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This study assesses spatiotemporal and sex-specific growth of Atlantic cod Gadus morhua in Icelandic waters. We use a Bayesian approach which lends itself to fitting and comparing nested models such as these. We then compare fitted parameters of these models to potential explanatory variables using a redundancy analysis (RDA) to look for drivers of growth in G. morhua. Results indicate that models that incorporate differences in growth among time, space and sex are the best-fitting models according to deviance information criterion (DIC). Results from RDA indicate that capelin Mallotus villosus recruitment and biomass is highly correlated with deviations in the von Bertalannfy growth parameter k and that L∞ is correlated with G. morhua landings in the model that uses year to account for time-varying growth and estimated G. morhua recruitment in the model that uses cohort to account for time-varying growth.

Selectivity curves for sampling size-at-age data are somewhat infamous for biasing growth curve parameter estimates. However, aspects of growth itself can also feed into this phenomenon and further increase bias into parameter estimates. We performed a simulation study by producing size-at-age data under a variety of growth curve parameter values and length-based selectivity curve parameter values for two selectivity functions by altering parameters both independently and in conjunction. In tests where parameters were altered one at a time the greatest amount of bias in growth curve parameter estimates came from sampling the data using dome-shaped selectivity. In addition, certain aspects of growth (namely variance in size-at-age) enhanced the biasing effect of both dome-shaped and asymptotic selectivity. When all parameters were altered together the greatest bias occurred in instances where length distributions overlapped to a greater degree and when asymptotic selectivity curves were more mildly sloped. We conclude that bias in growth curve parameter estimates is a result of the statistical weighting of both the probability of being a certain size at a given age and the probability of being captured at that size.

Arbuscular mycorrhizal fungi (AMF) are important for plant nutrient and water acquisition. Much is known about how nutrient addition and environment affect AMF, but little is known about nutrient by environment interactions. We measured AMF colonization with nutrient additions and along an environmental gradient to assess these interactions. We measured AMF colonization in roots of little bluestem (Schizachyrium scoparium (Michx) Nash) with nutrient addition and across an environmental gradient. We assessed how AMF colonization changed across different fertilization treatments, and used ridge regression to determine nutrient, environment, and nutrient by environment interaction variables that predicted AMF colonization. The addition of nitrogen decreased AMF colonization, while mean annual temperature (MAT) and soil pH both positively predicted the percentage of AMF colonization in Schizachyrium scoparium. Additionally, we found an interaction term between MAT and phosphorus treatments that significantly affected percent AMF colonization. Our results show the importance of understanding environmental conditions on AMF as well as nutrient by environment interactions when assessing how AMF respond to nutrient addition. Here we present a full-factorial nutrient addition study along an environmental gradient to assess how AMF root colonization is influenced by abiotic factors in addition to nutrients.

Frater P, Mikulyuk A, Barton M, Nault M, Wagner K, Hauxwell J, Kujawa E. 2017. Relationships between water chemistry and herbicide efficacy of Eurasian watermilfoil management in Wisconsin lakes. Lake Reserve Manage. 33:1–7.Eurasian watermilfoil (EWM) is an invasive aquatic plant with the potential to disrupt native aquatic plant communities, decrease property values, and affect recreational uses of lakes. Much time, effort, and money is put forth every year to combat the spread of this invader. We examined the long-term efficacy of EWM management using herbicide and derived an empirical equation to quantify long-term treatment success for the lakes in this study. We found that lakes with lower pH (

Several techniques have been proposed and tested to alleviate the common problem of selectivity bias in fish size-at-age data used for fitting growth models. Many of these techniques have not been directly compared to each other, though. Here, we test six methods for correcting selectivity bias in fish growth models using two selectivity shapes and across three life history types. We also include an example of fitted growth curve parameters from each method using data on Atlantic cod (Gadus morhua L.) from standardized surveys in the waters surrounding Iceland. Lastly, we present simulations that incorporate three types of misspecification on each method, selectivity type, and life-history strategy to discern the impacts of incorrect assumptions stemming from each method. Age structured populations are simulated, and the basic von Bertalanffy growth curve is used as the mean to assign normally-distributed length-at-age data which are sampled under two selectivity shapes. Growth parameters are then estimated using these data for each of six bias-correction methods. In general, likelihood-based bias-correction methods resulted in growth parameter estimates that are closer to true values used as well as more similar to parameter estimates derived from data sampled with no selectivity. The method introduced by Troynikov (1999) performed best for both simulation and misspecification scenarios. This result is true of both dome-shaped and asymptotic selectivity as well as across life-history types.

