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

Transcription

1 J Appl Phycol (2008) 20: DOI /s z Can macroalgae recover, 13 months after the 20 Tsunami?: a case study at Talibong Island, Trang Province, Thailand Anchana Prathep & Jaruwan Mayakun & Piyalap Tantiprapas & Anuchit Darakrai Received: 22 April 2007 / Revised and Accepted: 5 November 2007 / Published online: 15 uary 2008 # Springer Science + Business Media B.V Abstract The tsunami that hit the coast of Thailand along the Andaman Sea on 26 December 20 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 20 to uary 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. Keywords Community. Diversity. Macroalgae. Recovery. Thailand. Tsunami A. Prathep (*) : J. Mayakun : P. Tantiprapas : A. Darakrai Seaweed and Seagrass Research Unit, Centre for Biodiversity of Peninsular Thailand, Department of Biology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand anchana.p@psu.ac.th Introduction The tsunami of 26 December 20, a natural disaster in the Indian Ocean, caused severe damage to humankind as well as to marine life in coastal areas. Considerable effort has been made towards recovery. Studies that contribute to understanding the effects of the tsunami on marine organisms include those on microbial life in both seawater and coastal sediments (Ramesh et al. 2006), the coral reef community (Chavanich et al. 20; Hughes et al. 20; Kumaraguru et al. 20; Phongpaichit et al. 2006), mangrove ecosystems (Dahdouh-Guebas et al. 20; Danielsen et al. 20; Vermaat and Thampanya 2006) and on some littorinid mollusks (Sanpanich et al. 2006). However, only a few preliminary studies on the seagrass and seaweed community have been reported (Mantri 20, 2006; Prathep and Tantiprapas 2006). The 20 tsunami hit six provinces on the Andaman Sea coast in Southern Thailand, including Talibong island in Trang province where we had made a preliminary survey in May Later, starting in April 20, a bimonthly monitoring of the macroalgal community was carried out at Talibong. The island, which is a protected area with no hunting or fishing allowed, has an area of around 4,000 ha and is the biggest island in Trang Province. Talibong Island has recently been designated as Ramsar site No with a connection to the Had Chao Mai Marine National Park and the Trang River Estuaries. These are interconnected wetland ecosystems including riverine, estuarine, and coastal wetlands, mangroves, sandy beach and rocky marine shores, mud flats, coral reefs and seagrass beds. The island supports a broad diversity of marine organisms, including migrating seabirds and an important endangered species of dugong (Dugong dugon). Talibong is also known to have the healthiest and most richly diverse seagrass

2 908 J Appl Phycol (2008) 20: ecosystem in Thailand: 8 of the 12 known species reported in Thailand are found there (Changsang and Poovachiranon 1994; Poovachiranon and Changsang 1994). Having a contemporary dataset before the event allows us to clearly assess the effect of tsunami or other disturbances on individual species and communities. For example, disturbances such as occurred with Caulerpa brachypus forma parvifolia in Florida in the Unites States could be evaluated (Lapointe et al. 2006). Also, the recovery and resilience of the community can be monitored and better understood. The results of this study allow us to report (1) the before and after tsunami diversity and community structure of seaweeds at Talibong island, and (2) the recovery ability of the seaweed community. Materials and methods Monitoring seaweed biodiversity and percentage cover began under the Biodiversity Study of Seaweed in South East Asia. Talibong was chosen as a monitoring site for the Andaman Sea, Thailand. The preliminary survey around the island carried out from 2 5 May 2003, showed a high diversity and abundance of macroalgae. Fifteen permanent