The energetics of fish growth and how it constrains food-web trophic structure

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.All data and R code (data manipulation, analyses, figures and tables) can be downloaded from a GitHub repository (https://github.com/dbarneche/FishGrowth), which will be made publicly available upon publication.The allocation of metabolic energy to growth fundamentally influences all levels of biological organisation. Here we use a first‐principles theoretical model to characterise the energetics of fish growth at distinct ontogenetic stages and in distinct thermal regimes. Empirically, we show that the mass scaling of growth rates follows that of metabolic rate, and is somewhat steeper at earlier ontogenetic stages. We also demonstrate that the cost of growth, Em, varies substantially among fishes, and that it may increase with temperature, trophic level and level of activity. Theoretically, we show that Em is a primary determinant of the efficiency of energy transfer across trophic levels, and that energy is transferred more efficiently between trophic levels if the prey are young and sedentary. Overall, our study demonstrates the importance of characterising the energetics of individual growth in order to understand constraints on the structure of food webs and ecosystems.Macquarie UniversityCentre for Geometric Biology at Monash Universit

Fish reproductive-energy output increases disproportionately with body size

This is the author accepted manuscript. The final version is available from the American Association for the Advancement of Science via the DOI in this record All data, metadata, and R code can be downloaded and cited as “D. R. Barneche, D. R. Robertson, C. R. White, D. J. Marshall, Data and code from: Fish reproductive-energy output increases disproportionately with body size. Zenodo (available at https:// github.com/dbarneche/fishFecundity), doi:10.5281/zenodo.1213118.”Body size determines total reproductive-energy output. Most theories assume reproductive output is a fixed proportion of size, with respect to mass, but formal macroecological tests are lacking. Management based on that assumption risks underestimating the contribution of larger mothers to replenishment, hindering sustainable harvesting. We test this assumption in marine fishes with a phylogenetically controlled meta-analysis of the intraspecific mass scaling of reproductive-energy output. We show that larger mothers reproduce disproportionately more than smaller mothers in not only fecundity but also total reproductive energy. Our results reset much of the theory on how reproduction scales with size and suggest that larger mothers contribute disproportionately to population replenishment. Global change and overharvesting cause fish sizes to decline; our results provide quantitative estimates of how these declines affect fisheries and ecosystem-level productivity.Centre for Geometric Biology, Monash Universit

Global environmental drivers of marine fish egg size

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.All data, R packages, and code (data manipulation, analyses, figures andtables) can be downloaded from our GitHub repositories (www.github.com/dbarneche/noaaErddap; www.github.com/dbarneche/envPred;https://github.com/dbarneche/fishEggSize)Aim To test long‐standing theory on the role of environmental conditions (both mean and predictability) in shaping global patterns in the egg sizes of marine fishes. Location Global (50° S to 50° N). Time period 1880 to 2015. Major taxa studied Marine fish. Methods We compiled the largest geo‐located dataset of marine fish egg size (diameter) to date (n = 1,078 observations; 192 studies; 288 species; 242 localities). We decomposed sea surface temperature (SST) and chlorophyll‐a time series into mean and predictability (seasonality and colour of environmental noise – i.e. how predictable the environment is between consecutive time steps), and used these as predictors of egg size in a Bayesian phylogenetic hierarchical model. We test four specific hypotheses based on the classic discussion by Rass (1941), as well as contemporary life‐history theory, and the conceptual model of Winemiller and Rose (1992). Results Both environmental mean and predictability correlated with egg size. Our parsimonious model indicated that egg size decreases by c. 2.0‐fold moving from 1 to 30 °C. Environments that were more seasonal with respect to temperature were associated with larger eggs. Increasing mean chlorophyll‐a, from 0.1 to 1 mg/m3, was associated with a c. 1.3‐fold decrease in egg size. Lower chlorophyll‐a seasonality and reddened noise were also associated with larger egg sizes – aseasonal but more temporally autocorrelated resource regimes favoured larger eggs. Main conclusions Our findings support results from Rass (1941) and some predictions from Winemiller and Rose (1992). The effects of environmental means and predictability on marine fish egg size are largely consistent with those observed in marine invertebrates with feeding larvae, suggesting that there are important commonalities in how ectotherm egg size responds to environmental change. Our results further suggest that anthropogenically mediated changes in the environment will have profound effects on the distribution of marine life histories.Centre for Geometric Biolog

