Articles publicats en revistes (Biologia Evolutiva, Ecologia i Ciències Ambientals)

Marine ectotherms, organisms whose body temperature depends on their environment, often rely on physiological plasticity

to withstand rapid temperature increases when behavioural adjustments are insufficient. Despite extensive research

on thermal tolerance, gaps remain in understanding species- and population-level metabolic responses to acute thermal

stress, particularly in rapidly warming regions like the Mediterranean Sea. This study assessed metabolic responses to

acute warming in four echinoderm species with distinct thermal affinities but overlapping distributions in the Western

Mediterranean: the sea urchins Arbacia lixula (subtropical) and Paracentrotus lividus (temperate-cold), and the brittle

stars Ophiothrix sp. II (temperate) and Ophiocomina nigra (temperate-cold). Oxygen consumption, used as a proxy for

Basal Metabolic Rate (BMR), was measured at sequential temperatures (16 °C, 20 °C, 23 °C, 26 °C), following a short

acclimation period. Species exhibited divergent metabolic trajectories and thermal sensitivities (Q₁₀), reflecting their thermal

affinities, local adaptations, and phenotypic plasticity. A. lixula and Ophiothrix sp. II displayed sharp BMR increases,

indicating resilience but proximity to their upper thermal limits. In contrast, O. nigra maintained stable metabolic rates,

suggesting broad physiological plasticity. P. lividus displayed population-level divergence: individuals with cooler-origin

experienced metabolic suppression and severe thermal stress at 26 °C, whereas those with warmer-origin maintained

higher metabolic activity. Overall, phenotypic plasticity emerged as a key short-term strategy to cope with acute warming.

However, species with narrower thermal tolerance, such as P. lividus, might face long-term vulnerability under intensifying

marine heatwaves. These results highlight the importance of integrating thermal history, plasticity, and genetic variation

to accurately predict resilience to ocean warming.

mature non-breeders), sink–source status, and dispersal processes. Using this approach, we carried out a fine-scale assessment of the long-term dynamics and demographic drivers of one long-lived Bonelli’s eagle population from Western Europe (1986–2020). Our results illustrated a considerable population decline and subsequent recovery alongside multiple demographic insights scarcely documented to date in long-lived species. First, we reported a decrease and subsequent increase in floater numbers probably associated with parallel changes in the breeding population, hence contributing to the scarce empirical knowledge available about the role and dynamics of floaters. Second, we detected a change in average population functioning from a sink to a neutral

contributor, thus shedding light on the flexibility and drivers of sink-source dynamics. Third, we underscored the central role of non-breeder survival for population recovery, suggesting that long-lived species conservation action should not only focus on adult or breeding populations, as is typically the case. Fourth, we quantified the magnitudes and variations of local and dispersal processes in the long term and discussed their potential implications in terms of management implementation. Overall, our study highlights the potential of spatially explicit IPMs to build more complete assessments of population dynamics, contribute to better-informed conservation action, and help fill knowledge gaps in ecological sciences.

Adult sex ratios (ASRs) have proved to correlate with population trends, which make them

potential useful indicators of a species’ population trajectory and conservation status. We

analysed ASRs and proportion of juveniles in flocks of an endangered steppe bird, the Little

Bustard Tetrax tetrax, using surveys made during the non-breeding period in seven areas within

its Western European range (one in Portugal, four in Spain, and two in France). We found

overall male-biased ASRs, as all the seven surveyed areas showed a male-biased ASR mean value.

Five areas were below the threshold median value (female sex ratio = 0.4) considered to be

consistent with an increased probability of extinction, according to earlier population viability

analyses for the species.Wealso found a significant positive correlation between female ratio and

the proportion of young individuals in the non-breeding flocks surveyed. Our results (strongly

male-biased ASRs) support the hypothesis that the viability of Little Bustard populations in

Western Europe is threatened by an excess of female mortality, something that should be

quantified in the future, and emphasise the value of monitoring sex ratio as a population viability

indicator in species where monitoring survival is difficult to achieve.