JAPANESE JOURNAL OF ECOLOGY

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Climate fluctuations can shift the phenology of many species, often greatly impacting communities by, for example, causing seasonal mismatches between predators and prey. Thus, understanding the factors affecting such mismatches and the ecosystem ramifications there of has become increasingly important, highlighting the need for long-term studies. In this paper, we review empirical evidence for the mismatch principle in terrestrial and marine ecosystems and discuss the conditions that induce this phenomenon. In terrestrial ecosystems, the phenologies of birds, insects, and plants have become advanced, although to different degrees, due to global warming. Different physical factors (e.g., day length and temperature) and/or single factors differentially affect the phenology of these functional groups, thus generating mismatches between key species. Although the timing of breeding in seabirds is not always advanced, it can be affected by interannual changes of sea ice and sea water temperatures. Several studies have reported mismatches between the period of high food requirement in seabirds and the seasonal peak availability of prey. For example, the anchovy Engraulis japonicus, is the most important prey item of rhinoceros auklets Cerorhinca monocerata, breeding on Teuri Island. A long-term study has indicated that different patterns in the air pressure of the northern hemisphere have affected both spring air temperatures, which determine the timing of egg laying in auklets, and the strength of the Tsushima Current, which influences the seasonal availability of the anchovy. Therefore, in some years, a mismatch has formed between the timing of auklet breeding and peak prey availability. Clearly, global surface pressure patterns and water currents, both of which impact local climate factors, can affect the breeding success of seabirds either directly or indirectly through changes in the marine ecosystem. However, studies of auklets have also indicated that various mechanisms operate in different regions. Furthermore, because seabirds are homeotherms, their activity may be less affected by ambient temperature; thus, they can often adapt the timing of breeding each year to match peak prey availability. Therefore, to more fully understand the effects of climate change on seabirds, the impacts of global climate change on the physics and biota of local marine ecosystems must be examined. In particular, research should focus on the ability of seabirds to adjust the timing of breeding as well as the factors limiting associated activities.

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Variability in the composition, structure, and dynamics of ecosystems has been widely recognized in recent studies. It is thought that forest ecosystems barely reach the steady-state and equilibrium status. This "non-equilibrium status" of forest ecosystems is regulated by natural disturbances. Consequently, forest dynamics have been clarified in many regions by focusing on natural disturbance regimes. Furthermore, in current terrestrial ecosystem management, natural disturbances in ecosystems and landscapes have been acknowledged as part of the dynamics of ecological processes, one that helps to maintain ecological integrity and conserve biological diversity at various levels. However, the variability and complexity of forest ecosystems remain unknown. Natural disturbances, particularly larger ones, are unpredictable and their impacts on ecosystems are highly uncertain. For ecosystem management and restoration, clarification of the ecosystem responses to environmental variability is critical, and we should further investigate the complexity, unpredictability, and non-equilibrium nature of ecological processes. Therefore, data on the dynamic nature of ecosystems and ecological processes from the specific plot to the landscape level, as regulated by various natural disturbances, is needed to assess the non-equilibrium paradigm of forest ecosystems.

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