Okinawa Island Research Articles

Species composition of Ostracoda in the Okinawa islands, and geographical distribution of the two genera \(\textit{Loxoconcha}\) and \(\textit{Xestoleberis}\) (Arthropoda: Crustacea) around Japan

This study was conducted in the period of 2012 to 2015 in some locations of Japan. At each location, samplings were carried out on reef slopes using SCUBA diving, on reef flats, tidal beaches and river mouths during low tide. The specimens then were treated using a differential interference contrast microscope with a camera lucida (BX-50, OLYMPUS), a quick auto-coater (JFC-1500, Ion Sputtering Device), a scanning electron microscope (SEM) in the laboratory of Shizuoka University,… The result shows that total 139 species of recent ostracoda belonging to 28 families, 70 genera recorded in the Okinawa Islands, southern Japan are found. Most diversified families include Loxoconchidae (26 species - 18.7%), Xestoleberididae (17 species - 12.2%), Bairdiidae (13 species - 9.4%), Hemicytheridae (13 species - 9.4%), Leptocytheridae (8 species - 5.8%). Based on the distributional pattern of pore systems located below the eye tubercle of Loxoconcha and the types of pores on carapaces of Xestoleberis, the species groups of the two genera were divided into three groups, i.e., Groups A, B and C. Geographical distribution of three species groups was shown for each location in the present report. The geographical distribution of three species phylogenetic groups (i.e. Groups A, B and C) of the two genera Loxoconcha and Xestoleberis suggests that the fauna of two genera in the Okinawa islands are more similar to southern faunas (e.g., Vietnam, Philippines, Australia,…) than Japanese Island Arc fauna. Hence, the origin of two genera Loxoconcha and Xestoleberis in the Okinawa islands, southern Japan may be from the South.

Cryptic diversity of Eviota (Teleostei: Gobiidae) and their habitat use in the shallow waters of Okinawa Island

Cryptic diversity of Eviota (Teleostei: Gobiidae) and their habitat use in the shallow waters of Okinawa Island

An empirical projection of ocean acidification in southwestern Japan over the 21st century

Most of Japan's coral reefs are distributed in the Ryukyu Islands, in the southwestern part of Japan. Since they support biodiversity in the tropical and subtropical seas and are vulnerable to ocean acidification as well as ocean heat waves and pollution, projecting acidification over multidecadal or longer periods of time is a great interest. Currently, the majority of long-term acidification projections are based on Earth System Models (ESMs), and the validation of these projections relies on intercomparisons among ESMs. This study evaluated the multi-decadal trends in total dissolved inorganic carbon (DIC) concentrations around the Ryukyu Islands over the past 25 years from 1995 to 2019. A multiple linear regression using temperature, salinity and time parameters as explanatory variables was applied to evaluate the salinity-normalized dissolved inorganic carbon (nDIC) concentrations. The coefficient of time (+1.15 ± 0.03 μmol kg−1 yr−1) was not significantly different from the rise of nDIC that was calculated from the growth rate of atmospheric CO2 concentrations during the same period. Assuming that nDIC in this region will continue to increase at a rate that tracks the expected growth rate of atmospheric CO2 concentrations, we projected future trends of pH and aragonite saturation state (ΩA) under scenarios RCP4.5 and RCP8.5. The empirical projection of acidification by the end of the 21st century was generally consistent with projections based on ESMs. At present, global corals are generally distributed in waters with ΩA > 3.0. According to the empirical projection under the RCP8.5 scenario, ΩA around Okinawa Island would fall below 3.0 in winter in the 2030s and throughout the year in the 2060s.

Demographic history of Ryukyu islanders at the southern part of the Japanese Archipelago inferred from whole-genome resequencing data

The Ryukyu Islands are located in the southernmost part of the Japanese Archipelago and consist of several island groups. Each island group has its own history and culture, which differ from those of mainland Japan. People of the Ryukyu Islands are genetically subdivided; however, their detailed demographic history remains unclear. We report the results of a whole-genome sequencing analysis of a total of 50 Ryukyu islanders, focusing on genetic differentiation between Miyako and Okinawa islanders. We confirmed that Miyako and Okinawa islanders cluster differently in principal component analysis and ADMIXTURE analysis and that there is a population structure among Miyako islanders. The present study supports the hypothesis that population differentiation is primarily caused by genetic drift rather than by differences in the rate of migration from surrounding regions, such as the Japanese main islands or Taiwan. In addition, the genetic cline observed among Miyako and Okinawa islanders can be explained by recurrent migration beyond the bounds of these islands. Our analysis also suggested that the presence of multiple subpopulations during the Neolithic Ryukyu Jomon period is not crucial to explain the modern Ryukyu populations. However, the assumption of multiple subpopulations during the time of admixture with mainland Japanese is necessary to explain the modern Ryukyu populations. Our findings add insights that could help clarify the complex history of populations in the Ryukyu Islands.

