Search results for "SCA"
showing 10 items of 23299 documents
Otolith fingerprints reveals potential pollution exposure of newly settled juvenile Sparus aurata
2020
Abstract Coastal ecosystems are increasingly threatened by a wide range of human activities. Fish otolith chemistry, by creating a unique specific signature, can be used as a natural tag for determining life stage dispersal, spatial connectivity and population structure. In this study, we tested whether differences in otolith composition among juveniles of gilthead sea bream, Sparus aurata, could enable their proper allocation to polluted areas based on higher concentrations of elements related to contaminants. Otoliths were embedded, sectioned and analysed by LA-ICP-MS in line scan mode. Multivariate analysis confirmed clear separation between sites and elements. Samples from the site unde…
Fine-scale population dynamics in a marine fish species inferred from dynamic state-space models
2017
1. Identifying the spatial scale of population structuring is critical for the conservation of natural populations and for drawing accurate ecological inferences. However, population studies often use spatially aggregated data to draw inferences about population trends and drivers, potentially masking ecologically relevant population sub‐structure and dynamics. 2. The goals of this study were to investigate how population dynamics models with and without spatial structure affect inferences on population trends and the identification of intrinsic drivers of population dynamics (e.g. density dependence). 3. Specifically, we developed dynamic, age‐structured, state‐space models to test differe…
Trophic transfer of pesticides: The fine line between predator–prey regulation and pesticide–pest regulation
2020
International audience; Understanding pesticide impacts on populations of target/non-target species and communities is a challenge to applied ecology. When predators that otherwise regulate pest densities ingest prey contaminated with pesticides, this can suppress predator populations by secondary poisoning. It is, however, unknown how species relationships and protocols of treatments (e.g. anticoagulant rodenticide [AR]) interact to affect pest regulation.To tackle this issue, we modelled a heuristic non-spatialized system including montane water voles, specialist vole predators (stoats, weasels) and a generalist predator (red fox) which consumes voles, mustelids and other prey. By carryin…
A recipe for postfledging survival in great tits Parus major: be large and be early (but not too much)
2016
Survival of juveniles during the postfledging period can be markedly low, which may have major consequences on avian population dynamics. Knowing which factors operating during the nesting phase affect postfledging survival is crucial to understand avian breeding strategies. We aimed to obtain a robust set of predictors of postfledging local survival using the great tit (Parus major) as a model species. We used mark–recapture models to analyze the effect of hatching date, temperatures experienced during the nestling period, fledging size and body mass on first-year postfledging survival probability of great tit juveniles. We used data from 5192 nestlings of first clutches ringed between 199…
The role of fish life histories in allometrically scaled food‐web dynamics
2019
Body size determines key ecological and evolutionary processes of organisms. Therefore, organisms undergo extensive shifts in resources, competitors, and predators as they grow in body size. While empirical and theoretical evidence show that these size‐dependent ontogenetic shifts vastly influence the structure and dynamics of populations, theory on how those ontogenetic shifts affect the structure and dynamics of ecological networks is still virtually absent. Here, we expand the Allometric Trophic Network (ATN) theory in the context of aquatic food webs to incorporate size‐structure in the population dynamics of fish species. We do this by modifying a food web generating algorithm, the nic…
Urban landscape evolution as a consequence of an invasive pest: The case of a small sicilian town
2017
The Red Palm Weevil (RPW), after its accidental introduction in Italy in 2005, determined a progressive disruption of Canary palms mostly in the central and southern regions. As it is difficult to undertake the management of this pest, the possibility of substituting the killed/symptomatic palms with other ornamental trees has been recently discussed. In this context, understanding the citizens' needs about green areas can improve the management of public parks and urban greening. Involving citizens on the natural resource management using public participation processes is crucial. The case study of a small town of Sicily (Italy) was treated and the spread of this pest was monitored. Moreov…
Rapid response of a long-lived species to improved water and grazing management: the case of the European pond turtle (Emys orbicularis) in the Camar…
2014
7 pages; International audience; Among human activities, the effect of habitat management by grazing on population viability is ambiguous. Indeed, beneficial effects of grazing are expected by maintaining open meadows, but overgrazing is supposed to increase mortality by trampling. Grazing has been shown to negatively impact the survival of European pond turtle (Emys orbicularis) in the Camargue. Consequently, a new management plan was defined. We investigated the consequences of this management using capture-recapture methods to estimate variations of population sizes in this managed site and a control site over a 17 years period. Results show an increase of the number of adults and juveni…
Spatial Context of Breeding Ponds and Forest Management Affect the Distribution and Population Dynamics of the Great Crested Newt
2016
Intensive forest management and landscape degradation are threats to amphibian populations. We modelled and compared the extinction and colonization dynamics of the great crested newt in four different spatial contexts that describe landscape change from past to present and future forest landscapes in eastern Finland. In future landscape scenarios, we explored the effects of two forest use intensities with different logging rotation times. The introduction of fish into breeding ponds has been the main cause of local extinctions of the great crested newt. In the future, intensifying land-use and shorter logging rotation will decrease the connectivity between ponds the most. In conservation p…
Conservation implications of change in antipredator behavior in fragmented habitat: Boreal rodent, the bank vole, as an experimental model
2015
Abstract Habitat fragmentation is known to cause population declines but the mechanisms leading to the decline are not fully understood. Fragmentation is likely to lead to changes in predation risk, which may cause behavioral responses with possible population level consequences. It has recently been shown that the awareness of predator presence, resulting in a fear response, strongly affects behavior and physiology of the prey individuals. Costs arising from fear may be as important for the prey population size as the direct killing of prey. We tested how predation risk in the form of scent of a specialist predator, the least weasel (Mustela nivalis nivalis), affects bank vole (Myodes glar…
Ilkka Hanski and Small Mammals: from Shrew Metapopulations to Vole and Lemming Cycles
2017
10 pages; International audience; Ilkka Hanski may be best known for his work on insect and metapopulation dynamics, but he also contributed significantly to small mammal research. In the early 1980s he became interested in shrew dynamics, energetics, and of course, shrew metapopulations. He aimed at understanding the population biological consequences of body size in different shrew species. Feeding habits and environmental stochasticity affect shrew species in profoundly different ways: due to their short survival time small species have high extinction rates but their dispersal and colonization capacity is high which enables them to survive as metapopulations. After Hansson and Henttonen…