Juvenile mortality in captive lesser kudu (Tragelaphus imberbis) at Basle Zoo and its relation to nutrition and husbandry.     

Dorothea Besselmann  Daniela Schaub  Christian Wenker  Jürg V?llm  Nadia Robert  Claude Schelling  Hanspeter Steinmetz  Marcus Clauss 《Journal of zoo and wildlife medicine》2008,39(1):86-91

Since 1956, when the Basle Zoo (Switzerland) initiated the breeding of lesser kudu (Tragelaphus imberbis), 43% of the lesser kudu juveniles died before reaching an age of 6 mo. In this study, the objective was to obtain the pathological findings, nutritional history, and family tree information in order to evaluate the influence of husbandry on juvenile mortality in these animals. The main cause of death was white muscle disease (WMD), diagnosed in 14 cases (26%) of the deceased juveniles. Although enclosure size had remained constant and animal accessibility to the public was constantly high, both herd size and juvenile mortality had increased from 1956-2004. The diet consumed by the whole group in 2004 had deficient levels of vitamin E and selenium. The increasing linear trend of the mortality rate since the 1960s was significant, and there was a significant correlation between herd size and overall juvenile mortality. In contrast, there was no correlation between herd size and the occurrence of juvenile mortality associated specifically with WMD. Other investigated factors (sex, inbreeding, and season) had no significant effect on overall mortality up to 6 mo of age or on mortality associated with WMD. These results characterize both a dietary and a husbandry problem, and are supported by a lack of similar juvenile mortality in another facility where the diet was supplemented with vitamin E, animal numbers were kept low, and the enclosure structure offered more retreat options for the animals.  相似文献   

The use of vaccines to control disease is not a simple matter     

Hutber M 《Veterinary journal (London, England : 1997)》2007,173(3):480-481

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Reproductive resilience: a paradigm shift in understanding spawner‐recruit systems in exploited marine fish          下载免费PDF全文

Susan Lowerre‐Barbieri  Greg DeCelles  Pierre Pepin  Ignacio A Catalán  Barbara Muhling  Brad Erisman  Steven X Cadrin  Josep Alós  Andres Ospina‐Alvarez  Megan M Stachura  Michael D Tringali  Sarah Walters Burnsed  Claire B Paris 《Fish and Fisheries》2017,18(2):285-312

A close relationship between adult abundance and stock productivity may not exist for many marine fish stocks, resulting in concern that the management goal of maximum sustainable yield is either inefficient or risky. Although reproductive success is tightly coupled with adult abundance and fecundity in many terrestrial animals, in exploited marine fish where and when fish spawn and consequent dispersal dynamics may have a greater impact. Here, we propose an eco‐evolutionary perspective, reproductive resilience, to understand connectivity and productivity in marine fish. Reproductive resilience is the capacity of a population to maintain the reproductive success needed to result in long‐term population stability despite disturbances. A stock's reproductive resilience is driven by the underlying traits in its spawner‐recruit system, selected for over evolutionary timescales, and the ecological context within which it is operating. Spawner‐recruit systems are species specific, have both density‐dependent and fitness feedback loops and are made up of fixed, behavioural and ecologically variable traits. They operate over multiple temporal, spatial and biological scales, with trait diversity affecting reproductive resilience at both the population and individual (i.e. portfolio) scales. Models of spawner‐recruit systems fall within three categories: (i) two‐dimensional models (i.e. spawner and recruit); (ii) process‐based biophysical dispersal models which integrate physical and environmental processes into understanding recruitment; and (iii) complex spatially explicit integrated life cycle models. We review these models and their underlying assumptions about reproductive success vs. our emerging mechanistic understanding. We conclude with practical guidelines for integrating reproductive resilience into assessments of population connectivity and stock productivity.  相似文献   

Root development of winter wheat in erosion‐affected soils depending on the position in a hummocky ground moraine soil landscape          下载免费PDF全文