Two new species in Leptocheliidae (Crustacea: Peracarida: Tanaidacea) from Japan, with notes on their phylogenetic position and aspects of morphology

We describe two new species of leptocheliid tanaidaceans, Chondrochelia sublitoralis sp. nov. and Neoleptochelia japonica sp. nov., from Japan. Chondrochelia individuals were collected from 113 to 185 m depth in the Kumano Sea. Chondrochelia sublitoralis sp. nov. resembles Chondrochelia africana, Chondrochelia corsica, Chondrochelia taitungensis, and Chondrochelia tanykeraia in having females with slender chelipeds but differs from them in the length ratio of antennular articles and the setal pattern on maxillipeds, cheliped, pereopods 4–6, and pleopods. Males differ from Chondrochelia durbanensis, for which information on females is lacking, in having pereopod-1 propodus lacking ventrodistal spiniform setae and a uniarticulate uropodal exopod. Chondrochelia sublitoralis sp. nov. varies intraspecifically in the number of female antennular articles, five in larger and four in smaller females. Neoleptochelia japonica sp. nov., collected from the coast of Okinawa Island, differ from Neoleptochelia javaensis (previously the sole species in Neoleptochelia) in the setal pattern on antennae, maxillipeds, cheliped, and pleopods in females; and that on the cheliped in males. Male pereopods 1–3 show a unique subchelate condition that we speculate may function for clasping during copulation. Several females in both species had the second thoracomere demarcated on the carapace, whereas others did not. Cytochrome c oxidase subunit I (COI) gene sequences determined for C. sublitoralis sp. nov. and N. japonica sp. nov. showed intraspecific K2P distances of 0–0.4% and 0–0.5%, respectively. We inferred the phylogenetic positions of the two species in Leptocheliidae based on COI data.

A new species of slender flatworm in the genus Eucestoplana and a record of E. cf. cuneata (Platyhelminthes, Polycladida) from the Okinawa Islands, Japan, with an inference of their phylogenetic positions within Cestoplanidae

In this study, we describe a new species of elongated marine flatworm, Eucestoplana ittanmomensp. nov., collected from the intertidal zone of the Okinawa Islands, Japan. Eucestoplana ittanmomensp. nov. is distinguished from other congeners based on the following characteristics: i) its translucent body lacking coloration, ii) its dome-shaped penis sheath, iii) the absence of cilia on the inner wall of the male atrium except outside the penis sheath, and iv) the presence of an adhesive organ at the posterior end of the body. Additionally, we report the occurrence of E. cf. cuneata (Sopott-Ehlers & Schmidt, 1975) in Japan; E. cuneata has previously been documented in the Galapagos and Fiji Islands. We conducted phylogenetic analyses to infer the positions of the two Eucestoplana species within Cestoplanidae using a concatenated dataset comprising partial 18S and 28S rDNA sequences from E. cf. cuneata and E. ittanmomensp. nov. from Japan, as well as four known Cestoplana species with sequences available in public databases. Our phylogenetic analyses revealed that Cestoplana and Eucestoplana were reciprocally monophyletic. Furthermore, the genetic distance of the 16S rDNA sequences supported the genetic independence of the two sister species, E. cf. cuneata and E. ittanmomensp. nov.

