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The importance of disturbance Work in sea otters over the last few decades has transformed our understanding of the importance of specific species, or keystones, as drivers of community structure and stability. Foster et al . took the next step and tested whether otter foraging might influence genetic diversity in an eelgrass ecosystem (see the Perspective by Roman). The authors found that eelgrass genetic diversity was significantly higher where otters were present and that the impact was related to time: Longer otter presence was associated with higher genetic diversity. These results illustrate how the actions of a predator can affect the diversity of a producer in a tropic system. —SNV

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Plants can change the biotic and abiotic characteristics of soil, which can in turn affect the growth of plants. For example, changes in below‐ground microbial composition by one plant can affect the relative performance of a second plant, in turn affecting the outcome of plant–plant interactions, invasive species success, species abundance distributions, successional processes and plant community composition and diversity. The effects of plant–soil feedbacks on population, community and ecosystem processes in coastal and marine soft‐sediment systems have received relatively little attention, yet several recent examples offer compelling evidence for their importance. Marine soft‐sediment systems offer an ideal opportunity to test key theoretical predictions for when plant–soil feedbacks may contribute to species coexistence and influence community composition, including the role of phylogenetic distance and relatedness, the potential for intraspecific feedbacks, the importance of environmental context, the influence of climate change and the implications for ecosystem function. Synthesis. There is a documented disconnect between marine and terrestrial research that slows the advancement of generalisable theory. We suggest that bridging this gap in our understanding of plant–soil feedbacks may provide a unifying framework underlying plant community structure in both terrestrial and marine ecosystems.

The Pacific white-sided dolphin (Lagenorhynchus obliquidens) is one of the most abundant apex predators in the North Pacific Ocean, but little is known about how much food they consume and whether their food requirements vary seasonally. We attempted to address these two issues using the feeding records of five Pacific white-sided dolphins housed at the Vancouver Aquarium. These individuals consumed an average of 7.9 kg ± 0.35 (± SE) of fish and squid per day (~11,000 kcal day -1 ), which equated to ~7% of their body mass and an annual mean intake of 2,880 kg ± 131.8 (± SE) per dolphin (N = 5). Patterns of food consumption and seasonal changes were assessed using long-term feeding records (1977 to 2001) from a single adult female, and were found to be highest in terms of biomass and calories in late December, and about 15% less in late May and early June. Seasonal pool temperatures (range 6.5 to 21.5º C) were inversely related to food intake and accounted for part of the variation, suggesting that seasonal cues other than temperature triggered the changes in food consumption. Amounts of prey consumed by Pacific white-sided dolphins are undoubtedly higher in the wild than in captivity due to relative differences in their respective behaviors in the two environments. However, relative seasonal changes in energy requirements are likely to be independent of living conditions and have implications for estimating the energy requirements of Pacific white-sided dolphins in the wild.