RESUMEN
Describing the spatial patterns of benthic coastal habitats and investigating how those patterns affect the ecology of inhabiting species is a main objective of seascape ecology. Within this emerging discipline spatial scale is a principal topic. Different spatial scales inform on different characteristics of the habitat and therefore the relation between species and their habitats would be better defined when observed at multiple levels of spatial scale. Here we apply a multiscale seascape approach to investigate the habitat preferences of juvenile and adult individuals of dusky grouper (Epinephelus marginatus) in a Mediterranean marine protected area. Results show that the information obtained at different spatial scales is complementary, improving our capability to identify the preferred habitats and how it changes throughout ontogeny. These results show the relevance of implementing multiscale seascape ecology approaches to investigate the species-habitat relationships and to improve management and conservation of necto-benthic endangered top predators.
Asunto(s)
Lubina , Biodiversidad , Ecosistema , Animales , Conservación de los Recursos Naturales , Mar MediterráneoRESUMEN
Life-history traits such as spawning migrations and timing of reproduction are adaptations to specific environmental constraints and seasonal cycles in many organisms' annual routines. In this study we analyse how offspring fitness constrains spawning phenology in a large migratory apex predator, the Atlantic bluefin tuna. The reproductive schedule of Atlantic bluefin tuna varies between spawning sites, suggesting plasticity to local environmental conditions. Generally, temperature is considered to be the main constraint on tuna spawning phenology. We combine evidence from long-term field data, temperature-controlled rearing experiments on eggs and larvae, and a model of egg fitness, and show that Atlantic bluefin tuna do not spawn to optimize egg and larval temperature exposure. The timing of spawning leads to temperature exposure considerably lower than optimal at all spawning grounds across the Atlantic Ocean. The early spawning is constrained by thermal inhibition of egg hatching and larval growth rates, but some other factors must prevent later spawning. Matching offspring with ocean productivity and the prey peak might be an important driver for bluefin tuna spawning phenology. This finding is important for predictions of reproductive timing in future climate warming scenarios for bluefin tuna.
Asunto(s)
Migración Animal/fisiología , Calentamiento Global , Reproducción/fisiología , Temperatura , Atún/fisiología , Animales , Océano Atlántico , Clorofila , Femenino , Larva/crecimiento & desarrollo , Óvulo/crecimiento & desarrollo , Estaciones del Año , Factores de Tiempo , ZooplanctonRESUMEN
While large-scale patterns of pelagic marine diversity are generally well described, they remain elusive at regional-scale given the high temporal and spatial dynamics of biological and local oceanographic processes. We here evaluated whether the main drivers of pelagic diversity can be more pervasive than expected at regional scale, using a meroplankton community of a frontal system in the Western Mediterranean. We evidence that regional biodiversity in a highly dynamic ecosystem can be summarized attending to both static (bathymetric) and ephemeral (biological and hydrographical) environmental axes of seascape. This pattern can be observed irrespectively of the regional hydroclimatic scenario with distance to coast, salinity gradient and chlorophyll a concentration being the main and recurrent drivers. By contrast, their effect is overridden in common analyses given that different non-linear effects are buffered between years of contrasting scenarios, emerging the influence of secondary effects on diversity. We conclude that community studies may reveal hidden persistent processes when they take into account different functional effects related to hydroclimatic variability. A better understanding of regional dynamics of the pelagic realm will improve our capability to forecast future responses of plankton communities as well as impacts of climate change on marine biodiversity.