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Differences in phenological responses to climate change among species can desynchronise ecological interactions and thereby threaten ecosystem function. To assess these threats, we must quantify the relative impact of climate change on species at different trophic levels. Here, we apply a Climate Sensitivity Profile approach to 10,003 terrestrial and aquatic phenological data sets, spatially matched to temperature and precipitation data, to quantify variation in climate sensitivity. The direction, magnitude and timing of climate sensitivity varied markedly among organisms within taxonomic and trophic groups. Despite this variability, we detected systematic variation in the direction and magnitude of phenological climate sensitivity. Secondary consumers showed consistently lower climate sensitivity than other groups. We used mid-century climate change projections to estimate that the timing of phenological events could change more for primary consumers than for species in other trophic levels (6.2 versus 2.5–2.9 days earlier on average), with substantial taxonomic variation (1.1–14.8 days earlier on average). An ambitious study has used more than 10,000 datasets to examine how the phenological characteristics—such as the timing of reproduction—of various taxa alter in response to climate change, and suggests that differing levels of climate sensitivity could lead to the desynchronization of seasonal events over time. The shifting biological seasons Variations in the phenological responses of different species to climate change have fuelled concerns that key species interactions may desynchronize over time, with consequences for ecosystem functioning. Stephen Thackeray et al . examine the climate sensitivity of 812 terrestrial and aquatic taxa across the United Kingdom, using more than 10,000 phenological data sets spanning 1960 to 2012, together with temperature and precipitation data. There was a systematic difference in the magnitude and direction of phenological climate sensitivity across trophic levels, despite marked heterogeneity among organisms sharing taxonomic affinities and trophic position. In particular, secondary consumers showed lower levels of climate sensitivity than primary producers and consumers. The authors suggest that the differential sensitivity of phenology to climate across trophic levels could result in the desynchronization of seasonal events in the future.

Here, we assess the utility of PCR primers designed from the SRY sequence of the Eurasian otter Lutra lutra for sex identification using DNA from tissue and feces, or spraints, of L. lutra and tissue of five other otter species, and the lack of detection of artefacts using DNA of one prey species and human.

Atlantic salmon exhibit a partially heritable polymorphism in which the morphs are distinguished by the duration and location of the sea-phase of their life-cycle. These morphs co-occur, albeit in characteristically different proportions, in most Scottish rivers and in both the spring and autumn spawner runs; early running fish being generally associated with upland spawning locations while late running fish are associated with lowland spawning. Thus, differences in riverine and marine environment appear to be linked to differences in the relative abundance of the morphs, rather than to the specific morph which is optimally adapted. In this paper, we report a model-based synthetic study aimed at understanding the key dynamic elements which determine the long-term stability of this polymorphism, and thus determine the relative abundance of the various sea-age morphs. Given the recent accumulation of evidence for a genetic basis for the polymorphism, we argue that the key dynamic mechanism which equalises the realized fitness of the sea-age morphs must be one or more morph-specific density dependencies in the riverine phase of the life-history. We explore a number of specific mechanisms, firmly based in known salmon biology, by which such morph-specific density dependence could occur and investigate the robustness of the co-existence which they imply. We conclude that the co-occurrence of multiple sea-age morphs of Atlantic salmon in Scottish rivers is a stable genetic polymorphism, maintained by some combination of physical separation and asymmetric competition between spawners of different morphs or the riverine stages of their offspring or both.

In this paper, we describe a discrete-time formalism for describing the dynamics of the size-at-age distribution of a cohort of individuals exhibiting irreversible von Bertalanffy growth in a statistically uniform random environment. This formalism yields a highly efficient numerical implementation, which is particularly suited to automatic optimization. In the special case where mortality is sufficiently size-independent not to vary substantially across the bulk of the size distribution at any given age, we can further increase this efficiency by deriving compact update rules for the mean and coefficient of variation of size-at-age. In this case, we also demonstrate that the depensatory effect of random growth variability and the compensatory effect of deterministic von Bertalanffy growth balance to yield an attracting (initial condition independent) trajectory of mean length and length coefficient of variation against age. We demonstrate the applicability and extensibility of this formalism by two exemplary applications - juvenile salmonids and demersal cod.

1. We report a modelling study of a data-set describing the growth of individual Atlantic salmon (Salmo salar L.) parr in the Girnock Burn (Scotland). A development of the compensatory growth model due to Broekhusien et al. (1994) was fitted to these data by numerical optimization. 2. The model uses carbon mass as a surrogate for an energy currency. This mass is divided into structure and reserve components, so as to describe decoupled changes in length and wet-weight. 3. Using the same parameters for all fish, our model explained 83% of the variability in length and weight at age. Adding a single additional parameter for each individual enabled the model to explain over 96% of length and weight variability. 4. Weak negative correlation between size at first capture and within-study growth argues against genetic causality of observed growth variability. 5. The energetic basis of our model enables us to infer time-series of net assimilation and basal maintenance rates for the observed individuals. Maximal growth occurs early in the season when high assimilation is accompanied by low temperatures and maintenance rates. In late season, continuing high assimilation is balanced by high maintenance rates consequent on summer temperatures.

