Linking Northeast Pacific recruitment synchrony to environmental variability     

Megan M. Stachura  Timothy E. Essington  Nathan J. Mantua  Anne B. Hollowed  Melissa A. Haltuch  Paul D. Spencer  Trevor A. Branch  Miriam J. Doyle 《Fisheries Oceanography》2014,23(5):389-408

We investigated the hypothesis that synchronous recruitment is due to a shared susceptibility to environmental processes using stock–recruitment residuals for 52 marine fish stocks within three Northeast Pacific large marine ecosystems: the Eastern Bering Sea and Aleutian Islands, Gulf of Alaska, and California Current. There was moderate coherence in exceptionally strong and weak year‐classes and correlations across stocks. Based on evidence of synchrony from these analyses, we used Bayesian hierarchical models to relate recruitment to environmental covariates for groups of stocks that may be similarly influenced by environmental processes based on their life histories. There were consistent relationships among stocks to the covariates, especially within the Gulf of Alaska and California Current. The best Gulf of Alaska model included Northeast Pacific sea surface height as a predictor of recruitment, and was particularly strong for stocks dependent on cross‐shelf transport during the larval phase for recruitment. In the California Current the best‐fit model included San Francisco coastal sea level height as a predictor, with higher recruitment for many stocks corresponding to anomalously high sea level the year before spawning and low sea level the year of spawning. The best Eastern Bering Sea and Aleutian Islands model included several environmental variables as covariates and there was some consistent response across stocks to these variables. Future research may be able to utilize these across‐stock environmental influences, in conjunction with an understanding of ecological processes important across early life history stages, to improve identification of environmental drivers of recruitment.  相似文献   

Can mouth part deformities of <Emphasis Type="Italic">Chironomus riparius</Emphasis> serve as indicators for water and sediment pollution? A laboratory approach     

Miriam Langer-Jaesrich  Heinz-R. Köhler  Almut Gerhardt 《Journal of Soils and Sediments》2010,10(3):414-422

Purpose  

The significance of chironomids mouthpart deformities as suitable indicators for pollutant contamination of natural waters and sediments has been investigated and discussed for several decades. Uncertainties still exist as further laboratory studies, with different pollutants and with the same experimental design are required.  相似文献   

Growth response of mixed mediterranean oak coppices to rainfall reduction: Could selective thinning have any influence on it?     

Miriam Cotillas  Santi Sabat  Carlos Gracia  Josep Mª Espelta 《Forest Ecology and Management》2009,258(7):1677-1683

Climate change is one of the major challenges for ecosystem conservation. One of the most vulnerable areas to climate change is the Mediterranean Basin which is expected to suffer important changes in temperature and precipitation in the next few decades, leading to a warmer and dryer climate. Therefore, it is necessary to determine species-specific responses to increased drought to predict possible future changes in the structure and composition of Mediterranean forests, as well as to identify appropriate management strategies to mitigate these effects.The main aim of this study has been to experimentally simulate the effects of a 15% reduction in annual rainfall on the survival and growth of two co-occurring Mediterranean oaks with contrasting leaf-habit (the evergreen Quercus ilex spp. ilex and the winter-deciduous Quercus cerrioides) and, to assess whether traditional selective thinning carried out in these mixed oak coppices (i.e. selection of one to few stems per stump) can modify the consequences of rainfall reduction.Soil moisture decreased under the rainfall reduction level while it increased in the thinned plots. Reduced rainfall did not influence tree mortality, but did lead to species-specific effects on height growth: no changes were observed in Q. ilex while height growth rate of Q. cerrioides decreased (c.a. 20%). Selective thinning improved tree growth (c.a. 50%) in stands both under natural and, and to a lesser extent, under reduced rainfall conditions. Nevertheless, the positive effects of thinning rapidly declined during our three years experiment, probably because the vigorous resprouting of thinned stumps.Our results show that the forecasted reduction in annual rainfall for the Western Mediterranean Basin can constrain the growth of some deciduous oaks in mixed oak coppices. Traditional selective thinning can increase soil moisture and encourage tree growth, thus partially mitigating this effect. However, the transient results observed in this experiment suggest the need to reconsider the intensity and the frequency of this traditional management practice in light of new climatic scenarios.  相似文献   

Needle blight caused by Dothistroma pini in Slovakia: distribution,host range and mating types     

Emília Ondrušková  Zuzana Hečková-Jánošíková  Slavomír Adamčík  Miriam Kádasi Horáková  Dominika Rakúsová-Sládková  Katarína Adamčíková 《Scandinavian Journal of Forest Research》2018,33(7):650-656

