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1. Comparative studies about the relationships between vital rates and ecological traits at the community level are conspicuously lacking for most taxa because estimating vital rates requires detailed demographic data. Identifying relationships between vital rates and ecological traits could help to better understand ecological and evolutionary demographic mechanisms that lead to interspecific differences in vital rates. 2. We use novel dynamic N-mixture models for counts to achieve this for a whole avian community comprising 53 passerine species, while simultaneously accounting for density dependence and environmental stochasticity in recruitment and survival and, importantly, correcting our inferences for imperfect detection. Demographic stochasticity is taken into account in the form of the binomial and Poisson distributions describing survival events and number of recruits. We then explore relationships between estimated demographic parameters (i.e., vital rates) and ecological traits related to migration patterns, diet, habitat and nesting location of each species. 3. The relative importance of recruitment and adult survival as contributors to population growth varied greatly among species, and interspecific differences in vital rates partly reflected differences in ecological traits. Migratory mode was associated with interspecific differences in population growth and density dependence. Resident species had higher population growth rates than long- and short-distance migrants. We found no relationships between diet and population growth rate. Habitat differences were associated with different growth rates: alpine, wetland and farmland species had lower population growth rates than forest species. Differences in population growth rates among nesting locations showed that breeding habitat is essential for population dynamics. 4. Our study reveals relationships between ecological traits and contributions of vital rates to population growth and suggests ways in which patterns of population growth fluctuations in a community might be determined by life history. [ABSTRACT FROM AUTHOR]

Community dynamics are essential for ecosystems as they support the functioning of food webs and maintain biodiversity. However, the fluctuations of species abundances are rarely analyzed simultaneously despite their interconnectedness across space and time. We developed a Bayesian multi-species model that estimates community- and taxon-level parameters related to dynamics, abundance, detection probability, and environmental stochasticity. From this model, we analyze the variability of populations of a community of raptors composed of accipiters (sharp-shinned hawk [ Accipiter striatus ], and Cooper's hawk [ A. cooperii ]), buteos (red-tailed hawk [ Buteo jamaicensis ], and red-shouldered hawk [ B. lineatus ]) and owls (great horned owl [ Bubo virginianus ], and barred owl [ Strix varia ]). We show that migration pulses of accipiters, buteos, and dispersal of fledging owls drive variation in raptor abundances, indicating a defined production and dispersal period. Also, large-scale climatic processes such as the North Atlantic Oscillation (NAO) influenced the variation in abundances of raptors. When the NAO was in a positive phase, the abundance of raptors decreased, and inversely. Local weather did not affect raptor population abundances. Our approach facilitated the modelling of species-specific effects of environmental variation and guild-level dynamics that could be used for ecosystem-based conservation measures. • A multispecies model including population dynamics effects. • The model estimates both community-level and species-level related parameters. • Migration pulses of accipiter, buteo, and fledging owl's dispersal drive variation of raptor's abundances. • Local weather did not influence raptor's population abundances. • When the NAO was in a positive phase, the abundance of raptors decreased, and inversely. [ABSTRACT FROM AUTHOR]

Estimating survival and recruitment over large spatial scales is extremely challenging because it requires 'expensive' demographic data from marked animals. Dynamic N-mixture models (Dail & Madsen ) yield estimates of abundance, apparent survival, recruitment and detection probability from simple counts replicated in space and time, as frequently collected in monitoring programmes all over the world. However, the vital rates are assumed to be density- independent and constant over time, arguably unrealistic assumptions in many situations., We evaluated the performance of the traditional dynamic N-mixture model from simulated data generated with density dependence and environmental stochasticity in the vital rates. We then developed a series of more advanced models that take density-dependent vital rates and environmental stochasticity into account and assessed whether these models provide accurate estimates of vital rates, strength of density dependence and levels of environmental stochasticity., We found that the traditional Dail-Madsen model produced accurate estimates of abundances and vital rates when the assumptions were met, but not when vital rates were subject to density dependence and environmental stochasticity., Accurate parameter estimates were generally obtained when the data generation matched the data analysis model, but accuracy was substantially reduced otherwise. Interestingly, accurate estimates of abundance and detection were obtained from all models, regardless of the data generation model. Shorter time series from more sites yielded estimates of similar accuracy as longer series from fewer sites., The new dynamic N-mixture models represent a promising basis for developing integrated population models that combine data from different sources to get insights into population dynamics of species over large areas. [ABSTRACT FROM AUTHOR]

