Flowering and fruiting of Tape Seagrass Enhalus acoroides (L.f.) Royle from the Andaman Islands: observations from inflorescence buds to dehiscent fruits
Main Article Content
Abstract
Seagrass phenophases are crucial in understanding their reproductive biology but are seldom documented. We studied flowering and fruiting phenophases of Enhalus acoroides from a mixed-species intertidal seagrass meadow in Ritchie’s archipelago, Andaman Islands, India. The estimated mean densities of pistillate and staminate flowers were 16.0 ± 12.0/ m2 and 12.7 ± 7.3/ m2, respectively. We observed the bloom of free-floating male flowers (961.7 ± 360.4/ m2) during the spring low tides (at mean sea surface temperature ~30°C). Seagrass cover, shoot density, and canopy height of E. acoroides, along with flowering densities, showed a zonal variation within the sampled meadow. We report the first-time observations of several phenophases of E. acoroides, such as female inflorescence buds, male inflorescence, a bloom of released male flowers, pollination, and fertilized flowers from the Indian waters. We also report the prevailing threats to seagrass meadows, such as meadow scarring done by boat anchorage in the Andaman Islands.
Article Details
This work is licensed under a Creative Commons Attribution 4.0 International License.
Authors own the copyright to the articles published in JoTT. This is indicated explicitly in each publication. The authors grant permission to the publisher Wildlife Information Liaison Development (WILD) Society to publish the article in the Journal of Threatened Taxa. The authors recognize WILD as the original publisher, and to sell hard copies of the Journal and article to any buyer. JoTT is registered under the Creative Commons Attribution 4.0 International License (CC BY), which allows authors to retain copyright ownership. Under this license the authors allow anyone to download, cite, use the data, modify, reprint, copy and distribute provided the authors and source of publication are credited through appropriate citations (e.g., Son et al. (2016). Bats (Mammalia: Chiroptera) of the southeastern Truong Son Mountains, Quang Ngai Province, Vietnam. Journal of Threatened Taxa 8(7): 8953–8969. https://doi.org/10.11609/jott.2785.8.7.8953-8969). Users of the data do not require specific permission from the authors or the publisher.
References
Ackerman, J.D. (2006). Sexual reproduction of seagrasses: Pollination in the marine context, pp. 89–109. In: Larkum, A.W.D., R.J. Orth & C.M. Duarte (eds.). Seagrasses, biology, ecology, and conservation. Dordrecht, the Netherlands: Springer, 690 pp. https://doi.org/10.1007/978-1-4020-2983-74
Brouns, J.J.W.M. & F.M.L. Heijs (1986). Production and biomass of the seagrass Enhalus acoroides (L.f) Royle and its epiphytes. Aquatic Botany 25: 21–45. https://doi.org/10.1016/0304-3770(86)90038-0
Bujang, J.S., M.H. Zakaria, A. Arshad, S.L. Lam & H. Ogawa (2006). Flowers and sexes in Malaysian seagrasses. Coastal Marine Science 30(1): 184–188.
Darnell, K. & K. Dunton (2016). Reproductive phenology of the subtropical seagrasses Thalassia testudinum (turtle grass) and Halodule wrightii (shoal grass) in the northwest Gulf of Mexico. Botanica Marina 59(6): 473–483.
Das, H. (1996). Status of Seagrass habitats of Andaman and Nicobar Coast. Technical Report No. 4, SACON, 39 pp.
D’Souza, E., V. Patankar, R. Arthur, N. Marba & T. Alcoverro (2015). Seagrass herbivory levels sustain fite-Fidelity in a remnant Dugong population. PLoS ONE 10: 1–18. https://doi.org/10.1371/journal.pone.0141224.t001
Duarte, C.M., J.S. Uri, N.S.R. Agawin, M.D. Fortes, J.E. Vermaat & N. Marba (1997). Flowering frequency of Philippine seagrasses. Botanica Marina 40: 497–500. https://doi.org/10.1515/botm.1997.40.1-6.497
Duarte, C. & H. Kirkman (2001). Methods of the measurement of seagrass abundance and depth distribution, pp. 141–153. In: Short, F.T. & R.G. Coles (eds.). Global Seagrass Research Methods. Elsevier, 506 pp. https://doi.org/10.1016/B978-044450891-1/50008-6
Estacion, J.S. & M.D. Fortes (1988). Growth rates and primary production of Enhalus acoroides (L.f.) Royle from Lag-it, North Bais Bay, The Philippines. Aquatic Botany 29: 347–356. https://doi.org/10.1016/0304-3770(88)90078-2
Hartog, C.D. (1970). The Seagrasses of the world. North-Holland Publishing Company, Amsterdam, 21 pp.
Inglis, G. (1999). Variation in the recruitment behavior of seagrass seeds: implications for population dynamics and resource management. Pacific Conservation Biology 5: 251–259. https://doi.org/10.1071/PC000251
Jagtap, T. (1991). Distribution of seagrass along the Indian coast. Aquatic Botany 40: 379–386. https://doi.org/10.1016/0304-3770(91)90082-G
Jagtap, T. (1992). Marine flora of Nicobar group of Islands, Andaman Sea. Indian Journal of Marine Sciences 22: 56–58.
