Alternative stable states in coastal intertidal wetland ecosystems of Yangtze estuary, China

doi:10.13287/j.1001-9332.201701.021

Abstract

Abstract: Alternative stable states phenomenon widely exists in a variety of ecosystems and is closely related to ecosystem health and sustainable development. Although alternative stable states research has become the focus and hotspot of the ecology researches, only a few empirical evidences supported its behavior and mechanisms in coastal wetland ecosystems up to now. In our study, ta-king the intertidal wetland ecosystem in Chongming Dongtan Nature Reserve as study area, we aimed to: 1) test the existence of alternative stable states based on judgment conditions (bimodal characteristic and threshold effect) and determine the relative stable state types; 2) explore the formation mechanisms of alternative stable states by monitoring hydrological conditions, sediment accretion dynamics as well as vegetation growth parameters and analyzing the positive feedbacks between saltmarsh vegetation and sedimentary geomorphology. Our results showed that: 1) Normalized difference vegetation index (NDVI) frequentness distribution revealed obvious bimodality at saltmarsh pioneer zone. Propagule biomass threshold limited the establishment of plant patches representing the “saltmarsh” state. The presence of bimodality and biomass threshold demonstrated there are “mudflat” stable state and “saltmarsh” stable state with distinct structure and function in intertidal wetland ecosystem. 2) Current velocities, turbidities and direction perpendicular to the vegetation zone were the most important factors responsible for the sediments rapid accretion at saltmarsh pioneer zone in spring and summer. Sediments accretion significantly promoted the growth of saltmarsh plant. The positive feedbacks between plant growth and sediments accretion resulted in the formation of alternative stable states. 3) The expansion pattern of saltmarshes in the Chongming Dongtan intertidal wetland ecosystem also suggested that increases of sediments accretion could trigger the formation of “mudflat” stable state and “saltmarsh” stable state on landscape scale. The results from this study could enrich regime shift mechanisms researches and provide the scientific supports for coastal zone protection, restoration and comprehensive management, which could have important theoretical and practical meaning.

LI Hui, YUAN Lin, ZHANG Li-quan, LI Wei, LI Shi-hua, ZHAO Zhi-yuan. Alternative stable states in coastal intertidal wetland ecosystems of Yangtze estuary, China[J]. Chinese Journal of Applied Ecology, 2017, 28(1): 327-336.