We were ecstatic when our supervisors allowed us to work remotely. Friends in graduate school, we hadn't worked in the same place in years. But our lives had taken a similar turn. Paul—a scientist at a state agency at the time—was living apart from his wife on weekdays. Every Friday he'd leave his office and drive 3 hours to spend the weekend at home, but with his wife pregnant with their first child, that situation would soon become untenable. Lauren, a newly married postdoc, lived in a different state than her husband and was growing weary of long-distance romance. Our work lives revolved around computer analyses and writing, so remote work was feasible. It seemed like an ideal solution. ![Figure][1] ILLUSTRATION: ROBERT NEUBECKER Paul, an introvert, harbored fantasies of burying himself in computer tasks, free of the noise and distractions of offices. But when he started to work from home, he struggled to maintain focus and avoid getting sucked into house chores. As Wisconsin's bitter winter took hold, snow buried his office window, and he felt closed in. Three months into his new arrangement, he learned that Lauren, an extrovert, was also working from home. He found some relief in learning that she, too, was struggling with isolation. We weren't about to give up on remote work, but we needed better ways to cope. The two of us began to email back and forth, sharing challenges we faced and methods we'd found helpful for staying productive. After we got into the swing of things, we surveyed 16 other remote scientists to generate some tips for success. SET REALISTIC GOALS. When you don't have a boss looking over your shoulder, you become your own taskmaster. Setting small, manageable daily tasks that contribute to your longer-term goals can help keep you on track. Make sure to hold yourself accountable, for instance by scheduling regular check-ins with a supervisor or colleague. BE CONSISTENT. Wake up each morning, change out of your pajamas, and maintain a regular schedule. Act as if you have a job to go to—because, after all, you do. REDUCE DISTRACTIONS. Do not let laundry, dishwashing, cleaning, and other chores consume your workday. You may also have to guard against social disruptions, as some people seem to think that if you work remotely, you can do whatever you want at any time of day. CREATE A DISCRETE WORKSPACE. When you're working, be at work—both mentally and physically. It helps to have a separate office. If that's not possible, try to arrange your furniture in a way that distinguishes your work and nonwork space. REWARD PRODUCTIVITY. If you are productive for an hour or two and accomplish a task, then treat yourself to a 15-minute break. Get a cup of coffee, take a walk, browse the internet, play with your dog, or do something else that you enjoy. SEEK OUT HUMAN INTERACTION. Scientific discovery is collaborative, and it can be difficult to interact with colleagues while working from home. Get out and attend meetings and conferences. Schedule Skype calls with other scientists or communicate via Slack. Consider spending a few hours working in a social setting such as a coffee shop. When we first started to work remotely, we suffered from feelings of entrapment and isolation. But now—3.5 years in for Paul and 2 years in for Lauren—we've learned how to manage our new arrangement so that we can be productive scientists and live in the same city as our loved ones. We're not planning on a lifetime of full-time remote work—in fact, Lauren's remote journey will be over when she starts a faculty position next month—but we have to say that remote working has its perks. For one thing, it's hard to complain about a 10-second commute. [1]: pending:yes

Various factors have been known to influence the percentage of mycorrhizal colonization in plants. However, it is unknown whether certain factors matter at different scales or if one or several factors have an overarching effect on controlling rates of mycorrhizal colonization in plants. In this thesis I assessed the percentage of mycorrhizal colonization in Schizhachyrium scoparium at 5 different sites that occur along a latitude gradient to determine which factors had an overarching effect and if there were site-­‐specific differences in responses to nutrient addition. In the first chapter I present what factors affected the percentage of mycorrhizal colonization along a latitude gradient. I found that aridity was the only factor to contribute to changes in the percentage of mycorrhizal colonization. In my second chapter I used this information to account for differences between sites and assess responses in the percentage of mycorrhizal colonization among sites to see if there was a difference among sites. I found that the addition of nitrogen (N) decreased the percentage of mycorrhizal colonization in Schizachyrium scoparium across sites, but that the addition of phosphorus (P) had different effects among sites. Responses to the addition of P exhibited a U-­‐shaped pattern in relation to ambient N:P ratio in soil at the sites. The results found in the first chapter of this thesis are novel and important to understanding plant-­‐mycorrhizae relationships in plants while the results found in the second chapter agree with the current theory that exists to explain how resource stoichiometry affects the percentage of mycorrhizal colonization in plants.

