Evidence map›Paper›PMID 42009991›Full record

ArticleScientific reports2026

Intensive grazing by green turtles depletes seagrass meadows and constrains turtle growth in Kume Island, Japan.

Junichi Okuyama, Hideaki Nishizawa, Kenji Sudo, Hiromori Shimabukuro, Nao Yoshida, Yoshimitsu Tsukakoshi, Haruki Murai, Sachia Sasano, Motoya Tamaki

Abstract read
PubMed Full text at PMC Publisher
In one paragraph

Article in Scientific reports, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

9 authors.

Junichi OkuyamaFisheries Technology Institute, Japan Fisheries Research and Education Agency, Fukai Ota 148, Ishigaki, Okinawa, 907-0451, Japan. okuyama_junichi73@fra.go.jp.
Hideaki NishizawaGraduate School of Informatics, Kyoto University, Yoshida Honmachi, Sakyo, Kyoto, 606-8501, Japan.
Kenji SudoFisheries Technology Institute, Japan Fisheries Research and Education Agency, Ichimaruishi 2-17-5, Hatsukaichi, Hiroshima, 739-0452, Japan.
Hiromori ShimabukuroFisheries Technology Institute, Japan Fisheries Research and Education Agency, Ichimaruishi 2-17-5, Hatsukaichi, Hiroshima, 739-0452, Japan.
Nao YoshidaFisheries Technology Institute, Japan Fisheries Research and Education Agency, Fukai Ota 148, Ishigaki, Okinawa, 907-0451, Japan.
Yoshimitsu TsukakoshiKume-jima Sea Turtle Museum, Ou 170, Kumejima, Shimajiri, Okinawa, 901-3106, Japan.
Haruki MuraiGraduate School of Informatics, Kyoto University, Yoshida Honmachi, Sakyo, Kyoto, 606-8501, Japan.
Sachia SasanoFisheries Technology Institute, Japan Fisheries Research and Education Agency, Fukai Ota 148, Ishigaki, Okinawa, 907-0451, Japan.
Motoya TamakiFisheries Technology Institute, Japan Fisheries Research and Education Agency, Fukai Ota 148, Ishigaki, Okinawa, 907-0451, Japan.

Funding

Asahi Glass Foundation and Environmental Research and Technology Development Fund 4-2403Environment Research and Technology Development Fund (JPMEERF202404003) of the Environmental Restoration and Conservation Agency, provided by the Ministry of the Environment of Japan JPMEERF202404003
6 · The paper itself

Abstract

Conservation efforts have led to substantial recovery of green turtle (Chelonia mydas) populations globally, yet over- or intensive grazing by these megaherbivores is now degrading seagrass ecosystems. We assessed the impacts of turtle-driven grazing and its feedback on turtle nutritional status and growth at Kume Island, Japan, through a comprehensive study conducted between autumn 2023 and spring 2025. Our approach combined seagrass surveys, drone-based density estimation, capture-recapture studies, and stomach content analysis. The surveys revealed a 50.6% reduction in seagrass area since the 1990s, alongside a species shift from mid-sized, long-lived taxa (Thalassia hemprichii) to small, fast-growing species (Halophila ovalis). This species shift was consistent with changes observed in the turtles' diet composition. The foraging aggregation was dominated by immature turtles, with turtle densities reaching 452.6 individuals per km

Indexed as

HerbivoryHydrocharitaceaeTurtlesAnimalsConservation of Natural ResourcesEcosystemIslandsJapanSeasonsEcosystem managementHerbivore–seagrass interactionsIsolated oceanic islandOvergrazing mitigationSea turtles

Identifiers

PMID42009991
PMCPMC13265915

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.