Marine Habitat Changes Impact On Macro-benthos Communities In Bohai Bay

Theshortage ofarable land and resources, and the environmental degradation havebeen becoming the main problems we face in today’s society. When the land resourcescannot meet the requirements for production and living conditions gradually, peoplespeed up the development of marine resources, and this aggravates the Marineecological environment. The changes of the Marine ecological environment can beshown by the macro-benthos communities and diversity characteristics. Themacro-benthos community composition, total abundance, total biomass and otherbiological index changes can accurately reflectthe long-term changes of habitatenvironment. As the important reaction index of human interference, the changes ofmacro-benthos have been widely applied to the environment quality evaluation in thecoastal zone. At the same time, with the development of satellite remote sensingtechnology, the remote sensing technology has become an effective means ofmonitoring the changes of near-shore Marine habitats. Through the remote sensing, wecan be monitoring the changes of near-shore Marine habitats elements directly, andstudy on changes of the coastal biological community composition.This paper taking the Bohai Bay as the study area, using remote sensing to get thechanges of coastline, tidal flats and near-shore shallow in recent years and combiningwith previous the macro-benthos resources survey data, study that the habitat changesimpact on macro-benthos communities in Bohai Bay.The main work includes:(1)Applying the methods of segmentation (Multi-resolution) and classification (Nearest Neighbor), and the Landsat TM remote sensing date in1987,2005,2007,2008,2009,2010and2011, analyzed the evolution of coastline, mudflat, near-shore shallowin Bohai Bay Tianjin region with the software of eCognition, ENVI and ArcGIS.(2)Collect the relevant macro-benthos resources survey data as Polycheata,Mollusca, Crustacea, Echinodermata and Other, and filtrate the date that has the similartime with the remote sensing data, and get the changes of composition, dominantspecies, total number of species, total abundance, total biomass, shannon-wiener,abundance index, and even index.(3) Analyze the correlativity between the habitat changes(coastline, mudflat,near-shore shallow) and the macro-benthos communities (species composition,abundance, biomass and diversity) with the historical survey data at same period inBohai Bay, and calculate the correlation index “r” and significance level “p”.Combining with previous the macro-benthos resources survey data, study that thehabitat changes(coastline, mudflat, nearshore shallow) impacts on macro-benthoscommunities (composition, dominant species, total number of species, total abundance,total biomass, shannon-wiener, abundance index, and even index) in Bohai Bay.Draw the following conclusions:(1)From1987to2005, the increased coastline lengthwas75km andthe mudflatareas were occupiedwere45km2,andthe shallow sea areas were occupied were4km2inBohai Bay.It mainly is the reclamation of tidal flats. Then Tianjin north port began to dothe reclamation projects,by2008,there were124km coastline length increased,79km2mudflat areas were occupied, and26km2shallow sea areas were occupied.And, it is stillmainly reclaimed tidal flats. Since then, the north port center, fishing port and south portof Tianjin port, started large-scale and intensive reclamation projects, by2011,therewere209km coastline length increased, were182km2mudflat areas were occupied,and were221km2shallow sea areas were occupied.(2)For the past few years,communities changed in Bohai Bay.About species composition, the proportion of polychaetes increased at first, then maintained at ahigher level.The proportion of mollusks and crustaceans were on the decline.Theproportion of echinoderms and other species had little change, and were in a state of low.At the same time, the change of the dominant species was obvious over the years, andshowed a trend of decreaseabout quantity, and the species thatarestrong toleranceandshort-lived advantage opportunity. About the macro-benthos total abundance and totalbiomass,theywere clearly upward trend. About the Shannon-weaver diversity index,richness index and evenness index, they showed a trend of decrease.It shows that thebiodiversity, diversity and richness of the macro-benthossustained damage for the pastfew years in Bohai Bay.(3)There are negative correlations between the area of mudflat and near-shoreshallow water occupied and the increase of coastline and, the proportion of mollusk andcrustacean, the total of species of macro-benthos, Shannon-wiener, abundance index andeven index; among which, the area of mudflat occupied and the increase of coastlineand the proportion of crustacean are significantly correlated (P<0.05), the increase ofcoastline and the total abundance index is also significantly correlated (P<0.05). Theresults also show that there are positive correlations between the area of mudflat andnear-shore shallow water occupied and the increase of coastline and, the proportion ofpolychaetes, the total macro-benthos abundance and biomass; among which, the area ofmudflat and near-shore shallow water occupied and the increase of coastline and totalabundance are significantly correlated(P<0.05), the area of near-shore shallow wateroccupied and the total biomass are also significantly correlated(P<0.05).