Current Arable Farming Systems in the Czech Republic – Agronomic Measures Adapted to Soil Protection and Climate Change

The paper is focused on evaluation various soil tillage systems for maize in terms of productivity and reduction of soil erosion in the Czech Republic. The high slope of land, combined with expanding wide-row crops (when maize had the largest area) increase the risk of water erosion. Assessed yield data are from Southern Moravia in 2011-2016. Investigation of the effects of different soil tillage and silage maize stand establishment on soil and water runoff was carried out in the experimental station Lukavec near Pacov (Bohemian region). Average of six-years results showed that there are no any differences between conventional tillage (10.08 t ha-1) and minimum tillage (10.19 t ha-1), but year is significant. In trial, where different tillage systems were compared with/without phacelia as cover crop, according to three-year average, the highest grain yield was in chisel loosening (8.89 t ha-1) similar to ploughing (8.85 t ha-1). Lower yields were in no-tillage (8.61 t ha-1) and strip-tillage (8.55 t ha-1). Various conservation tillage systems have to be improved and modified for different soil and climate conditions. The benefit is in reduction of soil loss, which depends on crop residues coverage on soil surface. The soil sediment loss was the lowest in no-till variant (30 resp. 38 %) and less in minimum tillage (57 resp. 88 %) in comparison with ploughing (= 100 %). Decrease of soil sediment loss due to sown cover crops (Canary grass or rye) was almost less than 10 % in comparison with variant without cover crop. The results confirm the importance of soil conservation technologies (including strip-tillage) of soil tillage to reduce the risk of land degradation by water erosion

An invasive species reverses the roles in a host–parasite relationship between bitterling fish and unionid mussels

The impact of multiple invading species can be magnified owing to mutual facilitation—termed ‘invasional meltdown’—but invasive species can also be adversely affected by their interactions with other invaders. Using a unique reciprocal host–parasite relationship between a bitterling fish (Rhodeus amarus) and unionid mussels, we show that an invasive mussel reverses the roles in the relationship. Bitterling lay their eggs into mussel gills, and mussel larvae parasitize fish. Bitterling recently colonized Europe and parasitize all sympatric European mussels, but are unable to use a recently invasive mussel, Anodonta woodiana. The parasitic larvae of A. woodiana successfully develop on R. amarus, whereas larvae of European mussels are rejected by bitterling. This demonstrates that invading species may temporarily benefit from a coevolutionary lag by exploiting evolutionarily naive hosts, but the resulting relaxed selection may facilitate its exploitation by subsequent invading species, leading to unexpected consequences for established interspecific relationships

Presentation_1_Evidence for reproductive senescence across ray-finned fishes: A review.PDF

The origin, incidence, and consequences of reproductive senescence vary greatly across the tree of life. In vertebrates, research on reproductive senescence has been mainly focused on mammals and birds, demonstrating that its variation is largely linked to critical life history traits, such as growth patterns, juvenile, and adult mortality, and reproductive strategy. Fishes represent half of the vertebrate taxonomic diversity and display remarkable variation in life history. Based on a thorough literature review, we summarize current evidence on reproductive senescence in ray-finned fishes (Actinopterygii). While survival and physiological senescence are acknowledged in fish, their potential age-related reproductive decline has often been disregarded due to the prevalence of indeterminate growth. We demonstrate that age-related reproductive decline is reported across fish phylogeny, environments, and traits. An important point of our review is that the incidence of reproductive senescence in a species depends on both the number of studies for that species and the coverage of its maximum lifespan by the study. Reproductive senescence was documented for one-third of the studied fish species, with females suffering an age-related decline in reproductive traits less often than males or both parents combined. Neither parental care nor migratory strategy corresponded with the occurrence of reproductive senescence in fish. The traits that were affected by reproductive senescence most often were sex-specific, with pre-mating and mating categories of traits declining in females and sperm quality and quantity in males. We also demonstrate that reproductive senescence can be buffered by indeterminate growth. We provide rich evidence of reproductive senescence across ray-finned fishes, but we highlight the need for better data on age-related reproduction in fishes.</p

