Effects on river macroinvertebrate communities of tsunami propagation after the 2011 Great East Japan Earthquake

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Behavioral Response of Satellite‐collared Elephants to the Tsunami in Southern Sri Lanka1

After the Asian tsunami the media was inundated with reports of aberrant behavior among animals attributed to a “sixth sense” that allowed them to respond to the catastrophe ahead of the impact. We present behavior data from two satellite‐collared Asian elephants that ranged close to the tsunami impact area in Sri Lanka. These data indicate that neither elephant behaved in a manner consistent with a “sixth sense” that allowed an early detection of the approaching tsunami.     

Recovery of sandy beach and maritime forest vegetation on Phuket Island (Thailand) after the major Indian Ocean tsunami of 2004

Question: How rapidly has the sandy beach and maritime forest vegetation on Phuket recovered and regenerated after the impact of the major Indian Ocean tsunami of 2004? What are the characteristics of sandy beach species for regenerating their populations and the invasion patterns of originally non-sandy beach species or other newcomers after the tsunami? Location: Phuket Island, southern Thailand. Methods: Species composition of beaches was studied on the same research plots 6 months before and 9 months after the tsunami. The changes in individual species cover before and after the tsunami were determined by χ² tests. Change in community composition was analysed by detrended correspondence analysis. The relationship between species and environmental factors was analysed by canonical correspondence analysis. Results: The sites disturbed by the tsunami were often invaded by annuals, especially grasses and asteraceous plants, rather than by perennials. In contrast, species with clonal growth by stolons decreased significantly. Factors determining the species habitat differences were soil hardness (penetration resistance of sandy soil), per cent silt content, soil water content and beach management. Habitat differences among originally non-sandy beach herbaceous species that expanded their population or moved to the coast after the disaster were defined by sand accretion or erosion caused by the tsunami. Many sandy beach herbaceous communities changed into Dactyloctenium aegyptium communities because of the tsunami were originally constituted by non-sandy beach D. aegyptium with Cenchrus echinatus. Although the forest floors of most maritime forests were invaded by originally non-sandy beach Tridax procumbens, Eleusine indica or D. aegyptium because of the tsunami, this did not result in a change in the vegetation unit, because species' loss was restricted to the understorey. In time, these forests will recover their previous community composition. Conclusions: Our results suggest that originally non-sandy beach native species invaded the disturbed beaches rapidly after the tsunami but their habitats differ. Sites where sand accumulated on a beach because of the tsunami were invaded by D. aegyptium and E. indica, whereas soil erosion permitted invasion by Digitania adscendens. Tridax procumbens establishes rapidly on wet sites with hard soil, high per cent silt content and low beach management pressure. Sandy beach species with subterranean long rhizomes are strongly tolerant of such disasters. We concluded that the species composition of the beaches disturbed by a temporary large disaster is determined by dormancy and growth forms, with radicoid form being influential.     

Field study on planted forest structures and their role in protecting communities against tsunamis: experiences along the coast of the Biobío Region,Chile

A field study using satellite images was carried out to analyze the effect of coastal vegetation in mitigating the impact of a catastrophic tsunami on coastal villages in the Biobío Region, Chile, in February 2010. Two types of stand, Pinus radiata D. Don forests and Cupressus macrocarpa Hartw. shelterbelts, appear to have protected coastal areas behind them from the direct impact of the tsunami. The impacts of the horizontal and vertical structures of these coastal forests on the drag forces were analyzed by observing the characteristics of Pinus radiata forests and Cupressus macrocarpa shelterbelts. The stands absorbed the impact of the tsunami without incurring broken stems or uprooted trees due to their diverse horizontal structure, as they contained short trees with various diameters. However, small areas of the stands were damaged by salinity after the tsunami. For this tsunami, which was less than 3 m high, the horizontal and vertical structures of the P. radiata and C. macrocarpa stands provided effective protection for coastal villages since they reduced the velocity and height of the tsunami. A shelterbelt consisting of three rows of C. macrocarpa in front of the tsunami and a P. radiata forest with a density of 11 trees/100 m² and a width of >50 m immediately behind the shelterbelt are suggested as a means of protecting communities along the coastline of the Biobío Region against tsunamis.     