We test whether the spatial distribution of spawning sites in a natural population is related to the density and individual growth rate of juvenile stream-dwelling salmonids. For this purpose, fine-scale data on the spatial distribution of Atlantic salmon (Salmo salar) nest sites, juvenile densities and body size, and habitat characteristics were combined. The area of nests summed over reaches of 25 m in length was positively correlated with local young-of-the-year (YOY) densities and was the strongest predictor of local densities. In turn, increased YOY densities were related to slower growth, and YOY density was the strongest predictor of YOY size. Measured habitat variables had little effect on YOY density over the spatial scale examined, which suggests that redistribution of YOY salmon according to habitat preferences was limited. The distribution of spawning sites was therefore the best predictor of local densities and subsequently YOY growth. Thus, during the YOY stage when dispersal is limited, patchy spawning distributions combined with local density-dependence may be the dominant factor responsible for spatial variation in growth. Nous vérifions si la répartition spatiale des sites de fraie dans une population naturelle est reliée à la densité et au taux de croissance individuelle des jeunes salmonidés d'eau courante. Pour ce faire, nous avons combiné des données à échelle fine sur la répartition spatiale des sites de nidification de saumons atlantiques (Salmo salar), sur les densités et les tailles corporelles des jeunes et sur les caractéristiques de l'habitat. Il existe une corrélation positive entre la surface cumulée des nids sur des sections de 25 m de longueur et la densité locale des jeunes de l'année (YOY); c'est la meilleure variable prédictive des densités locales. Par ailleurs, les densités accrues de YOY sont reliées à une croissance ralentie et la densité des YOY est la meilleure variable prédictive de la taille des YOY. Les variables mesurées de l'habitat ont peu d'effet sur la densité des YOY à l'échelle spatiale considérée, ce qui laisse croire qu'il y a une redistribution limitée des saumons YOY d'après leurs préférences d'habitat. La répartition des sites de fraie est donc la meilleure variable prédictive des densités locales et subséquemment de la croissance des YOY. Ainsi, durant le stade YOY pendant lequel la dispersion est limitée, la répartition contagieuse de la fraie, combinée à une densité-dépendance locale, peut être le principal facteur responsable de la variation spatiale de la croissance. [ABSTRACT FROM AUTHOR]

The spatial extent of small pelagic fish spawning habitat is influenced by environmental factors and by the state of the adult population. In return, the configuration of spawning habitat affects recruitment and therefore the future structure of the adult population. Interannual changes in spatial patterns of spawning reflect variations in adult population structures and their environment. The present study describes the historical changes in the spatial distribution of spawning of anchovy ( Engraulis encrasicolus) and sardine ( Sardina pilchardus) in the Bay of Biscay during two periods: 1967–72 and 2000–2004. Using data from egg surveys conducted in spring, the spatial distributions of anchovy and sardine eggs are characterized by means of geostatistics. For each survey, a map of probability of egg presence is constructed. The maps are then compared to define (1) recurrent spawning areas, (2) occasional spawning areas and (3) unfavourable spawning areas during each period. Sardine spawning habitat is generally fragmented and appears spatially limited by the presence of cold bottom water. It is confined to coastal or shelf break refuge areas in years of restricted spawning extent. For anchovy, recurrent spawning sites are found in Gironde and Adour estuaries whilst spawning can extend further offshore in years of more intense spawning. For both species, the mean pattern of spawning has changed between 1967–72 and 2000–2004. Noticeably, the spatial distribution of anchovy eggs in spring has expanded northward. This trend possibly results from changes in environmental conditions during the last four decades. [ABSTRACT FROM AUTHOR]

• An approach that provides theoretical scenarios of harvest of interacting species for a sustainable use of natural resources. • A harvest approach of interacting species that accounts for predators and prey's joint dynamics, natural fluctuations in abundances and consider varying environments. • Correlated environmental effects are included in the model and affect both species at the same time. • Strong environmental stochasticity increased the variance of predator's and prey's yield, making the harvest of the interacting species less predictable. • Optimal yields for predators and prey can be obtained with different harvest strategies when both species are harvested simultaneously. The effects of harvest and fluctuating environment on inter-dependent predators and prey are complex and not well-known. We define a stochastic model where the predators and prey dynamically interact. The novelty of the model holds on the fact that predators and prey dynamics are simultaneously affected by correlated environmental noises. Interacting predators and prey are harvested using a proportional threshold harvesting strategy that accounts for stochastic population dynamics. Optimal yield of prey can be obtained with identical harvesting strategies when the predators and prey responded to the environment similarly (i.e., synchrony between species) and differently (i.e., asynchrony between species). Remarkably, our study demonstrates that two different harvesting strategies, the proportional harvesting strategy for the prey and the proportional threshold harvesting strategy for the predators, are needed to optimize the annual yield of predators and prey when both species are harvested simultaneously. Our study finds optimal strategies for harvesting interacting species affected by environmental variations (i.e., correlated noises) with parameters representing the joint dynamics of predators and prey at a stable state. [ABSTRACT FROM AUTHOR]