Fishery management policies need to be based on historical summaries of stock status which are well correlated with the size of the group of individuals who will be affected by any harvest. This paper is motivated by the problem of managing stocks of Atlantic salmon, which can be accurately monitored during the riverine stages of their life-history, but which spend a lengthy period at sea before returning to spawn. We begin by formulating a minimal stochastic model of stock-recruitment driven population dynamics, which linearises to a standard ARMA form. We investigate the relation between maturity dispersion and the auto-covariance of stock fluctuations driven by process noise in the recruitment process and/or random variability in survival from recruitment to spawning. We demonstrate that significant reductions in fluctuation intensity and/or increases in long-run average yield can be achieved by controlling harvesting in response to the value of a historical summary focussed on lags at which the uncontrolled population dynamics produce strong correlations. We apply our minimal model to two well-characterised Atlantic salmon populations, and find poor agreement between predicted and observed stock fluctuation ACF. Re-examination of the ancilliary data available for one of our two exemplary systems leads us to propose an extended model which also linearises to ARMA form, and which predicts a fluctuation ACF more closely in agreement with that observed, and could thus form a satisfactory vehicle for policy discussion.

Although gene flow and population fragmentationwill often have opposed effects on geneticstructure, their actual effects on many elusiveanimal species are unknown. We assessed sucheffects in British populations of the Eurasianotter Lutra lutra by analysis ofgenotypes consisting of 12 microsatellites from618 carcasses representing the period 1982-1998. Spatial patterns of genetic subdivisionand levels of polymorphism in the continuouspopulation in Scotland were estimated. Theseresults were used to infer patterns of geneflow in Scottish otters and assess theinfluence of fragmentation on the geneticstructure of otters in Wales and SW England.The latter showed no higher genetic divergencethan expected given the degree of isolation bydistance found in the Scottish population, andtheir distributions of microsatellite allelesizes provided no evidence for populationbottlenecks. Nonetheless, otters in southernBritain contained significantly lower levels ofmicrosatellite polymorphism than otters inScotland, and the population in the westernpeninsula of SW England was geneticallydistinct. These results suggested that thegenetic structure of the Scottish population isdue more to restricted contemporary gene flowthan to historical fluctuations insubpopulation size, and that the geneticstructure of the southern British populationsis due more to small historical effective sizesthan to recent declines. If spatiallyrestricted gene flow is typical of all Eurasianotter populations then data on dispersal shouldbe taken into account when sitting protectedareas for this species.[PUBLICATION ABSTRACT]

.— DNA sequence variation at the hypervariable 5’end of the mitochondrial control region was examined in 247 individuals to detect genetic divergence among 14 populations of red grouse (Lagopus lagopus scoticus) in northeastern Scotland. Ten haplotypes were resolved, several of which were shared among populations. Analysis of molecular variance, Nei's yST, and a cladistic estimate of the amount of gene flow indicated a lack of overall population differentiation. Patterns of overall panmixia are in stark contrast to previous reports of localized subdivision among the same set of populations detected using hypervariable microsatellite markers. Because grouse cocks are territorial and show extreme natal philopatry and females are the dispersing sex, such discordance could be explained by sexbiased dispersal, with extensive female‐mediated gene flow preventing mitochondrial DNA divergence. However, it is difficult to reconcile how effective dispersal of females would not homogenize both mitochondrial and nuclear structure simultaneously. We use a model that examines the spatial and temporal dynamics of diparentally and uniparentally inherited genes to show that, under realistic ecological scenarios and with specific differences in the dispersal of males and females, the local effective size of the nuclear genome can be less than that of the mitochondrial and the patterns of structuring we observe are meaningful.

Plant defense theories suggest that chemical or structural defences should be maximized when and where browsing is most likely to occur. We tested this hypothesis on four evergreen woody species growing in a Mediterranean area with a high density of ungulates. In this system, levels of browsing are more intense in the winter (due to the lack of annual plants) and young foliage is often preferred. Therefore we predicted that the chemical defences of these species, namely their phenolic content, would vary with leaf age, season and damage intensity. In addition, we tested whether ungulates preferentially selected species containing lower phenolic levels, and also whether browsing induced either chemical or morphological changes in damaged plants. Phenolic levels varied greatly between plant species; ungulates browsed preferentially on the species with the lowest phenolic levels. No difference in phenolic content was found between browsed and unbrowsed trees. Morphological changes in heavily browsed trees included an increase in shoot and leaf density and a net decrease in leaf size. We suggest that for Mediterranean plants, which have evolved under high browsing pressure from large mammals, the production of small leaves and dense shoots in response to browsing might decrease ungulate foraging efficiency and hence reduce the rate of further damage as effectively as high levels of chemical defence.

DNA sequence variation at the hypervariable 5′ end of the mitochondrial control region was examined in 247 individuals to detect genetic divergence among 14 populations of red grouse (Lagopus lagopus scoticus) in northeastern Scotland. Ten haplotypes were resolved, several of which were shared among populations. Analysis of molecular variance, Nei's γST, and a cladistic estimate of the amount of gene flow indicated a lack of overall population differentiation. Patterns of overall panmixia are in stark contrast to previous reports of localized subdivision among the same set of populations detected using hypervariable microsatellite markers. Because grouse cocks are territorial and show extreme natal philopatry and females are the dispersing sex, such discordance could be explained by sex-biased dispersal, with extensive female-mediated gene flow preventing mitochondrial DNA divergence. However, it is difficult to reconcile how effective dispersal of females would not homogenize both mitochondrial and nuclear structure simultaneously. We use a model that examines the spatial and temporal dynamics of diparentally and uniparentally inherited genes to show that, under realistic ecological scenarios and with specific differences in the dispersal of males and females, the local effective size of the nuclear genome can be less than that of the mitochondrial and the patterns of structuring we observe are meaningful. Corresponding Editor: J. Neigel