Prevalence and species richness of trematode parasites only partially recovers after the 2011 Tohoku,Japan, earthquake tsunami

Trematode parasites have complex life cycles and use a variety of host species across different trophic levels. Thus, they can be used as indicators of disturbance and recovery of coastal ecosystems. Estuaries on the Pacific coast of northeastern Japan were heavily affected by the 2011 Tohoku earthquake tsunami. To evaluate the effect of the tsunami on the trematode community, we examined trematodes in the mud snail, Batillaria attramentaria, at five study sites (three sites severely exposed to the tsunami and two sites sheltered from the tsunami) in Sendai Bay for 2 years prior to and 8 years after the tsunami. While the trematode prevalence decreased at all study sites, the species richness decreased only at the sites exposed to the tsunami. Although parasitism increased over the study period post-tsunami, the community had not fully recovered 8 years after the event. Trematode community structure has changed every year since the tsunami and has not stabilised. This could be explained by the alteration of first and second intermediate host communities. Our study suggests that it will take more time for the recovery of the trematode community and the associated coastal ecosystem in the Tohoku region.     

Vegetation bioshields for tsunami mitigation: review of effectiveness, limitations, construction, and sustainable management

Coastal vegetation has been widely recognized as a natural method to reduce the energy of tsunami waves. However, a vegetation barrier cannot completely stop a tsunami, and its effectiveness depends on the magnitude of the tsunami as well as the structure of the vegetation. For coastal rehabilitation, optimal planning of natural coastal systems, and their maintenance, we need to quantitatively elucidate the capacity of vegetation to reduce the energy of tsunami waves. The limitations of coastal forests in relation to the magnitude of a tsunami and the maintenance of forests as natural disaster buffer zones have to be understood correctly for effective coastal vegetation planning. Demerits of coastal forests have also been revealed: for example, an open gap in a forest (i.e., a road, river, difference in elevation, etc.) can channel and amplify a strong current by forcing it into the gap. Floating debris from broken trees also can damage surrounding buildings and hurt people. However, many studies have revealed that these demerits can be overcome with proper planning and management of mangroves and coastal forests, and that coastal vegetation has a significant potential to mitigate damage in constructed areas and save human lives by acting as buffer zones during extreme natural events. However, mangrove forests have been damaged by anthropogenic activities (i.e., tourism, shrimp farming, and industrial development), making coastal areas increasingly vulnerable to tsunamis and other natural disasters. The effectiveness of vegetation also changes with the age and structure of the forest. This highlights the fact that proper planning and management of vegetation are required to maintain the tsunami buffering function of coastal forests. Although many government and nongovernmental organizations have implemented coastal vegetation projects, many of them have been unsuccessful due to a lack of proper maintenance. A pilot project in Matara City, Sri Lanka, revealed that participation and support from local authorities and communities is essential to make the planting projects successful. An integrated coastal vegetation management system that includes utilization of the materials produced by the forest and a community participation and awareness program are proposed to achieve a sustainable and long-lasting vegetation bioshield.     

Lessons from the Tōhoku tsunami: A model for island avifauna conservation prioritization

Earthquake‐generated tsunamis threaten coastal areas and low‐lying islands with sudden flooding. Although human hazards and infrastructure damage have been well documented for tsunamis in recent decades, the effects on wildlife communities rarely have been quantified. We describe a tsunami that hit the world's largest remaining tropical seabird rookery and estimate the effects of sudden flooding on 23 bird species nesting on Pacific islands more than 3,800 km from the epicenter. We used global positioning systems, tide gauge data, and satellite imagery to quantify characteristics of the Tōhoku earthquake‐generated tsunami (11 March 2011) and its inundation extent across four Hawaiian Islands. We estimated short‐term effects of sudden flooding to bird communities using spatially explicit data from Midway Atoll and Laysan Island, Hawai'i. We describe variation in species vulnerability based on breeding phenology, nesting habitat, and life history traits. The tsunami inundated 21%–100% of each island's area at Midway Atoll and Laysan Island. Procellariformes (albatrosses and petrels) chick and egg losses exceeded 258,500 at Midway Atoll while albatross chick losses at Laysan Island exceeded 21,400. The tsunami struck at night and during the peak of nesting for 14 colonial seabird species. Strongly philopatric Procellariformes were vulnerable to the tsunami. Nonmigratory, endemic, endangered Laysan Teal (Anas laysanensis) were sensitive to ecosystem effects such as habitat changes and carcass‐initiated epizootics of avian botulism, and its populations declined approximately 40% on both atolls post‐tsunami. Catastrophic flooding of Pacific islands occurs periodically not only from tsunamis, but also from storm surge and rainfall; with sea‐level rise, the frequency of sudden flooding events will likely increase. As invasive predators occupy habitat on higher elevation Hawaiian Islands and globally important avian populations are concentrated on low‐lying islands, additional conservation strategies may be warranted to increase resilience of island biodiversity encountering tsunamis and rising sea levels.     

