and 2017 year – 37.8 t/ha. Varieties Slovyanka and Nadiyna 2011 and 2012 with yields of 42.6 and 44.3 t/ha and 46.5 and 45.3 t/ha, respectively. Characterizing the yield of potato tubers of medium-late varieties over the years of research, there was a decrease in this indicator compared with medium-early and middle-aged varieties. However, the high yield of the varieties of Dar is allocated – 40.0 t/ha, Alladin – 33.6 t/ha and Oxamit 31.3 t/ha. Among the years, the most favourable ones were: for Oxamit and Alladin – 2011 – 33.5 and 36.5 t/ha, and 2017 – 34.1 and 36.4 t/ha, respectively. Favourable years for harvesting varieties were 2011 and 2012 with yields of 45.7 and 45.8 t/ha. Thus, the highest yield of potato tubers on average over the years of studies of medium-early varieties of 41.2-43.3 t / ha were provided by weather conditions of 2011 and 2017 years, medium-ripe varieties 41.0-41.1 - 2012 and 2011, medium- late 37,6-38,5 t / ha - 2012 and 2011, respectively.


2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Hafsa Abouadane ◽  
Abderrahim Fakkar ◽  
Benyounes Oukarfi

The photovoltaic panel is characterized by a unique point called the maximum power point (MPP) where the panel produces its maximum power. However, this point is highly influenced by the weather conditions and the fluctuation of load which drop the efficiency of the photovoltaic system. Therefore, the insertion of the maximum power point tracking (MPPT) is compulsory to track the maximum power of the panel. The approach adopted in this paper is based on combining the strengths of two maximum power point tracking techniques. As a result, an efficient maximum power point tracking method is obtained. It leads to an accurate determination of the MPP during different situations of climatic conditions and load. To validate the effectiveness of the proposed MPPT method, it has been simulated in matlab/simulink under different conditions.


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