plots, 0.5 m 0.5 m, were randomly set up at three different sites along the west coast, with five plots at each site. The estimates of percentage cover of seaweed were made following Saito and Atobe (1970). Sites 1 ( N, E) and 2 ( N, E) have exposed sandy and rocky substrates, while Site 3 ( N, E) has sheltered rocky substrates (Fig. 1). Each plot was marked using GPS (GARMIN GPS 76); fluorescent tape was used to mark the corner of each plot. The monitoring study started in April 20. In a sudden twist, these sites became important for the study of biodiversity and community structure immediately preceding the December 20 Indian Ocean tsunami that hit the Andaman Coast where the study site is located. Diversity and percentage cover of macroalgae at each plot were estimated and compared at the sites from April 20 to uary Talibong Island is influenced by the Southwest Monsoon from May October, which represents the rainy season, and by the Northeast Monsoon from November April, the dry season. Field collections were made in April, September and November 20 (before the tsunami) and uary, March, May, August, October 20 and uary These collections bridge the differences in seasons, sites and percentage cover as well as the effects of tsunami on the seaweed community. To assess the effects of the tsunami, the datasets of only four collections were used: Fig. 1 Study sites along the coast of Talibong island, Trang Province, Andaman Sea, Southern Thailand, which were affected by the 20 tsunami

3 J Appl Phycol (2008) 20: Table 1 List of species and their distribution Taxa Site 1 Site 2 Site 3 Apr Sep Nov Mar May Aug Oct 06 Apr Sep Nov Ja Mar May Aug Oct 06 Apr Sep Nov Mar May Aug Oct 06 Phylum Cyanobacteria Lyngbya majuscula (Dillwyn) X X X X X Harvey ex Gomont Symploca sp. X X X Phylum Chlorophyta Caulerpa racemosa (Forsskål) J. Agardh C. taxifolia (Vahl) C. Agardh Dictyospheria carvernosa (Forsskål) Børgesen Valonia pachynema (Martens) Børgesen X X X X X X X X X Division Ochrophyta Dictyota dichotoma X (Hudson) Lamouroux D. cervinoides Kützing X X X X X X X Padina sanctae-crucis X X X X X X X X X X X X X X X X X X Børgesen Sargassum stolonifolium X X X X X X X X X X X X Phang et Yoshida Turbinaria ornata X X X X (Turner) J. Agardh Phylum Rhodophyta Filamentous red alga X Galaxuara obtusata (Ellis et Solander) Lamouroux Gelidiella acerosa (Forsskål) X X X X X X X X X X X X X X Feldmann and Hamel Gelidiopsis sp. X Gelidium sp. X X X X X X ia sp. X Laurencia composita X X X X X X X X X X X X X X Yamada Number of species X; Observed

4 910 J Appl Phycol (2008) 20: April 20 represented the first field collection, November 20 represented macroalgae community before the tsunami and uary 20 represented the macroalgae community 5 days after the tsunami hit; and uary 2006 represented the recovery of macroalgae, a year after the tsunami catastrophe. Statistical analysis Two-way analyses of variance (ANOVA) were employed to test whether there were differences in percentage cover of macroalgae between (1) sites and seasons and (2) sites and tsunami (comparing April 20, November 20, uary 20 and uary 2006). The graphical outputs show only the dominant species at each site and focus on the effects of the tsunami and species recovery abilities. Prior to analysis, homogeneity of variance was tested using Cochran s test and, where necessary, data were transformed. When significant differences between means were found, a Tukey s multiple comparison was applied (Zar 1984). Statistical analyses were carried out using STATISTICA version 6.0. Results There were variations in the diversity and community structure of seaweed between sites and seasons. A total of 18 species were found in this study. The highest diversity was found in April 20 at Site 1, with 11 species of macroalgae (Table 1). Laurencia composita, Lyngbya majuscula, Padina sanctae-crucis and Gelidella acerosa