Loading...
3 results
Search Results
Now showing 1 - 3 of 3
- Canopy microclimate modification in central and marginal populations of a marine macroalgaPublication . Monteiro, Cátia; Zardi, Gerardo I.; McQuaid, Christopher D.; Serrao, Ester; Pearson, Gareth; Nicastro, KatyThe effects of environmental changes on species distribution are generally studied at large geographical scales. However, aggregations of individuals can significantly moderate the impact of the environment at smaller, organismal scales. We focused on the intertidal macroalga Fucus guiryi and carried out field and laboratory common garden experiments to evaluate how the different individual morphologies and canopy densities typical of central and peripheral populations modify microhabitat conditions and associated levels of stress. We show that F. guiryi canopies significantly alter environmental conditions (i.e., temperature, humidity and light regimes) and mitigate the levels of stress experienced by individuals within the group. Southern algae are more branched and form denser canopies but, unexpectedly, despite these considerable differences, the mitigating effects of northern and southern canopies did not differ significantly. Microhabitat conditions beneath canopies were more stressful at marginal locations, indicating that southern populations are not more effective than northern algae at mitigating the harsher climate at the edge of the species distribution. Our findings highlight the importance of assessing structural changes in aggregating species across their distribution and relating these to local climates to understand the impact of environmental changes at scales relevant to individual organisms.
- Evidence for rangewide panmixia despite multiple barriers to dispersal in a marine musselPublication . Lourenço, Carla R.; Nicastro, Katy; McQuaid, Christopher D.; Chefaoui, Rosa; Assis, J.; Taleb, Mohammed Z.; Zardi, Gerardo I.Oceanographic features shape the distributional and genetic patterns of marine species by interrupting or promoting connections among populations. Although general patterns commonly arise, distributional ranges and genetic structure are species-specific and do not always comply with the expected trends. By applying a multimarker genetic approach combined with Lagrangian particle simulations (LPS) we tested the hypothesis that oceanographic features along northeastern Atlantic and Mediterranean shores influence dispersal potential and genetic structure of the intertidal mussel Perna perna. Additionally, by performing environmental niche modelling we assessed the potential and realized niche of P. perna along its entire native distributional range and the environmental factors that best explain its realized distribution. Perna perna showed evidence of panmixia across > 4,000 km despite several oceanographic breaking points detected by LPS. This is probably the result of a combination of life history traits, continuous habitat availability and stepping-stone dynamics. Moreover, the niche modelling framework depicted minimum sea surface temperatures (SST) as the major factor shaping P. perna distributional range limits along its native areas. Forthcoming warming SST is expected to further change these limits and allow the species to expand its range polewards though this may be accompanied by retreat from warmer areas.
- Latitudinal incidence of phototrophic shell-degrading endoliths and their effects on mussel bed microclimatesPublication . Lourenço, Carla R.; R Nicastro, Katy; McQuaid, Christopher D.; Sabour, Brahim; Zardi, Gerardo I.Aggregations of organisms commonly benefit their members by mitigating the effects of predators and environmental stresses. Mussel aggregations also form important intertidal matrices that support associated infaunal communities, the structures of which are largely shaped by the conditions within the interstitial spaces. Intertidal mussels are frequently parasitized by phototrophic endoliths that infest the shell and have thermoregulatory effects on both solitary and aggregated mussels by changing shell albedo. A large-scale sampling was carried out May June 2016 along Portuguese and Moroccan shores to investigate a latitudinal gradient of endolithic infestation of the intertidal mussel Mytilus galloprovincialis. Endolithic infestation increased towards lower latitudes most likely as a response of greater light availability. Additionally, artificial beds of either 100% non-infested or infested biomimetic mussels were used to test whether infestation alters the temperature and humidity of the interstitial spaces within beds, and if mussels surrounded by infested mussels experience lower body temperatures than those surrounded by non-infested ones. Conditions within beds of infested mussels were significantly cooler and more humid than in non-infested beds and individuals in the centre of infested mussel beds experienced significantly lower body temperatures. Under a scenario of warming climate, endolithic infestation of mussel beds might thus represent an ecological advantage not only for M. galloprovincialis as a species but also for the associated communities.