Impacts on Bats by a Supertyphoon vs. Ordinary Typhoons along a Habitat Urbanization Gradient

Two major human-caused threats to ecosystems are habitat modification and the increasing frequency and intensity of extreme weather events. To study the combined effect of these threats, the authors used acoustic monitoring of bats along a habitat modification gradient on the island of Okinawa, Japan. During the observation period, the island experienced numerous typhoons and one supertyphoon. Native bat species remained active even at high wind speeds (up to 30 m/s in some cases). Milder typhoons had no observable effect on bat populations, with activity levels fully recovering within a few hours or days. The super typhoon also did not seem to affect bats in fully or partially forested habitats but caused their local disappearance at the urban site, which they have not re-colonized three years after the event. Notably, bats that disappeared at the urban site were species roosting in well-protected places such as caves and concrete structures. In all cases, the biomass of small flying insects and the acoustic activity of insects recovered within days after extreme weather events. Thus, the striking difference between habitats in supertyphoon effects on bats cannot be explained by the super typhoon directly killing bats, destroying their roosting sites, or decreasing the abundance of their prey. The results underscore the importance of preserving natural habitats in areas particularly affected by changing climate and show that the survival of species and ecosystems during the numerous episodes of climate change in the Earth’s history does not necessarily mean their ability to survive the accelerating climate change of our time.

<sup>14</sup>C Ages of Samples Collected from Conglomeratic Beachrocks Developed at the Northern Coast of Geruma Island, West of Okinawa Island

<sup>14</sup>C Ages of Samples Collected from Conglomeratic Beachrocks Developed at the Northern Coast of Geruma Island, West of Okinawa Island

Reproductive characteristics and gamete development of the soft coral Sclerophytum cf. heterospiculatum in Okinawa Island, Japan

AbstractSexual reproduction data are important to understand how organisms can replenish their populations and proliferate on coral reefs. Despite the importance of such data, the reproductive characteristics of most soft coral species are still unknown. Here, we examined the reproductive strategies of a species from the often‐dominant genus Sclerophytum in a coral reef on subtropical Okinawa Island, Japan. DNA barcoding and histological examinations of the tissues were conducted to confirm colony conspecificity and identify reproductive characteristics, respectively, between March 2020 and March 2021. Results indicated that the studied species, identified as Sclerophytum cf. heterospiculatum, exhibits gonochorism with longer oogenesis and shorter spermatogenesis. Female colonies produced immature oocytes throughout the year, with mature oocytes observed from late July to early September, and thus, extended spawning is likely characteristic of this species. In male colonies, spermatogenesis took place over ~5 months, with spermaries present from April through August. Mature spermaries were noted beginning in July and the inferred peak of sperm release was between late August and early September, which suggests that spermatogenesis duration was ~5 months. The largest mean oocyte and spermary sizes (628.45 ± 61.36 and 240.04 ± 49.49 μm, respectively) were both recorded in August. Gamete spawning presumably occurred during the summer season, which suggests seasonality in reproduction as influenced by changes in seawater temperature. However, the proximate cue for exact dates of spawning could be the lunar period because the inferred release of spawning materials seemed to occur between full moon and last‐quarter moon phases in both the months of August and September. The results of this study represent the first detailed report of reproductive characteristics of the genus Sclerophytum in Japan.

On improvement of system reliability by multiplexing power supply network and its economic impact

In response to energy security concerns, distributed generations such as wind turbines, photovoltaic systems, and diesel generators have been increasingly utilized in many countries. However, the integration of these systems can result in challenges such as supply–demand imbalances, voltage rise, and protection issues in the utility grid. To address these challenges, various methods for accommodating renewable energy sources using self-employed power lines have been proposed. This paper presents a model for quantitatively analyzing the reliability of the power system and the associated economic impact of multiplexing power supplies in a power-sharing network, referred to as a digital grid. A case study of the electrical power system on Okinawa Island is presented, which demonstrates that the reliability of the power system can be improved through multiplexing the power supply using a triple-line, with an acceptable economic impact.

New lithistid sponge of the genus Sollasipelta (Porifera, Demospongiae,Tetractinellida, Neopeltidae) from submarine caves of the Ryukyu Islands,southwestern Japan, with redescription of S. sollasi.