Disturbance of Shallow Marine Soft-Bottom Environments and Megabenthos Assemblages by a Huge Tsunami Induced by the 2011 M9.0 Tohoku-Oki Earthquake

Huge tsunami waves associated with megathrust earthquakes have a severe impact on shallow marine ecosystems. We investigated the impact of a tsunami generated by the 2011 M9.0 Tohoku-Oki earthquake on the seafloor and large benthic animals in muddy and sandy ria coasts (Otsuchi and Funakoshi bays) in northeastern Japan. We conducted underwater field surveys using scuba equipment in water depths of <20 m before the tsunami (September 2010) and after the tsunami (September 2011 and September 2012). During the study period, episodic changes in topography and grain-size composition occurred on the seafloor of the study area. Megabenthos sampling revealed a distinct pattern of distribution succession for each benthic species. For example, the protobranch bivalve Yoldia notabilis (Bivalvia: Nuculanidae) and the heterodont bivalve Felaniella usta (Bivalvia: Ungulinidae) disappeared after the tsunami event, whereas the distribution of the venus clam Gomphina melanaegis (Bivalvia: Veneridae) remained unchanged. In addition, the patterns of succession for a single species, such as the giant button top shell Umbonium costatum (Gastropoda: Trochidae) and the heart urchin Echinocardium cordatum (Echinoidea: Loveniidae), varied between the two bays studied. Our data also show that reestablishment of some benthic animal populations began within 18 months of the tsunami disturbance.     

Microbial Ecology of Thailand Tsunami and Non-Tsunami Affected Terrestrials

The effects of tsunamis on microbial ecologies have been ill-defined, especially in Phang Nga province, Thailand. This ecosystem was catastrophically impacted by the 2004 Indian Ocean tsunami as well as the 600 year-old tsunami in Phra Thong island, Phang Nga province. No study has been conducted to elucidate their effects on microbial ecology. This study represents the first to elucidate their effects on microbial ecology. We utilized metagenomics with 16S and 18S rDNA-barcoded pyrosequencing to obtain prokaryotic and eukaryotic profiles for this terrestrial site, tsunami affected (S₁), as well as a parallel unaffected terrestrial site, non-tsunami affected (S₂). S₁ demonstrated unique microbial community patterns than S₂. The dendrogram constructed using the prokaryotic profiles supported the unique S₁ microbial communities. S₁ contained more proportions of archaea and bacteria domains, specifically species belonging to Bacteroidetes became more frequent, in replacing of the other typical floras like Proteobacteria, Acidobacteria and Basidiomycota. Pathogenic microbes, including Acinetobacter haemolyticus, Flavobacterium spp. and Photobacterium spp., were also found frequently in S₁. Furthermore, different metabolic potentials highlighted this microbial community change could impact the functional ecology of the site. Moreover, the habitat prediction based on percent of species indicators for marine, brackish, freshwater and terrestrial niches pointed the S₁ to largely comprise marine habitat indicating-species.     