Temperature effects on mass-scaling exponents in colonial animals: a manipulative test

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.All data and code necessary to reproduce this paper, its analyses, tables and figures can be obtained on GitHub https://github.com/dbarneche/MTRBrEs (Barneche et al. 2016a, doi: 10.5281/zenodo.159736)Body size and temperature are fundamental drivers of ecological processes because they determine metabolic rates at the individual level. Whether these drivers act independently on individual‐level metabolic rates remains uncertain. Most studies of intraspecific scaling of unitary organisms must rely on preexisting differences in size to examine its relationship with metabolic rate, thereby potentially confounding size‐correlated traits (e.g., age, nutrition) with size, which can affect metabolic rate. Here, we use a size manipulation approach to test whether metabolic mass scaling and temperature dependence interact in four species (two phyla) of colonial marine invertebrates. Size manipulation in colonial organisms allows tests of how ecological processes (e.g., predation) affect individual physiology and consequently population‐ and community‐level energy flux. Body mass and temperature interacted in two species, with one species exhibiting decreased and the other increased mass‐scaling exponents with increasing temperature. The allometric scaling of metabolic rate that we observe in three species contrasts with the isometric scaling of ingestion rates observed in some colonial marine invertebrates. Thus, we suggest that the often observed competitive superiority of colonial over unitary organisms may arise because the difference between energy intake and expenditure increases more strongly with size in colonial organisms.Australian Research Counci

Warming impairs trophic transfer efficiency in a long-term field experiment

This is the author accepted manuscript. The final version is available from Nature Research via the DOI in this recordIn natural ecosystems, the efficiency of energy transfer from resources to consumers determines the biomass structure of food webs. As a general rule, about 10% of the energy produced in one trophic level makes it up to the next1–3. Recent theory suggests this energy transfer could be further constrained if rising temperatures increase metabolic growth costs4, although experimental confirmation in whole ecosystems is lacking. We quantified nitrogen transfer efficiency (a proxy for overall energy transfer) in freshwater plankton in artificial ponds exposed to 7 years of experimental warming. We provide the first direct experimental evidence that, relative to ambient conditions, 4 °C of warming can decrease trophic transfer efficiency by up to 56%. In addition, both phytoplankton and zooplankton biomass were lower in the warmed ponds, indicating major shifts in energy uptake, transformation and transfer5,6. These new findings reconcile observed warming-driven changes in individual-level growth costs and carbon-use efficiency across diverse taxa4,7–10 with increases in the ratio of total respiration to gross primary production at the ecosystem level11–13. Our results imply that an increasing proportion of the carbon fixed by photosynthesis will be lost to the atmosphere as the planet warms, impairing energy flux through food chains, with negative implications for larger consumers and the functioning of entire ecosystems.AXA Research FundNatural Environment Research Council (NERC)European Research Council (ERC

Nestedness across biological scales

This is the final published version. Available from Public Library of Science via the DOI in this record.All data sets are available for download in the repository https:// bitbucket.org/maucantor/unodf_analyses/src.Biological networks pervade nature. They describe systems throughout all levels of biological organization, from molecules regulating metabolism to species interactions that shape ecosystem dynamics. The network thinking revealed recurrent organizational patterns in complex biological systems, such as the formation of semi-independent groups of connected elements (modularity) and non-random distributions of interactions among elements. Other structural patterns, such as nestedness, have been primarily assessed in ecological networks formed by two non-overlapping sets of elements; information on its occurrence on other levels of organization is lacking. Nestedness occurs when interactions of less connected elements form proper subsets of the interactions of more connected elements. Only recently these properties began to be appreciated in one-mode networks (where all elements can interact) which describe a much wider variety of biological phenomena. Here, we compute nestedness in a diverse collection of one-mode networked systems from six different levels of biological organization depicting gene and protein interactions, complex phenotypes, animal societies, metapopulations, food webs and vertebrate metacommunities. Our findings suggest that nestedness emerge independently of interaction type or biological scale and reveal that disparate systems can share nested organization features characterized by inclusive subsets of interacting elements with decreasing connectedness. We primarily explore the implications of a nested structure for each of these studied systems, then theorize on how nested networks are assembled. We hypothesize that nestedness emerges across scales due to processes that, although system-dependent, may share a general compromise between two features: specificity (the number of interactions the elements of the system can have) and affinity (how these elements can be connected to each other). Our findings suggesting occurrence of nestedness throughout biological scales can stimulate the debate on how pervasive nestedness may be in nature, while the theoretical emergent principles can aid further research on commonalities of biological networks.Conselho Nacional de Desenvolvimento Científico e TecnológicoSão Paulo Research FoundationKillam TrustsThe Brazilian Federal Agency for Support and Evaluation of Graduate Education within the Ministry of Education of BrazilFundação de Amparo à Pesquisa e Inovação do Estado de Santa Catarin