Eurasian watermilfoil (Myriophyllum spicatum) is a non‐native and invasive aquatic macrophyte with a broad North American distribution. It can have significant negative effects on invaded waterbodies, including decreased native macrophyte diversity, formation of recreational nuisances, and lowered lakefront property values. Previous research suggests that M. spicatum decreases in response to herbicide treatment, but most studies are spatially and temporally limited, usually focusing on a single waterbody for a single year. The long‐term effects of herbicides remain relatively unknown. Here, we share the results of an 11‐yr observational study of aquatic macrophyte diversity, dynamics, and response to herbicide treatment on 28 Wisconsin lakes (15 of which were adaptively managed with herbicide for M. spicatum and 13 of which acted as unmanaged reference lakes). We found that overall, adaptive management decreases M. spicatum abundance over time, but that the efficacy of individual herbicide treatments can vary. We also found that lakes with relatively new M. spicatum populations (discovered within the last decade) treated smaller areas with lower frequency than lakes with established populations, and were able to maintain lower M. spicatum abundance. This suggests that using adaptive, science‐based aquatic plant management strategies, including early detection and response, may increase invasive species management success. Finally, we show that the effect of herbicide treatment on native macrophytes is variable and can be significant. Overall, our results suggest that while herbicide treatment can be an effective adaptive management tool, particularly in lakes with relatively recent M. spicatum invasions, the specific effects of individual treatments can be unpredictable. This study allows lake stakeholders to better understand the efficacy of herbicide treatment, in addition to the possible non‐target effects on native macrophyte species.

Cites are relatively new landscapes for breeding Cooper's Hawks (Accipiter cooperii) that nest commonly in urban and rural habitats throughout North America. There is a call for data that may indicate if cities are low quality, sink habitats, as for some other raptors, or if cities function as high-quality, source habitats. Source habitats should exhibit high nesting densities, high reproductive output, and they should produce net emigration to sites that offer the potential for greater fitness. There are no reports of connectivity via dispersed individuals and their reproductive success (i.e., gene flow) between rural and urban subpopulations for Cooper's Hawks in North America. We report one of the highest nesting densities in North America, one nest/238 ha in the city of Oshkosh, Wisconsin in 2015, with regular spacing of nests suggestive of the saturated, stable population which occurs elsewhere throughout the state. Averages of 4.7 eggs and 4.1 nestlings per nest in Oshkosh, respectively, rank among the highest metrics for the species, and are similar to the stable and high reproductive indices found elsewhere throughout rural and other urban Wisconsin habitats across 34 y (1980–2015). An apparent low index of hatchling mortality rate (10%), or the loss of offspring from clutch to brood counts, was also found in Oshkosh. We detected both breeding and natal dispersal, with relatively high clutch and nestling counts, among eight individual Cooper's Hawks of both sexes moving into and emigrating from Stevens Point, Wisconsin with surrounding rural habitats. Most dispersal movements were less than 10 km. A relative similarity in maximum dispersal distances across 38 y (1980–2017) for rural-to-rural movements in males (35 km) and females (79 km), with those distances in males (27 km) and females (48 km) that moved between Stevens Point and its rural surroundings, suggest the maximum extent of natal dispersal movements is not habitat-specific in Wisconsin Cooper's Hawks. Discussion of various demographic contexts, including potentially confounding ecological variables, revealed limitations to previous reports and interpretations of reproductive output and nesting densities for the species, including assessments of habitat quality. We suggest high-quality rural and urban nesting habitats in Wisconsin are not source habitats for Cooper's Hawks within the state given none comparatively appears to offer the potential for greater fitness. Therefore, there should be no net dispersal among habitat types.

The Golden Ratio (a ratio of ~1.618:1) appears repeatedly in nature including structural and functional traits of organisms (e.g. Fibonacci spirals of snail shells and certain seed heads), the spiraled shape of galaxies and hurricanes, and even in much cultural architecture and art. In the mid-19th century, branching structures in plant and animal vascular systems were found to follow the Golden Ratio; that is, successive branches in the vascular systems of plants and animals tend to follow a length ratio of about 1.618:1. Here we present a model that uses this empirical evidence as a branching ratio in theoretical vascular systems. We then use a defined mass of the model system as a predictor of log-log scaling of terminal units. In this model, log terminal units and log mass scale similarly with that of other models as well as empirical evidence, but with more parsimony and a perspective not yet offered among all available models of allometric scaling. This model invites novel and broad hypotheses on the influence of the Golden Ratio on power scaling in organisms.