Coastal vegetation structures and their functions in tsunami protection: experience of the recent Indian Ocean tsunami

This study explored the effects of coastal vegetation on tsunami damage based on field observations carried out after the Indian Ocean tsunami on 26 December 2004. Study locations covered about 250 km (19 locations) on the southern coast of Sri Lanka and about 200 km (29 locations) on the Andaman coast of Thailand. The representative vegetation was classified into six types according to their habitat and the stand structures of the trees. The impact of vegetation structure on drag forces was analyzed using the observed characteristics of the tree species. The drag coefficient, including the vertical stand structures of trees, C _d-all, and the vegetation thickness (cumulative trunk diameter of vegetation in the tsunami direction) per unit area, dN _u (d: reference diameter of trees, N _u : number of trees per unit area), varied greatly with the species classification. Based on the field survey and data analysis, Rhizophora apiculata and Rhizophora mucronata (hereafter R. apiculata-type), kinds of mangroves, and Pandanus odoratissimus, a representative tree that grows in beach sand, were found to be especially effective in providing protection from tsunami damage due to their complex aerial root structure. Two layers of vegetation in the vertical direction with P. odoratissimus and Casuarina equisetifolia and a horizontal vegetation structure of small and large diameter trees were also important for increasing drag and trapping floating objects, broken branches, houses, and people. The vertical structure also provided an effective soft landing for people washed up by the tsunami or for escaping when the tsunami waves hit, although its dN _u is not large compared with R. apiculata-type and P. odoratissimus. In addition, the creeks inside mangroves and the gaps inside C. equisetifolia vegetation are assumed to be effective for retarding tsunami waves. This information should be considered in future coastal landscape planning, rehabilitation, and coastal resource management.     

大庆油田开发中石油类污染物对地下水环境影响模拟分析

分析了大庆市龙南油田开发建设工程对地下水环境的污染来源及污染途径,针对本油田工程工艺分析的特点,建立了石油类污染物在地下水环境中迁移、转化的数学模型,模型中考虑了石油类污染物的降解性和较强的吸附性,推导了连续源情况下地下水中石类污染物运移解析式并进行了预测分析,从而为油田开发建设工程环境影响评价提供了重要依据。     

A cross-cultural research experience: developing an appropriate methodology that respectfully incorporates both Indigenous and non-Indigenous knowledge systems

This paper engages with the methodology being used within a research project auditing concerns and aspirations in an impoverished Indigenous community in North West Australia. The community is in the heart of booming resource industries and it symbolizes the many challenges and opportunities for contemporary Australia. The paper advances the notion that social scientific research with Indigenous communities can be positioned not just as the result of consultation with the communities but as the authorized product of those communities. Although this adds to the complexity of the governing forces that impact on researchers, it also affords new possibilities for meaningful social change. If research starts with the proposition that social scientific research with Indigenous communities can be about what communities want to know, and finding out what they have to say, we may make more progress than by asking what needs to be done.     

Acehnese reefs in the wake of the Asian tsunami

The Sumatra-Andanaman tsunami was one of the greatest natural disasters in recorded human history. Here, we show that on the northwest coast of Aceh, Indonesia, where the tsunami was most ferocious, the damage to corals, although occasionally spectacular, was surprisingly limited. We detected no change in shallow coral assemblages between March 2003 and March 2005, with the exception of one site smothered by sediment. Direct tsunami damage was dependent on habitat and largely restricted to corals growing in unconsolidated substrata, a feature unique to tsunami disturbance. Reef condition, however, varied widely within the region and was clearly correlated with human impacts prior to the tsunami. Where fishing has been controlled, coral cover was high. In contrast, reefs exposed to destructive fishing had low coral cover and high algal cover, a phase shift the tsunami may exacerbate with an influx of sediments and nutrients. Healthy reefs did not mitigate the damage on land. Inundation distance was largely determined by wave height and coastal topography. We conclude that although chronic human misuse has been much more destructive to reefs in Aceh than this rare natural disturbance, human modification of the reef did not contribute to the magnitude of damage on land.     