Longitudinal demographic study of wild populations of African annual killifish

Abstract The natural history of model organisms is often overlooked despite its importance to correctly interpret the outcome of laboratory studies. Ageing is particularly understudied in natural populations. To address this gap, we present lifetime demographic data from wild populations of an annual species, the turquoise killifish, Nothobranchius furzeri, a model species in ageing research, and two other species of coexisting annual killifishes. Annual killifish hatch synchronously, have non-overlapping generations, and reproduce daily after reaching sexual maturity. Data from 13 isolated savanna pools in southern Mozambique demonstrate that the pools supporting killifish populations desiccated 1–4 months after their filling, though some pools persisted longer. Declines in population size over the season were stronger than predicted, because they exceeded the effect of steady habitat shrinking on population density that, contrary to the prediction, decreased. Populations of N. furzeri also became more female-biased with progressing season suggesting that males had lower survival. Nothobranchius community composition did not significantly vary across the season. Our data clearly demonstrate that natural populations of N. furzeri and its congeners suffer strong mortality throughout their lives, with apparent selective disappearance (condition-dependent mortality) at the individual level. This represents selective force that can shape the evolution of lifespan, and its variation across populations, beyond the effects of the gradient in habitat persistence

Evidence that nonsignificant results are sometimes preferred: Reverse P-hacking or selective reporting?

There is increased concern about poor scientific practices arising from an excessive focus on P-values. Two particularly worrisome practices are selective reporting of significant results and 'P-hacking'. The latter is the manipulation of data collection, usage, or analyses to obtain statistically significant outcomes. Here, we introduce the novel, to our knowledge, concepts of selective reporting of nonsignificant results and 'reverse P-hacking' whereby researchers ensure that tests produce a nonsignificant result. We test whether these practices occur in experiments in which researchers randomly assign subjects to treatment and control groups to minimise differences in confounding variables that might affect the focal outcome. By chance alone, 5% of tests for a group difference in confounding variables should yield a significant result (P < 0.05). If researchers less often report significant findings and/or reverse P-hack to avoid significant outcomes that undermine the ethos that experimental and control groups only differ with respect to actively manipulated variables, we expect significant results from tests for group differences to be under-represented in the literature. We surveyed the behavioural ecology literature and found significantly more nonsignificant P-values reported for tests of group differences in potentially confounding variables than the expected 95% (P = 0.005; N = 250 studies). This novel, to our knowledge, publication bias could result from selective reporting of nonsignificant results and/or from reverse P-hacking. We encourage others to test for a bias toward publishing nonsignificant results in the equivalent context in their own research discipline

Interaction between maternal and environmental effects in a seed beetle

We tested for genetic and maternal variation in host preference and host suitability using a half-sib/full-sib split-brood design with a seed beetle (Callosobruchus maculatus, Chrysomelidae). We used a quantitative genetics approach mating four females (dams) to a single male (sire) and then splitting their offspring onto 2 types of host environment (original and novel). We then separately collected offspring from both host types and raised them to adulthood. In addition, we assessed the host preference of individual females (dams and daughters) using preference trial where we counted the number of eggs laid on each host type. The main aim of this study is to test the effect of maternal-by-environment interaction (M×E) on offspring performance alongside the more commonly quantified genotype-by-environment interaction (G×E) in studies of heritability and evolution of quantitative phenotypic traits

Data from: Alternative intrapopulation life history strategies and their trade-offs in an African annual fish

In ephemeral habitats, the same genotypes cope with unpredictable environmental conditions, favouring the evolution of developmental plasticity and alternative life-history strategies (ALHS). We tested the existence of intrapopulation ALHS in an annual killifish, Nothobranchius furzeri, inhabiting temporary pools. The pools are either primary (persisting throughout the whole rainy season) or secondary (refilled after desiccation of the initial pool), representing alternative niches. The unpredictable conditions led to the evolution of reproductive bet-hedging with asynchronous embryonic development. We used a common garden experiment to test whether the duration of embryonic period is associated with post-embryonic life-history traits. Fish with rapid embryonic development (secondary pool strategy, high risk of desiccation) produced phenotypes with more rapid life-history traits than fish with slow embryonic development (primary pool strategy). The fast fish were smaller at hatching but had larger yolk sac reserves. Their post-hatching growth was more rapid, and they matured earlier. Further, fast fish grew to a smaller body size and died earlier than slow fish. No differences in fecundity, propensity to mate or physiological ageing were found, demonstrating a combination of plastic responses and constraints. Such developmentally related within-population plasticity in life history is exceptional among vertebrates