Effects of temperature and red tides on sea urchin abundance and species richness over 45 years in southern Japan

Ohgaki, Shinichiro; Kato, Tetsuya; Kobayashi, Naomasa; Tanase, Hidetomo; Kumagai, Naoki H.; Ishida, So; Nakano, Tomoyuki; Wada, Yoko; Yusa, Yoichi

doi:10.1016/j.ecolind.2018.03.040

Cited by 18 publications

(21 citation statements)

References 52 publications

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“…We suspected that SST would explain much of the predictable variation in macroalgal density and purple urchin density across the NCI (Ohgaki et al ), so we did not include a random effect of island, as there is a strong east–west temperature gradient across the islands. SST can also vary interannually due to the El Niño–Southern Oscillation (ENSO).…”

Section: Methodsmentioning

confidence: 99%

Trophic redundancy and predator size class structure drive differences in kelp forest ecosystem dynamics

Eisaguirre

Davis

et al. 2020

Ecology

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Ecosystems are changing at alarming rates because of climate change and a wide variety of other anthropogenic stressors. These stressors have the potential to cause phase shifts to less productive ecosystems. A major challenge for ecologists is to identify ecosystem attributes that enhance resilience and can buffer systems from shifts to less desirable alternative states. In this study, we used the Northern Channel Islands, California, as a model kelp forest ecosystem that had been perturbed from the loss of an important sea star predator due to a sea star wasting disease. To determine the mechanisms that prevent phase shifts from productive kelp forests to less productive urchin barrens, we compared pre-and postdisease predator assemblages as predictors of purple urchin densities. We found that prior to the onset of the disease outbreak, the sunflower sea star exerted strong predation pressures and was able to suppress purple urchin populations effectively. After the disease outbreak, which functionally extirpated the sunflower star, we found that the ecosystem response-urchin and algal abundances-depended on the abundance and/or size of remaining predator species. Inside Marine Protected Areas (MPAs), the large numbers and sizes of other urchin predators suppressed purple urchin populations resulting in kelp and understory algal growth. Outside of the MPAs, where these alternative urchin predators are fished, less abundant, and smaller, urchin populations grew dramatically in the absence of sunflower stars resulting in less kelp at these locations. Our results demonstrate that protected trophic redundancy inside MPAs creates a net of stability that could limit kelp forest ecosystem phase shifts to less desirable, alternative states when perturbed. This highlights the importance of harboring diversity and managing predator guilds.

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Section: Methodsmentioning

confidence: 99%

Trophic redundancy and predator size class structure drive differences in kelp forest ecosystem dynamics

Eisaguirre

Davis

et al. 2020

Ecology

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“…B was extirpated from the pools, leading to significant changes in the structure of the sea urchin community. Mass mortality events due to unusually low winter temperatures have occurred in the past at Shirahama, with documented events in 1963 and 1984 (Tokioka, 1963;Ohgaki et al, 2019) (as reference data, Figure S2 shows the water temperature data off Wakayama since 1982). In those cases, the intertidal zone was more affected than the subtidal zone, and urchin populations eventually recovered (Tokioka, 1966;Ohgaki et al, 2019).…”

Section: Drastic Decrease Of Sea Urchin Population and Behavioural Change After The Cold Eventmentioning

confidence: 99%

Effect of a cold event on population and community of pit-inhabiting sea urchins in Western Pacific coasts