湿地生态环境影响评价初步探讨

探讨了湿地生态环境影响评价的理论框架 ,指出由于湿地生态环境的特殊性 ,应将非污染型生态环境影响评价放到重要位置。应重视工程项目对湿地水文条件、植物区系、动物种群改变以及移民和诱导开发的影响分析。从湿地分类开始 ,以湿地功能为核心建立评价指标体系 ,把湿地潜在的生态环境效益和工程项目可能产生影响有机结合在一起 ,评价建设项目的急性和慢性影响 ,提出减缓影响的措施和替代方案。着眼于维持现存的生态过程和自然系统 ,保护湿地的生态效益和功能 ,为湿地可持续利用服务     

Seawater Inundation from the 2011 Tohoku Tsunami Continues to Strongly Affect Soil Bacterial Communities 1 Year Later

The effects of inundation caused by the 2011 Tohoku tsunami on soil bacterial communities in agricultural fields were evaluated. Bacterial communities were compared across three different types of soil, unflooded field (UF) soil, soil flooded for 2 weeks (short term (ST)), and soil flooded for 2 months (long term (LT)), using polymerase chain reaction-pyrosequencing of 16S rRNA genes. Acidobacteria were dominant in UF, with a relative abundance of approximately 35 %, and Proteobacteria dominated flooded soils (30–67 %). Hierarchical cluster analysis indicated that the community structure of soil bacteria in flooded soils (ST and LT) clearly differed from that in UF. Differences between LT and ST fields were rarely observed in terms of chemical properties and microbial community structure at the phylum level. However, sulfur-oxidizing bacteria (SOB) and nitrite-oxidizing bacteria (NOB) in LT tended to occur at high and low abundances, respectively. Halothiobacillus, a halotolerant SOB, was detected in all LT fields. Unexpectedly, a zeta-Proteobacteria, which had previously only been detected in marine environments, was detected in LT fields only. Our results demonstrate that the effects of the 2011 Tohoku tsunami on soil bacterial communities in agricultural fields may have lasted at least 1 year. Furthermore, SOB, NOB, and zeta-Proteobacteria may serve as indicators of the effects of seawater inundation on microorganisms.     

Coastal vegetation planting projects for tsunami disaster mitigation: effectiveness evaluation of new establishments

Coastal vegetation acts as a natural barrier against extreme natural and anthropogenic activities, protecting infrastructure and human lives. Establishment of hard infrastructure for tsunami protection is not feasible in developing countries due to its cost-intensive nature. Coastal vegetation can therefore be a feasible alternative for tsunami and general coastal protection in developing countries. This study investigates the effectiveness of current coastal vegetation projects and reports a pilot-scale vegetation project, which provides insights into the management and sustainability of such projects. Thirty-seven establishments of coastal vegetation for tsunami protection were identified for the study from Hambantota to Colombo along the southern coast in Sri Lanka. Evaluation was carried out to assess whether the coastal vegetation establishments fulfilled the planning objectives, such as vegetation alignment to tsunami direction, tree density and tree species, and whether monoculture or mixed species are grown. The study also assessed continuous maintenance and awareness about coastal vegetation, community participation and long-term institutional support from government, nongovernment groups, academic institutions, and other institutions within an integrated framework. Approximately 50% of the sites were found to be effective in terms of fulfilling the above requirements and had reasonable protection against future tsunami-type events. Continuous maintenance is ensured only for 35% of sites with community participation. The survey also revealed the importance of adopting scientific and nonscientific methods of vegetation establishment and selecting appropriate species and structure of vegetation strips for tsunami protection. It is expected that this will lead to the development of coastal vegetation guidelines for local authorities.     

Oral histories and the impact of archaeological fieldwork in contact encounters: meeting Socrates on the Omo

Whilst there is growing concern within archaeology about the wider impact of archaeological research in general, only limited attention has so far been paid to the impact fieldwork has on local communities. Here, using examples from fieldwork with an agro‐pastoral Mursi community in Ethiopia's Lower Omo Valley, we present a case in which local oral traditions are modified in response to archaeological discoveries. This illustrates a particular example of the impact of fieldwork during and after its completion; and the enduring traces of contact upon fieldwork participants. We argue that in employing an attitude of impact practice within fieldwork that foregrounds the Socratic notion of dialogue, the resulting focus highlights the value and significance of archaeology to local communities.     