Exotic species dominate many communities; however the functional significance of species' biogeographic origin remains highly contentious. This debate is fuelled in part by the lack of globally replicated, systematic data assessing the relationship between species provenance, function and response to perturbations. We examined the abundance of native and exotic plant species at 64 grasslands in 13 countries, and at a subset of the sites we experimentally tested native and exotic species responses to two fundamental drivers of invasion, mineral nutrient supplies and vertebrate herbivory. Exotic species are six times more likely to dominate communities than native species. Furthermore, while experimental nutrient addition increases the cover and richness of exotic species, nutrients decrease native diversity and cover. Native and exotic species also differ in their response to vertebrate consumer exclusion. These results suggest that species origin has functional significance, and that eutrophication will lead to increased exotic dominance in grasslands., It remains unclear whether exotic and native species are functionally different. Using a global grassland experiment, Seabloom et al. show that native and exotic species respond differently to two globally pervasive environmental changes, addition of mineral nutrients and alteration of herbivore density.

Invasions have increased the size of regional species pools, but are typically assumed to reduce native diversity. Invasions have increased the size of regional species pools, but are typically assumed to reduce native diversity. However, global-scale tests of this assumption have been elusive because of the focus on exotic species richness, rather than relative abundance. This is problematic because low invader richness can indicate invasion resistance by the native community or, alternatively, dominance by a single exotic species. Here, we used a globally replicated study to quantify relationships between exotic richness and abundance in grass-dominated ecosystems in 13 countries on six continents, ranging from salt marshes to alpine tundra. We tested effects of human land use, native community diversity, herbivore pressure, and nutrient limitation on exotic plant dominance. Despite its widespread use, exotic richness was a poor proxy for exotic dominance at low exotic richness, because sites that contained few exotic species ranged from relatively pristine (low exotic richness and cover) to almost completely exotic-dominated ones (low exotic richness but high exotic cover). Both exotic cover and richness were predicted by native plant diversity (native grass richness) and land use (distance to cultivation). Although climate was important for predicting both exotic cover and richness, climatic factors predicting cover (precipitation variability) differed from those predicting richness (maximum temperature and mean temperature in the wettest quarter). Herbivory and nutrient limitation did not predict exotic richness or cover. Exotic dominance was greatest in areas with low native grass richness at the site- or regional-scale. Although this could reflect native grass displacement, a lack of biotic resistance is a more likely explanation, given that grasses comprise the most aggressive invaders. These findings underscore the need to move beyond richness as a surrogate for the extent of invasion, because this metric confounds monodominance with invasion resistance. Monitoring species' relative abundance will more rapidly advance our understanding of invasions. Fil: Seabloom, Eric W.. University of Minnesota; Estados Unidos Fil: Borer, Elizabeth T.. University of Minnesota; Estados Unidos Fil: Buckley, Yvonne. The University Of Queensland; Australia Fil: Cleland, Elsa E.. University of California, San Diego; Estados Unidos Fil: Kendi, Davies. State University of Colorado Boulder; Estados Unidos Fil: Firn, Jennifer. Queensland University of Technology. Brisbane; Australia Fil: Hartpole, Stanley W.. Iowa State University; Estados Unidos Fil: Hautier, Yann. University of Zurich; Suiza Fil: Lind, Eric. Universidad de Minnesota; Estados Unidos Fil: MacDougall, Andrew. University of Guelph; Canadá Fil: Orrock, John L.. University of Wisconsin; Estados Unidos Fil: Prober, Suzanne M.. CSIRO Ecosystem Sciences; Australia Fil: Adler, Peter. Utah State University; Estados Unidos Fil: Alberti, Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Anderson, T. Michael. Wake Forest University; Estados Unidos Fil: Bakker, Jonathan D.. University of Washington; Estados Unidos Fil: Biederman, Lori A.. Iowa State