were found at all three sites. L. composita and P. sanctaecrucis were the most common species. Five days after the tsunami, 1 uary 20, only four species remained. One year later at the beginning of uary 2006, seven species were found. Thirteen months after the pre-tsunami study in April 20, only 50% of the original flora was present. This suggests that the recovery of seaweed diversity was slow. Thirteen species showed significant differences in percentage cover with respect to sites, seasons and their interactions (Table 2), while 11 species showed significant differences in percentage cover with respect to sites, before/ after the tsunami and their interactions (Table 2). P. sanctae-crucis, L. composita and S. stolonifolium were dominant and had the highest percentage cover at sites 1, 2 and 3, respectively. The percentage cover of P. sanctaecrucis fluctuated significantly throughout the study. The highest percentage cover was 31±10.77% (mean±s.e.) in May 20. However, the population had disappeared from all sites in the immediate post-tsunami study in uary 20 (Fig. 2a). The fan-shaped form of P. sanctae-crucis recovered very slowly and did not reach the same abundance as before the tsunami. The percentage cover of L. composita, the dominant red alga, decreased sharply. Only 3±2% was left in uary 20 compared to 34± 9.72% in November 20, a month prior the tsunami catastrophe (Fig. 2b). We also observed these seaweeds as well as the seagrass, Syringodium isoetifolium (Aschers.) Dandy, floating and washed up on the shore in uary 20. The recovery of both P. sanctae-crucis and L. composita, continues to be very slow and they have not, even in 2007, reached pre-tsunami levels. Although study Site 3 was not directly exposed to the impact of the tsunami, the seaweed community there was also affected. The percentage cover of S. stolonifolium dropped by 26%, from 83±3% in November 20 to 57± 2% (Fig. 2c). Shorter fronds were observed and many S. stolonifolium specimens were washed up on the shore. However, recovery was relatively fast and the percentage cover had already reached 76±5.57% by uary The increase in percentage cover of all three species came from old populations, which were not removed during the tsunami. No new recruitment was observed. There was considerable sedimentation, especially at site 2. We observed greater than 15 cm sediment covering the permanent plots. After 5 days, the sediment surface was covered by large patches of microbial organisms, turning the sediment surface white (Fig. 3a). Under the sediment, many benthic organisms, such as corals, molluscs, sponges and macroalgae were still present (Fig. 3b). These organisms died off and black anoxic conditions were observed. The strength of the tsunami wave differed from site to site. Site 3 was less affected since it does not directly face the direction from which the tsunami wave came, while Site 1 was less affected because of the more gradual slope of the beach. Discussion The variations in diversity of seaweed at Talibong Island seem to be the result of differences in substrates and degree of wave exposure. The complex nature of substrates is known to influence the diversity of algae and marine benthos (Dean and Connell 1987). The greater diversity in Site 1 might be due to the variety of substrate as well as having been exposed to less active waves during the rainy season. The difference in substrates also influenced the species composition at each site. Caulerpa spp. was dominant at Site 1, on the sandy substrate that allows stolons and rhizoids to grow into the sand. S. stolonifolium was dominant on the rocky substrate of Site 3, where the discoid holdfast is adapted to attach. In general, after the monsoon season, macroalgal abundance drops, perhaps due to the high wave energy,

