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The Balkan region has some of the best conserved rivers in Europe, but is also the location of ~3000 planned hydropower dams that are expected to help decarbonise energy production. A conflict between policies that promote renewable hydropower and those that prioritise river conservation has ensued, which can only be resolved with the help of reliable information. Using ground-truthed barrier data, we analysed the extent of current longitudinal river fragmentation in the Balkan region and simulated nine dam construction scenarios that varied depending on the number, location and size of the planned dams. Balkan rivers are currently fragmented by 83,017 barriers and have an average barrier density of 0.33 barriers/km after correcting for barrier underreporting; this is 2.2 times lower than the mean barrier density found across Europe and serves to highlight the relatively unfragmented nature of these rivers. However, our analysis shows that all simulated dam construction scenarios would result in a significant loss of connectivity compared to existing conditions. The largest loss of connectivity (−47 %), measured as reduction in barrier-free length, would occur if all planned dams were built, 20 % of which would impact on protected areas. The smallest loss of connectivity (−8 %) would result if only large dams (>10 MW) were built. In contrast, building only small dams (

Cummunality and Redundancy of parameters used in PLS-PM analyses

Description of latent variables used in the analyses

Correlation matrixes between latent variables by groups

Scores and graphic representation from the PCA analysis

Performance of the subset of candidate linear mixed-effect models

Habitat fragmentation is a principal threat to biodiversity and artificial river barriers are a leading cause of the global decline in freshwater biota. Whilst the impact of barriers on diadromous fish is well established, impacts on river-resident fish communities remain unclear, especially for low-head barriers. We examined the movement of five contrasting freshwater fish (topmouth gudgeon, European minnow, stone loach, bullhead, and brown trout) in an experimental cascade mesocosm with seven pools separated by small vertical barriers. Passage rates differed significantly among species and increased with body size and sustained swimming speed (Usus), ranging from an average of 0.2 passes/hr in topmouth gudgeon to 3.4 passes/hr in brown trout. A random-walk simulation indicated that barriers can result in net downstream movement and shifts in community composition. Passage rates in brown trout were leptokurtic: i.e. most individuals were relatively sedentary while a small proportion showed frequent movements. Upstream passage rates of brown trout increased with body length and boldness, while fish with lower aerobic scope tended to move downstream. Passage rates showed significant individual repeatability in brown trout, independent of body size, indicating the potential for in-stream barriers to exert selective effects on fish populations. Our results show that barrier effects can be more complex than simply blocking fish passage, and that river-resident fish can be impacted even by very small barriers. We show that fish passage depends on a wide range of morphological, physiological, and behavioural drivers, and that barriers can exert selective effects on these traits and cause shifts in community composition. Policy implications. Barrier mitigation measures need to embrace inter- and intraspecific variation in fish passage to avoid inadvertent artificial selection on fish communities. Given the high abundance of low-head structures in river systems worldwide, a paradigm shift is needed to recognise the subtle impacts of small barriers on freshwater biodiversity. Removal of small barriers or nature-like fishways should allow better passage of the wider fish community compared to widely used salmonid-centric fish passage options.

Additional file 1. Supplementary figures and dead-reckoning formulae.

Figure S1: Comparison of the rate of change of altitude and speed of an ultralight (A and C respectively) and a pigeon (B and D), flying at the same time, and with the same loggers. Violin plots show the distribution of the data during the flight; the upper and lower quartiles are represented by the upper and lower extremes of the box and the median by the thick black line.

Additional file 1. Methods expanded. Text S1. Device set up and capture protocol. Text S2. The importance of having the correct coordinate system and axis alignment. Text S3. Magnetometer calibration, rotation correction and deriving yaw (heading)—Gundog.Compass() explained. Text S4. Step counts as a distance estimate—Gundog.Peaks() explained. Text S5. Time Data in R (POSIXct). Text S6. VPC dead-reckoning—Gundog.Tracks()—explained.

Demographic senescence is increasingly recognised as an important force shaping the dynamics of wild vertebrate populations. However, our understanding of the processes that underpin these declines in survival and fertility in old age remains limited. Evidence for age‐related changes in foraging behaviour and habitat use is emerging from wild vertebrate studies, but the extent to which these are driven by within‐individual changes, and the consequences for fitness, remain unclear. Using longitudinal census observations collected over four decades from two long‐term individual‐based studies of unmanaged ungulates, we demonstrate consistent within‐individual declines in home range area with age in adult females. In both systems, we found that within‐individual decreases in home range area were associated with increased risk of mortality the following year. Our results provide the first evidence from the wild that age‐related changes in space use are predictive of adult mortality.

Glides were clearly identifiable as periods of straight flight and sustained altitude loss between bouts of circling behaviour (see Williams et al. 2015 for details). The circling is represented by a consistent sine-wave when the tri-axial magnetometry data is plotted against time. This indicates turning within the thermal updraft.