A new species of 'lithistid' (rock sponge) Sollasipelta subterranea sp. nov. is described from near-shore submarine caves of Okinawa and Shimoji Islands, the Ryukyu Islands, southwestern Japan. This new species is characterized by the smooth dentate ectosomal pseudophyllotriaenes, slender choanosomal oxea/style/subtylostyles and two types of amphiasters, one of which is in two size classes. Sollasipelta subterranea sp. nov. is morphologically closest to Sollasipelta sollasi (Lévi & Lévi, 1989), known from the Philippines deep sea, and our examination of the type specimen of S. sollasi revealed that the pseudophyllotriaenes and desmas are substantially different between the two species, and both species possess two types of amphiasters, one of which has two size classes. Sollasipelta cavernicola (Vacelet & Vasseur, 1965) and S. punctata (Lévi & Lévi, 1983) are transferred to the genus Daedalopelta Sollas, 1888, based on possession of one type of amphiastes as microscleres. Sollasipelta mixta (Vacelet, Vasseur and Lévi, 1976) is formally transferred to the genus Neopelta Schmidt, 1880, based on the morphological characters. A key to species of the genus Sollasipelta Van Soest & Hooper, 2020 is also provided. Sollasipelta subterranea sp. nov. represents the first 'lithistid' sponge from submarine caves of the Western Pacific and the first species of sponge inhabiting anchialine cave environments in the Indo-West Pacific. This is also a new record of the family Neopeltidae from Japanese waters.

Obesity and hypertension from a public health perspective in a small remote island of Okinawa, Japan.

This study investigated the relationship between obesity and hypertension from a public health perspective in a small remote island of Okinawa where obesity is prevalent. A cross-sectional study was conducted in 456 residents aged ≥18 years in Yonaguni island who underwent an annual health check-up and the Yonaguni dietary survey in 2022. Each participant responded to our original questionnaire and provided further dietary survey data via the Yonaguni municipal government. The odds ratio for hypertension was calculated in the obese group, using a logistic regression model with the non-obese group serving as the reference. Hypertension was defined as a systolic blood pressure ≥140 mmHg, a diastolic blood pressure ≥90 mmHg measured on an automated sphygmomanometer, and/or taking anti-hypertensive agents, while obesity was defined as a body mass index ≥25 kg/m2. The proportion of hypertension associated with obesity among all hypertensive subjects was calculated. The prevalence of obesity and hypertension was 54.3% and 49.0% in the 208 male subjects and 32.3% and 43.6% in the 248 female subjects, respectively. The odds ratio for hypertension in the obese group was 3.73 (95% confidence interval, 1.93-7.20) for men and 4.13 (2.06-8.29) for women after adjusting for age, alcohol drinking habit, behavior for lowering salt intake, and smoking habit. Hypertension in 49.5% (95% confidence interval, 29.4%-63.9%) of males and 37.9% (22.6%-50.2%) of females was associated with obesity in this island. Some areas of Japan could be urgently required to address obesity for preventing cardiovascular disease. A community-based, cross-sectional study in 456 residents aged ≥18 years in Yonaguni island, Okinawa prefecture, Japan.

First Japanese Records of the Indo-Pacific Scorpionfish (Scorpaenidae) <i>Scorpaenodes corallinus</i>, with a Re-evaluation of Coronal Spines as a Diagnostic Character

Fifteen specimens (70.9–95.5 mm standard length) of the Indo-Pacific species Scorpaenodes corallinus Smith, 1957, previously recorded from Mozambique, Tanzania, Kenya, the Seychelles, Indonesia, Australia, the Hawaiian Islands, New Caledonia and French Polynesia, and recently collected from Okinawa Island (Okinawa Islands) and Yoron Island (Amami Islands), represent the first Japanese records of the species. Examination of a wide range of specimens indicated that the presence of coronal spines (formerly considered diagnostic of the species) was inconsistent. The new standard Japanese name “Ichigo-isokasago” is proposed for the species.

Quantifying connectivity between mesophotic and shallow coral larvae in Okinawa Island, Japan: a quadruple nested high-resolution modeling study

Coral bleaching has recently been occurring extensively across the world’s oceans, primarily because of high water temperatures. Mesophotic corals that inhabit depths of approximately 30–150 m are expected to survive bleaching events and reseed shallow water corals afterward. In Okinawa, Japan, mesophotic coral ecosystems have been reported to serve as a refuge for preserving the genotypic diversity of bleaching-sensitive corals. The connectivity of larval populations among different habitats is a key element that determines the area to be conserved in desirable coral ecosystems. Because coral larvae are largely transported passively by ambient oceanic currents, particularly in the horizontal direction, numerical ocean circulation models greatly help to quantify connectivity with detailed spatiotemporal network structures. The present study aimed to quantify the short-distance connectivity of shallow and mesophotic coral larvae in reef areas on the northwest coast of Okinawa Island. To this end, a quadruple nested high-resolution synoptic ocean model at a lateral spatial grid resolution of 50 m was developed, which was capable of realizing detailed coastal currents influenced by complex nearshore topography, and coupled with an offline 3-D Lagrangian particle-tracking model. After validating the developed model, short-distance horizontal coral connectivity across reef areas on the northwest coast was successfully evaluated. The alongshore lateral connectivity had apparent asymmetry caused by depth-dependent horizontal currents, whereas the larvae spawned at shallow and mesophotic depths were reachable to each other. Such across-depth larval dispersal was attributable to the mixed-layer depth in the spawning period, viz., the boreal spring, which approximately coincides with the boundary between shallow and mesophotic coral, leading to the intensive vertical exchange of virtual larvae.