5 J Appl Phycol (2008) 20: Table 2 Summary of significant results (F-ratio) from two-way ANOVA test for effects of (1) different months on three different sites, and (2) tsunami event on three different sites Season Tsunami event Site Month Site* month Site Before/after the tsunami Site before/after the tsunami Caulerpa taxifolia 1.93 ns 1.23 ns 1.72 ns 3.22* 1.4 ns 1.13 ns C. racemosa 9.86*** 10.79*** 9.93*** 9.86** 10.79** 9.92*** Dictyosphaeria carvernosa 2.0 ns 2.39** 2.55** 0.96 ns 0.97 ns 0.98 ns Dictyota dichotoma 4.32* 4.47*** 4.46*** 4.29** 4.44** 4.42** D. cervinoides 2.15 ns 6.9*** 5.87*** 2.96 ns 6.42*** 7.59*** Filamentous red algae ns 1.13 ns 1.13 ns 1.12 ns 1.12 ns 1.12 ns Galaxuala obtusata 1.35 ns 0.77 ns 1.23 ns 0.97 ns 0.75 ns 1.31 ns Gelidella acerosa 2.20 ns 5.31*** 1.51 ns 0.29 ns 12.12*** 1.21 ns Gelidiopsis sp *** 15.67*** 15.69*** 15.51*** 15.54*** 15.62*** Gelidium sp ns 3.38*** 2.50** 1.76 ns 0.70 ns 0.71 ns ia sp *** 14.57*** 14.59*** 14.42*** 14.47*** 14.52*** Laurencia composita 15.24*** 6.03*** 8.57*** 86.78*** 8.4** 13.19*** Lyngbya sp *** 35.71*** 23.15*** 79.85*** 93.07*** 80.51*** Padina sanctae-crucis 28.12*** 10.07*** 7.38*** 13.79*** 23.84*** 9.28*** Sargassum stolonifolium *** 2.56* 56.24*** *** 9.99*** 5.85*** Symploca sp ns 3.12** 3.54*** 3.50* 3.51* 3.52** Turbinaria ornata 5.66** 6.88*** 8.57*** 1.08 ns 0.83 ns 0.92 ns Valonia pachynema 0.97 ns 0.98 ns 0.98 ns 0.97 ns 0.97 ns 0.97 ns *P<0., ** P<0.1, *** P<0.001; ns not significant; seaweed species not presented showed no significant relationship which stirs up sediments and covers small benthic algae such as G. acerosa. Fragments of L. composita, a fragile red alga, broken by the strong wave action were found floating. The typical seasonal pattern in the area has greater diversity and abundance in early wet season (Prathep 20). The post-tsunami macroalgal community is similar to that of the post-monsoon period, but the magnitude of the tsunami wave energy was much stronger. Also, posttsunami recovery is slower. The magnitude of the wave is comparable to those occurring during hurricanes in Australia, the United States and the Caribbean, which damage marine communities (Fourqurean and Rutten 20; Preen et al. 1995; Lapointe et al. 2006). The diversity and abundance of macroalgae at all three monitoring sites at Talibong Island decreased either directly from the physical impact or indirectly from sediments. The strong wave action removed not only the macroalgae but also the substrates. This, however, varied in degree of impact. The direct impact of the severe wave energy on shallow nearshore habitats (including coral reef ecosystems, seagrasses and mangroves) was extensive, although dependent on the amount of wave energy these ecosystems are normally exposed to. Organisms already adapted to high wave energy, as seen on temperate shores (Lewis 1964; Stephenson and Stephenson 1972) and in intertidal tropics shores (Prathep 20; Prathep et al. 2007), were less affected than sheltered habitat organisms. On the other hand, shallow bays typically protected from high wave action, such as Site 3, suffered less extensive damage. However, S. stolonifolium at the latter site declined greatly after the tsunami but fully recovered after 1 year. Damage by wave energy is species specific. Some species, such as L. composita and P. sanctae-crucis, are delicate and did not withstand the turbulent high energy environments. Neither species has recovered yet. Growth from solid, deeply anchored rhizome or rhizoid systems, combined with flexible fronds as seen in both seaweeds and seagrasses, is adapted to resist perturbation by hurricanes or storms (Cruz-Palacios and van Tussenbroek 20). However, since the magnitude of the tsunami wave energy was much higher than the usual storms, many seagrasses were also uprooted. The thin root-rhizome of Syringondium isoetifolium was more vulnerable than the deeply rooted Enhalus acriodes. Caulerpa brachypus forma parvifolia (Harvey) Cribb, with its small stolon and rhizoid system, was also extensively removed by hurricanes in Florida (Lapointe et al. 2006). Although wave forces and currents are known to influence recruitment, dispersal, community structure and dislodgement of algae and marine benthic organisms (Ballantine 1961; Lewis 1964; Norton 1991; Denny 1995), the impacts on macroalgae have only recently been studied (Thomsen and Wernberg 20). Thus, more studies are still needed to understand what causes the dislodgment of macroalgae. During catastrophic events such as tsunami or hurricanes, measurements of current and wave energy

6 912 J Appl Phycol (2008) 20: died only 3 5 days after the tsunami. Also, recovery from such burial conditions seems to be very slow. The resilience of coastal marine organisms and their ability to recover has been extensive discussed (Connell 1997; Nyström et al. 2000; Bengtsoon et al. 2003; Turner et al. 2003; Hughes et al. 20; Pascual and Guichard 20; Gallopín 2006; Woodroffe 2007). The recovery of the macroalgal community after 13 months is very slow and varied from site to site and species to species. The high sedimentation in Site 2 has totally changed the substrate to a soft bottom, thus limiting the recruitment and succession of those macroalgae previously adapted to a solid substrate. Once a species is removed, the process of successful recovery is complex and dependent on factors such as the degree and time of removal (Sousa 1984a, 1985), available Fig. 2 Variations in percentage cover of some dominant macroalgae. a Padina sanctae-crucis, b Laurencia composita, c Sargassum stolonifolium. Bars Standard error (n=5). Letters a c indicate significant group of means found with the Tukey HSD tests were not reported; such information would provide us with a better understanding of the impacts on the benthic community, including its dislodgement and recovery. The indirect impact of the tsunami was sedimentation. The water became more turbid with sediment, which was deposited, covering the macroalgae and corals, within 5 days after the tsunami. Sediment 15 cm deep was deposited on the permanent plots at Site 2. Although sediment dynamics (removal and deposition) are seasonal and play important roles in the marine community (Prathep et al. 2003), this much greater deposition had a critical influence on all marine communities. Such sediment deposition and removal are characteristic of hurricanes (Ballantine 1984; Glynn et al. 1964). Experiments on hurricane-like disturbances have shown that seagrasses and seaweeds buried under 10 cm sediment were more likely to suffer permanent damage than those buried under only 5 cm or without any sediment (Cruz-Palacios and van Tussenbroek 20). However, since the macroalgal community at Site 2 was buried under about 15 cm, many organisms were quickly subjected to anoxic conditions and Fig. 3 Greater sediment causing anoxic conditions at the study sites 5 days after the tsunami. a Large area covered by microbes, making the sediment surface white; b various small benthic organisms die off after being buried, turning the sediment underneath black

7 J Appl Phycol (2008) 20: space (Sousa 1984b; Farrell 1989) and dispersal mechanisms (Keough 1984). Abundance was affected by whether or not some parts of plants were left, in which case the recovery was faster such as with L. composita and S. stolonifolium. However, recovery is unlikely to establish the same community as was present before the tsunami since some species had still not recovered a year after the tsunami. A small scale disturbance, e.g. such as that from a boat anchor as experimentally tested in seagrass beds, showed that some associated seaweeds would recover after 4 5 months, but some species might take longer than 13 months (Creed and Amado Filho 1999). However, the high magnitude of the 20 tsunami wave energy caused greater damage