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Carry-over effects occur when past experience influences current individual performance. Although variation in conspecific density in one season has been shown to carry over to influence dynamics in the following season, the proximate ecological mechanisms driving these effects are unknown. One hypothesis is that high density decreases food availability, resulting in poor physiological condition, which in turn compromises performance the next season. Alternatively, high conspecific density could also lead to a high degree of antagonistic interactions, decreasing the amount of time individuals spend foraging. To investigate these hypotheses, we applied a factorial design where both conspecific density and per capita food availability during the non-breeding period were independently manipulated in seasonal populations of common fruit flies (Drosophila melanogaster Meigen, 1830). Individual condition at the beginning of the breeding period was influenced by per capita food availability but not density during the previous non-breeding period. In contrast, reproductive output was most strongly influenced by the interaction between per capita food availability and density in the previous non-breeding period, such that populations that experienced high non-breeding densities and low food availability had the lowest reproductive output. However, the strength of this effect was relatively weak. Our results demonstrate how environmental and social conditions in one part of the annual cycle can carry over to influence individual performance in subsequent periods. Key words: body condition, Drosophila melanogaster, food availability, fruit fly, population density, reproductive output, seasonal interactions. Les effets reportes se produisent quand l'experience passee influence la performance presente des individus. S'il a ete demontre que les variations de la densite de conspecifiques durant une saison ont une influence sur la dynamique durant la saison suivante, les mecanismes ecologiques proximaux a l'origine de ces effets ne sont pas connus. Une hypothese veut qu'une forte densite reduise la disponibilite de nourriture, ce qui se traduit par un faible embonpoint qui, lui, compromet la performance durant la saison suivante. Une autre explication serait qu'une forte densite de conspecifiques pourrait aussi mener a un degre eleve d'interactions antagonistes, reduisant du coup le temps affecte par les individus a la quete de nourriture. Afin d'evaluer ces hypotheses, nous avons applique un schema factoriel dans lequel la densite de conspecifiques et la disponibilite de nourriture par individu durant la periode internuptiale etaient manipulees de maniere independante dans des populations saisonnieres de drosophiles (Drosophila melanogaster Meigen, 1830). L'embonpoint individuel au debut de la periode de reproduction etait influence par la disponibilite de nourriture par individu, mais non par la densite durant la periode internuptiale precedente. En comparaison, la plus forte influence sur l'efficacite de la reproduction etait l'interaction entre la disponibilite de nourriture par individu et la densite durant la periode internuptiale precedente, l'efficacite de la reproduction etant la plus faible dans les populations caracterisees par une forte densite internuptiale et une faible disponibilite de nourriture. L'intensite de cet effet etait toutefois assez faible. Nos resultats demontrent comment des conditions ambiantes et sociales durant une partie du cycle annuel peuvent avoir des effets reportes qui influencent la performance des individus durant des periodes subsequentes. [Traduit par la Redaction] Mots-cles : embonpoint, Drosophila melanogaster, disponibilite de nourriture, drosophile, densite de population, efficacite de la reproduction, interactions saisonnieres., Introduction Carry-over effects occur when an individual's past experience explains its current performance (O'Connor et al. 2014). In seasonal environments, there is growing evidence that carry-over effects play an important [...]

Phenotypic plasticity allows organisms to adjust the timing of life‐history events in response to environmental and demographic conditions. Shifts by individuals in the timing of breeding with respect to variation in age and temperature are well documented in nature, and these changes are known to scale to affect population dynamics. However, relatively little is known about how organisms alter phenology in response to other demographic and environmental factors. We investigated how pre‐breeding temperature, breeding population density, age, and rainfall in the first month of life influenced the timing and plasticity of lay date in a population of Savannah Sparrows (Passerculus sandwichensis) monitored over 33 yr (1987–2019). Females that experienced warmer pre‐breeding temperatures tended to lay eggs earlier, as did older females, but breeding population density had no effect on lay date. Natal precipitation interacted with age to influence lay date plasticity, with females that experienced high precipitation levels as nestlings advancing lay dates more strongly over the course of their lives. We also found evidence for varied pace of life; females that experienced high natal precipitation had shorter lifespans and reduced fecundity, but more nesting attempts over their lifetimes. Rainfall during the nestling period increased through time, while population density and fecundity declined, suggesting that increased precipitation on the breeding grounds may be detrimental to breeding females and ultimately the viability of the population as a whole. Our results suggest that females adjust their laying date in response to pre‐breeding temperature, and as they age, while presenting new evidence that environmental conditions during the natal period can affect phenological plasticity and generate downstream, population‐level effects. [ABSTRACT FROM AUTHOR]