International audience; One of the predicted consequences of climate change is a shift in body mass distributions within animal populations. Yet body mass, an important component of the physiological state of an organism, can affect key life-history traits and consequently population dynamics. Over the past decades, the wandering albatross—a pelagic seabird providing bi-parental care with marked sexual size dimorphism—has exhibited an increase in average body mass and breeding success in parallel with experiencing increasing wind speeds. To assess the impact of these changes, we examined how body mass affects five key life-history traits at the individual level: adult survival, breeding probability, breeding success, chick mass and juvenile survival. We found that male mass impacted all traits examined except breeding probability, whereas female mass affected none. Adult male survival increased with increasing mass. Increasing adult male mass increased breeding success and mass of sons but not of daughters. Juvenile male survival increased with their chick mass. These results suggest that a higher investment in sons by fathers can increase their inclusive fitness, which is not the case for daughters. Our study highlights sex-specific differences in the effect of body mass on the life history of a monogamous species with bi-parental care.

Description of the mass standardization functions

International audience

National audience

Workshop report: An international workshop on modeling the distribution and abundance of boreal waterfowlwas held during the 5th North American Duck Symposium in Toronto, Canada, 17-18 August 2009. The workshop brought together Canadian and American researchers andmanagers with an interestin waterfowl habitat and population modeling and/or in biomonitoring over large spatial extents.

La ricerca è stata condotta da luglio 1997 a settembre 1999 in un?area del Parco Regionale della Maremma (Grosseto) per A) individuare le caratteristiche dei siti di tana e degli ingressi maggiormente utilizzati dagli istrici; B) rilevare il rapporto spazio- temporale esistente tra gli individui e le loro tane. Ventisette animali, 14 maschi e 13 femmine, sono stati catturati, muniti di radio-collare e localizzati periodicamente (min. 2 notti/settimana con 1 fix/2h per notte). È stata individuata mensilmente la tana di ciascun animale con radio-collare, mediante homing in. Ogni tana è stata georiferita e sono stati effettuati una serie di rilevamenti morfologici, vegetazionali e orografici del sito, oltre che la registrazione del numero di animali marcati in essa presenti. In totale, sono state individuate 31 tane differenti su 81 homing in condotti. Sono state calcolate e analizzate le distanze di ciascun animale dalla propria tana in otto fasce orarie di circa 3 ore ciascuna. Le analisi sono state svolte a livello annuale (settembre 1998 - agosto 1999), semestrale e trimestrale, verificando statisticamente le differenze tra le fasce orarie, e tra maschi e femmine. H. cristata sembra aver preferito i siti di tana coperti da vegetazione e su terreni acclivi, con pochi cambi di tana (tendenzialmente ogni tana viene mantenuta per almeno 2 mesi). Sembra inoltre che un sito di tana venga condiviso solo dal nucleo familiare (coppia con i piccoli dell?anno). L?attività spaziale degli istrici rispetto alla posizione delle loro tane ha presentato un ritmo bifasico, maggiore nelle ore centrali della notte e ridotta al sorgere del sole. Gli istrici sembrano modificare il proprio comportamento con le ore di buio disponibili, utilizzando anche le ore di luce quando le notti sono più brevi. Infatti, mentre gli spostamenti notturni sono presenti nel corso di tutto l?anno, quelli diurni risultano quasi assenti e concentrati nei pressi della tana nel semestre freddo, aumentando invece nel periodo estivo. Anche l?attività spaziale notturna presenta differenze tra i due semestri: nel periodo caldo gli spostamenti risultano maggiori rispetto a quello freddo, probabilmente a causa della presenza di campi coltivati nella parte settentrionale dell?area di studio. Tra maschi e femmine sono state rilevate differenze significative solo nella fascia centrale della notte (semestre caldo), con un maggior allontanamento della femmina dalla tana. All?interno di ciascuna tana sono sempre stati presenti gli stessi individui, presumibilmente coppie stabili, con un?attività spaziale sincrona a conferma della monogamia di questa specie.

Description of the Capture-Mark-Recapture method

Description of the Capture-Mark-Recapture method

Translocation into a novel environment through common fisheries management practices, such as fish stocking, provides opportunities to study behavioural and fitness impacts of translocations at realistic ecological scales. The process of stocking, as well as the unfamiliarity with novel ecological conditions and the interactions with resident fish may affect translocated individuals, leading to alterations of behaviours and causing fitness impacts. Our objectives were to investigate how aquatic top predators behaviourally establish themselves and compete with resident individuals following introduction in a novel lake environment and to investigate the resulting fitness consequences. Using high‐resolution acoustic telemetry, we conducted whole‐lake experiments and compared the activity, activity‐space size and fate of translocated and resident individuals in two model top predators, the northern pike Esox lucius (n = 160) and European catfish Silurus glanis (n = 33). Additionally, we compared the reproductive success of translocated and resident northern pike. The experiment was conducted with large (adult) individuals of different origins, resilient to predation, but subject to agonistic interactions and competition with resident fish. Over a period of several months, the translocated catfish exhibited consistently larger activity‐space sizes than resident catfish, but did not differ from residents in activity and survival. The pike from one of the two translocated origins we tested also showed elevated space‐use, and both translocated origins revealed higher mortality rates than their resident conspecifics, indicating maladjustment to their novel environment. When non‐resident pike reproduced, they overwhelmingly produced hybrid offspring with resident fish, indicating that introductions fostered gene flow of non‐native genes. Our study indicates that fish introductions result in behavioural and fitness impacts even in large‐bodied top predators that experience low levels of natural predation risk. Leibniz Community Besatzfisch (German Federal Ministry for Education and Research)