Is oxygen limitation in warming waters a valid mechanism to explain decreased body sizes in aquatic ectotherms?

Aim:The negative correlation between temperature and body size of ectothermic animals (broadly known as the temperature‐size rule or TSR) is a widely observed pattern, especially in aquatic organisms. Studies have claimed that the TSR arises due to decreased oxygen solubility and increasing metabolic costs at warmer temperatures, whereby oxygen supply to a large body becomes increasingly difficult. However, mixed empirical evidence has led to a controversy about the mechanisms affecting species’ size and performance under different temperatures. We review the main competing genetic, physiological and ecological explanations for the TSR and suggest a roadmap to move the field forward. Location: Global. Taxa: Aquatic ectotherms. Time period: 1980–present. Results: We show that current studies cannot discriminate among alternative hypotheses and none of the hypotheses can explain all TSR‐related observations. To resolve this impasse, we need experiments and field‐sampling programmes that specifically compare alternative mechanisms and formally consider energetics related to growth costs, oxygen supply and behaviour. We highlight the distinction between evolutionary and plastic mechanisms, and suggest that the oxygen limitation debate should separate processes operating on short, decadal and millennial time‐scales. Conclusions: Despite decades of research, we remain uncertain whether the TSR is an adaptive response to temperature‐related physiological (enzyme activity) or ecological changes (food, predation and other mortality), or a response to constraints operating at a cellular level (oxygen supply and associated costs). To make progress, ecologists, physiologists, modellers and geneticists should work together to develop a cross‐disciplinary research programme that integrates theory and data, explores time‐scales over which the TSR operates, and assesses limits to adaptation or plasticity. We identify four questions for such a programme. Answering these questions is crucial given the widespread impacts of climate change and reliance of management on models that are highly dependent on accurate representation of ecological and physiological responses to temperature

WPŁYW WYCIĄGÓW Z ROŚLIN BODZISZKOWATYCH NA BIELINKA KAPUSTNIKA

The conducted studies comprised the analyses of activity of extracts derived from selected plants of the Geranium family on some processes of large white butterfly (Pieris brassicae) development (oviposition, survival of eggs and caterpillar feeding). The results proved that all tested extracts showed activity against large white butterfly. Geranium pratense L. and Geranium senquineum L. showed better activity than other Geranium plants. Water extracts from these species protected cabbage plants against laying eggs, while applied on eggs caused their mortality. Alcohol and water extracts from G. pratense L. and water extracts from G. senquineum L. increased an amount of food put on mass gain of caterpillars.Analizowano oddziaływanie ekstraktów uzyskanych z wybranych roślin z rodziny Bodziszkowate na: rozwój bielinka kapustnika (przebieg składania jaj, przeżywalność jaj oraz na żerowanie gąsienic). Stwierdzono, że wszystkie testowane wyciągi, wykazywały aktywne działanie w stosunku do bielinka kapustnika. Szczególnie wyróżniały się bodziszek łąkowy i bodziszek czerwony. Wodne wyciągi z tych roślin chroniły rośliny kapusty przed składaniem na nie jaj przez samice, a zastosowane na jaja, powodowały ich zamieranie. Alkoholowy i wodny wyciąg z bodziszka łąkowego oraz wyciąg wodny z bodziszka czerwonego wpływały na zwiększenie ilości pokarmu zużywanego na przyrost masy ciała gąsienic

TRY plant trait database - enhanced coverage and open access

Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

TRY plant trait database - enhanced coverage and open access

Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives