Selective harvest of large individuals should alter natural adaptive landscapes and drive evolution toward reduced somatic growth and increased reproductive investment. However, few studies have simultaneously considered the relative importance of artificial and natural selection in driving trait changes in wild populations. Using 50 years of individual-based data on Windermere pike (Esox lucius), we show that trait changes tracked the adaptive peak, which moved in the direction imposed by the dominating selective force. Individual lifetime somatic growth decreased at the start of the time series because harvest selection was strong and natural selection was too weak to override the strength of harvest selection. However, natural selection favoring fast somatic growth strengthened across the time series in parallel with the increase in pike abundance and, presumably, cannibalism. Harvest selection was overridden by natural selection when the fishing effort dwindled, triggering a rapid increase in pike somatic growth. The two selective forces appear to have acted in concert during only one short period of prey collapse that favored slow-growing pike. Moreover, increased somatic growth occurred concurrently with a reduction in reproductive investment in young and small female pike, indicating a tradeoff between growth and reproduction. The age-specific amplitude of this change paralleled the age-specific strength of harvest pressure, suggesting that reduced investment was also a response to increased life expectancy. This is the first study to demonstrate that a consideration of both natural selection and artificial selection is needed to fully explain time-varying trait dynamics in harvested populations.adaptive landscapes ͉ conservation ͉ contemporary evolution ͉ fisheries ͉ top predators

Dengue, a viral infection transmitted between people by mosquitoes, is one of the most rapidly spreading diseases in the world. Here, we report the analyses covering 11 y (2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015) from the city of Guangzhou in southern China. Using the first 8 y of data to develop an ecologically based model for the dengue system, we reliably predict the following 3 y of dengue dynamics-years with exceptionally extensive dengue outbreaks. We demonstrate that climate conditions, through the effects of rainfall and temperature on mosquito abundance and dengue transmission rate, play key roles in explaining the temporal dynamics of dengue incidence in the human population. Our study thus contributes to a better understanding of dengue dynamics and provides a predictive tool for preventive dengue reduction strategies.D engue is one of the most rapidly spreading diseases in the world (1), including within the Guangdong province of southern China (2). During the last 50 y, the incidence of dengue has increased 30-fold with increasing geographic expansion to new countries (1). In 2010, an estimated 390 million dengue infections occurred, of which around 96 million showed symptoms (3). Dengue outbreaks in China were previously thought to be imported and initiated by people traveling to China from dengue-endemic areas elsewhere (4); however, recent studies suggest that dengue may now be endemic to China as well (2). The epidemiological triangle of both dengue fever and dengue hemorrhagic fever, which is the more serious form of dengue, includes hosts (humans), pathogens (one or more of five dengue virus serotypes) (5), and mosquito vectors (Aedes albopictus and Aedes aegypti) with their ecological interactions (6). The dengue outbreaks are qualitatively known to be strongly influenced by temperature (7), humidity, rainfall, and socioeconomic factors like urbanization (8). However, a full understanding of the quantitative nature of such effects is largely lacking. With this paper, we provide such a quantitative understanding of dengue dynamics.In 2014, an extensive dengue outbreak hit China, with 47,127 dengue cases diagnosed, a new record since 1986 (9). Since the 1990s, dengue epidemics have gradually spread from Guangdong, Hainan, and Guangxi provinces (9). We present here a time series analysis of dengue dynamics, using dengue surveillance data for the years 2005−2015 from Guangzhou, the largest city in Guangdong and the city with the most dengue cases in China. We split the main analysis by using the first 8 y to develop a model, and the three remaining years to test that model, as these latter years encompass exceptionally extensive dengue outbreaks.Monthly human dengue incidence data (number of diagnosed cases) were obtained from the China National Notifiable Disease Surveillance System (10) (Fig. 1). Monthly surveillance data of A. albopictus density, the only dengue vector species in Guangzhou, were obtained from local Centers for Disease Control and Prevention (11) (Metho...

Many species of fungi produce ephemeral autumnal fruiting bodies to spread and multiply. Despite their attraction for mushroom pickers and their economic importance, little is known about the phenology of fruiting bodies. Using Ϸ34,500 dated herbarium records we analyzed changes in the autumnal fruiting date of mushrooms in Norway over the period 1940 -2006. We show that the time of fruiting has changed considerably over this time period, with an average delay in fruiting since 1980 of 12.9 days. The changes differ strongly between species and groups of species. Early-fruiting species have experienced a stronger delay than late fruiters, resulting in a more compressed fruiting season. There is also a geographic trend of earlier fruiting in the northern and more continental parts of Norway than in more southern and oceanic parts. Incorporating monthly precipitation and temperature variables into the analyses provides indications that increasing temperatures during autumn and winter months bring about significant delay of fruiting both in the same year and in the subsequent year. The recent changes in autumnal mushroom phenology coincide with the extension of the growing season caused by global climate change and are likely to continue under the current climate change scenario.phenology ͉ global warming ͉ herbarium data ͉ fungi ͉ agarics P henological changes are among the most sensitive ecological responses to changing climate (1-3). The observed extension of the average annual growing season in Europe by nearly 11 days since the early 1960s (4) has been followed by rapid and recent changes in plant flowering time (5-8) and earlier spring migration in several bird species (9). In a recent study from the United Kingdom, it was reported for a set of mushroom species that fruiting on average started earlier and ended later in the season in recent years than 20 years ago, i.e., that the fruiting period has been greatly extended (10). These changes were linked to increased temperature and rainfall in August and October, respectively (10).Most fungi produce ephemeral fruiting bodies that can be observed only for a few days each year, which makes phenological data difficult and time-consuming to obtain. However, because of the short endurance of the fruiting bodies, collection time is a good estimate of fruiting time. A potential source of phenological information for this group of organisms is therefore herbarium collections, which, although sampled in a nonsystematic manner, share properties with random sampling processes. Herbarium data can enable us to understand and predict climate-induced ecological changes in the future by understanding how climate has affected ecological processes in the past. Several studies have already documented that herbarium collections may represent a valuable source of long-term and reliable phenological information (e.g., refs. 7 and 8).Our study of temporal trends in fruiting phenology is based on Ͼ34,500 herbarium records collected in Norway during the period 1940-2006 and representin...

The impact of the environment on interannual variability in fish recruitment has proven difficult to establish empirically, and environment-recruitment correlations have often been found to break down when more data become available. This may suggest that the statistical models have failed to capture the essential explanatory variables, or that environment-recruitment relationships are non-stationary, and thus actually change. The present paper explores the effect of climate, measured by the North Atlantic Oscillation (NAO), on the recruitment of North Atlantic cod Gadus morhua. The literature on the topic is reviewed and compared with results from a new analysis, in which data from all 22 main stocks are combined in 1 overall model. Results of the new analysis demonstrate (i) a geographic pattern in the effect of the NAO on recruitment, which resembles the geographic pattern of the correlation between the NAO and sea surface temperature, and (ii) trends in recruitment levels as well as in the effects of climate. These trends are not fully explainable through changes in spawning stock biomass. Summarizing the old and new insights, we arrive at the following general conclusions: NAO affects cod recruitment through local environmental variables such as sea temperature, salinity, oxygen, turbulence and advection. Cod recruitment is densitydependent, although the new analysis does not unequivocally support the existence of general patterns of density-dependent climate effects. There are trends in cod recruitment and in the relationship between climate and recruitment, possibly caused by demographic changes in the cod stocks (e.g. fishing-induced) and changes in the biotic or abiotic environment (regime shifts).KEY WORDS: Fish recruitment · Climate effect · Non-stationarity · Density-dependence · Gadus morhua Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 325: [227][228][229][230][231][232][233][234][235][236][237][238][239][240][241] 2006 ever proven difficult to establish empirically: reported environment-recruitment correlations have often been found to break down when more information becomes available (Drinkwater & Myers 1987, Myers 1998. A notable exception is temperature effects near species' northern or southern distributional ranges, which have generally been found to be consistent upon retesting.One possible explanation for the breakdown of correlations is that the models have failed to capture the essential explanatory variables. This is not unlikely, as the statistical modelling is complicated by the correlation among the explanatory variables and the limited number of years for which data are available for any given stock. Alternatively, the environmental effects may be non-stationary: the nature of the relationship between fish recruitment and the physical environment may vary over time ). For example, because cod have been heavily exploited by fisheries, many stocks have declined during recent decades. This has resulted in reductions in spaw...

Accumulating evidence shows that environmental fluctuations and exploitation jointly affect marine fish populations, and understanding their interaction is a key issue for fisheries ecology. In particular, it has been proposed that age truncation induced by fisheries exploitation may increase the population's sensitivity to climate. In this study, we use unique long-term abundance data for the Northeast Arctic stock of cod (Gadus morhua) and the Norwegian SpringSpawning stock of herring (Clupea harengus), which we analyze using techniques based on age-structured population matrices. After identifying time periods with different age distributions in the spawning stock, we use linear models to quantify the relative effect of exploitation and temperature on the population growth rates. For the two populations, age truncation was found to be associated with an increasing importance of temperature and a relatively decreasing importance of exploitation, while the population growth rate became increasingly sensitive to recruitment variations. The results suggested that the removal of older age classes reduced the buffering capacity of the population, thereby making the population growth rate more dependent on recruitment than adult survival and increasing the effect of environmental fluctuations. Age structure appeared as a key characteristic that can affect the response of fish stocks to climate variations and its consequences may be of key importance for conservation and management.