Marcus Herbrich  Horst H. Gerke  Michael Sommer 《植物养料与土壤学杂志》2018,181(2):147-157

Agricultural soil landscapes of hummocky ground moraines are characterized by 3D spatial patterns of soil types that result from profile modifications due to the combined effect of water and tillage erosion. We hypothesize that crops reflect such soil landscape patterns by increased or reduced plant and root growth. Root development may depend on the thickness and vertical sequence of soil horizons as well as on the structural development state of these horizons at different landscape positions. The hypotheses were tested using field data of the root density (RD) and the root lengths (RL) of winter wheat using the minirhizotron technique. We compared data from plots at the CarboZALF‐D site (NE Germany) that are representing a non‐eroded reference soil profile (Albic Luvisol) at a plateau position, a strongly eroded profile at steep slope (Calcaric Regosol), and a depositional profile at the footslope (Anocolluvic Regosol). At each of these plots, three Plexiglas access tubes were installed down to approx. 1.5 m soil depth. Root measurements were carried out during the growing season of winter wheat (September 2014–August 2015) on six dates. The root length density (RLD) and the root biomass density were derived from RD values assuming a mean specific root length of 100 m g^?1. Values of RD and RLD were highest for the Anocolluvic Regosol and lowest for the Calcaric Regosol. The maximum root penetration depth was lower in the Anocolluvic Regosol because of a relatively high and fluctuating water table at this landscape position. Results revealed positive relations between below‐ground (root) and above‐ground crop parameters (i.e., leaf area index, plant height, biomass, and yield) for the three soil types. Observed root densities and root lengths in soils at the three landscape positions corroborated the hypothesis that the root system was reflecting erosion‐induced soil profile modifications. Soil landscape position dependent root growth should be considered when attempting to quantify landscape scale water and element balances as well as agricultural productivity.  相似文献   

Binding of the respiratory chain inhibitor ametoctradin to the mitochondrial bc1 complex          下载免费PDF全文

Marcus Fehr  Antje Wolf  Gerd Stammler 《Pest management science》2016,72(3):591-602

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Impact of Spodoptera frugiperda neonate pretreatment conditions on Vip3Aa19 insecticidal protein activity and laboratory bioassay variation          下载免费PDF全文

Karen F Da Silva  Terence A Spencer  Carolina Camargo Gil  Blair D Siegfried  Frederick S Walters 《Pest management science》2016,72(4):837-844

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Extinction debt or habitat change? - Ongoing losses of woodland birds in north-eastern New South Wales, Australia     

Hugh A. Ford  Jeffrey R. Walters  Stephen J.S. Debus 《Biological conservation》2009,142(12):3182-3190

The loss, fragmentation and degradation of native vegetation are major causes of loss of biodiversity globally. Extinction debt is the term used to describe the ongoing loss of species from fragmented landscapes long after the original loss and fragmentation of habitat. However, losses may also result from habitat changes that are unrelated to fragmentation, which reduce breeding success and recruitment. Many woodland birds have declined in fragmented landscapes in Australia, probably due to loss of small, isolated populations, though the ecological processes are poorly understood. We record the progressive regional loss of two ground-foraging, woodland birds, the Brown Treecreeper Climacteris picumnus and Hooded Robin Melanodryas cucullata, in northern New South Wales, over 30 years. This has happened despite most habitat loss occurring over 100 years ago, suggesting the payment of an extinction debt. Our observations suggest that several ecological processes, caused by habitat loss, fragmentation or degradation, and operating over different time scales, have led to both species’ declines. Female Brown Treecreepers disperse poorly among vegetation remnants, leaving only males in isolated populations, which then go extinct. In contrast, Hooded Robins suffer high nest predation in fragmented landscapes, producing too few recruits to replace adult mortality. Foraging by both species may also be affected by regrowth of ground vegetation and shrubs. We found little support for a major role played by drought, climate change or aggressive Noisy Miners Manorina melanocephala. We propose that both extinction debt in the classical sense and ongoing habitat change frequently contribute to species’ decline in modified landscapes. Management to arrest and reverse such declines needs to consider these multiple causes of decline. For instance, reconnecting isolated populations may be inadequate alone, and activities such as appropriate grazing, fires and the addition of woody debris may also be required.  相似文献   