University; Estados Unidos Fil: Blumenthal, Dana. Rangeland Resources Research Unit; Estados Unidos Fil: Browns, Cynthia S.. State University of Colorado - Fort Collins; Estados Unidos Fil: Brudvig, Lars A.. Michigan State University; Estados Unidos Fil: Caldeira, Maria. Technical University of Lisbon; Portugal Fil: Chu, Chengjin. Lanzhou University; China Fil: Crawley, Michel. Imperial College London; Reino Unido Fil: Daleo, Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Damschen, Ellen I.. University of Wisconsin; Estados Unidos Fil: D'antonio, Carla. University of California; Estados Unidos Fil: Decrappeo, Nicole. Geological Survey Forest and Rangeland Ecosystem Science Center; Estados Unidos Fil: Dickman, Chris. University of Sydney; Australia Fil: Du, Guozhen. Lanzhou University; China Fil: Fay, Philip. Grassland Soil and Water Research Lab; Estados Unidos Fil: Frater, Paul. Iowa State University; Estados Unidos Fil: Gruner, Daniel S.. University of Queensland; Australia Fil: Hagenah, Nicole. University of KwaZulu-Natal; Sudáfrica Fil: Hector, Andrew. University of Zurich; Suiza Fil: Helm, Avellina. University Of Tartu.; Estonia Fil: Hillebrand, Helmut. Carl-von-Ossietzky University; Alemania Fil: Hofmockel, Kirsten. Iowa State University; Estados Unidos Fil: Humphries, Hope. State University of Colorado - Fort Collins; Estados Unidos Fil: Iribarne, Oscar Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Jin, Virginia L.. Agroecosystem Management Research Unit; Estados Unidos Fil: Kay, Adam. University of St. Thomas; Estados Unidos Fil: Kirkman, Kevin. University of KwaZulu-Natal; Estonia Fil: Klein, Julia. State University of Colorado - Fort Collins; Estados Unidos Fil: Knops, Johannes M. H.. University Of Nebraska; Estados Unidos Fil: La Pierre, Kimberly. Yale University; Estados Unidos Fil: Ladwig, Laura M.. University Of New Mexico; Estados Unidos Fil: Lambrinos, John G.. Oregon State University; Estados Unidos Fil: Leakey, Andrew. University of Illinois at Urbana-Champaign; Estados Unidos Fil: Li, Qi. Northwest Institute of Plateau Biology, Chinese Academy of Sciences; China Fil: Li, Wei. Southwest Forestry University; China Fil: McCulley, Rebecca. University Of Kentucky; Estados Unidos Fil: Melbourne, Brett. State University of Colorado Boulder; Estados Unidos Fil: Mitchell, Charles. University of North Carolina; Estados Unidos Fil: Moore, Joslin. Australian Research Centre for Urban Ecology; Australia Fil: Morgan, John. La Trobe University; Australia Fil: Mortensen, Brent. Iowa State University; Estados Unidos Fil: O'Halloran, Lydia. Oregon State University; Estados Unidos Fil: Pärtel, Meelis. University Of Tartu.; Estonia Fil: Pascual, Jesus Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Pyke, David A.. University of California; Estados Unidos Fil: Risch, Anita. Swiss Federal Institute For Forest, Snow And Landscape Research; Suiza Fil: Salguero Goméz, Roberto. The University Of Queensland; Australia Fil: Sankaran, Mahesh. National Centre for Biological Sciences; India Fil: Schuetz, Martin. Swiss Federal Institute For Forest, Snow And Landscape Research; Suiza Fil: Simonsen, Anna. University of Toronto; Canadá Fil: Smith, Melinda. State University of Colorado - Fort Collins; Estados Unidos Fil: Stevens, Carly. Lancaster Environment Center; Canadá Fil: Sullivan, Lauren. Iowa State University; Estados Unidos Fil: Wardle, Glenda M.. University of Sydney; Australia Fil: Wolkovich, Elizabeth M.. University of British Columbia; Canadá Fil: Wragg, Peter D.. The University Of Queensland; Australia Fil: Wright, Justin. University of Duke; Estados Unidos Fil: Yang, Louie. University of California; Estados Unidos

For more than 30 years, the relationship between net primary productivity and species richness has generated intense debate in ecology about the processes regulating local diversity. The original view, which is still widely accepted, holds that the relationship is hump-shaped, with richness first rising and then declining with increasing productivity. Although recent meta-analyses questioned the generality of hump-shaped patterns, these syntheses have been criticized for failing to account for methodological differences among studies. We addressed such concerns by conducting standardized sampling in 48 herbaceous-dominated plant communities on five continents. We found no clear relationship between productivity and fine-scale (meters(-2)) richness within sites, within regions, or across the globe. Ecologists should focus on fresh, mechanistic approaches to understanding the multivariate links between productivity and richness.