A new species of the mud shrimp genus Naushonia Kingsley, 1897 (Decapoda: Gebiidea: Laomediidae) from the Ryukyu Islands, southwestern Japan, inhabiting burrows of an axiidean shrimp.

A new species of the laomediid mud shrimp genus Naushonia Kingsley, 1897 is described and illustrated based on seven specimens collected from Okinawa Island, Ryukyu Islands, southwestern Japan. All specimens of Naushonia karashimai n. sp. were collected from burrows of a large axiidean shrimp, Neaxius acanthus (A. Milne-Edwards, 1879), which inhabits seagrass beds in inner reef lagoons. The new species is easily distinguished from all 16 known congeners by its tridentate rostrum and relatively narrow pereopod 1 palm with a proximally located pollex. Sequences of the mitochondrial 16S rRNA and COI genes were newly generated for five species and two species of Naushonia, including the new species, respectively. Preliminary phylogenetic analysis using sequences of the 16S rRNA gene was performed.

Gigantic Anemone Species in the Deep ‘Churaumi’—Description of a New Species of the Genus <i>Telmatactis</i> (Cnidaria: Anthozoa: Actiniaria: Metridioidea), <i>Telmatactis profundigigantica</i> sp. nov.

Although the members of the genus Telmatactis Gravier, 1916 have been reported from broad area of the world including Japanese waters, the localities of the species have been limited to shallow areas. In this study, we report a new species in this genus, Telmatactis profundigigantica sp. nov., collected from the deeper area than 200 m of the East China Sea off Okinawa Island, discovered by ROV, and taken care of in Okinawa Churaumi Aquarium. This new species is chiefly characterized by its comparatively huge size of its body, over 10 cm in diameter and height, far larger than the other known species of this genus. Moreover, this species has characteristic multiple-headed tentacles and large cnidae in its acrospheres. In the present article, we also discuss the severe toxicity of this species and touch on the ecology of deep-sea anemones.

Amidst nets and typhoons: conservation implications of bat–farmer conflicts on Okinawa Island

AbstractFlying foxes are keystone species on islands and are threatened worldwide, particularly by forest degradation, hunting and culling. They are often persecuted if they are perceived as agricultural pests, but the extent of crop damage from flying foxes and the factors triggering their visits to crops are not well established. This study aimed to investigate wildlife-caused damage to tankan oranges Citrus tankan on Okinawa Island, Japan, and interactions between the Ryukyu flying fox Pteropus dasymallus and farmers. We compiled data from three sources: official records of wildlife-caused crop damage, questionnaire surveys of 43 farmers and time-lapse camera surveys conducted at 14 locations during January–February 2018. Official records and the questionnaire survey indicated that the large-billed crow Corvus macrorhynchos caused most damage in a typical year (53–56% of the total damage), followed by P. dasymallus (18–28%). However, time-lapse camera surveys suggested negligible damage caused by P. dasymallus (2.1%) in 2018, a typhoon-free year. Farmers perceived a decline in local population size and stated that at least 2,000 P. dasymallus individuals had died in their orchards during 2008–2018. If this is extrapolated to the whole region, fatalities could have reached 6,500–8,500 individuals during that period. Binomial regression performed on official records demonstrated that damage by P. dasymallus was largely explained by interannual cyclonic activity. Prevalent netting practices could be a serious threat to P. dasymallus: 81% of interviewees reported that flying foxes die from entanglement in their nets. Nevertheless, half of these farmers were satisfied with current crop protection measures. These findings call for prompt remediation with particular focus on implementing more bat-friendly crop protection following strong typhoon seasons.