Mycorrhizal Hyphal Length as a Function of Plant Community Richness and Composition in Restored Northern Tallgrass Prairies (USA)     

Marcus A. Bingham  Mario Biondini 《Strength and Conditioning Journal》2009,62(1):60-67

We assessed the total length of external arbuscular mycorrhizal hyphae as a function of plant species and functional form richness in restored northern tallgrass prairies. Total hyphal length increased with species and functional form richness. Hyphal length also increased when plant communities were dominated by species with high root density, high root to shoot ratios, and high nitrogen use efficiency. Hyphal length was positively correlated with the biomass of late successional C₄ grasses (Andropogon gerardi Vitman, Panicum virgatum L., Schizachyrium scoparium [Michx.] Nash-Gould, and Sorghastrum nutans L.), which are obligately mycorrhizal and characterized by high root to shoot ratios, and high root surface area per unit of root biomass. We thus conclude that in order to recover extraradical arbuscular mycorrhizal hyphal length in restored northern tallgrass prairies, at least three factors need to be given priority: 1) achieving high levels of species and functional form richness; 2) making sure that late successional C₄ grasses are present; and 3) making sure that the seed mixture includes species that are characterized by high root to shoot ratio, high root density, and high nitrogen-use efficiency.  相似文献   

Response     

Marcus Gunew  Rhett Marshall  Megan Lui  and Caroline Astley 《The Journal of small animal practice》2009,50(4):207-207

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Aboveground carbon biomass of plantation-grown American chestnut (Castanea dentata) in absence of blight     

Douglass F. Jacobs  Marcus F. Selig  Larry R. Severeid 《Forest Ecology and Management》2009

Forest management activities may help reduce global net CO₂ concentrations by capturing and storing atmospheric CO₂. Research related to carbon sequestration potential of plantations in North America has focused predominantly on conifers, with relatively little emphasis thus far on temperate deciduous forest tree species. American chestnut (Castanea dentata (Marsh.) Borkh.), a former dominant tree species in eastern North America until its demise associated with the introduced chestnut blight (Cryphonectria parasitica (Murr.) Barr.), is a temperate deciduous species that holds promise for future carbon sequestration programs with expected availability of blight-resistant backcross hybrids. We quantified aboveground biomass and bole carbon of American chestnut interplanted with black walnut (Juglans nirga L.) and northern red oak (Quercus rubra L.) across four blight-free experimental sites varying in site quality and/or age (8, 8, 12, and 19 years) isolated from the native American chestnut range in the Coulee Region of southwestern Wisconsin, USA. American chestnut exhibited more rapid growth and greater aboveground biomass and bole carbon than either of the other interplanted species. Aboveground biomass ranged from 46.9, 60.7, 55.0, and 179.9 Mg ha⁻¹ for the 8-, 8-, 12-, and 19-year-old sites, respectively, while bole carbon content ranged from 13.6, 18.6, 14.1, and 60.1 Mg ha⁻¹ for the 8-, 8-, 12-, and 19-year-old sites, respectively. Cross-referencing our data to studies conducted within this same physiographic region using other important forestry species (i.e., Populus tremuloides Michx., Pinus resinosa Ait., and Pinus strobus L.) showed that American chestnut compared favorably in growth and carbon uptake. Incorporating American chestnut into carbon sequestration plantations provides additional ecological and economic benefits associated with consistent production of quality nuts for wildlife, valuable timber, and contribution toward species restoration. Our data lend support to building evidence demonstrating rapid and sustained growth of American chestnut and the potential role of plantation-grown American chestnut in helping to mitigate climate change through carbon sequestration.  相似文献