Dothistroma needle blight (DNB) has been observed in Slovakia during the last two decades. Up until 2017, Dothistroma septosporum has only been detected and molecularly confirmed to cause DNB in Slovakia. Here, we report the detection of Dothistroma pini at six localities around Slovakia, representing different plantation types. Four pine species (Pinus sylvestris, P. nigra, P. mugo and P. jeffreyi) were confirmed as hosts of D. pini in Slovakia, of which only P. mugo has been previously reported as host in Slovakia. Three gene regions (ITS, EF1 –α, and ß-tubulin) of each of the 13 isolates were sequenced and assigned as D. pini. Based on ITS sequences, the studied isolates represent the haplotypes Dp_HAP.1, Dp_HAP.2. Both mating types were detected but at different localities. Our results suggest that in addition to D. septosporum, D. pini may contribute to DNB also in Slovakia.  相似文献   

Phospholipid Fatty Acid (PLFA) Composition and Its Dynamics in a Desert Soil System     

Sofia Vishnevetsky  Miriam Cojocaru  Yosef Steinberger 《Arid Land Research and Management》2013,27(1):59-68

The effect of environmental conditions, and especially soil water content, on microbial community structure was quantified during a 15-month sampling period (1994-1995) in a Negev Desert soil system by determination of phospholipid fatty acids (PLFAs). Two rainy seasons were observed during the study period: (1) the rainy season of 1993-1994, with a total rainfall of 58mm, and (2) the rainy season of 1994-1995, with a total of 140mm, which is 55% more than the multiannual average. Soil samples collected from the 0-10cm layer exhibited changes in soil moisture and PLFA composition. Palmitic acid (nC16:0) was found to be the most common acid, with a maximum abundance found in May 1994 (27.2%). Oleic acid (C18:1 omega 9) was found to be the second highest in abundance, with high levels in January 1994 (14%), decreasing gradually to 1.3% of total ion current in January 1995. This decrease was interpreted as being caused by abiotic factors affecting the microbial community, resulting in fatty acid profile and lipid abundance. Other acids were found to be present in relatively small amounts. The iC17:1 omega 9 and C18:2 omega 8, 11 were found among the major PLFAs during the study period. The data obtained in this study were found to be similar to data obtained in soils of temperate climates, in spite of the hypothesis that the total PLFAs of the desert soil microbes are triggered and depend on soil water availability. This can afford special data interpretation of the viable biomass of the soil microbes and their metabolic status.  相似文献   

Possible involvement of fructose 1,6-bisphosphatase in cold-induced sweetening of potato tubers     

Pieternel A. M. Claassen  Miriam A. W. Budde 《Potato Research》1996,39(1):141-151

Summary In measuring fructose 1,6-bisphosphatase (EC 3.1.3.11; FBPase) in potato tubers, we used anti PFP antibodies to ensure that the assay was specific for FBPase and that PPi:fructose 6-phosphate 1-phosphotransferase (EC 2.7.1.90: PFP) did not contribute to the production of fructose 6-phosphate (Fru-6-P). The involvement of cytosolic FBPase in cold sweetening was determined by monitoring enzyme activity during storage ofSolanum tuberosum cv. Erntestolz tubers at 2 or 8°C. In contrast to the rapid increase in sucrose and reducing sugars, the specific activity of FBPase showed no change and PFP rose slightly during storage at 2°C. Sugar concentrations and enzyme activities remained virtually unchanged during storage at 8°C. These data allow the interconversion of fructose 1.6-bisphosphate (Fru-1,6-P₂) to Fru-6-P and vice versa by FBPase and PFP, respectively, in potato tubers, but do not support a causal relationship between coarse metabolic control of FBPase and cold-induced sweetening.  相似文献   

Acaricidal properties of the essential oil and precocene II obtained from Calea serrata (Asteraceae) on the cattle tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae)     

Ribeiro VL  dos Santos JC  Martins JR  Schripsema J  Siqueira IR  von Poser GL  Apel MA 《Veterinary parasitology》2011,179(1-3):195-198

Calea serrata Less. (Asteraceae), an endemic species of south Brazil known as "quebra-tudo", is used in Afro-Brazilian religious rituals and in folk medicine for treating liver disorders. Phytochemical studies of the n-hexane extract of this plant demonstrated the presence of precocene II, a benzopyran derivative known for its insecticidal activity. The aim of this work was to isolate this benzopyran and determine the chemical composition of the essential oil of C. serrata and further to evaluate the acaricidal activity of the essential oil and precocene II against the larvae of Rhipicephalus (Boophilus) microplus. The LC(99.9) and LC(50) values obtained with the oil, which presents precocene II and sesquiterpenes, were 3.94 μL/mL and 0.28 μL/mL, respectively. For precocene II this values were 4.25mg/mL and 1.78 mg/mL, respectively. The results indicate a synergistic interaction between the components of the oil and precocene II.  相似文献   