and it is taking much longer for the community to become reestablished. Further investigations and monitoring will allow us to understand the acute effects of the disturbance on the fragile macroalgae community, which is less well known than seagrasses, coral and mangroves. Such monitoring will also provide a better understanding of various ecological theories related to natural disturbances, recruitment and succession. Acknowledgements We are very grateful for the support of the members of the Seaweeds and Seagrass Research Unit, Centre of Biodiversity in Southern Peninsular Thailand. Thanks also to Professor Larry B. Liddle for manuscript improvement. Knowledge Network Institute of Thailand, Unocal Songkhla and Prince of Songkla University, Thailand provided funding; and Japanese Society for the Promotion of Science and Professor Hisao Ogawa provided support for the study. References Ballantine WJ (1961) A biologically-defined exposure scale for the comparative description of rocky shore. Field Stud 1:1 19 Ballantine DL (1984) Hurricane-induced mass mortalities to a tropical subtidal algal community and subsequent recoveries. Mar Ecol Prog Ser 20:75 83 Bengtsoon J, Angelstam P, Elmqvist T, Emanuelsson U, Folke C, Ihse M, Moberg F, Nyström M (2003) Reserves, resilience and dynamic landscapes. Ambio 32(6): Changsang H, Poovachiranon S (1994) The distribution and species composition of seagrass beds along the Andaman sea coast of Thialand. Phuket Mar Biol Cent Res Bull 59:43 52 Chavanich S, Siripong A, Sojisuporn P, Menasveta P (20) Impact of Tsunami on the seafloor and corals in Thailand. Coral reefs 24:535 Connell JH (1997) Disturbance and recovery of coral assemblages. Coral Reefs 16(Suppl.):S101 S113 Creed JC, Amado Filho GM (1999) Disturbance and recovery of the macroflora of a seagrass (Halodule wrightii Ascherson) meadow in the Abrolhos Marine National Park, Brazil: an experimental evaluation of anchor damage. J Exp Mar Biol Ecol 235: Cruz-Palacios V, van Tussenbroek BI (20) Simulation of hurricane-like disturbance on a Caribbean seagrass bed. J Exp Mar Biol Ecol 324:44 60 Dahdouh-Guebas F, Jayatissa LP, Di Nitto D, Bosire JO, Lo Seen D, Koedam N (20) How effective were mangroves as a defence against the recent tsunami? Curr Biol 15:R443 R447 Danielsen F, SØrensen MK, Olwig MF, Selvam V, Parish F, Burgess ND, Hiraishi T, Karunagaran VM, Rasmussen MS, Hansen LB, Quarto A, Suryadiputra N (20) The Asian tsunami: a protective role coastal vegetation. Science 310:643 Dean RL, Connell JH (1987) Marine invertebrates in an algal succession. II. Test of hypotheses to explain changes in diversity with succession. J Exp Mar Biol Ecol 109: Denny M (1995) Predicting physical disturbance mechanistic approaches to the study of survivorship on wave-swept shores. Ecol Monogr 65: Farrell TM (1989) Succession in a rocky intertidal community: the importance of disturbance size and position within a disturbed patch. J Exp Mar Biol Ecol 128:57 73 Fourqurean JW, Rutten LM (20) The impact of Hurricane Georges on soft-bottom back reef communities: site and species-specific effects in south Florida seagrass beds. Bull Mar Sci 75: Gallopín GC (2006) Linkages between vulnerability, resilience, and adaptive capacity. Global Environ Change 16: Glynn PW, Almodóvar LR, Gonzales JG (1964) Effects of Hurricane Edith on marine life in la Parguera, Puerto Rico. Carib J Sci 4: Hughes TP, Bellwood DR, Folke C, Steneck RS, Wilson JE (20) New paradigms for supporting the resilience of marine ecosystems. Trends Ecol Evol 20(7): Keough MJ (1984) Effects of patch size on the abundance of sessile marine invertebrates. Ecology 65: Kumaraguru AK, Jayakumar K, Jerald Wilson J, Ramakritinan CM (20) Imapact of the tsunami of 26 December 20 on the coral reef environment of Gulf of Mannar and Palk Bay in the Southeast coast of India. Curr Sci 89(10): Lapointe BE, Bedford BJ, Brumberger