References

[1] Carpenter SR, Cole JJ, Pace ML, et al. Early warnings of regime shifts: A whole-ecosystem experiment. Science, 2011, 332: 1079-1082
[2] Mumby PJ, Hastings A, Edwards HJ. Thresholds and the resilience of Caribbean coral reefs. Nature, 2007, 450: 98-101
[3] Steneck RS, Vavrinec J, Leland AV. Accelerating trophic-level dysfunction in kelp forest ecosystems of the Western North Atlantic. Ecosystems, 2004, 7: 323-332
[4] Cury P, Shannon L. Regime shifts in upwelling ecosystems: Observed changes and possible mechanisms in the northern and southern Benguela. Progress in Oceanography, 2004, 60: 223-243
[5] Xu C, Vergnon R, Cornelissen JHC, et al. Temperate forest and open landscapes are distinct alternative states as reflected in canopy height and tree cover. Trends in Ecology & Evolution, 2015, 30: 501-502
[6] Kéfi S, Rietkerk M, van Baalen M, et al. Local facilitation, bistability and transitions in arid ecosystems. Theoretical Population Biology, 2007, 71: 367-379
[7] Scheffer M, Carpenter SR. Catastrophic regime shifts in ecosystems: Linking theory to observation. Trends in Ecology & Evolution, 2003, 18: 648-656
[8] Scheffer M, Carpenter S, Foley JA, et al. Catastrophic shifts in ecosystems. Nature, 2001, 413: 591-596
[9] Collie JS, Richardson K, Steele JH. Regime shifts: Can ecological theory illuminate the mechanisms? Progress in Oceanography, 2004, 60: 281-302
[10] Barbier EB, Koch EW, Silliman BR, et al. Coastal ecosystem-based management with nonlinear ecological functions and values. Science, 2008, 319: 321-323
[11] Temmerman S, Meire P, Bouma TJ, et al. Ecosystem-based coastal defence in the face of global change. Nature, 2013, 504: 79-83
[12] Day JW, Boesch DF, Clairain EJ, et al. Restoration of the Mississippi Delta: Lessons from Hurricanes Katrina and Rita. Science, 2007, 315: 1679-1684
[13] van de Koppel J, van de Heide T, Altieri AH, et al. Long-distance interactions regulate the structure and resilience of coastal ecosystems. Annual Review of Marine Science, 2015, 7: 139-158
[14] van Wesenbeeck BK, van de Koppel J, Herman PMJ, et al. Potential for sudden shifts in transient systems: Distinguishing between local and landscape-scale processes. Ecosystems, 2008, 11: 1133-1141
[15] Wang C, Temmerman S. Does bio-geomorphic feedback lead to abrupt shifts between alternative landscape states? An empirical study on intertidal flats and marshes. Journal of Geophysical Research: Earth Surface, 2013, 118: 229-240
[16] Isbell F, Tilman D, Polasky S, et al. Low biodiversity state persists two decades after cessation of nutrient enrichment. Ecology Letters, 2013, 16: 454-460
[17] van de Koppel J, van der Wal D, Bakker JP, et al. Self-organization and vegetation collapse in salt marsh ecosystems. The American Naturalist, 2005, 165: E1-E12
[18] Cui L-F (崔利芳), Wang N (王宁), Ge Z-M (葛振鸣), et al. Vulnerability assessment on the coastal wetlands in the Yangtze Estuary under sea-level rise. Chinese Journal of Applied Ecology (应用生态学报), 2014, 25(2): 553-561 (in Chinese)
[19] Maff L, Oviedo G, Larsen PB. Indigenous and Traditional Peoples of the World and Eco-Region Conservation: An Integrated Approach to Conserving the World’s Biological and Cultural Diversity. Gland, Switzerland: WWF International, 2000
[20] Yan G (严格), Ge Z-M (葛振鸣), Zhang L-Q (张利权). Distribution of soil carbon storage in different saltmarsh plant communities in Chongming Dongtan wetland. Chinese Journal of Applied Ecology(应用生态学报), 2014, 25(1): 85-91 (in Chinese)
[21] Tian B (田波), Zhou Y-X (周云轩), Zhang L-Q (张利权), et al. A GIS and remote sensing-based ana-lysis of migratory bird habitat suitability for Chongming Dongtan Nature Reserve, Shanghai. Acta Ecologica Sinica (生态学报), 2008, 28(7): 3049-3059 (in Chinese)
[22] Cao H-B (曹浩冰), Ge Z-M (葛振鸣), Zhu Z-C (祝振昌), et al. The expansion pattern of saltmarshes at Chongming Dongtan and its underlying mechanism. Acta Ecologica Sinica (生态学报), 2014, 34(14): 3944-3952 (in Chinese)
[23] Zhu ZC, Zhang LQ, Wang N, et al. Interactions between the range expansion of saltmarsh vegetation and hydrodynamic regimes in the Yangtze Estuary, China. Estuarine, Coastal and Shelf Science, 2012, 96: 273-279
[24] Feng J-F (冯剑丰), Wang H-L (王洪礼), Zhu L (朱琳). Review on alternative stable states in ecosystems. Ecology and Environmental Sciences (生态环境学报), 2009, 18(4): 1553-1559 (in Chinese)
[25] Heffernan JB. Wetlands as an alternative stable state in desert streams. Ecology, 2008, 89: 1261-1271
[26] Schwarz C, Ysebaert T, Zhu ZC, et al. Abiotic factors governing the establishment and expansion of two salt marsh plants in the Yangtze Estuary, China. Wetlands, 2011, 31: 1011-1021
[27] Ren L-J (任璘婧), Li X-Z (李秀珍), Yang S-L (杨世伦), et al. The impact of salt marsh change on sediment accumulation and wave attenuation at the East Chongming Island. Acta Ecologica Sinica (生态学报), 2014, 34(12): 3350-3358 (in Chinese)
[28] Stallins JA. Geomorphology and ecology: Unifying themes for complex systems in biogeomorphology. Geomorphology, 2006, 77: 207-216
[29] Wang C, Wang Q, Meire D, et al. Biogeomorphic feedback between plant growth and flooding causes alternative stable states in an experimental floodplain. Advances in Water Resources, 2015, 93: 223-235
[30] Shen YM, Yang JS, Wang YH, et al. Impact of sediment supply on Spartina salt marshes. Pedosphere, 2008, 18: 593-598
[31] Duarte CM, Losada IJ, Hendriks IE, et al. The role of coastal plant communities for climate change mitigation and adaptation. Nature Climate Change, 2013, 3: 961-968
[32] He S-L (贺松林), Wang P-C (王盼成). The Basic character on process of runoff and sediment discharge at Datong station of the Changjiang River. Ⅱ. Analysis on sediment transport process. Journal of East China Normal University (Natural Science)(华东师范大学学报: 自然科学版), 2004(2): 81-86 (in Chinese)
[33] Zhang EF, Savenije HHG, Chen SL, et al. Water abstraction along the lower Yangtze River, China, and its impact on water discharge into the estuary. Physics and Chemistry of the Earth, 2012, 47/48: 76-85