EVPC - Annual Scientific Meeting 2010 in Munich/Germany entitled "Advances in Tropical Veterinary Parasitology"     

Pfister K  Scheuerle M 《Veterinary parasitology》2011,181(1):1

  相似文献   

Effect of season and superstimulatory treatment on in vivo and in vitro embryo production in wood bison (Bison bison athabascae)     

Jesus Manuel Palomino  Gabriela F. Mastromonaco  Miriam P. Cervantes  Reuben J. Mapletoft  Muhammad Anzar  Gregg P. Adams 《Reproduction in domestic animals》2020,55(1):54-63

Two experiments were done using a two-by-two design to determine the effects of season and superstimulatory protocol on embryo production in wood bison. In Experiment 1 (in vivo-derived embryos), ovarian superstimulation was induced in female bison during the ovulatory and anovulatory seasons with either two or three doses of FSH given every-other-day (FSH × 2 vs. FSH × 3, respectively). Bison were given hCG to induce ovulation, inseminated 12 and 24 hr after hCG, and embryos were collected 8 days after hCG (n = 10 bison/group). In Experiment 2 (in vitro embryo production), ovarian superstimulation was induced in female bison during the ovulatory and anovulatory seasons with two doses of FSH, and in vivo maturation of the cumulus–oocyte complexes (COC) was induced with hCG at either 48 or 72 hr after the last dose of FSH. COC were collected 34 hr after hCG, and expanded COC were used for in vitro fertilization and culture. In Experiment 1, the number of follicles ≥9 mm, the proportion of follicles that ovulated, the number of CL, and the total number of ova/embryos collected did not differ between seasons or treatment groups, but the number of transferable embryos was greater (p < .05) in the ovulatory season. In Experiment 2, no differences were detected between seasons or treatment groups for any end point. The number of transferable embryos produced per bison was greatest (p < .05) using in vitro fertilization and was unaffected by season (1.5 ± 0.2 and 1.1 ± 0.3 during anovulatory and ovulatory seasons, respectively), in contrast to in vivo embryo production which was affected by season (0.1 ± 0.01 and 0.7 ± 0.2 during anovulatory and ovulatory seasons, respectively). Results demonstrate that transferable embryos can be produced throughout the year in wood bison by both in vivo and in vitro techniques, but the efficiency of embryo production of in vivo-derived embryos is significantly lower during the anovulatory season.  相似文献   

Contribution of anecic earthworms to biopore formation during cultivation of perennial ley crops     

Timo Kautz  Marcel Lüsebrink  Stefan Pätzold  Doris Vetterlein  Ralf Pude  Miriam Athmann  Paul M. Küpper  Ute Perkons  Ulrich Köpke 《Pedobiologia》2014

Large sized biopores (diameter >2 mm) in the subsoil can be created by tap roots, which leave voids after their decay, or by the burrowing activity of anecic earthworms which may benefit from the temporary lack in tillage in perennial cropping systems. However, the interactions between root growth and earthworm activity in the process of biopore formation during perennial ley cropping are not well understood. The aim of this field study was to quantify the development of the abundance of the anecic earthworm Lumbricus terrestris and the biopore density during the cultivation of lucerne (Medicago sativa L.), chicory (Cichorium intybus L.) and tall fescue (Festuca arundinacea Schreb.) grown for either one, two or three years. An increased abundance of L. terrestris was already recorded after two years of continuous ley when compared with one year cultivation. The ley crop species had only minor influence on the abundance of L. terrestris. Biopore densities of both diameter classes under study (2–5 mm and >5 mm) were not significantly affected by the duration of ley cropping. In contrast, biopore densities were influenced by ley crop species. More biopores of diameter class 2–5 mm were recorded after chicory than after fescue. Lucerne cropping resulted in intermediate biopore density. Additionally, in an incubation experiment under field conditions, we quantified whether L. terrestris preferentially created new biopores or colonized abandoned, previously existing ones. After three weeks of incubation, one third of the adult individuals incubated in the experimental area created new biopores at 0.4 m soil depth. A similar percentage of individuals colonized previously existing biopores, partially widening the lumen of smaller sized biopores. The remaining individuals remained in the topsoil. Sub-adult individuals rarely formed new pores. Half of the introduced sub-adults remained in the topsoil. We conclude that in crop rotations new biopores can be generated during perennial ley cropping by taproot systems of ley crops, but that a two to three- year period without tillage is not sufficient for populations of anecic earthworms to make a marked contribution to biopore density in the subsoil. The relevance of anecic earthworms for altering physical and chemical properties of biopores during ley cropping still needs further investigation.  相似文献