Can macroalgae recover, 13 months after the 2004 Tsunami?: a case study at Talibong Island, Trang Province, Thailand

The tsunami that hit the coast of Thailand along the Andaman Sea on 26 December 2004 caused great damage to human life, property and coastal resources. Here we report the effect of the tsunami on the seaweed community, and its recovery, at Talibong Island, one of the affected areas in Trang province. We made surveys at three sites around the island from April 2004 to January 2006. Fifteen 0.5 m × 0.5 m permanent plots were set up on the west coast of the island to monitor changes in the seaweed community. Eighteen species were found. Sargassum stolonifolium and Laurencia composita were the most abundant, covering 90% and 39%, respectively, of the rocky substrate. Thirteen species varied among sites and seasons. Eleven species, however, were strongly affected by the tsunami. L. composita and Padina sanctae-crucis, for example, were initially washed up onto the shore by the strong wave action, which clearly resulted in a decrease in percentage cover. Also, many permanent plots were covered by sediment causing anoxic conditions, an indirect impact of the tsunami. A difference in species composition revealed a change in overall diversity. Particular morphologies and life forms were more sensitive to the extremes of the tsunami than others. Therefore, the recovery ability of populations of the affected species varied. We did not find any seasonal pattern to the recovery of seaweed after the tsunami within the 13 months of this study.     

Population Recovery of Nicobar Long-Tailed Macaque Macaca fascicularis umbrosus following a Tsunami in the Nicobar Islands,India

Natural disasters pose a threat to isolated populations of species with restricted distributions, especially those inhabiting islands. The Nicobar long tailed macaque.Macaca fascicularis umbrosus, is one such species found in the three southernmost islands (viz. Great Nicobar, Little Nicobar and Katchal) of the Andaman and Nicobar archipelago, India. These islands were hit by a massive tsunami (Indian Ocean tsunami, 26 December 2004) after a 9.2 magnitude earthquake. Earlier studies [Umapathy et al. 2003; Sivakumar, 2004] reported a sharp decline in the population of M. f. umbrosus after thetsunami. We studied the distribution and population status of M. f. umbrosus on thethree Nicobar Islands and compared our results with those of the previous studies. We carried out trail surveys on existing paths and trails on three islands to get encounter rate as measure of abundance. We also checked the degree of inundation due to tsunami by using Normalized Difference Water Index (NDWI) on landsat imageries of the study area before and after tsunami. Theencounter rate of groups per kilometre of M. f. umbrosus in Great Nicobar, Little Nicobar and Katchal was 0.30, 0.35 and 0.48 respectively with the mean group size of 39 in Great Nicobar and 43 in Katchal following the tsunami. This was higher than that reported in the two earlier studies conducted before and after the tsunami. Post tsunami, there was a significant change in the proportion of adult males, adult females and immatures, but mean group size did not differ as compared to pre tsunami. The results show that population has recovered from a drastic decline caused by tsunami, but it cannot be ascertained whether it has reached stability because of the altered group structure. This study demonstrates the effect of natural disasters on island occurring species.     

Impacts of the 2011 Tsunami on Sediment Characteristics and Macrozoobenthic Assemblages in a Shallow Eutrophic Lagoon,Sendai Bay,Japan

A huge tsunami is one of the greatest disturbance events in coastal benthic communities, although the ecological consequences are not fully understood. Here we examined the tsunami-induced changes in the sediment environment and macrozoobenthic assemblage in a eutrophic brackish lagoon in eastern Japan. The 7.2-m-high tsunami completely replaced muddy sediment with drifting sea sand throughout the lagoon, leading to the drastic changes in quantity and quality of sedimental organic matters, sulfide contents, and sediment redox condition. Intensive physical stress devastated the benthic community, but the disappearance of sulfidic muddy bottoms significantly improved the habitat quality for macrozoobenthos. The re-established macrozoobenthic community after 5 months was characterized by (1) a 2-fold higher total density, but sharp declines in species richness, diversity, and evenness; (2) an increased density of opportunistic taxa (e.g., polychaete Pseudopolydora spp. and amphipod Monocorophium uenoi) in newly created sandy bottoms; and (3) disappearance of several dominant taxa including bivalves and chironomid larvae. These findings indicate that the sensitivity and recovery potential of macrozoobenthos were highly taxa-specific, which was closely related to the taxa’s ecological characteristics, including tolerance to physical disturbance, life-history traits, and life form. Our data revealed the rapid recolonization of opportunistic macrozoobenthos after a huge tsunami, which would contribute to the functional recovery of estuarine soft-bottom habitats shortly after a disturbance event.