Kendrick, G.A., M. Waycott, T. Carruthers, M. Cambridge, R. Hovey, S. Krauss, P. Lavery, D. Les, R. Lowe, O.M. Vidal, J. Ooi, R. Orth, D.O. Rivers, L. Ruiz-Montoya, E.A. Sinclair, J. Statton, J.K. VanDijk & J.J. Verduin (2012). The central role of dispersal in the maintenance and persistence of seagrass populations. BioScience 62(56): 56–65. https://doi.org/10.1525/bio.2012.62.1.10
Komatsu, T., Y. Umezawa, M. Nakakoka, C. Supanwanid & Z. Kanamoto (2004). Water flow and sediment in Enhalus acoroides and other seagrass beds in the Andaman Sea, Off Khao Bae Na, Thailand. Coastal Marine Science 29: 63–68.
Lacap, C.D.A., J.E. Vermaat, R.N. Rollon & H.M. Nacorda (2002). Propagule dispersal of the SE Asian seagrasses Enhalus acoroides and Thalassia hemprichii. Marine Ecology Progress Series 235: 75–80. https://doi.org/10.3354/meps235075
Lawrence, K., T. Pongpiriyakit, S. Jiawkok, A. Meechukan & N. Madadam (2007). Seagrass replanting at Trang. Monitoring and assessment report on Coastal Habitats and Resources Management (CHARM) Project. Bangkok, Thailand, 22 pp.
Patankar, V., T. Wagh, & Z. Tyabji (2019). Observations on the female flowers and fruiting of Tape Grass Enhalus acoroides from South Andaman Islands, India. Journal of Threatened Taxa 11(5): 13617–13621. https://doi.org/10.11609/jott.4253.11.5.13617-13621
Ragavan, R., R. Jayaraj, M. Muruganantham, C. Jeeva, V. Ubare, A. Saxena & P. Mohan (2016). Species Composition and Distribution of Seagrasses of the Andaman and Nicobar Islands. Vegetos 29: 78–87.
Rattanachot, E. (2008). The Effect of Shoot Density on Growth, Recruitment, and Reproduction of Enhalus acoroides (L.f.) Royle at Haad Chao Mai National Park, Trang Province, Thailand. Master Thesis. Prince of Songkla University, 101 pp.
Rollon, R.N. (1998). Spatial Variation and Seasonality in Growth and Reproduction of Enhalus acoroides (L.f.) Royle Populations in the Coastal Waters of Cape Bolinao, NW Philippines. Ph.D. Thesis. IHE-Delft and Wageningen Agricultural University, The Netherlands, 135 pp.
Savurirajan, M., E. Jawed, R. Lakra, K. Satyam & T. Ganesh (2018). Species diversity and distribution of seagrasses from the South Andaman, Andaman, and the Nicobar Islands, India. Botanica Marina 61(3): 225–234. https://doi.org/10.1515/bot-2017-0109
Short, F. & S. Wyllie-Echeverria (1996). Natural and human-induced disturbance of seagrasses. Environmental Conservation 23(1): 17–27. https://doi.org/10.1017/S0376892900038212
Short, F.T. & M. Waycott (2010). Enhalus acoroides: The IUCN Red List of Threatened Species. Electronic version accessed 28 January 2022. https://www.iucnredlist.org/species/173331/6992567
Thangaradjou, T., K. Sivakumar, E.P. Nobi & E. Dilipan (2010). Distribution of seagrasses along the Andaman and Nicobar Islands: a post-tsunami survey, pp. 157–160. In: Raghunathan, C., C. Sivaperuman & Ramakrishna (eds.). Recent Trends in Biodiversity of Andaman and Nicobar Islands. Zoological Survey of India, Kolkata, 542 pp.
Vermaat, J.E., R. Rollon, C. Lacap, C. Billot, F. Alberto, H. Nacorda, F. Wiegman & J. Terrados (2019). Meadow fragmentation and reproductive output of the SE Asian seagrass Enhalus acoroides. Journal of Sea Research 52(4): 321–328. https://doi.org/10.1016/j.seares.2004.04.002
Waycott, M., K. Mc Mahon, J. Mellors, A. Calladine & D. Kleine (2004). A guide to tropical seagrasses of the Indo-West Pacific. James Cook University, Townsville, Queensland, Australia, 72 pp.
Yu, S., S.L. Liu, K. Jiang, J.P. Zhang, Z.J. Jiang, Y. Wu, C. Huang, C. Zhao, X. Huang & S. Trevathan-Tackett (2018). Population genetic structure of the threatened tropical seagrass Enhalus acoroides in Hainan Island, China. Aquatic Botany 150: 64–70. https://doi.org/10.1016/j.aquabot.2018.07.005