R (2006) Hurricanes Frances and Jeanne Remove Blooms of the Invasice Green Alga Cualerpa brachypus forma parvifolia (Hrvey) Cribb from coral reefs off northern Palm Beach County, Florida. Estuar Coast 29 (6A): Lewis JR (1964) The ecology of rocky shores. English University Press, London Mantri VA (20) Changes in local intertidal seaweed habitats in the Andaman andnicobar islands after 26 December 20 tsunami. Curr Sci 89(7): Mantri VA (2006) Seaweed floristic studies along tsunami affected Indian coasts: a litmus test scenario after 26th December 20. J Earth Syst Sci 115(3): Norton TA (1991) Conflict in constraints on the form of intertidal algae. Br Phycol J 126: Nyström MC, Folke C, Moberg F (2000) Coral reef disturbance and resilience in a human-dominated environment. Trends Ecol Evol 15: Pascual M, Guichard F (20) Criticality and disturbance in spatial ecological systems. Trends Ecol Evol 20(2):88 95 Phongpaichit S, Preedana S, Rungjindama N, Sakayaroj J, Benzies C, Chuapat J, Plathong S (2006) Aspergillosis of the gorgonian sea fan Annella sp. after the 20 tsunami at Mu Ko Similan National Park, Andaman Sea, Thailand. Coral Reefs 25:296 Poovachiranon S, Changsang H (1994) Community structure and biomass of seagrass beds in th Andaman sea. I Mangrove associated seagrass beds. Phuket Mar Biol Cent Res Bull 59:53 64 Prathep A (20) Spatial and temporal variations in diversity and percentage cover of macroalgae at Sirinart Marine National Park, Phuket Province, Thailand. Sci Asia 31: Prathep A, Tantiprapas A (2006) Preliminary report on the diversity and community structure of macroaglae before and after the 20 tsunami at Talibong island, Trang province, Thialand. Coast Mar Sci 30(1): Prathep A, Marrs RH, Norton TA (2003) Spatial and temporal variations in sediment accumulation in an algal turf and their impact on associated fauna. Mar Biol 142:

8 914 J Appl Phycol (2008) 20: Prathep A, Wichachucherd B, Thongroy P (2007) Spatial and temporal variation in density and thallus morphology of Turbinaria ornata in Thailand. Aquat Bot 86: Preen AR, Long WJ, Coles RG (1995) Flood and cyclone related loss, and partial recovery of more than 1000 km 2 of seagrass in Harvey Bay, Queenland, Australia. Aquat Bot 52:3 17 Ramesh S, Jayaprakashvel M, Mathivanan N (2006) Micorbial status in seawater and coastal sediments during pre-and post-tsunami periods in the Bay of Bengal, India. Mar Ecol 27: Saito Y, Atobe S (1970) Phytosociological study of intertidal marine algae I. Usujiri Benten-Jima, Hokkaido. Bull Fac Fish Hokkaido Univ 21(2):37 69 Sanpanich K, Wells FE, Chitramvong Y (2006) Effects of the 26 December 20 tsunami on littorinid mollusks near Phuket, Thailand. J Molluscan Stud 72: Sousa WP (1984a) The role of disturbance in natural communities. A Rev Ecol Syst 15: Sousa WP (1984b) Intertidal mosaics: patch size, propagule availability, and spatially variable patterns of succession. Ecology 65: Sousa WP (1985) Disturbance and patch dynamics on rocky intertidal shores. In: Pickett STA, White PS (eds). The Ecology of natural disturbance and patch dynamics. Academic, Orlando, pp Stephenson TA, Stephenson A (1972) Life between the Tide-Marks on a Rocky Shore. Freeman, San Francisco Thomsen MS, Wernberg T (20) Miniview: What affects the forces required to break or dislodge macroalgae? Eur J Phycol 40 (2): Turner MG, Collins SL, Lugo AL, Magnuson JJ, Rupp TS, Swanson FJ (2003). Disturbance dynamics and ecological response: the contribution of long-term ecological research. BioScience 53 (1):46 56 Vermaat JE, Thampanya U (2006) Mangrove mitigate tsunami damage: a further response. Est Coast Shelf Sci 69:1 3 Woodroffe CD (2007) The natural resilience of coastal systems: primary concepts. In: McFadden L, Penning-Rowsell E, Nicholls RJ (eds) Managing Coastal Vulnerability. Elsevier, Amsterdam, pp Zar JH (1984) Biostatistical analysis. Prentice-Hall, London