Domestic cats Felis catus have a complex and contentious history. They fill multiple societal roles (e.g. as pest controllers and companion animals), which has led to a variety of animal welfare, conservation, and human health concerns. Popular press articles play an important role in how people learn about key issues surrounding cats, but they may present some issues more frequently than other issues.We conducted a global media content analysis of 796 articles in the English‐language media from 1990 to 2018 on issues related to free‐roaming cats, such as their environmental impacts, the threats and welfare issues cats face, and how they are managed. We aimed to determine whether non‐experts learning about the issues around free‐roaming cats exclusively from the popular press would be exposed to multiple stakeholder views or opinions.Over 95% of articles analysed were from North America. Most of the people interviewed in the popular press were from non‐governmental organizations, mainly from cat welfare or cat rights groups (which are often focused on only one side of the issue). Researchers, shelter organizations, veterinarians, and groups that have different opinions than cat rights or welfare organizations on how to resolve issues surrounding free‐roaming cats were rarely interviewed by the popular press. Most articles focused on cat welfare issues and the management strategies of euthanasia or trap–neuter–release (TNR), whereas less than one‐third of the articles acknowledged that cats have any impact on wildlife or the broader environment.We found that the popular press often presented an oversimplified picture of issues related to free‐roaming cats and provided unbalanced coverage. We also show evidence of framing by the popular press, including mainly presenting the viewpoints and perspectives from animal welfare and rights groups, focusing on TNR or euthanasia as the only viable cat management strategies when many alternatives exist and often have greater support from experts, and discussing the impacts of cats on birds and small mammals but not reptiles or amphibians. A free Plain Language Summary can be found within the Supporting Information of this article. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

Pesticides have been used in Canada since 1945 as part of large‐scale aerial spray applications to control insect pests on forested lands. Some of the pesticides used historically were efficacious, nonselective, persistent, and have led to serious impacts on the environment. A well known, and extensively documented example is the large‐scale aerial spray programs in New Brunswick, Canada. From 1952 to 1993, 97% of the 6.2 million ha of the forested lands of New Brunswick were treated with at least one application of one insecticide, the majority of which were applied to control outbreaks of eastern spruce budworm (Choristoneura fumiferana). The most well known insecticide was dichlorodiphenyltrichloroethane (DDT), applied from 1952 to 1968, which still persists in treated soils and adjacent water bodies, and caused the individual and cumulative ecosystem effects that can still be measured today. The insecticides that replaced DDT were nonpersistent and unlikely to be found today. However, during the years of application some of the insecticides were likely to have impacted local ecosystems to some degree. To aid future studies on the efficacy and environmental impact of these insecticides we created a digital spatial data set of known pesticide application in New Brunswick forestry from 1952 to 1993. The data set includes active ingredient, formulation, application rate, tank mix, aircraft type, and other ancillary information. The current version of the data is available on the New Brunswick Department of Natural Resources and Energy Development, GIS Open Data Page and in the supplemental material. Use of the data set for academic and educational purposes is encouraged, provided that both this data paper and the data source are properly cited; the Government of New Brunswick should be acknowledged as the data source (Open Government License http://www.snb.ca/e/2000/data-E.html). [ABSTRACT FROM AUTHOR]

Migration strategies differ greatly among and within avian populations. The associated trade-offs and fitness consequences of diverse strategies and how they persist are pertinent questions in migration research. Migration is a costly endeavour, presumably compensated for by better survival conditions in the non-breeding area. One way to assess the cost of alternative strategies is to investigate the investment in movement across the entire annual cycle, an assessment made increasingly feasible with improvements in tracking technology. Our study focuses on lesser black-backed gulls, generalist seabirds that exploit a broad range of resources, exhibit diverse migration strategies and have potentially altered migration strategies in response to human activities and climate change. We used GPS tracking to quantify lesser black-backed gulls' movement throughout their annual cycle and compare trade-offs among four migration strategies. The annual cumulative distance travelled by long distance migrants wintering in west Africa, over 4000 km from their breeding colony, did not differ significantly from individuals of the same breeding colony wintering only a few hundred kilometres away in Great Britain. Short distance migrants returned to the colony first, and long distance migrants returned last. Sex and wing length were not correlated with maximum range, cumulative distance travelled or timing. Individuals spent only a small proportion of their time in flight and spent on average 17% of their time at sea throughout an annual cycle, suggesting a reliance on inland resources for many individuals. Analysing movement throughout the annual cycle can change our perspective and understanding of consequences of different migration strategies. Our study shows that a range of migration strategies coexists and we propose that the long term costs and benefits of these strategies balance out. Diversity in migration strategies may contribute to the resilience of this species in the face of ongoing anthropogenic impact on the environment. [ABSTRACT FROM AUTHOR]

Historical and long-term environmental datasets are imperative to understanding how natural systems respond to our changing world. Although immensely valuable, these data are at risk of being lost unless actively curated and archived in data repositories. The practice of data rescue, which we define as identifying, preserving, and sharing valuable data and associated metadata at risk of loss, is an important means of ensuring the long-term viability and accessibility of such datasets. Improvements in policies and best practices around data management will hopefully limit future need for data rescue; these changes, however, do not apply retroactively. While rescuing data is not new, the term lacks formal definition, is often conflated with other terms (i.e. data reuse), and lacks general recommendations. Here, we outline seven key guidelines for effective rescue of historically collected and unmanaged datasets. We discuss prioritization of datasets to rescue, forming effective data rescue teams, preparing the data and associated metadata, and archiving and sharing the rescued materials. In an era of rapid environmental change, the best policy solutions will require evidence from both contemporary and historical sources. It is, therefore, imperative that we identify and preserve valuable, at-risk environmental data before they are lost to science.