Bacterial communities and toxin profiles of Ostreopsis (Dinophyceae) from the Pacific island of Okinawa, Japan

Variations in toxicity of the benthic dinoflagellate Ostreopsis Schmidt 1901 have been attributed to specific molecular clades, biogeography of isolated strains, and the associated bacterial community. Here, we attempted to better understand the biodiversity and the basic biology influencing toxin production of Ostreopsis. Nine clonal cultures were established from Okinawa, Japan, and identified using phylogenetic analysis of the ITS-5.8S rRNA and 28S rRNA genes. Morphological analysis suggests that the apical pore complex L/W ratio could be a feature for differentiating Ostreopsis sp. 2 from the O. ovata species complex. We analyzed the toxicity and bacterial communities using liquid chromatography-mass spectrometry, and PCR-free metagenomic sequencing. Ovatoxin was detected in three of the seven strains of O. cf. ovata extracts, highlighting intraspecies variation in toxin production. Additionally, two new potential analogs of ovatoxin-a and ostreocin-A were identified. Commonly associated bacteria clades of Ostreopsis were identified from the established cultures. While some of these bacteria groups may be common to Ostreopsis (Rhodobacterales, Flavobacteria-Sphingobacteria, and Enterobacterales), it was not clear from our analysis if any one or more of these plays a role in toxin biosynthesis. Further examination of biosynthetic pathways in metagenomic data and additional experiments isolating specific bacteria from Ostreopsis would aid these efforts.

An environmental DNA metabarcoding survey reveals generic-level occurrence of scleractinian corals at reef slopes of Okinawa Island.

Coral reefs have the highest biodiversity of all marine ecosystems in tropical and subtropical oceans. However, scleractinian corals, keystone organisms of reef productivity, are facing a crisis due to climate change and anthropogenic activities. A broad survey of reef-building corals is essential for worldwide reef preservation. To this end, direct observations made by coral-specialist divers might be supported by another robust method. We improved a recently devised environmental DNA (eDNA) metabarcoding method to identify more than 43 scleractinian genera by sampling 2 l of surface seawater above reefs. Together with direct observations by divers, we assessed the utility of eDNA at 63 locations spanning approximately 250 km near Okinawa Island. Slopes of these islands are populated by diverse coral genera, whereas shallow 'moats' sustain fewer and less varied coral taxa. Major genera recorded by divers included Acropora, Pocillopora, Porites and Montipora, the presence of which was confirmed by eDNA analyses. In addition, eDNA identified more genera than direct observations and documented the presence of previously unrecorded species. This scleractinian coral-specific eDNA method promises to be a powerful tool to survey coral reefs broadly, deeply and robustly.

Occurrence of brown root rot in Ocean Expo Park, Okinawa, Japan: Infection route and preventive control measures

AbstractOcean Expo Park, established in 1976 on subtropical Okinawa Island, Japan, has approximately 8000 planted or naturally grown trees in an area of 77.2 ha. Windfall of these trees occurs mainly due to typhoons; wood chips made from the trunks and roots of windfall trees are commonly used as mulching material throughout the park areas, despite possible infection by pathogenic fungi such as Phellinus noxius, the pathogen causing brown root rot. P. noxius is distributed in tropical and subtropical areas worldwide and has a broad host range. The fungus can infect host plants with mycelia via root‐to‐root contact or with basidiospores. Here, we report the current status of tree damage caused by brown root rot in the park and infer the infection routes of P. noxius based on microsatellite markers. Among a total of 294 trees surveyed in the park, P. noxius was isolated from 13 trees of five species. P. noxius was observed more frequently on Ficus microcarpa than on other tree species. Ficus superba var. japonica was identified as a new host species, and Bombax ceiba was first recorded as a host plant of P. noxius in Japan. Among the 13 P. noxius isolates from the diseased trees, 2 isolates from adjacent diseased trees were considered to be of the same genet, while the other 11 isolates were different genets, indicating that infection by basidiospores occurred frequently among trees in the entire park, although spread via root systems also occurred between at least two adjacent trees. An identical genet was not detected at distant locations, which suggests that the disease does not spread via chips. However, mulching with chips can lead to wood decay due to decaying fungi other than P. noxius. Therefore, in accordance with the precautionary principle, the park currently prohibits the chipping and mulching of windfall or damaged trees and is considering disposal methods such as burning.