But 60% of species displayed different lunar activity patterns in different populations, suggesting that many species exhibit behavioral plasticity in their lunar activity. We conclude that neither phylogenetic signal, tapetum lucidum as proxy for visual acuity, nor lunar illumination are able to reliably predict lunar activity patterns for all species, and natural selection may favor behavioral flexibility in nocturnal activity.

To that end and in order to effectively test the visual acuity hypothesis, we incorporated estimates of low-light visual acuity based on the tapetum lucidum as a proxy for the acuity of taxon-typical “night vision”. The goal of this novel approach is to fill the knowledge gap regarding the role of lunar illumination in driving nocturnal activity patterns among elusive predator and prey species. Because Prugh and Golden (2014) also found a strong phylogenetic signal in their results, and tapetum structure is the result of independent evolution in different mammalian clades (Schwab et al., 2002), our analysis incorporated phylogenetic relatedness among the factors that might influence nocturnal activity.

Longer-term experiments that focus on fitness-related responses are recommended.

We next consider how past adaptation can be inferred from comparisons across space and time. We discuss the limitations of these methodologies, consider how these data will be useful for understanding the fate of marine biodiversity and the potential emergent changes in ecosystem function, and highlight the most promising paths toward that understanding.

Ocean acidification poses a global threat to biodiversity, yet species might have the capacity to adapt through evolutionary change. Here we summarize tools available to determine species’ capacity for evolutionary adaptation to future ocean change and review the progress made to date with respect to ocean acidification. We focus on two key approaches: measuring standing genetic variation within populations and experimental evolution. We highlight benefits and challenges of each approach and recommend future research directions for understanding the modulating role of evolution in a changing ocean.

In a similar fashion as the comparison QST vs FST, the comparison PST vs FST has been used in several studies in order to detect selection (reviewed by Brommer, 2011). However, the interpretation of these results should be carried out with caution, as PST could include environmental and nonadditive genetic effects (Pujol et al., 2008). The fact that our PST estimates were greater than QST corroborates that PST vs FST comparisons should be avoided as a general method to study local adaptation, as also suggested by Pujol et al. (2008). Then, the use of PST as a proxy for QST can only be justified when between and within population estimates of additive genetic variation are available or can be reliably inferred by different approaches (Brommer, 2011; Cohen and Dor, 2018; Gentili et al., 2018; Monzón-Arguëllo et al., 2014).

In this study we carried out a natural experiment across an environmental gradient. We collected samples of L. saxatilis from the “Crab+” (extremely sheltered habitat), “Crab” (sheltered habitat) and “Wave” (exposed habitat) ecotypes from Galician shores and we analysed the shell traits.

. The demonstration of adaptation for alternative selective pressures not only requires the elucidation of the genetic basis of phenotypic variation but also determining that fitness differences can predict the observed patterns of variation (Linnen and Hoekstra, 2009).

This study has found that T. hirsuta may be displaced by M. galloprovincialis in a future ocean, causing a shift in the biogenic habitat of the Australian shores. Such a shift in habitat may affect the infauna; future conditions may cause infauna to prefer specific mussel habitats (either T. hirsuta or M. galloprovincialis) and lead to an overall decline in infaunal molluscs.

Polychaetes generally had a positive response to climate change scenarios. Warming and elevated pCO2 interacted to increase the number of species of polychaetes in the elevated pCO2 treatment at ambient temperature (Fig. 4; ANOVA Temp × CO2, F1,32 = 11.03, P < 0.02, Supplementary Table 4). Under warming, there were fewer polychaete species recruiting to T. hirsuta compared with that observed at ambient temperature, but there was no effect of warming on the number of polychaete species that recruited to M. galloprovincialis (Supplementary Table 4). When T. hirsuta and M. galloprovincialis were present in the same mesocosms, there were significantly more polychaetes under ambient temperature than under warming (Fig. 4; ANOVA Temp × Presence, F1,32 = 4.66, P < 0.05; Species × Presence, F1,32 = 4.66, P < 0.05, Supplementary Table 4). There were no significant effects of any treatments on the number of species, the number of individuals of Crustacea and the number of species of Mollusca (Fig. 4; Supplementary Table 4). Molluscs were negatively affected by elevated pCO2 but unaffected by warming (Fig. 4).

This study has shown that the invasive M. galloprovincialis was more tolerant of elevated pCO2 compared with the native T. hirsuta. We have also shown that the two mussel species possess unique infaunal communities, which are also altered by climate change conditions.

Species do not exist in isolation but rather in communities where they interact. These interactions can be broadly grouped into interactions that reduce the overall abundance of species i.e. “negative interactions” (e.g. competition and predation) or interactions that increase their abundance i.e. “positive interactions” (Bertness et al., 1999).