Yamamori

Katô

2021

J. Mar. Biol. Ass.

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Coastal tide pools in southern Japan are inhabited by the rock-boring sea urchin Echinostrephus molaris, which excavate pits in the substrate. These pits are subsequently used by non-boring sea urchins such as Anthocidaris crassispina and Echinometra sp. B, and the recolonized pits are often inhabited by a commensal limpet-like trochid snail species, Broderipia iridescens. We explored the population and community dynamics of these sea urchins and the limpet-like snail by monitoring occupancy of 512 pits in tide pools in Shirahama, Japan from May 2017–May 2019. Initially, nearly all pits were occupied by any one of the three sea urchin species, but an unusual cold event in February 2018 caused a mass die off of these sea urchins. After this event, occupancy decreased from 99% to 15%, and the tropical species Echinometra sp. B disappeared from the study pools. We observed slow population recovery of E. molaris and A. crassispina, provably via migration of sub-adults from the subtidal zone. Turnover rate of the pit-occupying sea urchin species was <1.0% before the cold event, but drastically increased after the cold event. Population size of the commensal snail decreased along with those of their host, but the rate of commensalism was constant at 50–55% throughout the study period, suggesting that these snails followed their host sea urchins repeating inter-pit migration. Despite mass mortality and slow recovery, the sea urchin density remained high enough to maintain persistent sea urchin barrens throughout the study period.

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“…Both the Kuroshio and Oyashio Currents show spatial and temporal fluctuations 27 – 33 . Previous studies have suggested that spatiotemporal variability of these ocean current systems has likely caused changes in dominant species 34 , 35 , recruitment strength 34 , 36 , 37 , mortality 35 , 38 , 39 , and abundance of coastal organisms 34 – 38 . Therefore, we speculate that increasing spatiotemporal variability of ocean current systems increases the relative frequencies of the linear, reversible, and abrupt trajectories and some model coefficients of each trajectory (α of the linear, δ o and δ r of the reversible, ϕ 1 of the stable, and δ of the abrupt trajectory) and decreases the relative frequency of the stable trajectory and three measures of community temporal invariability: species richness, species composition, and community abundance.…”

Section: Introductionmentioning

confidence: 99%

Quantifying the dynamics of rocky intertidal sessile communities along the Pacific coast of Japan: implications for ecological resilience

Ishida

Tachibana

Hori

et al. 2021

Sci Rep

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Long-term patterns in trajectories of natural communities provide insights into ecological resilience, but their assessment requires long-term census data. We analyzed 16-year census data for intertidal communities from 30 rocky shores along Japan’s Pacific coast to assign community change to four possible trajectories (stable, reversible, abrupt, or linear) representing different aspects of ecological resilience, and to estimate multiple metrics of temporal invariability (species richness, species composition, and community abundance). We examined (1) how the prevalence of the four trajectories differs among regions, (2) how the features (model coefficients) of each trajectory vary among regions, and (3) how the temporal invariabilities differ among trajectories and regions. We found that the stable trajectory was the most common. Its features differed among regions, with a faster recovery to steady-state equilibrium in low-latitude regions. Furthermore, trajectories and temporal invariabilities both varied among regions, seemingly in association with the strength of ocean current fluctuations. Thus, the relationship between community temporal invariability and trajectory may be weak or absent, at least at the regional scale.

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Effects of temperature and red tides on sea urchin abundance and species richness over 45 years in southern Japan

Cited by 18 publications

References 52 publications

Trophic redundancy and predator size class structure drive differences in kelp forest ecosystem dynamics

Trophic redundancy and predator size class structure drive differences in kelp forest ecosystem dynamics

Effect of a cold event on population and community of pit-inhabiting sea urchins in Western Pacific coasts

Quantifying the dynamics of rocky intertidal sessile communities along the Pacific coast of Japan: implications for ecological resilience

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Effects of temperature and red tides on sea urchin abundance and species richness over 45 years in southern Japan

Cited by 18 publications

References 52 publications

Trophic redundancy and predator size class structure drive differences in kelp forest ecosystem dynamics

Trophic redundancy and predator size class structure drive differences in kelp forest ecosystem dynamics

Effect of a cold event on population and community of pit-inhabiting sea urchins in Western Pacific coasts

Quantifying the dynamics of rocky intertidal sessile communities along the Pacific coast of Japan: implications for ecological resilience

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Effects of temperature and red tides on sea urchin abundance and species richness over 45 years in southern Japan